Undergraduate Student Chemistry Conference...2018/04/13 · Welcome Message from Dr. Ian Hamilton,...
Transcript of Undergraduate Student Chemistry Conference...2018/04/13 · Welcome Message from Dr. Ian Hamilton,...
46th Southern Ontario
Undergraduate Student
Chemistry Conference
March 24th, 2018
Hosted by the Department of Chemistry and
Biochemistry
#SOUSCC2018
Campus
Map#SOUSCC2018
Welcome Message from Dr. Ian Hamilton, Department Chair, Chemistry and Biochemistry
On behalf of the Department of Chemistry and Biochemistry, I am delighted to welcome you to the 46th Southern Ontario Undergraduate Student Chemistry Conference at Wilfrid Laurier University, Waterloo, Ontario. We hope that while you’re here you have the opportunity to talk with our faculty and students about our research facilities and graduate programs.
The SOUSCC 2018 program includes 103 oral presentations and 33 poster presentations for a total of 136 presentations from excellent undergraduate students in universities across southern Ontario. We are also pleased to welcome Dr. Cathleen Crudden, from Queen’s University, as our plenary speaker.
This conference would not be possible without our sponsors and volunteers, so we thank them greatly. The majority of our volunteers are undergraduate students dedicated to their studies and we appreciate their time commitment. These students were coordinated by our Laurier Chemistry Association (LCA), current holders of the Canadian Society for Chemistry (CSC) Student Chapter Merit Award.
We hope that SOUSCC46 serves as an inspiration to you, the next generation of chemists and biochemists, and allows you to share and celebrate your research with your peers, colleagues, and friends.
Yours sincerely,
Ian Hamilton, Professor and Chair Department of Chemistry and Biochemistry Wilfrid Laurier University
Cathleen Crudden (Queen's University)
Cathleen Crudden is full Professor and Canada Research Chair (Tier 1) atQueen’s University. She also holds a cross appointment as a ResearchProfessor at the Institute of Transformative Bio-Molecules (ITbM) in NagoyaJapan. She is one of only four international faculty at ITbM, where she runs asatellite lab funded by the Japanese government. She has won numerousresearch awards including the 2018 Canadian Catalysis Society Award, the2017 R. U. Lemieux award and the 2011 Clara Benson award. She is a fellowof the Chemical Institute of Canada (2014) and the Royal Society ofChemistry (UK, 2017). She was a Killam Research Fellow from 2015-2016.Cathleen has been a visiting professor in the labs of Professor Ryoji Noyori,was awarded a Global Center of Excellence Professorship at Kyoto Universityand a Visiting Professorship in Tarragona, Spain.
Cathleen was one of the first grantees of the CREATE program ($1.6M,2010-2016) and is PI on a successful 2014 CFI grant for $8.8M in the area ofsurface science. She is also one of two Canadians that are part of a Japan–Germany–Canada trilateral research partnership.
Cathleen was President of the Canadian Society for Chemistry in2012/2013 and served on the Board of Directors for two terms representingthe Catalysis Division. She also served on the Editorial Advisory Board forACCN for ten years, and has been one of two Canadian members of theorganizing committee of Pacifichem for the past 10 years. She is chair of theNSERC–Chemistry Liaison Panel.
Cathleen is Associate Editor for ACS Catalysis and sits on the editorial advisory boards of Chemical Record (Japan), Synthesis, Organometallics, ACSOmega and Chemical and Engineering News. Her work in catalysis and materials has received significant acclaim, with recent work identifying a new class of carbon-based SAMs being called "game changing" and "the new gold standard" by international experts in the area.
Dr. Cathleen
Crudden#SOUSCC2018Plenary Speaker
Organizing Committee Members for SOUSCC46
Steve MacNeil Lillian DeBruin Louise Dawe Ken Maly Lana Hiscock
Zahra Yussuf
A warm thank you to our judges. Your expertise and generosity with your time is sincerely appreciated.
Thank You!
#SOUSCC2018
This Photo by Unknown Author is licensed under CC BY-SA
THANK
YOU
TO OUR SPONSORS
Canadian Association of
Theoretical Chemists
Pearson Education Canada
Chemical Institute of
Canada
Chemical Education Fund
Divisions: Biological and Medicinal
Chemistry, Analytical, Chemistry
Education, Environment, Inorganic,
Organic, Physical, Theoretical and
Computational, Materials Chemistry
Local Sections: Peterborough and
Toronto
Wiley
Wilfrid Laurier University
Department of Chemistry and Biochemistry, Faculty of
Science Students’ Association, Faculty of Science,
Office of the Vice-President: Academic, Teaching and
Learning, Office of Research Services
CEM Corporation
Mirexus Inc.
University of Windsor
Department of Chemistry
and Biochemistry
#SOUSCC2018
THANK
YOU TO OUR VOLUNTEERS
Sincerest thanks to all the volunteers who have helped run SOUSCC
2018 at Wilfrid Laurier University. Your contributions before and
during the conference were greatly appreciated. A special thank you
goes out to Emrys for designing our volunteer shirts and the
members of the Laurier Chemistry Association for planning the
social events and organizing a photo booth for the banquet. Thank
you all so much for your hard work, commitment, and effort. This
conference would not have been possible without the help of each
and every one of you.
"Alone we can do so little; together we can do so much.”Helen Keller
Tala Aduadas Kwasi Adjei
Hira Ahmad
Kissa Batul Breanna Chapman Ruhana Chowhan
Robert Clarke Rachel Dickie
Patryk Dorozynski Heather Gaebler Shaeley Gibbons Chenique Gilroy
Emrys Halbertsma Timothy Ho
Neil Jurkiewicz Hailey Keeler Zoe Mowbray
Brittany Nagy
Rahma Noushin
Amanda Pang
Kevin Pattison
Ummesalama Potia
Alena Pratasouskaya
Nicole Ritter
Kayla Samms
Fredrick Sato
Edward Schmidt
Elizabeth Silva
Misha Singh
Dana Sowa
James Stevenson
Mayuran Sweentherarajah
Amisha Yadav
#SOUSCC2018
Program at a Glance
8:15-9:15am
Registration &
Coffee Bricker Academic (BA) Foyer
Poster Set-up Paul Martin Center (PMC)
9:15-9:30am Opening Remarks BA201
9:30-10:20am Keynote lecture
10:30-12:10pm
Session 1
BA110 BA111 BA112 BA208 BA209 BA210 BA211
IN/M
1
IN/M
2 OR 1 PCT 1 AN 1 B/M 1 GEN
12:10-
12:40pm Lunch Senate & Board Chamber
12:40-1:40pm Poster Session Paul Martin Center (PMC)
1:40-3:20pm Session2
BA110 BA111 BA112 BA208 BA209 BA210 BA211
IN/M 3
IN/M 4
OR 2 PCT 2 AN2 B/M 2 B/M 4
3:20-3:50pm Coffee Break
3:50-5:30pm Session 3
BA110 BA111 BA112 BA208 BA209 BA210 BA211
IN/M 5
IN/M 6
OR 3 PCT 3 PCT 4 B/M 3 B/M 5
5:40-6:00pmJudges' Meeting SR113
Poster Take-down Paul Martin Center (PMC)
6:00-9:00pm Banquet & Awards Turret
IN/M Inorganic & Materials OR Organic
B/M Biological & Medicinal AN Analytical
PCT
Physical; Comp;
Theoretical GEN General
#SOUSCC2018
Detailed Oral Presentation Schedule
Room
ID Name Title
10:30-10:50am 34 CruzDesigning Patchy Rod-Like Micelles: Manipulating
Competitive Seeded-Growth Kinetics and Visualizing
Patchiness by Selective Staining
10:50-11:10am 51 VentimigliaSynthesis of a Fluorogenic Substrate to Monitor Redox
activity in Cystathionine
11:10-11:30am 63 PlummerEffects of Metacognitive Practices on Introductory Organic
Chemistry Students. A Closer Look at Learning Task
Inventories
11:30-11:50am 83 Bani MS in probing protein-small molecule interaction
11:50-12:10pm 91 YousifSynthesis of small molecule biological antifreezes and
applications in cryopreservation
Room
ID Name Title
10:30-10:50am 21 AdjeiNickel & Palladium (N,O)-Donor Ligand Complexes:
Structure & Catalysis
10:50-11:10am 33 Yunyaeva Ionic Networks for Controlled Drug Delivery
11:10-11:30am 84 DengOptimized synthesis of pyridine-based porphyrins for
comparative homogeneous electrocatalytic reduction of CO2
11:30-11:50am 85 ChanAlignment of multi-walled carbon nanotubes on a silicon
substrate using an alignment relay technique
11:50-12:10pm 90 Abdulla The Analysis of Carbene-Stabilized Phosphorus(I) Cations
Room
ID Name Title
10:30-10:50am 28 GillSynthesis and characterization of hydrophobic In-fumarate
metal-organic frameworks
10:50-11:10am 30 Gray TiO2 Graphene Hybrids
11:10-11:30am 46 HungCatalytically Active Silicon Hydride Nanosheets for CO2
Reduction
11:30-11:50am 100 FerragSynthesis and characterization of high-swelling hydrogels
of Polyacrylamide and Polyvinylpyrrolidone cross-linked
with N-methylenebisacrylamide
11:50-12:10pm 105 ClassenSynthesis of Thermo-responsive and Self-immolative
Polymers from Poly(ethyl glyoxylate)
IN/M 2
BA111
GEN 1
BA211
IN/M 1
BA110
Room
ID Name Title
1:40-2:00pm 47 KiteleyExploring Alternative Methods for the Synthesis of
Difunctional Germanes
2:00-2:20pm 68 NascimentoDiscovering Frustrated Lewis Pairs Through Phosphenium
Cations
2:20-2:40pm 72 LyBright electrochemiluminescence from carbon quantum
dots at low costs
2:40-3:00pm 99 KooSynthesis of Novel Benzosiloles as Electrochemiluminescent
chromophores
3:00-3:20pm 135 LabinePhotoelectrochemical Reduction of Carbon Dioxide using
Mesoporous Titanium Dioxide Modified with Copper
Nanoparticles.
Room
ID Name Title
1:40-2:00pm 17 BraithwaiteThe Effects of Hydrogen Peroxide on the Corrosion of
Simulated Spent Nuclear Fuel (SIMFUEL)
2:00-2:20pm 44 ParkPhosphine Michael Addition to Maleimides for Nanomaterial
Modification
2:20-2:40pm 53 Nguyen Conductive Stretchable Fibres for Imperceptible Electronics
2:40-3:00pm 57 Nilsson Hemilabile NHCs for Oxidation Chemistry with Ni(II)
3:00-3:20pm 81 NoadeAlumina Sol Gel and Polydimethylsiloxane Composite
Interlayers for Increased Stretchability in Deformable
Electronic Devices
Room
ID Name Title
3:50-4:10pm 12 Poisson“Smart” self-assembled chromogenic materials on
enhanced screen printed nanosurfaces.
4:10-4:30pm 20 PetrovskiPurification of Fullerenes by Flash Column Chromatography
with Functionalized Iptycene onto Silica Gel
4:30-4:50pm 92 McLaughlinInert-Bond Activation Using a Pentanuclear Nickel Hydride
Cluster
4:50-5:10pm 102 Ravichandran Determination of Phosphonium Salt Dissociation Constants
5:10-5:30pm 134 PottierN-Heterocyclic Carbene Ligated t-Butylthiolates of Ag(I)
and Cu(I)
IN/M 5
BA110
IN/M 3
BA110
IN/M4
BA111
Room
ID Name Title
3:50-4:10pm 10 RielAdsorption Studies on Carbon Substrates: Quantification of
Glucose
4:10-4:30pm 55 StephensReactivity Studies of a Stabilized Low-Coordinate Palladium
Complex
4:30-4:50pm 65 RazumkovSynthesis of New Phosphorus-containing Functional Groups
Using 2-Phosphaethynolate Anion
4:50-5:10pm 70 St. Onge Utilization of Pincer Ligands in Main Group Chemistry
5:10-5:30pm 118 SuhReactivity and Tuning of a Pentanuclear Nickel Carbide
Cluster
Room
ID Name Title
10:30-10:50am 8Del Mundo
Cruz
Exploring the Diels-Alder Reaction for Structured Silicone
Materials
10:50-11:10am 48 Dickson Insertion of Electrophilic Alkynes into Silylamines
11:10-11:30am 111 BurtonDomino Palladium–Hydride Insertion/C–H Bond Activation:
Cycloisomerization of 1,6-Diynes
11:30-11:50am 119 Bridge Progress Toward the Formal Synthesis of Chanoclavine I
11:50-12:10pm 122 Desai Synthetic Approach to Produce a C-glycoside Tn Antigen
Room
ID Name Title
1:40-2:00pm 67 WojtkiewiczIncreasing Stretchability of Conjugated Polymers Using
Metal-Ligand Coordination
2:00-2:20pm 96 PalDiastereoselective Preparation of Chiral Amino Sulfoxides
Through Sulfenate Chemistry
2:20-2:40pm 103 JeevaSynthesis of New Reactive BODIPY Dyes and their
Applications in Solar Cells
2:40-3:00pm 125 Kapeniak Expanding the Role of CO2 Surrogates in Organic Synthesis
3:00-3:20pm 132 Liu Synthesis of sugar-derived aryl ethers
OR 2
BA112
IN/M 6
BA111
OR 1
BA112
Room
ID Name Title
3:50-4:10pm 35 Short Synthesis of indol-annulated S-containing polycycles
4:10-4:30pm 37 RamserranOptimization of an Enantioselective Desymmetrization of
Malonamides via Intramolecular Buchwald-Hartwig Cross-
Coupling Reaction
4:30-4:50pm 40 PowellExtending π-Conjugation in Boron Difluoride Formazanates
via Sonogashira Coupling
4:50-5:10pm 109 SammonsCyclization and Characterization of cis-1-alkenyl β-
aminoalkyl sulfoxides
5:10-5:30pm 139 BotelhoA New Method for the Activation of Donor-Acceptor
Cyclopropanes
Room
ID Name Title
10:30-10:50am 124 ReidEnzyme Encapsulation and Immobolization of
Deoxyribonuclease 1
10:50-11:10am 86 KailassRatiometric Fluorescent Chemosensing Carboxylesterase 2
Activity
11:10-11:30am 98 ChorolovskiCharacterization of a unusual transcription factor in the
protist, Giardia intestinalis
11:30-11:50am 117 FatimaTemporal and Spatial Expression of Giardia intestinalis
Flavohemoglobin
11:50-12:10pm 24 KrekhnoGene expression analysis of three isotypes of cytochrome
b5 during encystation of Giardia intestinalis
Room
ID Name Title
1:40-2:00pm 6 BickersNuclear Magnetic Resonance Studies of RNA Aptamer-
Fluorophore Complexes
2:00-2:20pm 29 Butler Role of RNase L in Cellular Stress-Induced RNA Disruption
2:20-2:40pm 36 AbdelrahimImproving phosphoprotein yield from an RNA-guided
genetic code recoding system in Escherichia coli
2:40-3:00pm 101 Bodagh Photoactivation of Inhibitors of Anti-Cancer Therapy
3:00-3:20pm 110 BahnamSynthesis and characterization of immunologically active
glycolipids isolated from S. pneumoniae
B/M 2
BA210
OR 3
BA112
B/M 1
BA210
Room
ID Name Title
3:50-4:10pm 2 Tajik Investigation into a Virus-Based Artificial Cellulosome
4:10-4:30pm 4 ShepherdsonEngineering a controlled environment within a spherical
capsule protein
4:30-4:50pm 11 ToDevelopment of Lysyl- and Alanyl-Phosphatidylglycerol
Synthesis to Investigate Bacterial Resistance to
Daptomycin
4:50-5:10pm 93 TanInvestigation on the Contribution of Electronic Effect of Mn-
Porphyrin-Based MRI Contrast Agents on T1 Relaxivity
5:10-5:30pm 115 TuFluorescent integrated stapled ghrelin(1-20) analogues for
the targeting of GHSR-1a in cancer
Room
ID Name Title
1:40-2:00pm 38 RickeardA Comparison and Contrast of Different Construction
Methods of Asymmetric Model Membranes
2:00-2:20pm 76 QureshiAnalysis of the Binding of Bifunctional Aptamers using
Isothermal Titration Calorimetry (ITC)
2:20-2:40pm 82 SchalikeNMR and Electrochemical Analysis of Bovine Cytochrome b5
G62 Deletion Mutant
2:40-3:00pm 107 QaqishSynthesis of the KRN 7000 Glycosphingolipid Acetal Free
Analogue
3:00-3:20pm
Room
ID Name Title
3:50-4:10pm 9 McCordThe Optimization of Enzymes for the Synthesis of Single
Chain Siloxane Phospholipids
4:10-4:30pm 13 PatelAnalyzing Biological Stability of Azobenzene-Containing
Short Interfering RNA
4:30-4:50pm 27 LazzamProbing Biofilm-Forming Bacteria with N-Acetyl
Glucosamine Analogues
4:50-5:10pm 78 LiEnzyme-powered Three-Dimensional DNA Walking Device
for Discriminating Single Nucleotide Variants
5:10-5:30pm 114 PalumboUsing Variable Temperature NMR to Examine the Structure
and Stability of Immature Human SOD1
B/M 5
BA211
B/M 3
BA210
B/M 4
BA211
Room
ID Name Title
10:30-10:50am 41 ChoiStructural and Mechanical Properties of Palm Oil in the
Presence of dispersed particulates
10:50-11:10am
11:10-11:30am 112 YeCan Molecular Simulations Help Understand Alzheimer's
Disease?
11:30-11:50am 113 AltenhofOptimal Control of Frequency-Swept Pulses for the
Acquisition of Ultra-Wideline Solid-State NMR Spectra
11:50-12:10pm 137 Cresswell Investigating Vibration-Plasmon Coupling in a Nanoreactor
Room
ID Name Title
1:40-2:00pm 15 De VlugtComputing Bound States of Rotor Chains and Arrays Using
Direct Operation and Renormalization Groups
2:00-2:20pm 25 OlechnowiczInvestigating CO2 Adsorption and Dynamics in the Metal-
Organic Framework ZnAtzOx-MeOH
2:20-2:40pm 43 HoDiscovering the structural stability of CAU-1 and its
properties for CO2 adsorption under extreme pressure by in
situ vibrational spectroscopy
2:40-3:00pm 59 LeGold Nanoclusters and Their Complexes: Experimental and
Computational Studies
3:00-3:20pm 80 LeEffect of Electrolyte Composition on Plasma Electrolytic
Oxidation Coatings on AM60 Magnesium Alloy
Room
ID Name Title
3:50-4:10pm 3 Lott A Novel Instrument for the Study of Gas Phase Ultrafast
Transient Absorption Dynamics in
4‑(N,N‑Dimethylamino)benzonitrile
4:10-4:30pm 23 SzukaloA molecular dynamics investigation on the interplay of
hydrophobic and hyrdrophylic interactions in an aqueous
droplet
4:30-4:50pm 50 LeggeProbing Surface Chemistry at the Monolayer Level with PM-
IRRAS
4:50-5:10pm 121 JosephCorrective method for density-functional calculations of
hyperfine coupling constants
5:10-5:30pm 127 MathersNaphthalene Dithioimides: Analysis of Steric Barriers to
Thionation
PCT 3
BA208
PCT 1
BA208
PCT 2
BA208
Room
ID Name Title
3:50-4:10pm 5 TullyInvestigation of the Permation of Hydrogen in X65 and X70
Carbon Steel
4:10-4:30pm 31 Laylo Electrocleaning Study of Daguerreotypes
4:30-4:50pm 56 NaveedNonlinear Phenomena in the Electrochemical Oxidation of
Bisulfite
4:50-5:10pm 106 MohammadThe Effect of Oxygen and Nitrite on the Corrosion of
Copper under Nuclear Waste Disposal Conditions
5:10-5:30pm 129 MirzoyanNear-field infrared spectroscopic properties of boron nitride
nanotubes upon polymer binding
Room
ID Name Title
10:30-10:50am 22 AlmusnedThe Role of Molybdenum in the Passivity of Ni-Cr-Mo Alloys
in Chloride Containing Environments
10:50-11:10am 26 KorkolaStudying the Folding of an Intrinsically Disordered Human
Protein Using Electrospray Ionization Mass Spectrometry
11:10-11:30am 32 KavuruUnderstanding Conformational Dynamics of Substrate
Binding to GST M2-2 using TRESI-HDX
11:30-11:50am 54 DeckertSelective molecular receptor for the detection and removal
of mercury ions from solutions.
11:50-12:10pm 88 Bulcan-GnirssA Study of the Fluorescent Properties of Rhenium -
Naphthalimide Conjugates
Room
ID Name Title
1:40-2:00pm 1 ShakeelDeveloping a Ligand–Modified Potentiometric Electrode for
the Detection of Aqueous Heavy Metal Ions
2:00-2:20pm 39 Li Chun FongA Biosensor for Au
3+ based on a DNAzyme and Iodide
2:20-2:40pm 58 WongThe Effects of Trivalent Chromium on Human Bladder
Cancer Cells Probed by Scanning Electrochemical
Microscopy
2:40-3:00pm 97 Maloney
Liquid Chromatography- Tandem Mass Spectroscopy
Method Validation and Analysis of Trichothecenes in
Agriculturally Relevant Wheat Samples
3:00-3:20pm 126 KatariaExamining the Effects of Oxidative Damage on Protein
Stability
AN 2
BA209
PCT 4
BA209
AN 1
BA209
#SOUSCC2018
Detailed Poster Schedule
poster # ID Name Title
1 14 Chen Effect of Substrate Surface Stiffness on Bacterial Adhesion
2 16 Fish
Assessing the Structural and Functional Characteristics of the
ADP/ATP Carrier Towards a Comparative Analysis with
Uncoupling Proteins
3 18 MathavarajahCln5 plays a role in adhesion, autophagy, cell differentiation,
and phagocytosis in Dictyostelium discoideum
4 19 BaoDevelop high efficiency electronic structure computational
method for solid state systems calculations
5 42 Leung
A novel enzyme based platform coupled to mass
spectrometry for the identification and screening of toxic
reactive metabolites from anti-thyroid drugs
6 45 AngelucciMeasurements of Atmospheric HCl in Toronto To Understand
Reactive Chlorine Chemistry
7 49 NeterThe Synthesis and Characterization of Alkynyl Substituted
Dibenzanthracenes
8 52 HungStimuli Responsive Hydrogels and their Self-Shaping
Applications
9 60 MoranTowards the synthesis of fluoro-substituted
dibenz[a,c]anthracenes using the Wittig reaction
10 61 Baig
The Use of Microfluidic Chemostats for the Observation of
Conjugation between Escherichia coli S17-1 and BL21(DE3)
pLysS Strains
11 62 AsifOptimizing a Decay Vessel for Continuously Monitoring the
Progression of Soft Tissue Decay in the Laboratory
12 64 KellerBorinic Acid Catalyzed Ring-Opening of an Acyclic 3,4-Epoxy
Alcohol using Substituted Aniline Nucleophiles
13 66 DaoUrea-linked Polymerization of Primary Amino Porphyrin
Complexes in Mild Conditions with CO2
14 69 WongInvestigation of Protein Folding, Aggregation and Substrate
Binding Sites Using High Resolution Mass Spectrometry
15 71 KynePoly(norbornene) Dopamine Polymer Electrode for Lithium
Storage
16 73 NardangeliApplication of Reductive Transposition in the Synthesis of
Pancratistatin
poster # ID Name Title
17 74 Schroeder Mild Metal Mediated Cyclization of a Thiourea to a Substituted
2-Aminobenzothiazole
18 75 Thomson Total Synthesis of (-)-Oxycodone
19 77 Lee Nickel-Catalysed Aminations of Diaryl Ethers
20 89 ColomboOptical biosensing of oligonucleotide modified gold
nanoparticles by induced DNA disassembly
21 94 RiddellExploring and optimizing sulfenate alkylation reactions for
applications in natural product synthesis
22 95 FramePreparation of Various β‑Amino Iodides and Bromides for
Alternative Synthetic Approaches to Sulfenate Substitution
23 104 DionisiSynthesis of Cyano-substituted carbene-stabilized
phosphorus(I) cations
24 108 WongDevelopment of a Next Generation Covalent MRI Tag Based
on Manganese Porphyrin
25 116 Jurkiewicz
The secondary structure and membrane association of the M2-
subdomain of TOC159, a protein of the chloroplast outer
membrane
26 120 AdrianoSynthesis of Supramolecular Vanadate Receptors – Structural
Mimics of Vanadium Haloperoxidase
27 123 ZhaoRemarkably High Stabilities of MnTCP: A Non-Gd Extracellular
MRI Contrast Agent
28 128 OlsonSynthesis and Characterization of Mn(I) Complexes for
Asymmetric Polar Bond Reduction
29 131 Mashmoushi Determining the Calcium Bound Structure of Daptomycin
30 133 PatelCrystallization of a Putative Polysaccharide Lyase TDE0626
from Treponema denticola
31 136 NguyenCharacterization of a GH88 Family Glucuronyl Hydrolase from
Tannerella forsythia
32 138 Farac
Synthesis and Characterization of Novel Copper(I) and
Nickel(II) Complexes with a Tetradentate Bis(amino)-Bis(N-
heterocyclic carbene) (CNNC) ligand
#SOUSCC2018
Oral Presentation Abstracts
1 - Developing a Ligand–Modified Potentiometric
Electrode for the Detection of Aqueous Heavy Metal Ions
Zainab Shakeel1, Bryan Koivisto1
1Ryerson University
The rapid detection of heavy metal contaminants such as cadmium, lead, and mercury
present in our water supply is of great importance. Traditional analytical tests designed
to detect these metals use expensive instruments that are time-consuming and
challenging to maintain. To improve analytical testing, handheld analytical devices have
recently gained popularity with market demand projected to reach $9.55 billion USD by
2020 from $8.10 billion USD in 2015, as these provide a user friendly and economically
feasible alternative that delivers instantaneous results. The purpose of this study is to
develop a means to perform both quantitative and qualitative analysis using a spectro-
electrochemical cell. Our heavy metal-detecting device would be comprised of a
phosphorylated heavy metal chelating ligand that is anchored onto titania (TiO2), and is
connected in series to a voltmeter that measures changes in voltage resulting from a
metal binding event.
Current efforts in metal detection involve maximizing binding affinities of the ligand to
Pb2+, Hg2+, and Cd2+ ions, which are soft Lewis acids. In this study, we present our
ligand that pursuit to introduce target-specific binding using nitrogen, oxygen, and sulfur
atoms.
2 - Investigation into a Virus-Based Artificial
Cellulosome
Amanda Tajik1, Taylor Urquhart1, John Honek1
1University of Waterloo
Bacteriophage M13 (dimensions 6 nm x 900 nm) are Escherichia coli targeting viruses,
which have been extensively investigated for applications in phage display. Both
chemical modifications and amino acid mutations can be made to the coat proteins of
M13 without affecting assembly of the viral coat. The current project seeks to employ the
major M13 coat protein, pVIII (2700 copies per phage), for the development of novel
nanodimensional multienzyme complexes, specifically in this case, an artificial
cellulosome. Cellulosomes are multienzyme complexes capable of breaking down
cellulose, which is regularly resistant to facile degradation. Variation of cellulosome
enzyme composition has been shown to control cellulolytic efficiency in natural systems.
A strategy based on the chemical modification of M13 followed by scaffold extension
employing streptavidin-biotin clusters attached to cellulases is being investigated. If
successful, this approach may lead to the fabrication of novel virus-based composite
materials capable of highly controllable cellulolytic activities, allowing for more efficient
harnessing of the energy stored within biopolymers.
3 - A Novel Instrument for the Study of Gas Phase
Ultrafast Transient Absorption Dynamics in
4‑ (N,N‑ Dimethylamino)benzonitrile
Tyler Lott1, Nicolas Rivas1, Ariel Petruk1, Kostyantyn Pichugin1, Germán Sciaini1
1Ultrafast Electron Imaging Laboratory (UeIL), Department of Chemistry, and Waterloo
Institute for Nanotechnology (WIN), University of Waterloo
4‑ (N,N‑ Dimethylamino)benzonitrile) (DMABN) has drawn significant interest within the
field of physical chemistry over the past 60 years. The remarkable dual fluorescent
behaviour which is commonly known to exist has led to many studies concerned with the
characterization and the description of the locally excited (LE) and intramolecular charge
transfer (ICT) states. In particular, the ICT states are the most remarkable and many
contributions have been made and continue to be made to explore the dynamics of
excitation and relaxation. Most notably, fluorescence and transient absorption
measurements have been thoroughly conducted in the condensed phase with limited
experimental research produced to investigate gas phase dynamics. Through a unique
approach to instrumental design, a cell capable of gas phase spectroscopic
measurements has been constructed. Through the employment of femtosecond
transient absorption techniques, the uniquely designed gas-cell is utilized to investigate
the excited state dynamics of DMABN in various gaseous mediums.
4 - Engineering a controlled environment within a
spherical capsule protein
Evan Shepherdson1, Hawa Gyamfi1, John Honek1
1University of Waterloo
Bionanotechnology has tremendous potential to improve current drug discovery
programs through the development of new platforms and strategies for delivery at the
nanoscale. This can be especially critical in the delivery of hydrophobic therapeutics.
Engineering better delivery platforms can serve to stabilize and protect labile compounds
from degradation, increase the solubility of hydrophobic drugs, and preferentially deliver
cargo to specific tissues. Current platforms being explored in this area include
liposomes, micelles, dendrimers, and nanoparticles. Spherical capsule proteins, such as
viral capsids and iron-storage proteins, are naturally evolved complexes, that self-
assemble into defined structures and are controllable by a combination of bioconjugation
as well as genetic strategies. The current project is to explore approaches to engineer
the hydrophobicity of the interior cavity of a nanodimensional (12 nm) spherical capsule
protein and to explore the chemistry and biochemistry of these molecular spaces.
Approaches to the controllable encapsulation of defined micelles by the host capsule
protein will be presented and a discussion of the impact that the structure of the micelle
as well as the protein has on the resulting nanocomposite will be provided.
5 - INVESTIGATION OF THE PERMEATION OF
HYDROGEN IN X65 AND X70 CARBON STEEL
Claire Tully1, Maxwell Goldman1, David Shoesmith1, James Noël1
1The University of Western Ontario
X-series carbon steel (X65 and X70) is used for transmission pipelines in the oil and gas
industry. Pipelines are typically protected from the environment by applying either a
coating or cathodic protection. Applying too much current during cathodic protection can
cause atomic hydrogen to diffuse into the steel, resulting in embrittlement, blisters, and
cracks. We investigated the rate of hydrogen diffusion using the Devanathan-Stachurski
method.Calcium and magnesium were introduced to simulate groundwater conditions
and to determine their role on the rate of hydrogen absorption into X-series steels.
Calcium was found to cause a sharp decrease in the permeation of hydrogen, due to the
formation of calcium carbonate deposits on the steel surface, whereas, magnesium
caused a gradual decrease in the rate of hydrogen absorption, likely due to the
thickening of the magnesium hydroxide film on the steel surface. The permeation of
hydrogen into the steel affects the physical properties of the steel, and trapped hydrogen
may affect the passive properties of an iron oxide formed on the steel surface. Linear
polarization resistance measurements were used to measure the resistance of the
surface oxide. The measured resistance of the oxides formed on the X65 and X70
showed that hydrogen charging had a more pronounced effect on the X65 than on the
X70.Once the hydrogen enters the metal, no solution species can affect its diffusion
within the metal.
6 - Nuclear Magnetic Resonance Studies of RNA
Aptamer-Fluorophore Complexes
Sarah Bickers1, Kyle Piccolo1, Thorsten Dieckmann1
1Department of Chemistry, University of Waterloo
Aptamers are single stranded oligonucleotides selected in vitro to bind target ligands
with high affinity and specificity for various applications. Using SELEX, the RNA aptamer
SRB-2 was selected to bind the sulforhodamine B fluorophore for potential use in cellular
RNA imaging. Fluorophore aptamers bind fluorescent dyes predominantly through π-
stacking and electrostatic interactions, requiring target molecules to share similar
structure and charges. Uniquely, SRB-2 recognizes and binds additional fluorophores—
sulforhodamine 101, rhodamine B, and tetramethylrosamine—which all differ in
molecular charge and charge distribution. The different molecular electrostatics suggests
SRB-2 binds each dye through residue specific interactions and distinct binding modes.
Identification of residues involved in aptamer binding provides the foundation for
enabling modification of dye substituents to increase binding efficacy and stability for in
vivo localization of RNA. Utilizing 1D and 2D NMR techniques, preliminary site specific
information of analogous and characteristic aptamer-dye interactions were obtained
through comparison of SRB-2 in absence and in complexation with the dyes.
8 - Exploring the Diels-Alder Reaction for Structured
Silicone Materials
Jaaziel Del Mundo Cruz1, Paul M. Zelisko1
1Brock University, Department of Chemistry and Centre of Biotechnology, 1812 Sir Isaac
Brock Way, St. Catharines, Ontario L2S 3A1
Thermoset materials, unlike thermoplastics, are far superior in their mechanical and
physical properties because they are cross-linked materials (i.e. the polymers are
covalently bonded to each other). As a result, thermosets cannot be melted and
remoulded, making recycling them quite difficult. With the aid of Diels-Alder (DA)
reaction, this problem of recyclability can be addressed. Depending on the dienophile
and the diene, the reaction should go forward at a certain temperature to form an adduct
where the starting materials are covalently bonded. If the material is damaged, at
another temperature (usually higher), the starting materials can be recovered (retro-DA),
and the forward reaction can be performed once again to regenerate the bonds between
the polymer strands. In this project, a maleimide and a furan will be employed, as the
dienophile and diene, respectively, and will be used to functionalize siloxane polymers.
As an added environmental benefit an enzyme, Novozym-435, was used to perform
some of the key chemical steps in the synthetic pathway of the recyclable siloxanes. The
compounds were analyzed using 1H NMR, 13C NMR and 29Si NMR.
9 - The Optimization of Enzymes for the Synthesis of
Single Chain Siloxane Phospholipids
Kelli McCord1, Paul Zelisko1
1Brock University, Department of Chemistry and Centre for Biotechnology, 1812 Sir
Isaac Brock Way, St. Catharines, Ontario L2S 3A1
The use of enzymes for biocatalysis is a very promising area of research as it presents a
greener alternative to harsh, non-renewable, metal-based catalysts that are commonly
used. Specifically, lipases can eliminate the need for organic solvents in a reaction and
are naturally occurring so they act as a renewable source of catalytic material. The
efficiency and selectivity of lipases in the chemoenzymatic synthesis of organic and
silicon-containing single chain phospholipids was assessed. Siloxane-containing lipids
have been shown to self-assemble into ≈120nm unilamellar vesicles (ULVs), and as a
result have a great deal of potential for drug delivery and surface modifications.
Immobilized lipases from C. antarctica (B and A), R. miehei (RM) and T. lanuginosa (TL)
were used for catalysis in two main lipid syntheses. In both reaction schemes
glycerophosphocholine (GPC) was combined with a 10-fold excess of either organic
palmitic acid or the organosiloxy 5-(1,1,3,3,3-pentamethyldisiloxanyl)pentanoic acid. The
efficiency and selectivity of a variety of lipases in performing these chemical
transformations was assessed through 31P NMR and 1H NMR. Due to the differences in
the active sites of the four lipases it was expected that the enzymes would yield products
differing in preference for the sn1 position or the sn2 position. To our knowledge this is
the first extensive research being done to determine the efficiency or selectivity of
lipases in phospholipid synthesis. The ultimate goal of this research is to increase the
efficiency and selectivity of siloxane phospholipid synthesis.
10 - Adsorption Studies on Carbon Substrates:
Quantification of Glucose
Donna Riel1, Dario Bonetta1, Liliana Trevani1
1Faculty of Science, University of Ontario Institute of Technology.
The purpose of this project was to identify and optimize a method for the quantification of
glucose in aqueous solutions. This is advantageous in studying the adsorption of
glucose on different carbon substrates since previous studies have shown glucose, a
highly hydrophilic molecule, can be used to change the surface wetting properties of
carbon (Odetola et al., Int. J. Hydrogen Energy, 41(19), 8199-8208, 2016). This is a
preferred step in the synthesis of hybrid carbon/metal oxide materials.
Different methods for the determination of glucose in aqueous solution were analyzed as
a first step for glucose adsorption kinetics and thermodynamic studies. Our results have
shown that the determination of glucose using gas chromatography after derivatization
of glucose into volatile alditol acetates (Blakeney et al,Carbohydrate Research, 113,
291-299, 1983) is a suitable approach for these studies. It has the required sensitivity for
the quantifiation of glucose before and after adsorption onto carbon.
Two high surface area carbon substrates, activated carbon (Darco KB-G) and carbon
black (VulcanÒ XC-72), have been used to validate the proposed method. A detailed
description of the method, and preliminary adsorption data will be discussed.
11 - Development of Lysyl- and Alanyl-
Phosphatidylglycerol Synthesis to Investigate Bacterial
Resistance to Daptomycin
Avery To1
1Department of Chemistry, University of Waterloo
Daptomycin (Dap) is an important last-defense antibiotic used in clinic to treat serious
infections caused by Gram positive bacteria. It is a cyclic lipodepsipeptide consisting of a
10 amino acid macrocyclic peptide core containing an ester linkage, to which is attached
a lipidated linear tripeptide. Its activity is Ca2+-dependent in that it must bind Ca2+ in
order to be active. Further, its target site is the bacterial cell membrane where
phosphatidylglycerol (PG) must be present for activity. While resistance to Dap is not yet
common, the number of reports describing Dap-resistant bacterial strains from clinical
isolates is increasing yearly. One mechanism by which bacteria develop resistance
against Dap is by increasing the amount of lysyl-phosphatidylglycerol (LPG), a cationic
PG derivative, in their cell membranes. How LPG confers resistance is not known with
certainty. Some studies suggest that it prevents Dap from
inserting into the membrane as a result of electrostatic repulsion between Ca+2-bound
Dap and LPG. However, other studies have shown that the presence of alanyl-
phosphatidylglycerol (APG) in bacterial membranes may also be capable of conferring
resistance to Dap. This suggests that aminoacyl PGs may confer resistance simply by
reducing the amount of PG in the membrane. We wish to study the effect of LPG and
APG on Dap membrane binding. LPG and APG are commercially available; however,
both are prohibitively expensive. Two inefficient and lengthy syntheses of LPG were
reported in the late 1960’s. Here we present more efficient syntheses of these
aminoacyl PGs using modern phosphoramidite chemistry.
12 - “Smart” self-assembled chromogenic materials on
enhanced screen printed nanosurfaces.
Jade Poisson1, Simone Quaranta1, Nadia O Laschuk1, Iraklii I Ebralidze1, Franco
Gaspari1, E. Bradley Easton1, Olena V Zenkina1
1University of Ontario Institute of Technology
Nanoparticle conductive or semi-conductive films allow for the unique optical
properties of inorganic and organometallic complexes to be in the solid state while
retaining the redox activity of the species. Many inorganic and organometallic complexes
have unique optical properties that lend to distinctive properties in the films. Herein, we
investigated the stability and optical properties of osmium (II) and iridium (III) complexes
functionalized via a silane linkage onto various nanoparticle substrates including indium
doped tin oxide (ITO, of varying diameter), aluminum doped zinc oxide (AZO) and
antimony doped tin oxide (ATO). The nanoparticles were screen-printed onto ITO-coated
glass films. Functionalization occurred via a monolayer self-assembly mechanism and
demonstrated distinct change in optical properties upon the application of a potential.
The osmium complex presents electrochromic properties and the iridium complex
presents luminescent and electrochromic properties. Both complexes underwent metal
to ligand charge transfer resulting in a colourless (oxidized) and coloured (reduced)
state.
The samples were characterized through many methods including differential pulse
voltammetry (DPV), cyclic voltammetry (CV), electrochemical impedance spectroscopy
(EIS), surface area analysis (BET). The stability/kinetics were indicated by
spectroelectrochemistry (SEC). Upon analysis of the films it was determined that the ITO
(<50 nm) nanoparticles provided the largest reductive/oxidative efficiency with a
moderate surface area. Future work would involve the combination of these optical
properties onto a single film. Combined, the films would have the ability to switch
between different optical properties with varied applied potential.
13 - Analyzing Biological Stability of Azobenzene-
Containing Short Interfering RNA
Ayushi Patel1, Matthew Hammill1, Jean-Paul Desaulniers1
1University of Ontario Institute of Technology
The RNA interference (RNAi) pathway is an endogenous process that regulates gene
expression. In this process, double stranded RNA (dsRNA) gets cleaved into small
interfering RNA (siRNA) which triggers the degradation of the mRNA that matches its
sequence. From this discovery, siRNAs have gained a lot of interest for potential
therapeutic treatment, including cancer. This technology of treating cancer is optimal
because of selective targeting; siRNAs can target and kill tumor cells, whereas the
healthy cells remain unaffected. However, there are limitations to using siRNA as
therapeutic treatment because of the native structure of the siRNA. As a result, chemical
modifications are incorporated into the siRNA to overcome such challenges. In this
study, siRNAs are modified with a photoregulated molecule, azobenzene, in the
phosphate backbone. The biological functionality of azobenzene-modified siRNA
(siRNAzo) can be controlled, in an on/off manner. In the presence of different
wavelengths, azobenzene groups isomerizes which alters the conformation of the
siRNA. In the presence of visible light, azobenzene is in trans conformation (active state)
and in the presence of UV (ultraviolet) light, azobenzene is in cis conformation (inactive
state). The siRNAzos were tested against firefly luciferase using gel electrophoresis to
determine exonuclease stability. Our results indicate that siRNAzo in the cis
conformation have enhanced exonuclease resistant compared to the trans conformation.
15 - Computing Bound States of Rotor Chains and
Arrays Using Direct Operation and Renormalization
Groups
Isaac De Vlugt1, Dmitri Iouchtchenko1, Tom Halverson1, Pierre-Nicholas Roy1
1University of Waterloo
A direct operation Lanczos method is proposed for the calculation of energy levels for
linear and nonlinear nano-molecular assemblies of endofullerenes. The specific system
of interest is that of rigid HF encapsulated in C60, where only screened dipole-dipole
interactions and rotational energy terms are considered in the Hamiltonian. A
comparison is drawn between employing direct operation and explicitly constructing the
Hamiltonian matrix and evaluating matrix-vector products in a Lanczos algorithm for the
linear systems. Direct operation is shown to out-perform the matrix-vector product
method for large basis sizes. Additionally, renormalization groups at the two-dipole level
are explored theoretically and computationally and are shown to not scale well with
system or basis size.
17 - The Effects of Hydrogen Peroxide on the Corrosion
of Simulated Spent Nuclear Fuel (SIMFUEL)
Lindsay Braithwaite1, Ziyan Zhu1, David W. Shoesmith1, James J. Noel1
1University of Western Ontario
Spent UO2-based nuclear fuel deposited in a deep geological repository may be
exposed to oxidizing conditions in the event of container failure. Radiolysis of
groundwater which reaches the fuel surface will produce many products including the
oxidant hydrogen peroxide (H2O2), which is expected to cause UO2 corrosion. Noble
metal fission products in the spent fuel congregate into ε particles, which could catalyze
H2O2 decomposition. The goal of this project is to use electrochemical experiments to
investigate the effect of ε particles on H2O2-induced fuel corrosion and H2O2
decomposition on the fuel surface.
The working electrodes were UO2 SIMFUEL pellets; one doped with 7 rare-earth metals
and one doped with 4 noble metals and 7 rare-earth metals. Corrosion of each electrode
in solutions of 10-4 M to 10-2 M H2O2 was monitored over 24 hours using corrosion
potential and linear polarization resistance measurements. The corrosion potential was
confirmed to be dependent on H2O2 concentration. By measuring concentration changes
in H2O2 and dissolved U by UV-Vis spectrophotometry and inductively coupled plasma-
mass spectrometry, respectively, the dominant mechanism of H2O2 consumption was
found to be decomposition on the UO2 surface rather than UO2 oxidation. Cyclic
voltammetry experiments revealed that the kinetic current produced by H2O2 reduction
on the SIMFUEL surfaces is higher in the presence of ε particles. Tafel slopes produced
from cyclic voltammetry data show that the mechanism of H2O2 reduction is the same
with or without ε particles and the initial chemical oxidation of UO2 by H2O2 is rate
determining.
20 - Purification of Fullerenes by Flash Column
Chromatography with Functionalized Iptycene onto
Silica Gel
George Petrovski1
1University of Waterloo
Fullerenes have unique properties that have been exploited in renewable energy
sources as well as a variety of applications for future technology. Commercialization of
fullerenes is not yet possible due the difficulty of obtaining vast amounts of pure
fullerenes. When fullerenes are made, a variety of carbon allotropes are made along
with fullerenes. However, to apply fullerenes into technology, a certain level of purity is
required. Previously in the Schipper lab a flash chromatography method was devised to
purify fullerenes. The problem was that the purification worsened with repeated runs
because the molecule used for the purification were unstable and degraded over many
uses so we hypothesized that functionalizing large aromatic molecules onto silica gel
with stronger bonds holding the molecules on the silica gel.
21 - Nickel & Palladium (N,O)-Donor Ligand Complexes:
Structure & Catalysis
Jeanette Adjei1, Alan J. Lough2, Robert A. Gossage1
1Ryerson University, 2University of Toronto
2-Oxazolines are a subclass of azole heterocycles, its ring structure consists of a
nitrogen and oxygen atom which are connected via an sp2-hybridized carbon atom.
Oxazoline ligands has garnered attention due to its versatility as a synthetic intermediate
and metal binding agent used extensively in homogenous catalysis. The Gossage group
has explored the coordination capabilities of oxazoline to transition metals via N, O
chelation; of which has resulted in various oxazoline based metal complexes. Particular
complexes have shown the ability to catalyze carbon-carbon bond formation. Currently,
Group 10 transition metals such as nickel and palladium are of current interest to the
Gossage group due to their prevalence in catalysis. This research project focuses on the
synthesis, characterization and coordination chemistry of a series of novel and existing
bidentate oxazoline ligands. The synthesis of these ligands employs facile approaches in
which the ligands are generated in two steps. Additionally, recrystallization is utilized as
a purification method over the expensive and time-consuming column chromatography.
Finally, the resulting palladium and nickel complexes are characterized via
electrochemistry, crystallography and UV-Vis. The catalytic activities of the palladium
and nickel complexes for Suzuki cross-coupling and polymerization chemistry are
explored, respectively.
22 - The Role of Molybdenum in the Passivity of Ni-Cr-
Mo Alloys in Chloride Containing Environments
Baian Almusned1, Jeffrey D. Henderson1, Martin Badley1, Brad Kobe2, James J Noel1,2,
David W. Shoesmith1,2
1University of Western Ontario, 2Surface Science Western,
Nickel alloys, containing various amounts of Cr and Mo, are known to withstand a wide
range of corrosive media and, thus, may replace conventional steels in aggressive
industrial applications. The widespread application of these alloys necessitates research
to better characterize the role of individual alloying elements, with the ultimate goal of
optimizing alloy composition. Additions of Cr are known to promote the formation of an
inert, protective (passive) oxide film which enforces low corrosion rates. While the oxide
decreases the general corrosion rate, the film can be susceptible to breakdowns at
discrete sites (i.e., localized corrosion), where metal dissolution can then rapidly occur.
Crevice corrosion, occurring between surfaces in contact, is the most likely form of
localized corrosion for Ni-Cr-Mo alloys exposed to hot chloride-containing environments.
Additions of Mo are known to increase resistance to localized corrosion, although the
exact mechanism by which this occurs remains unresolved.
The motivation of this research is to better understand how compositional changes (i.e.,
the Cr/Mo ratio) influence the corrosion resistance of alloys exposed to anticipated
localized corrosion environments. A series of electrochemical and surface analytical
techniques have been applied to the investigation of the behaviour of four commercially
available Ni-Cr-Mo alloys under simulated crevice conditions. The techniques employed
include corrosion potential, potentiodynamic, and potentiostatic measurements,
electrochemical impedance spectroscopy, X-ray photoelectron spectroscopy, and time-
of-flight secondary ion mass spectrometry.
23 - A molecular dynamics investigation on the interplay
of hydrophobic and hyrdrophylic interactions in an
aqueous droplet
Ryan Szukalo1, Styliani Constas1
1The University of Western Ontario
An investigation of the how the hydration mechanism of typically hydrophobic solutes
react when charge is introduced is of fundamental importance when attempting to design
new nanomaterials for applications involving aqueous environments. Although rich
literature has been conducted on the hydrophobic effect, the buckyball represents a
boundary condition case where neither small or large hydrophobic solute theory can be
directly applied, as both the kinetics and thermodynamics do not obey either large or
small criteron of the hydrophobic effect. A further advantage to studying the C60
buckyball is it's structure represents the building block for an entire class of carbon
nanotubes, rich with application in aqueous environments. We used molecular dynamic
simulations of systems containing both neutral buckyballs and charged buckyballs at the
interface of a water nanodroplet containing up to 2000 water molecules, with sodium
counterions to balance the net system charge. These systems were used to probe how
hydrophobic solutes equilibriate on a surface, on how this process changes upon the
addition of realistic charge values.
24 - Gene expression analysis of three isotypes of
cytochrome b5 during encystation of Giardia intestinalis
Zakhar Krekhno1, Janet Yee1
1Trent University
Giardia intestinalis is an important waterborne parasite that infects around 280 million
people worldwide. It causes a disease called giardiasis, with symptoms including
diarrhea, vomiting and abdominal pain. Giardia exists in two different lifeforms, an active
trophozoite and an infectious cyst, and the process of encystation (transforming from
trophozoite into a cyst) has long been a target for anti-giardiasis therapy. Cytochromes
b5 are heme-containing proteins involved in electron transport processes of eukaryotes.
Giardia lacks heme-biosynthetic enzymes and does not possess mitochondria, where
heme biosynthesis occurs, nor does Giardia possess electron transfer partners of
cytochrome b5 that are commonly found in other eukaryotes. Consequently, the fact that
its genome encodes for four isotypes of cytochrome b5 is intriguing., As the roles of the
Giardia cytochromes b5 are likely unique to this organism, the pathways they are
involved in can potentially be targeted for anti-giardiasis treatment. Our lab has
previously examined protein levels of cytochrome b5 isotypes I, II and III during
encystation, and found that cytochrome b5-II is upregulated 4-fold, indicating a possible
involvement of this protein in encystation. However, a recent RNA-sequencing analysis
performed by another research group indicated that cytochrome b5-II mRNA levels
decreased during encystation. In this study, I used quantitative RT-PCR (RT-qPCR) to
analyze mRNA levels of the three Giardia cytochromes b5 isotypes and a nitric oxide-
detoxifying flavohemoglobin during encystation and showed that cytochrome b5-II is
upregulated early in the process. I will discuss possible reasons for discrepancies in our
RT-qPCR results and the results from RNA-sequencing.
25 - Investigating CO2 Adsorption and Dynamics in the
Metal-Organic Framework ZnAtzOx-MeOH
Maya Olechnowicz1, Bligh Desveaux1, Bryan Lucier1, Yining Huang1
1University of Western Ontario
Highly porous compounds, known as metal-organic frameworks (MOFs), have gained
significant attention due to their impressive performance in gas adsorption, separation,
and storage. In addition, there is an increased pressure to manage and reduce industrial
carbon dioxide emissions. Promising industrial gas storage capabilities of these
inorganic-organic hybrid compounds arise from their unique structural characteristics,
including record-breaking surface areas, high porosity levels and adjustable pore sizes.
This study focuses on the motions and dynamics of CO2 gas molecules within the
framework of the CO2-selective, ultra-microporous MOF ZnAtzOx-MeOH. The synthesis
of ZnAtzOx-MeOH was optimized and the product was confirmed using powder X-ray
diffraction (PXRD). The MOF was analyzed using variable-temperature (VT) solid-state
NMR in order to obtain information regarding CO2 adsorption behaviours within the
framework. The number of unique CO2 absorption sites were identified and simulated in
order to identify the dynamics of gas molecules at each site at different temperatures.
The results indicate that there are at least 3 unique adsorption sites within the framework
of ZnAtzOx-MeOH.
26 - Studying the Folding of an Intrinsically Disordered
Human Protein Using Electrospray Ionization Mass
Spectrometry
Natalie Korkola1, Martin J Stillman1
1Stillman Bioinorganic Group, Department of Chemistry, University of Western Ontario
It is well known that the structure of a protein is very important when it comes to
performing its function. The protein must be in its folded native conformation to be
active, but this structure can be unwound upon addition of a denaturant, which disrupts
the stabilizing bonds of the higher order structure. Many proteins however, do not
possess a well defined folded structure. Metallothionein is one of these disordered
proteins. In this study, the structure of apo metallothionein was probed using cysteine
modification with N-ethyl maleimide at pH 7.4 with and without the presence of the
denaturant guanidinium chloride. The modification patterns were monitored on an
electrospray ionization mass spectrometer [1]. It was found that the structure differed
depending on whether or not a denaturant was added, showing that apo metallothionein
does adopt a folded structure at biological pH. A method for the use of guanidinium
chloride for studies in mass spectrometry was also developed. The results were
compared with studies done on myoglobin: a well-understood protein with a defined
higher order structure. The myoglobin was denatured by pH adjustment, and the
changes in charge state were monitored by electrospray ionization mass spectrometry.
The myoglobin was found to display the expected patterns for the folded and unfolded
states.
For previous work, see:
[1] Irvine, G.W.; Santolini, M.; Stillman, M.J. Selective cysteine modification of metal-free
human metallothionein 1a and its isolated domain fragments: Solution structural
properties revealed via ESI-MS. Protein Sci. 2017, 26, 960-971.
27 - Probing Biofilm-Forming Bacteria with N-Acetyl
Glucosamine Analogues
Daniel Lazzam1, Benjamin DiFrancesco1, Adam Forman1, Mark Nitz1
1University of Toronto
Biofilm-forming bacteria present serious problems in many areas of society, from health
care to the food industry. The protective biofilm matrix that makes these problems so
significant is made up largely of polysaccharides; specifically, Poly N-acetyl
Glucosamine (PNAG). In an attempt to learn more about the formation of this polymer,
azide-tagged N-acetyl glucosamine (GlcNAc) analogues were synthesized and used as
substrate for PgaCD, the enzymes responsible for PNAG formation, in order to help
track polysaccharide formation and determine biosynthesis directionality, which we
determined to require addition to the non-reducing end of PNAG polysaccharide.
Furthermore, azide tagged GlcNAc-based metabolic analogues were fed to biofilm-
forming bacteria in order to track the various uses and fates of GlcNAc in bacteria,
particularly in cell wall biosynthesis in addition to biofilm formation. These results help
shed light on the interconnectedness of bacterial processes contributing to biofilm
formation and pathogenicity.
28 - Synthesis and characterization of hydrophobic In-
fumarate metal-organic frameworks
Karanpreet Gill1, Yue Zhang2, Bryan E. G. Lucier3, Yining Huang4
1University of Western Ontario, 2University of Western Ontario, 3University of Western
Ontario, 4University of Western Ontario
Metal-organic frameworks (MOFs) are versatile porous crystalline materials known for
their large surface area, high thermal stability, and excellent porosity. These properties
afford MOFs various applications in gas storage, catalysis, gas separation, and drug
delivery, among other fields. Synthesis of hydrophobic MOFs is of particular interest, as
water can decompose the framework or occupy binding sites for target molecules such
as CO2. Our research group previously determined that In-fumarate synthesized in
ethanol (In-fumarate-E) produced a hydrophilic MOF, but methanol solvent yielded a
hydrophobic product (In-fumarate-M).
In this study, additional hydrophobic In-fumarate MOFs were successfully produced via a
one-step synthesis or post-synthetic modification route. The use of NaF (In-fumarate-E-
NaF) or LiF (In-fumarate-E-LiF) in MOF synthesis produced crystalline In-fumarate
frameworks that adsorbed less H2O from the atmosphere in comparison to In-fumarate-
E, as shown using thermal gravimetric analysis (TGA). FTIR spectra suggests some of
the hydroxyl bridging groups connecting two indium metal centers in In-fumarate-E are
altered in the hydrophobic compounds. Solid-state NMR (SSNMR) experiments of the
post-synthetic modification product In-fumarate-E-to-M further supports this hypothesis.
SSNMR experiments of the In-fumarate-E-NaF MOF clearly indicate that Na is bound
and incorporated within the framework. The surface areas and CO2 adsorption
capacities of all MOFs within this study were also examined. These hydrophobic MOFs
show potential for practical applications involving the presence of H2O and serve as a
promising basis for the design of framework analogs.
29 - Role of RNase L in Cellular Stress-Induced RNA
Disruption
Phillipe Butler1, Amadeo M. Parissenti1,2,3,4
1Department of Chemistry and Biochemistry, Laurentian University, Sudbury, ON,
Canada, 2Health Sciences North Research Institute, Sudbury, ON, Canada, 3Division of
Medical Sciences, Northern Ontario School of Medicine, Sudbury, ON, Canada, 4RNA
Diagnostics Inc., Toronto, ON, Canada
30 - TiO2 Graphene Hybrids
James Gray1, Andrew Vreugdenhil1
1Trent University
Titanium dioxide graphene hybrid materials have been proposed as effective
photocatalysts as the graphene is expected to reduce the TiO2 electron-hole
recombination process. Graphene is a two-dimensional (2D) allotrope of carbon and is
typically classified as single, double, or few-layer graphene (FLG). The number of
graphene layers can dramatically change the material’s thermal and electrical
characteristics as well as other properties. In this work, a probe sonicator was used to
exfoliate graphene from graphite in the presence of an exfoliating agent in water. The
resulting graphene dispersion was characterized using Raman spectroscopy. Anatase
titanium dioxide (TiO2) was added to the graphene to generate a TiO2 graphene hybrid
using sonication or thermal processing. The photocatalytic activity of the resulting TiO2
graphene hybrid was explored through its catalysis of a standard photoreaction with
hydrogen peroxide and the decolouration of methylene blue solutions.
31 - Electrocleaning Study of Daguerreotypes
Patricia Laylo1, Madalena Kozachuk1, T.K. Sham1, James Noël1
1University of Western Ontario
Invented in 1839 by Louis-Jacques-Mandé Daguerre, the daguerreotype was the first
reproducible form of the photographic image. It launched a 30-year period known as
“daguerreotypomania” before being surpassed by other, more convenient imaging
methods. The production of a daguerreotype involves photosensitizing a silver surface
by reaction with selected halides, exposing the plate to the image (light), subsequently
developing it by exposure to mercury vapour, and fixing the image by removal of excess
photosensitive species. The daguerreotype appearance is due to the interaction of light
(reflection or scattering) with particles on the metal surface. Similar to other metallic
artifacts of this age and nature, daguerreotypes are prone to tarnish, and depending on
composition, the tarnish products can affect the appearance of the daguerreotype
differently. Historically, various daguerreotype preservation methods have been used.
While these methods result in visible improvement to the image, the surface of the
daguerreotype may be affected due to these conservation efforts. Most recently,
electrocleaning is proving to be a viable method of daguerreotype restoration, preserving
the image without affecting the surface. The purpose of this study was to develop a
further understanding of the chemistry behind the electrocleaning process, as well as the
chemistry of the daguerreotype itself. Surface analysis techniques used included optical
microscopy, scanning electron microscopy, inductively coupled plasma-mass
spectrometry and synchrotron X-ray spectroscopy. Three electrolytes were used in the
electrocleaning process: NH4OH, NaNO3 and Na3C6H5O7. From this examination, the
tarnish on the surface was identified and the optimal cleaning solution determined.
32 - Understanding Conformational Dynamics of
Substrate Binding to GST M2-2 using TRESI-HDX
Abhilash Kavuru1, Derek Wilson1
1York University
Glutathione S-Transferase (GST) is a large class of enzymes responsible for detoxifying
cells from reactive electrophilic xenobiotic species by conjugating them with reduced
glutathione (GSH). The GST superfamily consists of many isotypes (Alpha, mu, omega,
pi, sigma, theta and zeta) which exist as dimers (~50 kDa) and have mostly similar
structures. The mu class is characterized by a β2-α3 loop known as "mu loop". GST M2-
2 has prominent activity in detoxification of the dopamine metabolite, aminochrome and
other similar xenobiotes. The substrate binding interactions with GST M2-2 can be
understood using time-resolved electrospray ionization hydrogen deuterium exchange
(TRESI-HDX) to visualize how the conformation of the enzyme shifts as the substrate
binds. The HDX of GST M2-2 apoenzyme is compared with the HDX of M2-2 bound to
GSH and to that of M2-2 bound to 1-chloro-2,4-dinitrobenzene (CDNB). As the
conformation shifts, some regions of the enzyme become more exposed to the
environment resulting in an increased deuterium uptake in that region while areas that
become less exposed see a decrease in deuterium uptake.
33 - Ionic Networks for Controlled Drug Delivery
Olga Yunyaeva1, Tristan Harrison1, Paul J. Ragogna1, Elizabeth R. Gillies1,2
1Department of Chemistry and the Centre for Advanced Materials and Biomaterials
Research (CAMBR), Western University, London, ON, N6A 5B7, Canada., 2Department
of Chemical and Biochemical Engineering, Western University, London, ON, N6A 5B7,
Canada.
In the last 7 decades, controlled drug delivery has seen vast advancements as the field
continues to grow with advancing technology. Hydrogels have shown great promise as
vehicles for drug release due to their ability to swell many times their weight, hold
pharmaceutical agents in their network and release them upon application of a stimulus.
This presentation will focus on exploring ionic hydrogels synthesized from
polyphosphoniums and biocompatible sodium hyaluronate. These networks are held
together by ionic interactions, are capable of being loaded with drugs and releasing them
when exposed to biological salt concentrations. The swelling of these networks was
tested along with the drug loading and release of fluorescein dye as a drug mimic.
34 - Designing Patchy Rod-Like Micelles: Manipulating
Competitive Seeded-Growth Kinetics and Visualizing
Patchiness by Selective Staining
Menandro Cruz1, Jiangping Xu1, Jessica Yu1, Ian Manners2, Mitch Winnik1
1University of Toronto, 2University of Bristol
Rod-like micelles formed by crystallization-driven self-assembly (CDSA) of
poly(ferrocenyldimethylsilane) (PFS)-containing block copolymers (BCP) have been of
interest primarily due to the living nature of micelle growth process. The resulting
micelles are often very uniform in length and morphology. Despite extensive studies of
CDSA by sequential homopolymerization to generate novel block structures, there have
been very few studies of copolymerization by pairs of block copolymers. Here, I describe
a systematic study of co-assembly of PFS-b-polyisoprene (PFS-b-PI) and PFS-b-
poly(dimethylsiloxane) (PFS-b-PDMS), showing that the kinetics of PFS-b-PI is sensitive
to its block ratio. Block copolymer composition can then be utilized to manipulate the
resulting morphologies of rod-like comicelles. In order to characterize the resulting
morphology from competitive co-assembly of PFS-b-PI and PFS-b-PDMS unimers, PI
corona chains have to be stained selectively in order to determine whether the resulting
morphology is patchy or blocky. However, visualization of coronal segregation between
PI and PDMS corona chains of rod-like comicelles made by CDSA has been a challenge
because there is no source of contrast for the polymers when analyzed by transmission
electron microscopy. Here, I show that nanoscale coronal segregation can be visualized
using Karstedt’s catalyst as a source of Pt for staining PI chains through Pt(0)-olefin
coordination. This technique allows selective staining of PI and poly(methylvinylsilane)
(PMVS) corona chains in cylindrical BCP micelles with crystalline PFS core. Identifying
localization of different corona chains of mixed BCP micelles has been of interest in
order to investigate their growth kinetics and subsequently control their degree of
patchiness.
35 - Synthesis of indol-annulated S-containing
polycycles
Mukund Jha1, Spencer Short1, Steven Rhodes1
1Nipissing University
Substituted indoles are among a group of highly sought-after scaffolds because of their
potential of being biologically active. Similarly, polycyclic fused indole moieties are also
of considerable interest as they are often found to be a part of bioactive natural/synthetic
compounds. Hence, developing efficient syntheses of molecules having these structural
motifs are in great demand in the current literature. Unlike indole-fursed pyrans the
chemistry and biological properties of their fused-thiopyran counterparts have not been
explored in greater detail. We have an ongoing interest in the development of novel
strategies to access functionalized indoles. Over the last decade our research group has
demonstrated the synthesis of variety of indole-fused heterocyclic frameworks (e.g
thiopyrano[2,3-b:6,5-b']diindole, thiopyrano[2,3-b]indol-2- one, dihydrothiopyrano[2,3-
b]indole, thiopyrano[2,3-b]indole, benzo[4,5][1,3]thiazino[3,2-a]indole,
dihydroisothiochromeno[3,4-b]indoles and isothiochromeno[1,8,7-bcd]indole) using
indoline-2- thione as a versatile precursor. A brief review of these studies as well as
some recent results will be presented.
36 - Improving phosphoprotein yield from an RNA-
guided genetic code recoding system in Escherichia coli
Malaz Abdelrahim1, Jeremy Thomas Lant2, Patrick O'Donoghue1,2
1Western University, Department of Chemistry, 2Western University, Department of
Chemistry
Expansion of the genetic code beyond the 20 standard amino acids and 64 codons has
been a rapidly growing field on interest. The natural genetic code expansion mechanism
for the twenty first amino acid selenocysteine (Sec) has the ability to recode a codon at
only a specific location of interest, rather than at all instances of that codon as in
previous approaches. This provides a new and selective method to express and
translate phosphoproteins of interest through modifying the existing selenocysteine
translation machinery. Our goal was to engineer the Sec system to produce phosphor-
threonine (pThr)-containing proteins. With the use of RNA-guided recoding, we
established site-directed incorporation of pThr at position 308 in the active site of the
protein kinase B (Akt1). This was accomplished using an engineered mutant of the Sec-
specific elongation factor SelB (SelBSep), and co-expression of a tRNASec mutant.
Modification of an existing protein purification protocol allowed for optimized pThr308
yield and increased phosphorylation was supported by electrophilic separation of
phosphoproteins. Following protein purification, phosphorylated Akt1 production was
confirmed on a Phostag gel by a distinct band shift compared to an unphosphorylated
variant of the protein. The data obtained suggests that pThr was successfully
incorporated in Akt1.
37 - Optimization of an Enantioselective
Desymmetrization of Malonamides via Intramolecular
Buchwald-Hartwig Cross-Coupling Reaction
Jennalee Ramserran1, Dr. Russell Viirre1
1Department of Chemistry and Biology, Ryerson University
The Buchwald-Hartwig reaction is a Pd-catalyzed cross-coupling reaction between an
aryl halide and a nitrogen nucleophile. The Viirre Group has had an interest in exploiting
the use of this reaction to desymmetrize prochiral malonamide compounds via an
enantioselective intramolecular arylation of one the amide nitrogen atoms. Preliminary
work done in the group had achieved moderately good enantioselectivities using
catalysts comprised of a palladium source and a chiral phosphine ligand. In order to
improve upon these results, a pre-catalyst consisting of a palladium complexed with a
non-commercially available chiral phosphine ligand has been prepared. The purpose of
this project was to optimize reaction conditions using this complex to maximize the yield
and enantioselectivity in the malonamide desymmetrization. This presentation will
discuss the results of these studies.
38 - A Comparison and Contrast of Different
Construction Methods of Asymmetric Model Membranes
Brett Rickeard1
1University of Windsor
Plasma membranes (PM) have highly complex structures, including a diverse
assortment of lipid species throughout the lipid bilayer, as well as an asymmetric
configuration between the inner and outer leaflets. However, most cell membrane
research has been studied using symmetric liposomes. This is primarily due to the
difficulty of preparing compositionally accurate asymmetric membranes. In this project,
the structural accuracy and characteristics of current asymmetric model membranes
construction methods were tested using techniques such as small-angle neutron
scattering (SANS), small-angle X-ray scattering (SAXS), and NMR. The specific
asymmetric construction model tested was designed by Dr. Erwin London. Using
London's method, we created asymmetric large unilamellar vesicles (aLUV) via
cyclodextrin mediated exchange. The final vesicles were composed of a POPC/POPG
inner leaflet, and a DPPC outer leaflet. The SANS data showed that the aLUV from the
London's preparation method had little to no structural features. This could be due to the
low yield produced from London's method, or the surplus of protons present in the
vesicle core, causing incoherent scattering. London's method uses a sucrose core for
vesicle separation via density gradient. We investigated the effects of sucrose on aLUV
composition via SANS and SAXS. We found that sucrose lowers the intensity of the
SANS data due to its incoherent scattering qualities. A sucrose core also compromises
vesicle durability and limits the range of viable analytical techniques. Currently, we are
working on fine tuning the solvent suppression on proton NMR for the purposes of
optimizing an NMR based asymmetry assay.
39 - A Biosensor for Au3+ based on a DNAzyme and
Iodide
Lena C.M. Li Chun Fong1, Po-Jung Jimmy Huang1, Juewen Liu1
1University of Waterloo
The traditional role of DNA as merely a chemically inert genetic molecule has been
revised since the discovery of catalytic DNA in 1994. DNAzymes can catalyze various
reactions including RNA-cleavage. However, they are only active in the presence of
metal cofactors which stabilize the highly negative transition state. DNAzyme-based
biosensors exploit this strict requirement for cations. The Ce13d DNAzyme has
previously been reported to detect both lanthanides and thiophilic metal ions. Here, we
aim to develop a highly selective Au3+ biosensor based on Ce13d, which would be
cheaper, faster and more convenient than conventional analytical techniques such as
ICP-MS. The detection system consists of a modified DNA susbstrate strand with a
single ribo-adenine (rA) and scissile sulfur atom. Gel-based assays were performed to
quantify RNA-cleavage which provides an indirect measure of Au3+ concentration. The
addition of I- and EDTA causes a shift of specificity towards Au3+, while all the other
metals were silent under this condition.
40 - Extending π-Conjugation in Boron Difluoride
Formazanates via Sonogashira Coupling
Zachary K. Powell1, Ryan R. Maar1, Joe B. Gilroy1,2
1Department of Chemistry, 2Centre for Advanced Materials and Biomaterials Research
BF2 adducts of chelating N-donor ligands have garnered significant interest amongst
material scientists due to their stability, diverse coordination chemistry and often tunable
light absorption, emission and electrochemical properties. As a result, these compounds
have diverse applications such as in organic solar cells, organic light-emitting diodes and
imaging agents. One such class of compounds that has received much focus are BF2
adducts of formazanates, characterized by a [Ar1 N N=C(R3) N=NAr5]⁻ backbone.1, 2
These compounds can possess extensive π-conjugation – a vital characteristic if a
compound is to be strongly absorbing – and past studies within the group have
demonstrated that extending this conjugation red-shifts their low energy absorption
features. We set out to discover a set of conditions under which BF2 formazanates can
undergo Sonogashira cross-coupling to extend π-conjugation at the Ar1/Ar5 positions of
the formazanate backbone and to ultimately synthesize polymers using these conditions.
While no polymers have yet been synthesized, two new compounds were discovered
that demonstrate the anticipated effects and shed light on potentially competing
reactivity pathways encountered under Sonogashira cross-coupling conditions. During
this presentation, details of the synthesis and characterization of these compounds will
be discussed.
References
1. Maar, R. R.; Barbon, S. M.; Sharma, N.; Groom, H.; Luyt, L. G.; Gilroy, J. B. Chem.
Eur. J. 2015, 21, 15589 15599.
2. Barbon, S. M.; Staroverov, V. N.; Gilroy, J. B. Angew. Chem. Int. Ed. 2017, 56, 8173
8177.
41 - Structural and Mechanical Properties of Palm Oil in
the Presence of dispersed particulates
David Jung-Won Choi1, Derick Rousseau1, Hardeep Devgan1
1Ryerson University
The goal of this research was to assess the role of added sugar (50 wt%), lecithin (0.15
wt%) and aeration on the microstructural, crystallization and mechanical properties of
two types of palm oil over 4 weeks, with the intent being to explore whether the presence
of dispersed sugar, lecithin and air would promote palm fat crystallization. Mixtures were
cooled from 60 to 20°C at 5 °C/min with stirring at 100 rpm in a lab-scale scraped-
surface heat exchanger. Microstructure was examined using confocal microscopy and
polarized light microscopy whereas fat crystal properties were assessed with pulsed
NMR and DSC. Small-deformation rheology examined the evolution in viscoelasticity. In
the absence of sugar, fat crystallization began with the formation of spherulites and
sizable needle-like crystals were observed in the subsequent weeks. There was an
absence of spherulites in the presence of sugar, in conjunction with the reduction of the
needle-like crystal size and thickness. With addition of sugar and aeration, there was a
reduction in enthalpy and a slight increase in solid fat content after the first week in both
palm fats. Addition of sugar also resulted in an increase in the elasticity of both palm
fats, yet both aeration and addition of lecithin reduced elasticity. Once the role of air in
fat-sugar composites are understood, mixtures with a reduced proportion of saturated
fats can be developed.
43 - Discovering the structural stability of CAU-1 and its
properties for CO2 adsorption under extreme pressure
by in situ vibrational spectroscopy
Ryan Park-Lin Ho1, Shan Jiang1, Yang Song1, Yining Huang1
1University of Western Ontario
Metal-Organic Frameworks (MOF) are a relatively new hybrid porous material made up
of metal ions and organic linkers that have received lots of attention in recent years due
to its many potential applications such as gas storage and purification, chemical
separation, catalysis, and sensing. In this study, the MOF CAU-1 was examined under
high pressure conditions using a Diamond Anvil Cell (DAC), as an empty framework as
well as loaded with CO2, and the changes could be observed using an Infrared
Spectrometer. Under high pressure, the MOF can undergo interesting structural and
chemical changes that are rarely observed under ambient conditions. CAU-1 was
chosen due to its structure containing large aminoterephthalic acid linker chains whose
amino groups allow for high CO2 adsorption capacity, which makes it a strong candidate
for CO2 storage. The IR spectra of empty CAU-1 under pressure showed an irreversible
phase transition while the CO2 loaded CAU-1 showed marked differences in structural
stability and increasing interactions with CO2 under high pressure. The results from this
study highlight the potential of CAU-1 to be used in greenhouse gas storage and
capture.
44 - Phosphine Michael Addition to Maleimides for
Nanomaterial Modification
Jun-Hyeong Park1, Mark S. Workentin1, Paul J. Ragogna1, Michael A. Kerr1
1University of Western Ontario
Nanoscale materials, such as nanoparticles or carbonaceous materials, have been
identified as promising candidates for application in optics, electronics, and biomedicine,
because of their unique structural, mechanical, and optical properties. A key to their
implementation in these applications is the functionalization of the interface of these
materials that adjusts the physical and reactive properties. The thiol-Michael addition
reaction to a maleimide has been an important tool in materials science due to its “click”
nature, which allows for selective and efficient surface functionalization of materials
under mild conditions. Our groups have successfully demonstrated this reactivity on gold
nanoparticles.1,2 Phosphines are often utilized as a catalyst in this type of reaction, but
their use as the primary nucleophile has been underexplored. Such a species could be
advantageous as they can participate in multiple additions to electrophiles.3 The addition
of a variety of phosphines to maleimide will be discussed along with details on
understanding the outcomes of these reactions. Ideally, these benchmark reactions will
deliver functionality to the material (nanoparticle) surfaces.
References:
1. Luo, W.; Gobbo, P.; Gunawardene, P. N.; Workentin, M. S. Langmuir 2017, 33, 1908-
1913.
2. Weissman, M. R.; Winger, K. T.; Ghiassian, S.; Gobbo, P.; Workentin, M. S.
Bioconjug. Chem. 2016, 27, 586-593.
3. Rabiee Kenaree, A.; Berven, B. M.; Ragogna, P. J.; Gilroy, J. B. Chem. Commun.
2014, 50, 10714-10717.
46 - Catalytically Active Silicon Hydride Nanosheets for
CO2 Reduction
Chenxi Qian1, Wei Sun1, Darius Hung1, Dr. Geoffrey Ozin1
1University of Toronto
Heterogeneous conversion of CO2 to value-added chemicals and fuels by Si surface
hydrides has recently attracted broad research interest. Being earth-abundant, low-cost
and non-toxic, elemental Si is one of the most promising candidates for comprising such
a catalyst, enabling CO2 conversion to synthetic fuels on a giga tonne per year scale. It
is well known however that silicon hydrides react stoichiometrically with CO2 and all
attempts have failed to achieve catalytic conversion of CO2. The problem originates with
the formation of inactive surface silanols and siloxane groups with permanent loss of Si
hydrides. Here, aiming at cracking the core of the problem, we deposited Pd
nanoparticles on the surface of Si nanosheets using an innovative synthetic strategy.
An operando infrared study, with isotope labeling, showed Si hydrides successfully
regenerated on such nano surfaces exposed to CO2 and H2. We demonstrate for the first
time that nanosheets of hydride-capped silicon decorated with Pd nanoparticles can
enable the reverse water gas shift reaction in an unprecedented catalytic cycle.
47 - Exploring Alternative Methods for the Synthesis of
Difunctional Germanes
Curtis Kiteley1
1University of Western Ontario
Germanium plays an important role in modern technology in semiconductors and
optical devices. Current processing methods involve the synthesis of GeCl4 from GeO2,
and requires the use of chlorine-based reagents, which pose a risk to both human health
and the environment.1 Recently, an environmentally friendly process for the synthesis of
a GeCl4 substitute, 1, has been developed which avoids the use of chlorine reagents.2
Although tetraorganogermanes can be synthesized from 1 using Grignard reagents, the
synthesis of difunctional germanes using Grignard reagents was not successful. In this
work, the synthesis of difunctional germanes using 1 and organolithium reagents will be
presented.
1 Ullmann’s Encycl. Ind. Chem.; 2000; Vol. 66, 629.
2 Glavinović, et al.; Sci. Adv. 2017, 3, 1.
48 - Insertion of Electrophilic Alkynes into Silylamines
Courtney Dickson1
1University of Western Ontario
Abstract: Functionalizing amines is critical for their use in agriculture, pharmaceuticals,
and as fine chemicals. Transition metals have previously been used as catalysts for
such reactions; however, they are often expensive and low in abundance. Due to the
importance of amines, there is a high demand for finding new, more efficient ways to
synthesize them. Low valent main group complexes, such as disilenes are able to
activate ammonia1. The addition of an electrophilic alkyne to the resulting silylamine
results in further functionalization of the amine2. The effects of varying the bulk of the
substituents on the silicon and nitrohen of the silylamine on the alkyne insertion reaction
will be presented.
1Meltzer, A.; Majumdar, M.; White, A. J. P.; Huch, V.; Scheshkewitz, D. Organometallics, 2013, 32, 6844. 2George, T. A.; Lappert, M. F. J. Organomet. Chem., 1968, 14, 327.
50 - Probing Surface Chemistry at the Monolayer Level
with PM-IRRAS
Sydney Legge1, Wilson Luo1, François Lagugné-Labarthet1, Mark Workentin1
1The University of Western Ontario
Polarization modulation infrared reflection-absorption spectroscopy (PM-IRRAS) is a
powerful technique that provides significantly improved surface sensitivity compared to
traditional infrared vibrational measurements. PM-IRRAS allows one to measure the
infrared spectrum of a monolayer of molecules adsorbed onto a surface while also
providing information about the orientation of molecules in the monolayer. The molecular
organization of surface molecules is a critical parameter that defines surface properties
and reactivity. PM-IRRAS is therefore an ideal technique to study these surface
characteristics. This study focuses on the principles of PM-IRRAS and its applications in
the detection and characterization of self-assembled monolayers (SAMs) of thiol-
containing molecules on gold mirror substrates. In a proof of concept study, PM-IRRAS
is used to determine the orientation of adsorbed 4-nitrothiophenol (4-NTP). This
approach is then used to probe SAMs of a cyclopropenone-masked cyclooctyne capable
of undergoing catalyst-free click chemistry following exposure to ultraviolet (UV) light
(reaction scheme shown). This rapid, bio-orthogonal, and highly chemoselective click
reaction is an incredibly useful tool with a wide variety of applications in synthesis and
surface modification. Overall, this work demonstrates the use of PM-IRRAS across
different fields of chemistry and materials science.
51 - Synthesis of a Fluorogenic Substrate to Monitor
Redox activity in Cystathionine –
Leslie Ventimiglia1, Scott Smith1, Bulent Mutus1
1University of Windsor
Cystathionine γ – lyase (CSE) is a primary enzyme of the transsulfuration pathway. It is
responsible for degrading sulfur containing amino acids, primarily cystathionine.
Additionally, it is instrumental in producing Hydrogen sulfide (H2S), one of the known
gasotransmitters serving a role in vasodiliation and cell signal transduction. Literature
and previous work done in our lab have elucidated the potential disulfide reducing
capabilities of CSE, a homotetramer containing two CXXC motifs associated with
potential disulfide reduction in each subunit. To characterize the CXXC active site, a
fluorogenic pseudo substrate (FITC-Cys2) was synthesized using cystine, a
hypothesized substrate to CSE to measure enzyme activity using fluorescence. Kinetic
data using the synthesized cystine probe has offered little evidence in favour of cystine
as a substrate to CSE. Despite this, the pseudo-substrate has shown activity with a
known disulfide reducing enzyme, Protein Disulfide Isomerase (PDI). Additional assays
using homocystine, a known disulfide containing substrate to CSE, must be performed to
elucidate the potential high selectivity of its possible disulfide reducing active site.
53 - Conductive Stretchable Fibres for Imperceptible
Electronics
Kathy Nguyen1, Tricia Breen Carmichael1
1University of Windsor
Electronic textiles (e-textiles) are textiles that incorporate electrical components to impart
electrical functionality, such as conductivity. Truly wearable e-textiles deliver the
electrical functionality while maintaining the softness and stretchability of the textile.
However, creating conductive textiles is a challenge due to the porous structures of
textiles, which consist of an interconnected network of fibers and voids. Current literature
coats textiles with conductive inks that can electrically functionalize textiles, however,
wicking into the fabric’s voids stiffening the textile and diminishes the wearability. To
fabricate truly wearable electronics, it is imperative to find methods that would
functionalize the individual fibres, leaving the voids intact. In this project, we describe a
low-cost, solution-based, electroless nickel-immersion gold (ENIG) process that can be
applied to elastomeric fibres (e.g. Polyurethanes, latex), creating highly conductive and
stretchable gold-coated fibres. These single fibres can then be woven into textiles,
making stretchable, conductive e-textiles. We demonstrate the fibre’s applicability
through different innovative designs. We discuss fabricateing wearable wiring and strain-
sensors by weaving the stretchable conductive fibres through polyester or nylon. This
research provides exciting grounds for design opportunities in the field of wearable
electronics.
54 - Selective molecular receptor for the detection and
removal of mercury ions from solutions.
Alexandra Deckert1, Sarah King1,2, Olena Zenkina1
1University of Ontario Institute of Technology, 2Cardiff University
Trace amounts of heavy metal ions could cause significant harm to biosystems and the
environment. Mercury is well known to be extremely toxic to humans; these metal cause
serious health problems including mental health issues, birth pathologies, and death.
Mercury can exist in three forms: elemental mercury, inorganic mercury, and the most
toxic to humans organic mercury. Current methods for monitoring of metal ions suffer
from high instrumentation cost, spectral interferences, often require destructive sample
pre-treatment, and highly qualified personnel to perform the analysis.2 .This work
investigates mercury detection by exploiting the high affinity of mercury (II) towards the
ligand 4-(2,6-di(thiophen-2-yl)pyridin-4-yl)phenol. This ligand acts as a selective “turn
off” selective fluorimetric sensor for parts per billion to parts per million (ppb to ppm )
levels of mercury. No interference was found in the presence of 19 metal ions including:
Al3+, As3+, Ba2+, Ca2+, Cd2+ Co2+, Cs+, Cu2+, Fe2+, Fe3+, K+, Li+, Mg2+, Na+, Ni2+, Pd2+,
Ru3+, Sn2+, Zn2+. From Job’s fluorimetric titration experiment we were able to define the
metal to ligand stoichiometry as 1:1. This novel mercury complex was characterized via
UV-Visible spectroscopy (UV-Vis) and fluorescence emission spectroscopy. The novel
synthesis of this ligand was investigated and was characterized using 1H, 13C{1H}NMR,
IR, UV-Vis. and fluorescence spectroscopy.
55 - Reactivity Studies of a Stabilized Low-Coordinate
Palladium Complex
David Stephens1, Kyle Jackman1, Johanna Blacquiere1
1University of Western Ontario
Copolymers of polar monomers and olefins have beneficial properties that differ from
homopolymers such as improved toughness and adhesion. Transition metal catalyzed
copolymerization suffers from side reactions due to the instability of low-coordinate
catalyst intermediates. Hemilabile ligands can occupy the open coordination site and
improve catalyst performance. The 1-azaallyl moiety can act be hemilabile ligand as it
binds in either a 1-or 2-coordinate fashion and can switch between these modes.
Deprotonating a metal complex with a phosphine-imine ligand yields a complex with a
phosphine 1-azaallyl ligand that has an agostic interaction with one of the methyl groups
on the C-terminus of the 1-azaallyl moiety. Reacting this agostic complex with pyridine
easily affords the pyridine adduct highlighting the reactivity of this complex. The kinetics
of the ligand dissociation was explored for the pyridine adduct by VT NMR experiments.
The dissociation of pyridine is more difficult than interrupting the agostic interaction. This
is reflected in the reactivity of this agostic complex and the pyridine adduct with styrene,
methyl acrylate, and carbon monoxide. The pyridine adduct and agostic complex react
readily with carbon monoxide and produce several products with significant
decomposition regardless of reaction temperature. No detectable reaction was seen with
styrene but methyl acrylate reacted with the agostic complex demonstrating the unique
reactivity of this complex. Additionally, several attempts at copolymerizing styrene and
CO under multiple pressures of CO were made but no copolymerization was seen under
any of the conditions tested.
56 - Nonlinear Phenomena in the Electrochemical
Oxidation of Bisulfite
Fatima Naveed1, Jichang Wang1
1Department of Chemistry and Biochemistry, University of Windsor
Bisulfite has been commonly used as a mild reducing agent in various chemical
industrial productions and food industry. For example, they are used in almost all
commercial wines to prevent oxidation and preserve flavor. In fruit canning, sodium
bisulfite is used to prevent browning and to kill microbes. Understanding the oxidation
kinetics and mechanism of bisulfite is therefore very important to its applications. In this
research, electrochemical oxidation of sodium bisulfite at a Pt electrode was
investigated, in which the absence of oxidants makes the analysis of the oxidation
products easier. Linear sweep voltammetry study illustrates that bisulfite system
compromises of a negative differential resistance (NDR), which is an essential condition
for the occurrence of nonlinear instabilities, observable in the form of spontaneous
oscillations of current at potentiostatic conditions or potential under galvanostatic
conditions. Cyclic voltammetry experiments demonstrate that Pt surface is more reactive
than PtO. Reaction parameters that were systematically explored in this project are
bisulfite concentration and external resistance, where chronoamperometric experiments
carried out at potentials around the bisulfite oxidation peak with a suitable external
resistance lead to observations of significant spontaneous oscillations. Such a transition
may be understood based on the influence of the two parameters on the behavior of
NDR.
57 - Hemilabile NHCs for Oxidation Chemistry with Ni(II)
Hannah Nilsson1, Johanna Blacquiere1
1University of Western Ontario
Improving synthetic efficiency of pharmaceuticals and fine chemicals is of great interest
to the scientific community for the environmental and economical benefits it entails.1 This
project works towards the synthesis of an oxidation catalyst that uses abundant,
environmentally friendly O2 as the oxidant. Nickel(II) ligated with an N-heterocyclic
carbene (NHC) ligand has been previously observed to react with O2; the Ni-NHC
oxidizes an allyl ligand to form propenal.2 After aerobic oxidation, previously studied
complexes dimerize and subsequently decompose; eliminating the possibility for the
complex to be catalytic. The theorized mechanism for the allylic oxidation with Ni-NHC
passes through a Ni-OH species. In pursuit of developing an aerobic oxidation catalyst,
we target the synthesis of nickel complexes that react with O2 to make propenal and
form a stabilized Ni-OH intermediate.3 A Ni-NHC complex with a pendant pyridyl group is
synthesized and characterized by variable temperature NMR spectroscopy, UV-Visual
spectroscopy, and mass spectrometry. The hemilabile pyridyl group on new complex is
expected bind nickel after oxidation to increase the coordination number, which is
hypothesized to stabilize the Ni-OH intermediate sterically and electronically. Evidence
supports the synthesis of the target complex and preliminary evidence suggests the
complex reacts with O2.
1. Dach, R.; Song, J.; Roschangar, F.; Samstag, W.; Senanayake, C. Org. Process Res.
Dev. 2012, 16 (11), 1697–1706.
2. Dible, B.; Sigman, S. J. Am. Chem. Soc. 2003, 125 (4), 872–873.
3. Hazlehurst, R.; Hendriks, S.; Boyle, P.; Blacquiere, J. Chemistry Select 2017, 2 (23),
6732–6737.
58 - The Effects of Trivalent Chromium on Human
Bladder Cancer Cells Probed by Scanning
Electrochemical Microscopy
Jonthan Wong1, Fraser Filice1, Lina Yao1, Zhifeng Ding1
1University of Western Ontario
Our work has demonstrated the detrimental effects of dichromate on the cell’s behaviour
and functions [FP Filice, MSM Li, JM Wong, ZF Ding, J. Inorg. Biochem. 2018,
DOI:10.1016/j.jinorgbio.2018.02.009]. In contrast, trivalent chromium (Cr(III)) is essential
in trace amounts and serves many biological roles. Cr(III) notably acts as a regulator in
the insulin pathways. In this thesis work, by subjecting single T24 human bladder cancer
cells to increased concentrations of Cr(III), we explore the toxicity of the essential metal
in a long duration study. Scanning Electrochemical Microscopy (SECM) is a non-
invasive analytical technique that is utilized to characterize interfacial chemical activity
and obtain topographical images. By monitoring the electrochemical current feedback at
an ultramicroelectrode approaching to a live T24 cell, we can track external redox active
mediating species or reactive oxygen species generated from the cell. SECM is
therefore an optimal candidate to probe the physiological behaviour of single cells.
Coupling with a finite element analysis model, COMSOL Multiphysics software, a
simulated current response can be obtained and used to quantify the permeability of the
cell under given stress conditions by Cr(III). The toxicity of Cr(III) is further explored
using a MTT viability study, to gain insight into the correlation of cell permeability to
viability. These quantified features will shed light onto the possible cell process such as
lipid peroxidation that is occurring as the cell is subjected to the external stress. These
exciting results further demonstrate the versatility and power of SECM as a bioanalytical
technique to probe cell physiology.
59 - Gold Nanoclusters and Their Complexes:
Experimental and Computational Studies
An Le1, Ian Hamilton1, Vladimir Kitaev1
1Wilfrid Laurier University
Gold nanoparticles have attracted attention in recent years because of their unique
properties which can differ significantly from those of the bulk metal. Gold nanoparticles
can be chiral giving them extended functionalities. Due to their organic shell, monolayer-
protected AuNPs in general can be dissolved in various solvents and are amenable to
chiroptical techniques such as electronic circular dichroism. Density functional theory
(DFT) is a computational quantum mechanical modelling method and is the backbone of
electronic structure calculations. Used primarily for the modelling and simulation of
chemical many-body systems, DFT solves the Schrӧdinger equation for an interacting
system by mapping it exactly to a much simpler non-interacting system. Both
experimentally and computationally, Aun complexes with n = 20-22, have remained
ambiguous over the past decade. The Au20 tetrahedral structure is known to be
extremely stable. Computational studies of Aun(SR)m where R is a functional group such
as –H or –CH3 are entirely feasible. Experimentally, the peak at ~ 500 nm was observed
in all of the absorbance spectra. This could be a gold plasmon peak. This interference
lowers the chances of obtaining evidence for the desired Aun complexes. Since gold
nanoparticle complexes have many applications in nanomedicine and chiral gold
nanoparticle complexes could provide additional functionality in nanostructured devices,
it is crucial to do more work in this area.
63 - Effects of Metacognitive Practices on Introductory
Organic Chemistry Students. A Closer Look at Learning
Task Inventories
Tarique Plummer1, Stephen L. MacNeil1, Eileen Wood1
1Wilfrid Laurier University
Organic Chemistry students generally find the course to be quite demanding. The
challenge of educators is to assist the students in being cognitively critical, reflective as
well as targeted in their studying modus operandi. One way of doing this is to teach
students about metacognition, an awareness and understanding of one’s own thought
processes, and provide opportunities for students to practice metacognitive strategies.
We have been engaged in a research program that measures the effects of
metacognitive activities on introductory organic chemistry students’ self-reported
metacognitive skills and performance. One of these metacognitive activities, Learning
Task Inventories (LTIs), asks students to (1) indicate, on a chapter-per-chapter basis,
the learning tasks they think they can perform after having been exposed to chapter
resources, (2) complete a short multiple choice quiz pertaining to a subset of these
learning tasks and (3) respond to a short survey on the usefulness of the LTIs. This
presentation will describe the effects of LTIs on students’ self-reported metacognitive
skills and performance. The experimental design encompassed 259 students enrolled in
an Organic Chemistry I course during the fall term of 2015 who completed introductory
and end-of-term surveys, including a Metacognitive Awareness Inventory (MAI), and 8
weekly LTIs, among other metacognitive activities, over the term. Responses were
analyzed using Statistical Package for the Social Science (SPSS).
65 - Synthesis of New Phosphorus-containing
Functional Groups Using 2-Phosphaethynolate Anion
Kevin M. Szkop1, Dr. Andrew R. Jupp1, Hlib Razumkov1, Prof. Dr. Douglas W. Stephan1
1University of Toronto
Main group analogues of organic functional groups have always attracted inorganic
chemists. In the last 5 years, new synthetic strategies for phosphorus-containing starting
materials has led to a renewed interest in the field. In particular, an improved synthesis
of sodium 2-phosphoethynolate, [Na(diox)3][PCO] gives access to a reagent useful in the
formation of novel phosphorous-containing compounds. In this study, nucleophilic
addition of phosphides to triphenylgermylphosphaketene, derived from [Na(diox)3][PCO],
yields crystalline anionic diphosphaureas in high yields. Notably, the negative charge
shows appreciable delocalization on the anionic PCO fragment. Subsequent electrophile
addition resulted in formation of a range of substituted diphosphoureas or
phosphanylidenes, with O- or P- preference depending on the electrophile. Included in
these products is a stable and crystalline benzyl-substituted diphosphourea, the first
compound of this type to be studied crystallographically. The synthesis, properties,
relevance and future directions of these rare reagents will be discussed.
67 - Increasing Stretchability of Conjugated Polymers
Using Metal-Ligand Coordination
Kacper Wojtkiewicz1, Simon Rondeau-Gagne1
1University of Windsor
Stretchable and mechanically robust materials are now becoming crucial for the
development of wearable electronics. In particular, semiconducting conjugated polymers
have been shown to be remarkable candidates when preparing new electronic devices
as the exhibit good charge transport properties, synthetic versatility and easy tunability.
In recent years, the development of these types of materials have been utilized the use
of dynamic crosslinking, especially metal-ligand interactions, is a promising avenue to
prepare and design stretchable materials while also enabling novel properties such as
self-healing. However, in their synthesis and application, there are many challenges
overcome to achieve stretchable conjugated polymers, due to the intrinsic competition
between electronic and mechanical properties.
The objective of the project is to develop a novel strategy towards developing
intrinsically stretchable and self-healing conjugated polymers for application in
stretchable electronics. This main objective will be achieved by incorporating metal
coordinating moieties, namely imine side-chains, to the polymer in order to chelate to
Iron(II). This dynamic coordination will allow for the polymer network to dissipate strain,
thus enhancing the mechanical properties of the materials. Moreover, this will also allow
for regeneration of the polymer network after being damaged through a process known
as self-healing. This presentation will discuss our recent progress toward new metal-
coordinating conjugated polymers, especially focusing on their design and preparation.
68 - Discovering Frustrated Lewis Pairs Through
Phosphenium Cations
Maxemilian Nascimento1, Charles L.B. Macdonald1
1University of Windsor
The activation of small molecules has been a large area of interest but this process
has typically been done using expensive transition metal catalysts. In recent years it has
been shown to be viable through the use of Frustrated Lewis Pairs (FLPs), which do not
contain any transition metals.1 FLPs often consist of a borane as a Lewis acid and a
phosphine as a Lewis base but there have been no reports of phosphenium ions acting
as the Lewis acid in an FLP.2 The topic of discussion will be exploring N-Heterocyclic
Phosphenium ions (NHPs) as Lewis acids in an FLP system, including both
intramolecular as well as intermolecular FLP designs.
(1) Stephan, D. W. Org. Biomol. Chem. 2008, 6 (9), 1535.
(2) Weicker, S. A.; Stephan, D. W. Bull. Chem. Soc. Jpn. 2015, 88 (8), 1003–1016.
70 - Utilization of Pincer Ligands in Main Group
Chemistry
Blake St. Onge1, Ala'aeddeen Swidan1, Charles L.B. Macdonald1
1University of Windsor
The utilization of pincer ligands in organometallic chemistry offers different modes of
reactivity of metals, allowing for unique catalytic reactivity and application. Pincer ligands
have not been exploited to the same extent with main group elements. Utilizing concepts
established in transition metal chemistry, we are investigating new pincer complexes
with potential of harnessing reactive main group centers.1 The presentation will consist
of the complexation of various group 13-15 main group elements into bis((1H-
benzo[d]imidazol-2-yl)methyl)amine (with group 15), and 2,6-bis(1-(3,5-
bis(trifluoromethyl)benzyl)-1H-benzo[d]imidazol-2-yl)pyridine (with groups 13 and 14). X-
ray structures, results and reactivity will be detailed.
(1) Dunn, N. L.; Ha, M.; Radosevich, A. T. Main Group Redox Catalysis: Reversible P
III/P V Redox Cycling at a Phosphorus Platform. J. Am. Chem. Soc. 2012, 134 (28),
11330–11333.
72 - Bright electrochemiluminescence from carbon
quantum dots at low costs
Malin Ly1, Shuijian He1, Liuqing Yang1, Ruizhong Zhang1, Jonathan R. Adsetts1, Zhifeng
Ding1
1University of Western Ontario
Electrochemiluminescence (ECL) is a light emitting process resulting from the
interactions between electrogenerated radical species. The smart combination of
electrochemistry and chemiluminescence gives ECL the controllable properties over light
emission by simply adjusting the electrode potentials and reactant concentrations. ECL
has now become a powerful and widely used technique in the fields of light-emitting
devices and immunoassays. For an economical and environmental friendly luminescent
material in the above applications, carbon quantum dots (CQDs) were successfully
synthesized using folic acid as a starting substance via one-pot pyrolysis. The obtained
CQDs were characterized using photoluminescence (PL) spectroscopy. It was
discovered that our CQDs exhibit blue luminescence with maximum excitation and
emission wavelengths at 355 and 440 nm, respectively. The luminescence quantum
yield was determined to be 5.4% relative to quinine sulfate. ECL of the CQDs was very
strong in the presence of K2S2O8 as a coreactant and an ECL efficiency of 12.5%
relative to the Ru(bpy)3Cl2/K2S2O8 coreactant system was reached. The spooling ECL
spectra revealed a potential-dependent emission. The ECL emission peak wavelength of
the above coreactant system was determined to be 700 nm, which is 260 nm red shifted
when compared with its maximum fluorescence emission. This significant difference
between ECL and PL peak wavelengths may ascribe to their different emission
mechanisms: the ECL emission came from the surface states while the PL emission was
from the core states of CQDs. With such excellent photoluminescence and
electrochemiluminescence performances, stable and low-cost CQDs are anticipated for
light emitting electrochemical cells and immunoassays.
76 - Analysis of the Binding of Bifunctional Aptamers
using Isothermal Titration Calorimetry (ITC)
Ruqaiya Qureshi1, Philip E Johnson1
1York University
In recent years, DNA aptamers have become of increasing importance due to their great
potential in biosensing applications, nanowire assemblies and drug design in
pharmaceutical industries. Therefore, in order to explore the binding affinity and
behaviour of the aptamers, ITC was performed using the aptamers and ligands under a
constant set of conditions. All the experiments were carried out at 15 C, in 20 mM Tris,
140 mM NaCl and 5 mM KCl. We are interested in fusing two aptamers together to form
bifunctional aptamers consisting of two binding sites, to analyze their binding behaviour
with ligands. We have chosen to study the cocaine-binding and DCA- binding aptamers,
as shown in Figure 1. Therefore, when the ligands were titrated with the aptamer
solutions, DCA and cocaine were found to bind the DCA binding site and cocaine
binding sites respectively, in an independent manner. Additionally, we will present the
dissociation constants associated with bindings at each of the two sites for the
bifunctional aptamers and discuss the thermodynamic parameters of each binding event.
All these results help make connections between the binding behaviour and the structure
of the aptamers.
78 - Enzyme-powered Three-Dimensional DNA Walking
Device for Discriminating Single Nucleotide Variants
Yongya 1
1Brock Uinversity
Single nucleotide variants (SNVs) are important both clinically and biologically, because
single base differences in nucleic acid sequences can have profound biological
consequences. Herein, we engineered a nicking endonuclease-powered three-
dimensional (3D) DNA walking device that discriminates SNVs with both high sensitivity
and high specificity at low target concentrations. Particularly, we introduced a new in-
solution tuning method that harnesses a single fuel molecule to regulate the
thermodynamic gain of the 3D walking device via noncovalent DNA catalysis. Our device
produced discrimination factors that are comparable with commonly used molecular
probes (e.g., molecular beacons and strand displacement beacons) but improved the
assay sensitivity by ~100 times. Our results also demonstrate that rationally designed
DNA catalysis can be used to quantitatively improve the molecular devices with high
structural and functional complexity.
80 - Effect of Electrolyte Composition on Plasma
Electrolytic Oxidation Coatings on AM60 Magnesium
Alloy
Mandy Le1, David Shoesmith1, Vahid Dehnavi1, Jamie Noel1
1University of Western Ontario
In the biomedical industry, there exists a strong interest in the use of Magnesium (Mg)
alloys as biodegradable implant materials due to their intrinsic biocompatibility and great
mechanical properties. However, Mg alloys have a high rate of degradation in the
physiological environment and low wear resistance. Therefore, implants composed of
Mg alloys may lose their mechanical integrity before the completion of the healing
process. Surface treatment is the general approach to overcome these deficiencies.
Several treatments have been developed, among which plasma electrolytic oxidation
(PEO) has proved promising results. PEO is a new electrochemical surface treatment for
some metals to enhance their corrosion and wear resistance. Electrolyte composition
and electrical parameters during deposition play a vital role in the formation of PEO
coatings and in determining their properties. To investigate the effect of electrolyte
composition on coating morphology and corrosion properties, electrolyte solutions
containing different concentrations of sodium metasilicate, potassium hydroxide and
triphosphate decahydrate were prepared, and samples were coated at three current
densities. The morphology, chemical composition and microstructure of the coatings
were analyzed using scanning electron microscopy (SEM) and energy dispersive X-ray
spectroscopy (EDX). Phase compositions of the coatings were determined with X-ray
diffraction (XRD) and electrochemical tests were carried out to study the corrosion
properties of PEO coatings. The results suggest that changing the composition of the
electrolyte affects coating growth behaviour, surface morphology, and corrosion
resistance. The outcomes from this research help us choose electrolyte compositions
that result in coatings with improved properties for different applications.
81 - Alumina Sol Gel and Polydimethylsiloxane
Composite Interlayers for Increased Stretchability in
Deformable Electronic Devices
Calum Noade1, Tricia Breen Carmichael1
1University of Windsor
In the field of stretchable and bendable electronics, there exists a myriad of different
approaches to developing such devices. Some researchers have opted to use inherently
conductive polymers such as PEDOT:PSS, while others use thin films incorporating
silver nanowires, carbon nanotubes, and other conductive films. Of the various methods
to impart conductivity to an elastomer, a metal layer such as gold is the most conductive
initially (i.e. before stretching). Gold is not intrinsically stretchable, and when deposited
on an elastomer such as poly(dimethylsiloxane) (PDMS) and stretched, it will relieve
strain by forming channel cracks perpendicular to the vector associated with stretching,
rendering the sample non-conductive at approximately 10-20% elongation. New
research aims to relieve this strain of stretching by using a roughened, adhesive
interlayer which employs a composite of alumina sol gel and PDMS, deposited on a
PDMS substrate followed by gold deposition. The roughened surface causes a
localization of strain at particular points on the interlayer in order to interrupt channel
cracks and maintain conductivity upon stretching. A condensed, amorphous sol gel has
not previously been used to impart roughness to an elastomer substrate in the
development of deformable electronics. Initial testing suggests that this interlayer can be
used effectively to fabricate deformable electronic devices which will experience a
minimal increase in resistance upon elongation.
82 - NMR and Electrochemical Analysis of Bovine
Cytochrome b5 G62 Deletion Mutant
Rebecca Schalike1
1Trent University
Cytochromes b5 (CYTB5s) are small electron-transfer heme-proteins that are
widespread among eukaryotes. The structure of CYTB5 has been determined in a
variety of species, and a highly conserved protein fold has been identified. The heme
cofactor is coordinated two axial histidine ligands, H39 and H63. In certain species, the
imidazole rings of these ligands have a perpendicular conformation, while in others, such
as the well-studied bovine CYBT5, the imidazole rings are coplanar. To determine
whether this structural difference was related to a difference in residue spacing between
the coordinating histidines, we prepared a bovine CYTB5 variant (DG62) in which
glycine-62 was was deleted. While DG62 retains the coordination geometry of wild type
protein, my research aims to study other possible effects on the heme environment
through the use of 1-D 1H-NMR spectroscopy and on the reduction potential of the
protein by cyclic voltammetry (respectively). NMR experiments comparing wild type and
DG62 in the upfield (-1 to -8 ppm) and downfield (10 - 30 ppm) permitted assignment of
several peaks originating from the peripheral groups of the heme cofactor and indicate
differences in the local heme environment. Electrochemical experiments are in progress
and the results of these will also be presented.
83 - MS in probing protein-small molecule interaction
Elida Bani1
1York University
Alpha-synuclein is associated with Parkinson Disease, and it tends to aggregate when
overexpressed or mutated typically at the N-terminal domain. There are evidence that
the aggregates are toxic to neurons. Thus, preventing monomers to aggregate or
dissociating oligomers could stop PD from progressing. Here we demonstrate the use of
TRESI-HDX Quadrupole coupled with Time Of Fly Mass Spectrometer to probe the
interaction of small molecules with alpha-synuclein as a monomer and an oligomer. The
findings indicate that none of the small molecules interact with monomeric alpha-
synuclein. However, the EGCG show to protect the peptide 114-124 of the C-terminal
domain of oligomeric alpha-synuclein. Ultimately, since EGCG shows interaction with
oligomers by dissociating them and no interaction with monomers, it has been
suggested that oligomers and monomers of alpha-synuclein possess different properties
from each other.
84 - Optimized synthesis of pyridine-based porphyrins
for comparative homogeneous electrocatalytic
reduction of CO2
Billy Deng1, Maryam abdinejad1, Caitlin Dao1, Xiao-an Zhang*1, Bernie Kraatz1
1University of Toronto
The conversion of carbon dioxide (CO2) into fuels has been a focal point in
contemporary research aiming to tackle the issue of climate change. However, reducing
the CO2 into usable compounds such as methanol is a challenge due to the high
thermodynamic and kinetic stability partially attributed to the linear structure of CO2.
Pyridine (Py) and pyridine derivatives have been shown as efficient electrocatalysts for
stepwise CO2 reduction to methanol by serial proton-coupled electron transfers, but are
noted for their low stability and current densities.
Here, we have designed and optimized the synthesis of different symmetrical and
nonsymmetrical pyridine porphyrin (Pyp) isomers, which are very stable catalysts due to
the unique porphyrin structure. We will also compare the electrochemical behaviors
between Pyp isomers in terms of CO2 reduction using Cyclic Voltammetry (CV). The
impact of conjugation on redox efficiency will be assessed.
85 - Alignment of multi-walled carbon nanotubes on a
silicon substrate using an alignment relay technique
Iris Chan1, Monika Kulak1, Derek Schipper1
1University of Waterloo
A novel method was recently developed by the Schipper group at the University of
Waterloo to address both the sorting and alignment of single-walled carbon nanotubes
(SWNTs) for applications in nanoelectronic devices. This procedure employs an
alignment relay technique (ART) where information is passed from a liquid crystal
medium to small organic molecules to form an aligned, functionalized surface for
nanotube deposition.1 This technique has successfully sorted and aligned SWNTs
simultaneously. Additional advantages of the method include operationally simplicity,
compatibility with common substrates under benchtop conditions, and lack of necessity
for specialized instruments. The work discussed here application of the ART to multi-
walled carbon nanotubes (MWNTs) to further expand on the applicabilities of the
method. Optimization of the technique for MWNTs was done by adjusting deposition
time, concentration, and ionic surfactant, in addition to exploring the effects of
sonochemical treatment on the degree of alignment. It was observed that the alignment
technique is preferential for a certain size of MWNTs, and specific sonication
conditions improved tube alignment. Thus, using the ART with sonochemical treatment
to produce aligned MWNT surfaces may potentially be useful in improving the
mechanical reinforcement and electrical conductivity of nanotube-composite materials.
(1) S. Selmani, D. J. Schipper, Angew. Chem. 2018, 130, 2423.
86 - Ratiometric Fluorescent Chemosensing
Carboxylesterase 2 Activity
Karishma Kailass1, Andrew Beharry1
1University of Toronto
Fluorescent probes are powerful tools to monitor enzymatic activity in live cells with high
spatial and temporal resolution. In particular, ratiometric probes (i.e. fluorescence at
different wavelengths) can provide accurate analysis by internal referencing.
Carboxylesterase 2 (CES2) is the major human carboxylesterase isozyme that is
overexpressed in tumour tissues, and thus serving as an excellent target for cancer
diagnosis. To this regard, we designed and synthesized a series of ratiometric
fluorescent probes, which produces large fluorescent responses in two emission
channels (yellow and orange) in the presence of CES2. This presentation will discuss
the characterization of these probes and their ability to detect and monitor CES2 activity
in vitro and in live cells.
88 - A Study of the Fluorescent Properties of Rhenium -
Naphthalimide Conjugates
Mariel Bulcan-Gnirss1, William Turnbull1, Emily Murrell1, Leonard G. Luyt1,2,3
1University of Western Ontario, 2London Regional Cancer Program, 3Lawson Health
Research Institute
1,8-Naphthalimides have been employed as cellular imaging agents due to their
fluorescent properties. The functionalization of an amino group to the 4th position of the
naphthalimide ring system creates a complex that has absorption in the visible region of
the electromagnetic spectrum, with a large Stokes shift. Langdon-Jones et al. reported
on 4-amino-1,8-naphthalimides containing a di-picolylamine binding unit to chelate Re(I).
Coordination was found to increase fluorescence lifetimes and inhibit quenching
pathways, thus improving the quantum yields. Since Re is often used as a non-
radioactive analogue of 99mTc, the most commonly used radioisotope for single photon
emission tomography (SPECT) imaging, bioconjugates of these Re/99mTc labeled
naphthalimides could be employed as dual modality fluorescence/ SPECT imaging
agents. In this work, the fluorescence properties of the metal complexes were studied by
altering the net charge of the chelation system. Three 4-amino 1,8-naphthalimide
analogues were synthesized, consisting of tridentate chelators conjugated to the
naphthalimide scaffold. Coordination with Re(I) tricarbonyl resulted in metal complexes
with charges ranging from -1 to +1. The absorbance maximum of the negative to the
positive species was seen to shift bathochromically when the charge state of the Re
complex changed from negative (429nm), to neutral (425nm), to positive (423nm). To
investigate differences in fluorescent properties, fluorimetry was used to determine the
quantum yields of all species synthesized. The findings from this study will assist in
designing future metal-based naphthalimide molecular imaging agents.
90 - The Analysis of Carbene-Stabilized Phosphorus(I)
Cations
Charles L. B. Macdonald1, Louae Abdulla1, Justin F. Binder1
1University of Windsor
The chemistry of low-oxidation state main group elements has been an area of
growing interest over the last century.1 Phosphorus(I) containing molecules have only
been lightly studied since their introduction to the inorganic world.2 A new, convenient,
and tuneable method for synthesizing NHC-stabilized phosphorus(I) cations has been
developed by our group using a previously reported triphosphenium reagent and N-
heterocyclic carbenes (NHCs).3 The synthesis and spectroscopic characterization of a
sterically encumbered derivative will be discussed, along with studies into its reactivity
towards various substrates.
(1) Chivers, T.; Konu, J. THE FUTURE OF MAIN GROUP CHEMISTRY.
Comments Inorg. Chem. 2009, 30 (5–6), 131–176.
(2) Dimroth, K.; Hoffmann, P. Phosphacyanines, a New Class of Compounds
Containing Trivalent Phosphorus. Angew. Chem. Int. Ed. 1964, 3 (5), 384–384.
(3) Kosnik, S. C.; Binder, J. F.; Nascimento, M. C.; Macdonald, C. L. B. Preparation
and Reactivity of a Triphosphenium Bromide Salt: A Convenient and Stable Source of
Phosphorus(I). J. Vis. Exp. 2016, No. 117.
91 - Synthesis of small molecule biological antifreezes
and applications in cryopreservation
Greg Yousif3, Seyed Iraj Sadraei1, John. F Trant2
1PhD graduate student mentor, 2Supervisor, 3Presenting Author
Certain organisms have evolved carbohydrates that act as antifreezes, antifreeze
glycoproteins (AFGPs), helping to survive sub-zero environments. The biological
antifreezes act through two different mechanisms: thermal hysteresis (TH) which is the
selective depression of the freezing point without changing the melting point of water
(this prevents the formation of ice crystals in the hysteretic gap); and ice recrystallization
inhibition (IRI), where the compounds prevent the growth of large crystals at the expense
of small crystals during the thawing process. Natural AFGPs show IRI activity, and this
could be useful for the cryopreservation of organs and tissue; however, they also have
potent TH activity that leads to damage during freezing. These two effects must be
decoupled in any useful cryopreservative, otherwise organs will be damaged as they are
frozen. We have made small molecule glycolipids, far simpler analogues of the
glycopeptides that have been shown to exhibit equipotent IRI activity as the AFGPs, but
do not exhibit TH activity. These materials are being used by our collaborators to
cryopreserve mammalian cells. Many different diseases and terminal conditions cannot
be cured unless through organ replacement. The eventual goal of this project is to
develop a means by which whole organs can be stored for longer durations of time
allowing for increased chance of survival for people faced with debilitating health
circumstances. In this presentation, the theory underlying biological antifreezes and their
potential for applications in biomedicine, the synthesis of our materials, and the
cryopreservative data related to our systems will be discussed.
92 - Inert-Bond Activation Using a Pentanuclear Nickel
Hydride Cluster
Matthew McLaughlin1, Manar M. Shoshani1, Samuel A. Johnson1
1University of Windsor
The activation of inert-bonds, such as C-C, C-H, and C-O bonds, in cheap and abundant
chemical feedstocks provides a hypothetical alternate route to essential chemicals and
fuels. By developing cost-efficient catalysis for these difficult bond transformations,
presently unusable materials could become future feedstocks. The pentanuclear nickel
hydride cluster, [(iPr3P)Ni]5H6 (1), has recently demonstrated the ability to activate
typically inert-bonds under mild conditions due to cooperative reactivity between the five
Ni centres, reminiscent of surface catalysis. Studies into the mechanisms of inert-bond
activation by 1 are underway, in the hopes of better understanding how these species
dismantle and remake typically inert bonds under mild conditions, with the potential to
discover new reactivity. In previous work, it has been suggested that [(iPr3P)Ni]5H4 (2) is
the reactive intermediate in bond activation. The current goal is to develop a synthetic
route to species 2, which is likely highly reactive, and study its interactions and reactivity
with inert-bond containing substrates.
The proposed intermediate, 2, has been observed using proton NMR at low temperature
when one equivalent of isobutylene is exposed to 1. Since the suggested intermediate 2
has been observed while in the presence of 1, we propose that it is possible to produce
2 by abstracting a hydride from 1 using trityl tetrakis[3,5-bis(trifluoromethyl)-
phenyl]borate, followed by a mild base to remove the remaining proton. Initial attempts
to abstract a hydride from 1 resulted in the paramagnetic intermediate [(iPr3P)Ni]5H6+ (3),
and attempts to transform 3 into the proposed intermediate 2 are currently underway.
93 - Investigation on the Contribution of Electronic
Effect of Mn-Porphyrin-Based MRI Contrast Agents on
T1 Relaxivity
Lida Tan1
1University of Toronto Scarborough
Magnetic resonance imaging(MRI) is a non-invasive diagnostic technique that allows the
visualization of abnormal tissues. The distinction between diseased and healthy tissues
may require contrast agents to improve sensitivity and enhance tissue
contrast. Gadolinium-based contrast agents(GBCAs) are commonly used in MRI
diagnosis, which have several drawbacks including in-vivo toxicity upon Gd-dissociation
and decreased sensitivity (measured as r1) at high magnetic fields. Manganese(III)
porphyrins have proven to be a potential alternative to GBCAs due to a better
biocompatibility over Gd and a significantly high r1 at clinically relevant fields. The
challenge remains in improving the sensitivity of these compounds. We attempt to
optimize r1 based on the Solomon-Bloembergen-Morgan model. The r1 depends on
several intrinsic factors, of most relevance to this project the electron spin relaxation
time(te). Other important factors such as water exchange(tM) and rotational correlation
time(tR) and their effects on r1 have been studied previously, however, the effect of
electron charge transfers between ligand and metal on r1 remains under investigation. It
is hypothesized that the increase in spin-delocalization and electron density facilitated by
adjacent functional group would favorably affect r1 at relevant fields. Here we
synthesized porphyrin derivatives with a strongly withdrawing nitro group and electron
donating amino group directly linked to the meso position. The successful synthesis of
the products was characterized by 1HNMR, ESI-MS, HPLC, and UV-vis when applicable.
Both derivatives showed significant spectral differences compared to previously
synthesized porphyrins in our lab. We are currently working on building the NMRD
profile to convince our hypothesis.
96 - Diastereoselective Preparation of Chiral Amino
Sulfoxides Through Sulfenate Chemistry
Priya Pal1, Adrian Schwan1, Erwin Remigio1
1University of Guelph
The oxidation of sulfides play an important role in organic chemistry since sulfones and
sulfoxides are found in many natural, pharmaceutical, and agricultural compounds.1
Sulfenate anions are the conjugate base of sulfenic acids and are synthesized in situ as
a reactive intermediate.2 The prochiral nature of the sulfenate allows for the investigation
of stereoselective alkylation reactivity of aryl and alkyl sulfenates.
The S-alkylation of the sulfenate anion leads to a chiral sulfoxide that can induce chirality
in other reactions.3 Such chiral sulfoxides provide assistance in asymmetric synthesis
and chiral drug synthesis. Asymmetric synthesis reactions have chiral elements that are
formed, which produces unequal amounts of diastereomeric products. This type of
selectivity is profoundly important in chemical and pharmaceutical industries and chiral
sulfur compounds can be used in the production of amino acids.4 In this study,
sulfenates are generated to create chiral sulfoxides using coordinating N-groups. The R
group used in my synthesis was anthracene and the N-group electrophile used was (S)-
N-Boc-2-amino-3-phenylpropyl iodide. The synthesis investigated was derived from
previous work performed by the Schwan group with chiral sulfoxides. The goal of
increased yields and diastereoselectivity was pursued.
1. Fukuda, N.; Ikemoto, T. J. Org. Chem. 2010, 75, 4629–4631.
2. Singh, S. P.; O’Donnell, J. S.; Schwan, A. L. Org. Biomol. Chem. 2010, 8, 1712–1717.
3. Söderman, S. C.; Schwan, A. L. J. Org. Chem. 2013, 78, 1638–1649.
4. Matsui, T.; Dekishima, Y.; Ueda, M. Appl. Microbiol. Biotechnol. 2014, 98, 7699–7706.
97 - Liquid Chromatography- Tandem Mass
Spectroscopy Method Validation and Analysis of
Trichothecenes in Agriculturally Relevant Wheat
Samples
Emily Maloney1,2
1Agriculture and Agri-Foods Canada, 2University of Western Ontario
An efficient method for regulation was developed to monitor the mycotoxins produced by
Fusarium graminearum. The variable geographical factors and the inherent risk to
human and animal health warrants the need for a simple, quantitative method for
regulation purposes.
Previous attempts at complete separation were unsuccessful due to the structural and
behavioural similarities of the trichothecene family. The newly determined HPLC-MS/MS
method monitors the presence and quantities of deoxynivalenol, 3-acetyldeoxynivalenol,
15acetyldeoxynivalenol, deoxynivalenol-B-glucoside, NX-2, NX-3, Sambuconal, Aflatoxin
G1, Aflatoxin B1, Diacetoxyscop, OTA, Xearleone and Sterigmatocystin.
Chromatographic multi-separation was achieved using Agilent C18 Eclipse 2.1x100mm
solid phase and acetonitrile with 0.1% formic acid and water mobile phases. With
specific focus on DON, 15-ADON, 3-ADON and the NX toxins a standardized sample
preparation method was used with five commercially available grain including durum,
whole wheat, red wheat, 12 grain and whole wheat flour. Method accuracy was verified
by analyzing certified reference material and resulted in levels higher than allowed by
Canadian regulations.
98 - Characterization of a unusual transcription factor in
the protist, Giardia intestinalis
Jessica Chorolovski1, Ally Yang2, Timothy Hughes2, Janet Yee1
1Biochemistry and Molecular Biology Program, Trent University, 2Department of
Molecular Genetics, University of Toronto
The TATA-binding protein (TBP) is one of the most studied eukaryotic transcription
factors due to its importance in the transcription by all three RNA polymerases. The
TBP in Giardia intestinalis, a common protozoan contaminant of freshwater, is one of the
most divergent of the TBPs known to date. The Giardia TBP has substitutions in 3 out of
4 critical phenylalanine residues that contribute to the "kink" induced in the DNA
sequence when TBP binds to the TATA-box in other eukaryotes. Moreover, canonical
TATA-boxes with a consensus sequence TATA(A/T)A(A/T)(A/G) appear to be absent in
the majority of Giardia gene promoters. These observations led us to question the DNA-
binding specificity of the Giardia TBP (gTBP) and its role in transcription
regulation. Previous studies in our laboratory showed that gTBP does not bind TATA or
TATA-like sequences but binds selectively to only a few of the Giardia gene promoters
that were tested. To further explore the DNA sequence recognized by gTBP, I used a
high throughput method where the binding preference of gTBP is examined for all
possible 8 nucleotide DNA sequences. Intriguingly, a sequence motif consisting of
AGGGGC was identified to be the highest ranked recognition sequence from this
analysis. The verification of this result and its significance will be discussed.
99 - Synthesis of Novel Benzosiloles as
Electrochemiluminescent chromophores
Donghyun Koo1, Tyler Day1, Brian Pagenkopf1
1University of Western Ontario
Thienyl appended siloles are excellent and novel materials for chemosensors, electro-
current chromophores and light emitting diode applications. Siloles with thienyl
substituents at C2 and C5 show enhanced the luminescence properties.
Benzosiloles, as aryl fused silole derivatives, are alternative molecules which are more
readily synthesized. A recent preparation of benzosiloles developed by the Chatani
group using the rhodium catalyst ([RhCl(cod)]2), combined with the Pagenkopf group's
knowledge of thienyl-siloles, new thienyl-benzosiloles has been designed and
synthesized. The synthesis employs the cycloaddition of 2-silylphenylborates and
thienyl-acetylenes catalyzed by a well-defined rhodium catalyst. Novel thienyl-
benzosiloles with different thiophene chain lenghts have been synthesized, and their
electrogenerated chemiluminescence (ECL) is being investigated.
100 - Synthesis and characterization of high-swelling
hydrogels of Polyacrylamide and Polyvinylpyrrolidone
cross-linked with N-methylenebisacrylamide
Celia Ferrag1, Svetlana Mikhaylichenko1, Kagan Kerman1
1University of Toronto
High swelling hydrogel polymers are three-dimensional networks of cross-linked
polymeric chains. They have the capacity to swell and de-swell extensively due to the
presence of the hydrophilic functional groups attached to their backbone. The chemical
and physical properties of these hydrogels allow them to have various applications in
biotechnology, tissue engineering, biosensors, consumers products such as diapers,
hemostasis bandages and drug delivery systems. The purpose of this study is to
synthesize and characterize a new co-polymer polyvinylpyrrolidone (PVP) cross-linked
with N-methlyenebisacrylamide and also a known co-polymer of acrylamide and N-
methlyenebisacrylamide (PAA). A novel radical polymerization system, which involves
only using a potassium persulfate initiator as well as combining it with a redox system,
was used to synthesize both co-polymers. In this study, we also investigated the swelling
properties of the hydrogels as well as their ability in trapping and releasing molecules in
a controlled manner to provide a method of molecule transport and potentially a drug
delivery system. The drug model used to quantitatively determine the release of a target
molecule from PAA and PVP was curcumin. The release of curcumin was detected and
measured using two types of methods: UV-Vis spectrometry as well as an
electrochemical detection approach, which allowed for a lower detection limit. Both
detection methods successfully showed the release of curcumin from the PAA hydrogels
which can be controlled by varying the concentrations of the cross-linker. Furthermore,
a rheological analysis was done to systematically confirm the gel-like behavior of the
polymers as well as their reusability.
101 - Photoactivation of Inhibitors of Anti-Cancer
Therapy
Reta Bodagh1, Andrew Beharry1
1University of Toronto
Over-expression of the DNA repair enzyme O6-methylguanine-DNA methyltransferase
(MGMT) diminishes the effects of the anti-cancer alkylating agent, temozolomide (TMZ).
By employing inhibitors of MGMT, such as O6-benzylguanine or PaTrin-2, the
therapeutic effects of TMZ have been shown to substantially increase. However, MGMT
inhibitors are not cancer selective and as a result, MGMT is inhibited in all cells leading
to normal cell toxicity. To this regard, we are modifying MGMT inhibitors with
photoremovable protecting groups such that they are inactive against MGMT in the dark.
By confining light irradiation to cancer cells only, the inhibitors are expected to activate
and inhibit MGMT, thereby increasing the effects of TMZ with reduced toxicity to normal
cells. Using fluorescence-based MGMT activity assays, we have established that caging
these inhibitors diminishes their inhibitory effect on MGMT. The synthesis, purification,
and characterization of these caged inhibitors will be described in this presentation.
102 - Determination of Phosphonium Salt Dissociation
Constants
Rabinththan Ravichandran1, Benjamin Hisey1, Paul J. Ragogna1, James A. Wisner1
1University of Western Ontario
Ionic liquids are a class of salts where the salt is observed as a liquid at room
temperature and have melting points lower than that of water. This allows them to be
used in a wide array of applications such as green solvents, as separation agents, and
electrolytes. This project focuses on phosphonium ionic liquids which are a class of
compounds composed of a phosphorus atom at the (V) oxidation state with 4
substituents bound to it as well a counter anion. What has not been determined for these
compounds is the dissociation constant. A dissociation constant describes the
equilibrium of a molecule splitting into its component ions when placed in a solvent.
NMR spectroscopy was used to determine the dissociation constant of different
phosphonium salts that were synthesized for this analysis. The cation that was used was
tributyl-(4-vinylbenzyl)phosphonium and the anions that were used were chloride,
bromide, triflate, tetraphenylborate, bistriflimide, nitrate, and tetrafluoroborate. The
titration was performed by varying the concentration in a window of 0.1 Mm to 0.1M and
then fitting the data into a quadratic equation describing the equilibrium. Origin data
software was used to preform non-linear regression on the data and the dissociation
constants for the chloride, bromide, nitrate, tetraphenylborate and tetrafluoroborate salts
were determined to be 979.7 ± 85.4 M, 57.4 ± 11.1 M, 123.5 ± 33.2 M, 14.7 ± 2.5 M and
46.9 ± 14.9 M respectively.
103 - Synthesis of New Reactive BODIPY Dyes and their
Applications in Solar Cells
Fiona Jeeva1, Svetlana Mikhaylichenko1, Maryam Abdinejad1
1Department of Physical and Environmental Sciences, University of Toronto
Scarborough, 1295 Military Trail, Toronto, M1C 1A4, ON, Canada
Dye-sensitized solar cells (DSSCs) are third generation solar cells gaining in popularity
due to high efficiency relative to their low cost. Traditionally, ruthenium based dyes were
used to as sensitizers; however due to expense and limited resources, research into
organic based dyes have grown substantially in interest. The goal of this project is
synthesis of a novel 4,4-difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY) based
compound conjugated with a triphenylamine derivative for potential use as a dye
sensitizer for DSSCs. The two compounds, 8-phenyl-BODIPY and 4,4’-
dimethoxytriphenylamine (TPA-(OMe)2) were successfully synthesized using a one-pot
reaction with reagents pyrrole and benzaldehyde and an Ullmann type reaction,
respectively. Both products were brominated, with subsequent borylation of the
brominated TPA(OMe)2 in preparation for the Suzuki-Miyaura coupling reaction to obtain
the final product. From UV-Vis analysis, approximately 130 nm bathochromic shift was
observed of the TPA-(OMe)2 when compared to the UV-Vis spectra of triphenylamine
obtained from governmental sources. 15 nm bathochromic shift was shown for the 8-
phenyl-BODIPY with a bromine atom substituted at the b-position. Due to much higher
conjugation and electron donating ability of TPA-(OMe)2, significant bathochromic shift –
indicative of higher DSSC efficiency – is expected of the final product due to the
presence of the additional electron donating groups.
105 - Synthesis of Thermo-responsive and Self-
immolative Polymers from Poly(ethyl glyoxylate)
Kyle Classen1
1University of Western Ontario
Stimuli-responsive polymers are interesting materials as they demonstrate different
physical or chemical properties upon exposure to stimuli such as light[1], heat[2], and
acid[3]. Recently, self-immolative polymers (SIPs), a novel class of stimuli-responsive
polymers, have attracted great attention as they undergo depolymerization via an end-
to-end mechanism, initiated by a single bond cleavage at the polymer terminus.[4,5,6] The
Gillies group has developed self-immolative poly(ethyl glyoxlyate)s (PEtGs) that degrade
to potentially non-toxic products, making them of interest for biological applications.[7]
Furthermore, the reactivity of the pendant ester groups of PEtG allows for post-
polymerization modification. It was found by J.F. Lutz that poly[oligo(ethylene glycol)
methacrylates] exhibit thermo-responsive behavior, so by analogy we envisioned that
PEtGs decorated with poly(ethylene glycol) (PEG) side chains would
demonstrate similar thermo-responsive behavior.[8] In this regard, we synthesized
various PEG amines and reacted them with PEtGs under mild conditions to produce
several unprecedented biodegradable SIPs in good yields. These materials were fully
characterized using methods including FT-IR and 1H NMR spectroscopy, gel permeation
chromatography, differential scanning calorimetry, and thermogravimetric analysis. Their
thermo-responsive behavior was studied via cloud point measurements. In this talk, the
synthesis, characterization, and thermo-responsive behavior of these polymers will be
discussed.
106 - The Effect of Oxygen and Nitrite on the Corrosion
of Copper under Nuclear Waste Disposal Conditions
Maryam Mohammad1,2, Joseph Turnbull1,2, David Shoesmith3, Ryan Szukalo3, Mehran
Behazin2, Dmitrij Zagidulin3, Sridhar Ramamurthy9, Clara Wren3
1The University of Western Ontario, 2NWMO, 3The University of Western Ontario, 4NWMO, 5The University of Western Ontario, 6The University of Western Ontario, 7NWMO, 8The University of Western Ontario, 9Surface Science Western, 10The University
of Western Ontario
Nuclear power generation has been a consistent source of energy in Canada for over 40
years, and a permanent method of disposal for used nuclear fuel is being extensively
investigated. Canada's lond-term disposal plan is emplacement of used nuclear fuel
sealed in a copper coated steel container in a deep geological repository (DGR).
Conditions in a DGR following closure are expected to evolve from a hot, aerated humid
environment to a cool, fully anoxic condition. During the aerated humid phase,
HNO3 produced by the radiolysis of the humid air can deliquesce on the copper
container surface. In this project the processes by which HNO3 could corrode the copper
are being investigated using a combination of electrochemical and surface analytical
techniques. The key oxidants under investigation are dissolved O2, HNO3, and nitrous
acid (HNO2), the latter is a product expected to form upon oxidation of Cu by HNO3.
These oxidants appear to react cooperatively on the Cu with the initial production of
Cu+ being important in the overall corrosion process. Cyclic voltammetry technique was
used to investigate the kinetics of reduction of these species and how they interact.
Chloride is one of the anions expected to be dominant in the groundwater composition,
hence series of experiments were designed to explore the effect of chloride. This anion
is known to complex Cu+ as CuClx(1-x)+ and appears to have an influence on the overall
corrosion process.
107 - Synthesis of the KRN 7000 Glycosphingolipid
Acetal Free Analogue
Michael Qaqish1, Michael Reynolds1, John F. Trant1
1University of Windsor, Department of Biochem
Synthesis of the KRN 7000 Glycosphingolipid Acetal Free Analogue: Michael Qaqish,
Michael Reynolds, John F. Trant
Carbohydrates fulfill many roles in biological systems including (but not limited to): acting
as cellular structural supports, mediating cell signaling and acting as an energy supply.
They can also act as “superantigens” for the immune system when part of certain fat
molecules called glycosphingolipids. These molecules are able to activate invariant
Natural Killer T-Cells (iNKT cells); white blood cells that mount a dangerous, non-specific
systemic immune response potentially leading to cell death. However, this same immune
response (if controlled), has promise to act as a last line antiviral and/or a potential
anticancer agent by potentially turning the immune system against a previously ignored
virus, infection or tumour. The identification and synthesis of such immunoactive agents
for clinical and mechanistic applications is of great interest in carbohydrate immunology.
KRN7000 is of particular interest. It was first isolated from a marine sponge and is the
most potent activator of iNKT cells. However, if almost any part of the molecule is
modified, all biological activity is lost. One of the few exceptions is that the
enzymatically-sensitive bond attaching the sugar to the lipid can be replaced with a
stable carbon linkage. However, the synthesis is too long to be commercially useful. We
wish to discuss our approach towards this molecule that attempts to streamline the
approach by very subtly modifying KRN7000 in a new way. The synthesis, and its
implications for biological activity, will be discussed.
109 - Cyclization and Characterization of cis-1-alkenyl β-
aminoalkyl sulfoxides
Scott Sammons1, Adrian Schwan1
1University of Guelph
ABSTRACT: Stereoselective cyclization of 1-alkenyl β-aminoalkyl sulfoxides and
sulfones holds significance in the synthesis of biochemically active heterocycles.1
Cycloalliin (1) possesses inherent antioxidant and anticancer properties, while 3,5-
disubstituted 1,4-thiazane S-oxide (2) has antibiotic activity.2,3,4 Conversion of 3,5-
disubstituted 1,4-thiazane dioxides to 2,5-disubstituted pyrrolidines (3), known as ant
venom alkaloids, show value in the development of new therapeutic drugs.5 Preceding
endeavors by Söderman and Schwan have led to the thorough characterization of the
stereochemical cyclization of trans-1-alkenyl β-aminoalkyl sulfoxides and sulfones, as
well as the direct conversion of the heterocyclic products to the 2,5-disubstituted
pyrrolidine ant venom alkaloids. Comprehensive characterization of the trans isomer
provides incentive for the determination of the stereochemical cyclization patterns of cis-
1-alkenyl β-aminoalkyl sulfoxides, as the mechanism of cyclization remains currently
unknown. The synthesis of cis-1-alkenyl β-aminoalkyl sulfoxides is to be initiated with L-
phenylalanine starting material, with optimism that the stereochemical patterns will be
determined upon cyclizing the cis isomer. A thiocyanate SN2 attack on the iodinated Boc-
protected β-amino product of the Lange reaction shows promise in accessing the
stereospecific cis isomer desired. An alternate synthetic pathway can be employed,
initiated with a terminal alkyne starting material and utilizing tantalum pentachloride as a
reagent for the reduction of an alkynylsulfide to a cis-alkenylsulfide. The synthesis and
characterization of the cis alkenyl sulfoxide isomer and efforts towards an optimized,
alternative synthetic route will be presented.
110 - Synthesis and characterization of immunologically
active glycolipids isolated from S. pneumoniae
Peter Bahnam1, Greg Yousif2, Emmanuel Igbokwe2, Iraj Sadraei3, John F. Trant4
1Presenter, 2Research Mentors, 3PhD Graduate Student Mentor, 4Research Supervisor
Carbohydrates can act as superantigens for the immune system when they are
conjugated to certain fat molecules as glycolipids. A specific subset of glycolipids can
activate invariant Natural Killer T-cells (iNKT cells) – white blood cells that mediate a
dangerous non-specific systemic immune response that can potentially lead to death.
However, if this same immune response is controlled it has promise to act as a last line
antiviral and/or a potential anticancer agent by potentially turning the immune system
against previously ignored virus-infected or tumour cells. These iNKT cells are found in
all mammals. This is unusual as immune systems normally differ completely between
two individuals, let alone different species. Until recently, the only known activators had
been isolated from sea sponges found off the coast of Japan. However, a few years ago,
two molecules were isolated from dangerous bacteria, Streptococcus pneumoniae, that
can activate this system. The Trant Team is carrying out the first synthesis of these two
compounds; both have biological activity and bypass the non-polar lipid bilayer in the
cells of the tissue they target. The isolated compounds may or may not have been
contaminated, and their structure may be not be correct: we are making these materials
so we can confirm both the actual structure of these materials, and that the observed
biological activity is due to these compounds. Our more efficient synthesis, the
nanoparticle self-assembly behaviour of these materials, and possibly the preliminary
immunological results obtained by our collaborators (Haeryfar group) will be presented.
111 - Domino Palladium–Hydride Insertion/C–H Bond
Activation: Cycloisomerization of 1,6-Diynes
Jose Rodriguez1, Ivan Franzoni2, Katherine Burton3, Amalia Poblador-Bahamonde4,
Mark Lautens5
1University of Toronto, 2University of Toronto, 3University of Toronto, 4University of
Geneva, 5University of Toronto
The use of C-H bond activation has become progressively relevant in the synthesis of
complex organic molecules. This strategy circumvents the need for prefunctionalization
of starting materials, while simultaneously expanding the number of possible synthetic
disconnections. Our work involves application of ammonium halide salts as practical
hydride donors for a novel Pd-catalyzed cycloisomerization of 1,6-diynes. This route
proceeds via a domino reaction, undergoing addition of a Pd-hydride species across a
π-system, followed by intramolecular Mizoroki-Heck reaction, and subsequent C-H bond
functionalization. Experimental data suggests an outer-sphere-type C-H bond activation,
allowing access to formerly unexplored silylated 2-azafluorene derivatives. Several
functional groups were tolerated, and further derivatizations were performed on products
to validate their synthetic utility.
112 - Can Molecular Simulations Help Understand
Alzheimer's Disease?
Xinyu (Linda) Ye1
1Western University
Alzheimer’s disease is one of the leading causes of senile dementia in the elderly; the
formation of extracellular amyloid plaques in neuronal membranes is a hallmark of the
disease. Despite this, the underlying mechanism of toxicity of the amyloid plaques
remain unknown. Previously published work used molecular dynamic (MD) simulations
to observe changes in biological membranes, upon insertion of Ab40 peptides. The
study observed membrane curvature upon Ab40 aggregation, and proposed the Theory
of Frustrated Helices. It stated that the twisted “frustrated” structure of Ab40 favored
curvature of the membrane. This study is a continuation of the previous study, and aims
to use MD simulations to gain insight into the various interactions and perturbations of
Ab40, to understand the mechanism in which the peptides exert its toxicity. The
hydrogen bonding interactions, order parameters, membrane thickness and area per
lipid were investigated in this study.
113 - Optimal Control of Frequency-Swept Pulses for the
Acquisition of Ultra-Wideline Solid-State NMR Spectra
Adam Altenhof1, Austin W. Lindquist1, Lucas D.D. Foster1, Sean T. Holmes1, Robert W.
Schurko1
1University of Windsor
Solid-state NMR (SSNMR) spectra often feature broad patterns, which range from
hundreds of kHz to several MHz in breadth; those that exceed ca. 250 kHz are
considered ultra-wideline NMR (UWNMR) patterns. Since high-power rectangular pulses
are insufficient for the excitation of UWNMR patterns, special techniques must be used
for their acquisition.[1] Frequency-swept (FS) pulses are utilized for broadband excitation
and refocusing, and are therefore useful in the acquisition of UWNMR spectra.[1] In
particular, Wideband Uniform Rate Smooth Truncation (WURST) pulses have been used
for acquiring UWNMR spectra of both spin-1/2 and quadrupolar nuclides; however,
these pulses have limitations in terms of their excitation bandwidths and ability to
produce distortion-free spectra.[2] We explore two new facets of pulses used in
UWNMR: (i) the use of other FS pulses such as hyperbolic secant (HS) and tanh/tan
(THT) for broadband excitation and refocusing, and (ii) the design of new broadband
pulses via the use of optimal control theory (OCT).[3] In the first case, HS and THT
pulses were tested on spin-1/2 and quadrupolar nuclides, and the results are compared
to those obtained from WURST pulses. In the second case, new OCT Optimized
Broadband Excitation and Refocusing (OCTOBER) pulses, are generated from WURST,
HS, and THT pulses as starting points using OCT.[4]
(1) Schurko, R. W. Acc. Chem. Res. 2013, 46, 1985.
(2) O’Dell, L. et al. Chem. Phys. Lett. 2008, 464, 97.
(3) Garwood, M. et al. J. Magn. Reson. 2001, 155-177.
(4) Tosner, Z. et al. J. Magn. Reson. 2009, 197, 120.
114 - Using Variable Temperature NMR to Examine the
Structure and Stability of Immature Human SOD1
Jeffrey Palumbo1
1University of Waterloo
Amyotrophic lateral sclerosis (ALS) is an adult onset neurodegenerative disease that
can be inherited or arise sporadically, and is associated with protein misfolding. Patients
with hereditary, or familial, ALS commonly develop the disease because of a toxic gain
in function arising from mutations in copper, zinc superoxide dismutase (SOD1). These
mutations generally promote misfolding and aggregation of SOD1 protein, which is
thought to be toxic.
SOD1 undergoes several post-translational modifications during its maturation. These
modifications include the binding of zinc and copper, formation of an intrasubunit
disulphide bond, and dimerization. Generally, immature states are more likely to
aggregate than mature SOD1. In this project, the structural stability of disulphide
reduced, one-zinc bound (E,Zn2SH) dimeric SOD1 has been studied and compared to
disulphide-reduced unmetallated monomeric SOD1 (apo2SH) using variable
temperature NMR experiments. These variable temperature experiments yield amide
proton temperature coefficients, which report on local stability. The stability of the
E,Zn2SH SOD1 is of particular interest for understanding how this little studied
maturation state interacts with the copper chaperone for SOD1, and how its maturation
is impacted by ALS mutations.
The NMR analysis reveals that while there is an overall increase in stability, localized
near the zinc binding site, there is concurrent destabilization of the SOD1 dimer interface
to promote its dissociation and enhance binding to the copper chaperone.
115 - Fluorescent integrated stapled ghrelin(1-20)
analogues for the targeting of GHSR-1a in cancer
Geran B. Tu1, Tyler Lalonde1, Kelvin Tsao2, Jeffrey W. Keillor2, Leonard G. Luyt1,3
1University of Western Ontario, 2University of Ottawa, 3Lawson Health Research Institute
The growth hormone secretagogue receptor type 1a (GHSR-1a) is upregulated in a
variety of cancers which makes it a target of interest for the early detection of
tumors. GHSR-1a can be targeted by modifying the receptor’s endogenous ligand,
ghrelin, to improve binding affinity. Attaching a fluorophore to these ghrelin analogues
allows them to be used as in vitro imaging agents. To reduce the cost of synthesis for
the ghrelin analogues, ghrelin is truncated from 28 amino acids to a shorter
length. However, truncation destabilizes the α-helical secondary structure of ghrelin
which is necessary for binding to GHSR-1a. A fluorescent dye-integrated staple was
reacted with Cys residues on the peptide in the 12th and 16th positions (i, i+4) or the 8th
and 15th positions (i, i+7) with the goal of re-establishing α-helicity and improving binding
affinity to GHSR-1a. The stapled peptides were compared to their unstapled straight-
chain forms, but the cysteine residues were replaced with the bioisostere serine due to
cysteine’s tendency to form disulfide bonds. Circular dichroism (CD) spectroscopy and
fluorimetry were performed on the i, i+7 variant. Based on the CD spectra, serine
versions of both peptides were non-helical and the i, i+7 stapled variant was also non-
helical. The i, i+7 variant had λex=440 nm and λem=485 nm which makes it ideal for use
in fluorescence microscopy. The i, i+4 variant has been synthesized and will be
evaluated in the future. This is the first demonstration of an integrated fluorescent staple
being used to cyclize a ghrelin analogue.
117 - Temporal and Spatial Expression of Giardia
intestinalis Flavohemoglobin
Rubab Fatima1
1Trent University
Giardia intestinalis is a parasitic protist that causes giardiasis, an infection of the small
intestine resulting in diarrhea, nausea, and abdominal cramps. Nitric oxide (NO) is a
toxic free radical generated by the host’s immune system that causes cytotoxicity to
Giardia cells. Giardia encodes several heme proteins, one of which is flavohemoglobin
(gFlHb); flavohemoglobins are nitric oxide dioxygenases used by bacteria to detoxify NO
radicals but are rarely found in eukaryotic organisms. It is likely that Giardia expresses
gFlHb,to counter host-derived nitrosative stress.
In this research, an antibody against gFlHb was used in western blotting and
immunofluoresce microscopy experiments to study the time course of gFlHb expression
in response to nitrosative stress, as well as the spatial localization of gFlHb within the
Giardia trophozoite. Axenic cultures of Giardia trophozoites were exposed to nitrosative
stress using NONOates, a class of compounds that release NO with predictable release
kinetics. Separate time course experiments were run with each of the following
compounds at 0.1 mM concentration: propylamine propylamine NONOate, t1/2 =15
minutes; dipropylenetriamine NONOate, t1/2 =3 hours; diethylenetriamine NONOate,
t1/2 =24 hours. Three time points of treated cells, along with untreated controls, were
then analyzed for each NONOate experiment using westerns blots and
immunofluorescence microscopy to study the temporal and spatial expression of gFlHb,
respectively. Time course experiments showed that the expression of gFlHb is
upregulated in response to nitrosative stress. The localization of gFlHb within Giardia
trophozoites is diffuse throughout the cytoplasm and is not altered with exposure to
nitrosative stress.
118 - Reactivity and Tuning of a Pentanuclear Nickel
Carbide Cluster
Galen Suh1, Manar Shoshani1, Sam Johnson1
1University of Windsor
The activation and cleavage of strong bonds, such as sp3 C-C bonds and C-H bonds ,is
a challenging, lucrative and important field in chemistry. This is due to the vast
importance of C-C and C-H bond activation across many fields, from pharmaceutical to
petrochemical. Transition metals have seen use in recent years as catalysts for bond
functionalization. This allows reactions involving these difficult functionalizations to be
sustainable and practical. However, what are currently the most efficient choices of late
transition metal catalysts must be improved drastically before they can be used. A
compound discovered in recent years by the Sam Johnson Research Group at the
University of Windsor, a pentanuclear nickel carbide cluster of the form Ni5(iPr3P)5H4C,
shows promising reactivity using an uncommonly studied metal, nickel, which possesses
greatly untapped potential. Thanks to its’ central carbide, the cluster is suspected to
possess greatly increased stability for use in reactions. Using nuclear-magnetic
resonance spectroscopy (NMR), the compound was discovered to perform uniquely
selective reactions with fluorinated aromatics, and through x-ray diffraction
crystallography, two additional modified versions of the cluster were discovered
suggesting its’ potential to be a tunable reagent which can be adapted to specific
reactions. Through further NMR kinetics studies, X-ray diffractometer crystallography
and elemental analysis, the potential for the compound to be a catalyst is to be explored
further in this project.
119 - Progress Toward the Formal Synthesis of
Chanoclavine I
Benjamin Bridge1
1University of Western Ontario
Chanoclavine I (4, Scheme 1) is a naturally occurring alkaloid found primarily in
claviceps fungi.1 Many of these alkaloids exhibit biological activity, with effects including
constriction of blood vessels and hallucinations.2 As such, these compounds have
garnered the attention of medicinal and synthetic chemists for their unique scaffolds and
bioactive properties. Here-in we discuss strategies toward a formal synthesis of
chanoclavine I from a novel donor-acceptor (DA) cyclopropane (1). Treatment of the DA
cyclopropane with nucleophilic N-methylhydroxylamine results in the formation of an
intermediate nitrone (2). Upon heating, 2 undergoes a [3+2] nitrone-olefin cycloaddition
to form 3, containing the tricyclic structure of chanoclavine I.
[1] Liu, H.; Jia, Y. Nat. Prod. Rep. 2017, 34, 411-432.
[2] Krska, R.; Crews, C. Food Additives and Contaminants. 2008, 25, 722-731.
121 - Corrective method for density-functional
calculations of hyperfine coupling constants
Jenée Joseph1, Viktor Staroverov1
1University of Western Ontario
Density functional theory is extensively used to predict many molecular properties
including the isotropic hyperfine Fermi coupling term. This term is underestimated by the
local density approximation; but generalized gradient approximations (GGAs) perform
better but still produce errors. We investigated the hypothesis that these errors arise in
part as a result of singular nature of GGA exchange-correlation potentials at the nucleus,
where the potential behaves as -c/r, where c is a functional and nucleus-dependent
constant. This affects the spin density at the nucleus and ultimately the Fermi coupling
term. A method to eliminate the singularity is presented by the graphical determination of
the constant. This constant is then added to the nuclear charge of the corresponding
nucleus in order to correct for the singularity. Although the constant could be accurately
determined, there was no significant change in the coupling term. Thus, the singular
behaviour of GGA potentials at atomic nuclei is not a serious defect as far as prediction
of Fermi coupling terms is concerned.
122 - Synthetic Approach to Produce a C-glycoside Tn
Antigen
Advait Desai1, John F. Trant1, Iraj Sadraei1
1University of Windsor
Many biological processes including bacterial and viral infections (notably HIV and the
flu), immunogenic responses, and cancer pathogenesis/metastasis are mediated by
carbohydrate interactions. An example of such a carbohydrate is the Tn antigen. The Tn
antigen is particularly interesting as it shows up in a large number of different cancer
cells including: gastric, colon, breast, lung, esophageal, prostate, and endometrial
cancer. If the immune system could be trained to target this molecule, then the immune
system could be used to help cure cancer. A key drawback to using this method is the
inherent low in vivo half-lives of carbohydrate containing materials. This Trant Team
project aims to remove the unstable acetal functionality of the Tn antigen by replacing
the exocyclic anomeric oxygen with a methylene (C-glycoside) to make new acetal-free
C-glycoside analogues of the Tn antigen. Removing the labile functionality should result
in greatly enhanced lifetime, and bioavailability relative to the native system with no loss
of activity as the exocyclic oxygen is not involved in the vast majority of molecular
recognition events. This molecule is being made by total synthesis for its incorporation
into new anti-cancer vaccines.
124 - Enzyme Encapsulation and Immobolization of
Deoxyribonuclease 1
Graham Reid1, Steven Rafferty1, Andrew Vreugdenhi1
1Trent University
Abstract:
Enzyme encapsulation is a method of enzyme immobilization that involves
surrounding or enclosing an enzyme in a liposomal vesicle, polymer, sol-gel or other
host material. The purpose of encapsulation is to enhance enzyme stability by
preserving native enzyme structures, activities, and minimizing enzymatic degradation
(1). For this study, encapsulation was paired with another immobilization technique
referred to as cross-linking, which uses a bifunctional reagent to prepare enzyme
aggregates. Formation of these aggregates is beneficial as they lead to areas of highly
concentrated enzyme activity along with high stability and low productions costs (2). In
this work we have used encapsulation and cross-linking in tandem to create a highly
concentrated and protected enzymatic material. We have encapsulated the enzyme
Deoxyribonuclease I, into Santa Barbara Amorphous silica gel (SBA-15). Key
parameters for enzyme encapsulation are maintenance of enzyme activity, enzyme
loading efficiency and reduction of enzyme leaching. The utility of the hosted enzyme
material has been evaluated in terms of its ability to digest double stranded DNA under a
variety of unfavourable conditions.
References:
1)Betancor, L. Luckarift, H.R. 2008. Bioinspired enzyme encapsulation for biocatalysis.
Trends in Biochemistry. Cell Press. 26;10, pp. 566-572
2)Cao,L. van Langen, L. Sheldon, R. 2003. Immobilized enzymes: carrier-bound or
carrier-free?. Current Opinion in Biotechnology. ELSEVIER. 14;4, pp. 387-394
125 - Expanding the Role of CO2 Surrogates in Organic
Synthesis
Timothy Hurst1, Julie Deichert1, Lucas Kapeniak1, Jesse Harris1, Roland Lee2, Philip
Jessop1, Victor Snieckus1
1Queen's University, 2MacEwan University
CO2 is an important building block in organic synthesis and is the basis of the Kolbe-
Schmitt reaction for the commercial production of Aspirin. We will report on the use of
sodium methyl carbonate (SMC) as a surrogate CO2 electrophile in classical
organometallic reactions. Under ambient conditions, SMC is a white solid and can be
used to circumvent the use of excess gaseous or solid CO2. The reactions of SMC with
Grignard and organolithium reagents provide new and general methods for the synthesis
of alkyl, aryl, and alkynyl acids and symmetrical benzophenone derivatives, respectively.
A one-pot procedure for the preparation of unsymmetrical benzo- and aceto-phenones
will be presented as well.
126 - Examining the Effects of Oxidative Damage on
Protein Stability
Drishti Kataria1, Lars Konermann1
1University of Western Ontario
Oxidative damage to proteins is closely linked to aging and aging-related diseases.
Oxidation can change the protein structure and net charge, affecting sterics and
electrostatics. In this work we explored the use of electrospray mass spectrometry
techniques to probe oxidation-induced changes in the structure and stability of the model
protein hemoglobin. Specifically, we conducted collision-induced dissociation
experiments. We found that chloramine-T oxidizes methionine residues in the α and β
subunits of hemoglobin. The mass spectra showed that the β subunit is more oxidized
than the α subunit due to its larger number of methionine residues (3 vs. 1). We initially
expected that oxidative damage would have negative effects on protein structural
stability and cause the oxidized hemoglobin to dissociate more readily in the gas phase
compared to the non-oxidized controls. Surprisingly, it was found that oxidized
hemoglobin is less susceptible to dissociation. We tentatively ascribe this behavior to
stabilizing electrostatic effects mediated by newly formed methionine sulfoxide sites.
Further experiments using ion mobility techniques will provide more insights into the
effects of oxidation on the structural stability of hemoglobin.
127 - Naphthalene Dithioimides: Analysis of Steric
Barriers to Thionation
Sarah Mathers1, Paniz Pahlavanlu1, Dwight S. Seferos1
1University of Toronto
Thionated naphthalene diimides (NDIs) have become an area of active research due
to their potential as n-type organic semiconductor materials. We have previously shown
that the selective dithionation of NDIs can be achieved through the use of sterically bulky
imide substituents and core-flanking groups. We have also noted the decreased
solubility of these compounds upon increased thionation, which has implications not only
for their ability to be studied but also their environmental impact and processing safety.
This project set out to synthesize an NDI with 12-unit polyethylene glycol (PEG) imide
substituents in order to afford increased solubility to the thionated analogues. The need
for core substituents was also investigated using an un-core substituted NDI with 2-
octyldodecyl imide substituents, and it was found that the core substituents were
necessary for microwave thionation. Therefore, we focused on the synthesis of a
bromine core-flanked NDI with mPEG12 imide substituents. From there, we further
investigated the effect of the core and imide substituents in a computational investigation
using steric maps and buried volume calculations to quantify the extent of steric bulk
around thionation sites, in comparison to the size of common thionation reagents. A
variety of different imide substituents and core flanking groups have been analyzed to
determine the minimum steric hindrance necessary to effectively block thionation of a
given carbonyl.
129 - Near-field infrared spectroscopic properties of
boron nitride nanotubes upon polymer binding
Ruben Mirzoyan1, Gilbert Walker1
1University of Toronto
Boron nitride nanotubes (BNNTs) are inorganic materials with a large bandgap and
interesting optical properties. Under certain frequencies of light in the mid-infrared,
photons couple to the vibrations of the polar lattice to generate surface phonon
polaritons (PhPs), waves that confine energy at the nanotube surface and allow long
distance propagation with low loss. This phenomenon is desirable for sensing and
nanocircuitry applications. Recently, it has been shown that a conducting polymer, poly-
(3-hexylthiophene) (P3HT) interacts strongly with BNNTs and sorts them from reaction
mixtures containing hexagonal boron nitride. The nature of the polymer binding
interaction is not understood, though it is valuable from a practical perspective. Using
scattering-type scanning near-field optical microscopy (s-SNOM), a near-field infrared
spectrum of a single boron nitride nanotube is obtained both with and without the
presence of an interacting polymer. The imaging capabilities enable the discrimination
between the polymer and nanotube, allowing visualization of how the two entities
interact. Furthermore, the possibility of altered PhP propagation due to interaction with
the conducting polymer is considered.
132 - Synthesis of sugar-derived aryl ethers
Jacklyn Liu1, Victoria Dimakos1, Mark S. Taylor1
1University of Toronto
Aryl ethers are prevalent functional groups in biologically relevant molecules. Transition
metal-mediated processes have greatly enabled the facile synthesis of these types of C-
O bonds. The Chan-Evans-Lam reaction involves a cross coupling of aryl boronic
acids/esters with sp2-hybridized alcohols in the presence of a copper catalyst to form aryl
ethers.1,2,3 Our group has recently reported the regioselective cross coupling of
carbohydrate secondary hydroxyl groups with aryl boronic acids under copper-mediated
conditions to generate novel aryl ethers.4 In this project we investigated the copper-
mediated cross coupling of various substituted aryl boron compounds with sugar-derived
hemiacetals. This method has potential applications in the installation of aryl ether
protecting groups, the construction of complex carbohydrate derivatives, and can
additionally facilitate biological studies.
References
1. Lam, P.Y.S., Clark, C.G., Saubern, S., Adams, J., Winters, M., Chan, D.M.T., Combs,
A. Tetrahedron Lett., 1998, 39, 2941 - 2944.
2. Chan, D.M.T., Monaco, K.L., Wang, R.P., Winteres, M.P. Tetrahedron Lett., 1998, 39,
2933 - 2936.
3. Evans, D.A., Katz, J.L., West, T.R. Tetrahedron Lett., 1998, 39, 2937 - 2940.
4. Dimakos, V., Garrett, G.E., Taylor, M.S. J. Am. Chem. Soc., 2017, 139, 15515 -
15521.
134 - N-Heterocyclic Carbene Ligated t-Butylthiolates of
Ag(I) and Cu(I)
Rachel Pottier1, John Corrigan1
1University of Western Ontario
An active area of chemical and materials science research involves the controlled
assembly of metal-chalcogen cluster architectures on the nanoscale (“nanoclusters”). In
particular, the assembly of such monodisperse systems for the Group 11 metal Ag has
yielded a rich structural chemistry.[1] One avenue for their preparation involves the use
of solubilized [Ag-SR]n coordination polymers in conjunction with sulfide sources. In this
work we have developed the preparation of several copper- and silver-thiolate
coordination complexes containing N-heterocyclic carbene (NHC) ligands as precursors
for metal-sulfide cluster complexes. The NHC IPr (IPr=1,3-bis(2,6-
diisopropylphenylimidazolin-2-ylidene) is employed with the copper- or silver-tert-butyl
thiolate to yield either the linear coordination compounds [(IPr)M(SBut)] or IPr containing
metal thiolate clusters depending on the relative amount of NHC used. All complexes
have been characterized through single crystal X-ray diffraction. In further study, these
binary clusters may prove suitable for controlled nanocluster formation.
[1] Y.-P. Xie, J.-L. Jin, G.-X. Duan, X. Lu and T. C. W. Mak, Coord. Chem. Rev., 2017,
331, 54–72.
135 - Photoelectrochemical Reduction of Carbon
Dioxide using Mesoporous Titanium Dioxide Modified
with Copper Nanoparticles.
Molly Labine1, Aicheng Chen1
1University of Guelph
Conversion of CO2 into alternative fuels has the potential to reduce atmospheric
greenhouse gas emissions produced by fossil fuel combustion while also recycling them
back into valuable chemicals to address our steadily increasing global energy
demand. While copper and titanium dioxide are two well-studied and popular electro-
and photo-catalysts, the practical efficiency of each is limited by large necessary
overpotentials and high recombination rates, respectively. Here, we report on the
photoelectrochemical reduction of CO2 using integrated mesoporous TiO2 and Cu
nanoparticles (TiO2/Cu). Mesoporous TiO2 was created using an electrochemical
anodization process and was further treated electrochemically to improve its
conductivity. Copper nanoparticles approximately 50 nm in diameter were uniformly
deposited onto the mesoporous TiO2 by a photo-assisted method. Scanning electron
microscope (SEM) and X-ray photoelectron spectroscopy (XPS) were employed to
characterize the morphology and composition of the formed TiO2/Cu
nanomaterials. Linear sweep voltammetry and chronoamperometry were used to
assess the electrochemical and photoelectrochemical catalytic activity of the combined
TiO2/Cu nanomaterials toward CO2 reduction, showing a significant synergistic
effect. The facile fabrication and enhanced catalytic activity of the TiO2/Cu
nanomaterials developed in this study make them promising for the efficient
transformation of CO2 into useful products.
137 - Investigating Vibration-Plasmon Coupling in a
Nanoreactor
OCdt. Cresswell1, Dr. Malardier-Jugroot1, Capt. McTaggart1
1Royal Military College of Canada, 2Royal Military College of Canada, 3Royal Military
College of Canada
The existence of vibration-plasmon coupling has been confirmed, however an exact
model for the relationship has not been developed. Through the investigation of the Uv-
Vis spectroscopy of a organic molecules in a nanoreactor in comparison to their
simulated IR spectra, a relationship between the IR and UV bands, and therefore the
vibration and plasmon energies, of simple organic molecules can be examined.
139 - A New Method for the Activation of Donor-Acceptor
Cyclopropanes
Michael Botelho and Michael Kerr
Western University
Regarding the total synthesis of natural products, donor-acceptor cyclopropanes have proven to
be a useful class of organic compounds due to their ability to undergo unique chemical
transformations. These distinctive transformations arise from an electronic “push-pull” effect that
is established by the synergism of the donor and the acceptor group. Herein, a new method
regarding the activation of these polarized donor-acceptor bonds is explored. The method
investigated in this report involves the formation of a phenoxenium ion and its potential ability to
induce interesting nucleophilic additions and/or intramolecular reactions within the substrate.
#SOUSCC2018
Poster Presentation Abstracts
14 - Effect of Substrate Surface Stiffness on Bacterial
Adhesion
Yuelang Chen1, Ruby Sullan1
1University of Toronto
The initial surface adhesion of Escherichia coli bacteria was studied on polymeric
polydimethylsiloxane (PDMS) of varying stiffness, in order to investigate the effect of
substrate surface rigidity on bacterial adhesion. Different PDMS stiffness was
established by varying the mass ratio between base and crosslinking agent (80:1 for soft
surface and 10:1 for hard surface), where higher degree of crosslinking results in stiffer
surface and vice versa. E. coli bacteria with restored cellulose (cellulose+) and its
knockout mutants, cellulose negative (cellulose-) and curli negative (curli-), were used to
examine how bacterial cell-surface structures influence adhesion on hard and soft
surfaces. After incubation on PDMS substrate at 37oC for 15, 60 and 120 minutes, a
negative correlation was observed, using spinning-disk confocal microscopy, between
percent surface area coverages and PDMS surface stiffness for all three strains. In
addition, bacteria cells tend to form clusters on hard PDMS surface, where Z-stack
imaging showed multiple layers of bacteria in each cluster. On the contrary, on soft
PDMS surface, a uniform monolayer of bacteria was observed for all strains. Our results
suggest that E. coli bacteria preferentially adhere to soft over hard PDMS surface.
16 - Assessing the Structural and Functional
Characteristics of the ADP/ATP Carrier Towards a
Comparative Analysis with Uncoupling Proteins
Michael Fish1, Lillian DeBruin1, Masoud Jelokhani-Niaraki1
1Department of Chemistry and Biochemistry, Wilfrid Laurier University
The ADP/ATP carrier is an inner mitochondrial membrane protein responsible for the
exchange of ATP produced in the mitochondrial matrix for ADP in the cytosol. It is
composed of six, transmembrane alpha helices with three, short, antiparallel helices on
the matrix side. An "alternating access mechanism" has been proposed in which salt
bridges at the matrix and cytosolic faces are disrupted and formed based on the
substrate bound resulting in conformational changes which open the carrier to the
appropriate face. Uncoupling proteins are also found in the inner mitochondrial
membrane, are responsible for proton transport and are thought to have very similar
structure to the ADP/ATP carrier. This research sought to evaluate the structure-function
relationships of the ADP/ATP carrier towards a comparative analysis with uncoupling
proteins using a biophysical approach. The protein was successfully overexpressed in
the bacterial membrane of Escherichia coli using auto-induction and purified using
immobilized metal affinity chromatography (IMAC), confirmed by SDS polyacrylamide
gel electrophoresis (SDS-PAGE) and Western Blot which revealed a monomer and
potential dimer. The far-UV circular dichroism (CD) spectrum revealed minima at 208
and 222 nm, indicating alpha helical structure. Future plans include reconstitution in
proteoliposomes, functional analysis of proton transport and ATP transport using
fluorescence spectroscopy and comparative analysis with uncoupling proteins.
18 - Cln5 plays a role in adhesion, autophagy, cell
differentiation, and phagocytosis in Dictyostelium
discoideum
Sabateeshan Mathavarajah1, Meagan McLaren1, Robert Huber1
1Trent University
Batten disease, clinically known as neuronal ceroid lipofuscinosis (NCL), is a currently
untreatable neurodegenerative disease. There are 13 distinct genes which link to NCL
and encode proteins not completely understood. NCL proteins localize to various
subcellular compartments, and one of these proteins, CLN5, has yet to be fully
characterized in terms of localization and function. Unfortunately, studying CLN5 has
been limited to animal models, since many lower eukaryotic systems lack a homolog of
this gene (e.g., yeast, C. elegans, and D. melanogaster). Our recent work revealed a
CLN5 homolog in the social amoeba Dictyostelium discoideum (gene: cln5, protein:
Cln5), which is recognized as a model organism for biomedical research by the National
Institutes of Health. Specifically, we showed Cln5 secretion and function as a glycoside
hydrolase. Here, we extend this work by using homologous recombination to generate a
cln5 knockout cell line. Similar to mammalian cells, Cln5-deficiency displayed defects in
adhesion and cell differentiation. Additionally, we revealed characteristic NCL
phenotypes such as lipofuscin and trace metal accumulation, and differential activity of
the lysosomal enzymes (alpha-mannosidase and beta-glucosidase). A novel
phenotype we observed was aberrant cell-cell adhesion in cln5- cells. Our data provides
the first evidence that CLN5 function is linked to cell-cell adhesion. Furthermore, we also
show phagocytosis and developmental defects in Dictyostelium. In conclusion, this
research provides new insight into the function of CLN5 in humans that may guide
therapy design, as we have identified two phenotypes that could be used for small-
molecule drug screening (lysosomal enzyme activity).
19 - Develop high efficiency electronic structure
computational method for solid state systems
calculations
Songhao Bao1, Marcel Nooijen1
1University of Waterloo
The general goal of this project is to develop an efficient and accurate, electronic
structure method for the calculation of solid state systems. An important first step is a
Hartree-Fock Self-Consistent Field calculation and the determination of the one-particle
density matrix. We developed a scheme to calculate the density matrix using a similarity
transformation analogous to the Coupled Cluster method, but applied to a periodic one-
body hamiltonian. A general python program was written to calculation density matrix
from model block Huckel 1d periodic system. Both a conventional k point scheme and
the coupled cluster based similarity transformation scheme was applied. A few test
cases were examined and the result of calculations with both methods and were
compared to test the efficiency and accuracy of the latter scheme. The new CC scheme
proved accessible, and the translational symmetry and real space sparsity was
evaluated. In the future, this similarity transformation algorithm can be implemented for
the Hartree-Fock calculation using realistic atomic orbital integrals. More importantly a
similar idea is applicable for the full Coupled-Cluster calculation with correlated wave
functions for periodic systems by introducing periodic localized orbitals (PLOs), which
would enhance the efficiency and accuracy of current computational method for solid
state systems.
42 - A novel enzyme based platform coupled to mass
spectrometry for the identification and screening of
toxic reactive metabolites from anti-thyroid drugs
Felicia Leung1, George Luka1,2, Shadi Dalili1, Heinz-Bernhard Kraatz1,2
1University of Toronto Scarborough, 2University of Toronto
Metabolic activation of sulfur based anti-thyroid drugs results in the formation of toxic
reactive metabolites. These metabolites covalently modify proteins, during the first step
in drug-induced toxicity. Methimazole is a commonly used sulfur based anti-thyroid drug
associated with idiosyncratic toxicity. Bioactivation of Methimazole results in the
formation of reactive metabolites that are mainly responsible for this adverse drug
reaction. Current drug metabolism and development are based on using microsomal
assays to generate reactive metabolites. The generated metabolites are then trapped,
collected and tested. Methimazole, however, deactivates enzymes involved in its
oxidation. Furthermore, due to the complexity of the matrices and the low concentration
of toxic reactive metabolites, these techniques exhibit low sensitivity and selectivity. This
makes it not suitable for studying reactive metabolites resulting from the bioactivation of
anti-thyroid drugs, a necessary step in the anti-thyroid drug development process.
In this research, an enzyme based screening platform was developed to generate
reactive metabolites from anti-thyroid drugs. The screening platform involved the use of
a genetically modified oxidoreductase enzyme. This enzyme is capable of selectively
oxidizing anti-thyroid drugs and generating its reactive metabolites. The activity of the
engineered oxidoreductase was tested against Methimazole using ultraviolet-visible
spectrophotometry. Next steps include coupling this developed platform with mass
spectrometry to detect and characterize the reactive metabolites. The metabolites
generated by the developed platform will be compared to those generated using
biological microsomes and other chemical oxidants. Next steps include the synthesis of
a selenium analogue of Methimazole for testing with the developed screening platform.
45 - Measurements of Atmospheric HCl in Toronto To
Understand Reactive Chlorine Chemistry
Andrea Angelucci1, Teles Furlani1, Cora Young1, Trevor VandenBoer1
1York University
Production of ozone in the atmosphere is typically initiated by hydroxide radicals. It has
also been shown that tropospheric ozone can lead to various adverse health
effects2. Chlorine radicals have been found to produce more ozone per mole than
hydroxide radicals can1. One major reservoir for chlorine in the troposphere is the
formation of HCl, which occurs via proton abstraction from organic compounds. In this
study, HCl was measured using a Picarro Cavity Ring-Down Spectrometer (CRDS) in
ambient outdoor air (≈220m above sea level). Complimentary NOx, O3, and solar
irradiance measurements were also made using an EcoTechEC9841 (LDL<0.4ppb), an
EcoTech Serinius 10 (LDL < 0.5 ppb), and a solar radiation smart sensor (paired with a
HOBO MicroStation data logger), respectively. Measurements were done at York
University in Toronto, Ontario (43.77N, 79.51W) between late February and early March
2018. We used this data to further validate the HCl measurement technique and better
understand the chemistry of atmospheric reactive chlorine.
1. Young, C. J., Washenfelder, R. A., Edwards, P. M., Parrish, D. D., Gilman, J. B.,
Kuster, W. C., … Brown, S. S. (2014). Chlorine as a primary radical: Evaluation of
methods to understand its role in initiation of oxidative cycles. Atmospheric Chemistry
and Physics, 14(7), 3427–3440.
2. Lippmann M. Health effects of tropospheric ozone: review of recent research
findings and their implications to ambient air quality standards. J Expo Anal Environ
Epidemiol. 1993 Jan-Mar;3(1) 103-129. PMID: 8518544.
49 - The Synthesis and Characterization of Alkynyl
Substituted Dibenzanthracenes
Cassandra Neter1, Kenneth E. Maly1
1Wilfrid Laurier University
Liquid crystals are materials that exhibit properties intermediate between a crystalline
solid and an isotropic liquid. This unique phase is commonly referred to as the
mesophase and therefore, liquid crystals are identified as mesogens. This research
focuses on discotic mesogens which are flat disc-like molecules possessing a polycyclic
aromatic core and flexible peripheral side chains. In the liquid crystalline phase, it is
hypothesized that these molecules rearrange into hexagonal columnar mesophases due
to π-π interactions, allowing charge transport to occur along the columnar axis. Since
they are capable of promoting charge transport, discotic liquid crystals are of interest
for potential applications such as organic semiconductors and photovoltaics. Previous
research in the lab has explored various derivatives of dibenz[a,c]anthracene, and
through various techniques, it was determined that electron withdrawing groups attached
to the aromatic core caused the compound to display a mesomorphic phase. The
objective of this research is to prepare an alkyne-substituted dibenz[a,c]anthracene
derivative and, once synthesized, characterize its properties through POM (polarized
optical microscopy) and DSC (differential scanning calorimetry). Our progress towards
the synthesis of the target compound will be reported. Through this research, it
is possible to determine the effects of alkynyl substituents at the 10 and 13 positios on
the mesomorphic properties of dibenzanthracenes.
Figure 1. Target compound.
52 - Stimuli Responsive Hydrogels and their Self-
Shaping Applications
Darius Hung1, Yun Feng Li1, Dr. Eugenia Kumacheva1
1University of Toronto
Soft materials that can undergo shape transformations in response to changes in
ambient environment have promising applications in tissue engineering, robotics and
biosensing. Generally, stimulus-responsive materials attain two stable shapes,
corresponding to the “on” and “off” states of the external trigger. Primary and binary
hydrogels incorporating NIPAM, AMPS and 1’-3’-3’-Trimethyl-6-hydroxyspiro(2H-1-
benzopyran-2-2’-indoline) were synthesized. The composite gel sheet was patterned to
introduce small-scale multiple polymer components with distinct compositions. In
response to different stimuli, the non-Euclidean sheets undergo differential swelling or
shrinkage, which creates internal stresses within the gel sheet. Through minimization of
elastic energy, the hydrogels transform into specific and controlled three-dimensional
morphologies. By additionally exploiting stimuli-induced ring opening and closing of the
spirobenzopyran moiety, careful manipulation of external stimuli allowed an in-depth
study on the degree of size and shape transformations possible for our system. The
obtained insight into the relationships between stimulus and hydrogel morphology will
allow for future development of self-learning cognitive gels, that will have particular
importance and relevance in the field of soft matter.
60 - Towards the synthesis of fluoro-substituted
dibenz[a,c]anthracenes using the Wittig reaction
Kegan Moran1, Kenneth E. Maly1
1Wilfrid Laurier University
Liquid crystals have recently become an area of great interest in synthetic organic
chemistry for their potential use as organic semiconductors. Dibenz[a,c]anthracenes are
commonly used in our group as a core for discotic liquid crystals. Alkoxy-substituted
dibenz[a,c]anthracenes have been previously shown to display columnar liquid crystal
phases. Their liquid crystalline temperature range broadens when substituted with
electron withdrawing groups that promote pi-pi interactions. The objective of this
research is to prepare a fluorinated alkoxy-substituted dibenz[a,c]anthracene to
investigate its liquid crystalline properties. It is expected that using fluoro substituents will
greatly increase pi-pi interactions via arene-perfluoroarene interactions, resulting in a
broader liquid crystalline temperature range compared to its non-fluorinated equivalents.
Presented will be an overview of discotic liquid crystals and arene-perfluoroarene
interactions as well as the work towards the synthesis of the target molecule. Access to
this molecule has been attempted using an approach that employs the Wittig reaction
between a fluoro-substituted phosphonium salt and an alkoxy-substituted phenanthrene
quinone.
61 - The Use of Microfluidic Chemostats for the
Observation of Conjugation between Escherichia coli
S17-1 and BL21(DE3) pLysS Strains
Sumaiya Baig1, Reta Bodagh1, Gurjit Mander1, Yanming Qi1, Steven Chatfield2, Paul
Piunno1, Joshua N. Milstein1
1University of Toronto Mississauga, Department of Chemical and Physical Sciences, 2University of Toronto Mississauga, Department of Biology
A microfluidic chemostat has been developed for investigations of bacterial conjugation
dynamics. The chemostat is a polydimethylsiloxane (PDMS) on glass microfluidic device
made by inexpensive and easily accessed soft-lithography techniques based on the use
of toner-on-thermoplastic molds. The device has been designed to permit for controlled
growth and observation of cells within a small chamber (~ 2 μL volume) all the while
permitting for accurate control of environmental conditions, including temperature,
nutrient concentrations and total cell concentrations. The utility of the chemostat will be
assessed via studies of the dynamics of plasmid conjugation between two Escherichia
coli strains, namely S17-1 and BL21(DE3) pLysS. These investigations may serve as a
model for future investigations of the spread of antibiotic resistance genes in bacteria, a
rising global health concern. The design, fabrication, and evaluation of the microfluidic
chemostat will be discussed, along with preliminary results of comparative
investigations, in which the results obtained using the chemostat will be compared to
those obtained from the use of traditional culturing techniques.
62 - Optimizing a Decay Vessel for Continuously
Monitoring the Progression of Soft Tissue Decay in the
Laboratory
Maliha Asif1, Jonathan Abraham1, Paul Piunno1, Ulrich J. Krull1, Marc Laflamme1
1University of Toronto Mississauga, Department of Chemical and Physical Sciences
Preservation of soft tissue, such as muscles, nerves and blood vessels, occurs only
under very specific environmental and geochemical conditions; however, the processes
associated with soft tissue preservation are not clearly understood. Current research in
taphonomy aims to characterize the geochemical environment which forms in proximity
to decaying tissue. Differences in sediment permeability and oxygen availability have
been demonstrated to be instrumental in the processes of decay and preservation,
which lead to the formation of a decay microenvironment. A vessel was constructed to
allow for the monitoring of a decay microenvironment and designed to accommodate the
attachment of pH electrodes, CO2 gas sensors, and dissolved oxygen probes. An
Arduino microcontroller based data acquisition system was created to log data from
multiple chemical sensors in the sediment and in the surrounding aqueous environment.
The design, calibration and results from preliminary investigations using this vessel will
be discussed. Future taphonomical experiments can utilize this decay monitoring system
for the observation and replication of biogeochemical processes influencing the
preservation and decay of soft tissue in a laboratory setting. Understanding the
preservation of exceptional soft tissue fossils, such as those found in the Burgess Shale
of British Columbia, can allow for improved interpretation of the fossil record and
improved linkages to be assembled between life forms from the Cambrian era with
extant organisms, thereby providing improved phylogenetic and morphological
information about preserved communities.
64 - Borinic Acid Catalyzed Ring-Opening of an Acyclic
3,4-Epoxy Alcohol using Substituted Aniline
Nucleophiles
Liwah Keller1, Grace Wang1, Mark Taylor1
1University of Toronto,
Epoxy alcohols are a useful intermediate in synthesizing numerous multi-functionalized
molecules such as polyols, monosaccharides1, and other substituted heterocycles2 and
carbocycles3. Often, the epoxide ring is opened through an acid- or base- catalyzed
attack by a heteroatom nucleophile, to produce a beta-hydroxy compound. Although
there have been numerous catalysts made for the selective nucleophilic ring-opening of
2,3-epoxy alcohols, there are few that are effective in catalyzing these reactions regio-
selectively for 3,4-epoxy alcohols. The few catalysts that have been designed are metal-
based4,5,6,7. In this project, a different approach is used— a diaryl borinic acid catalyzes
ring-opening reactions of an acyclic 3,4-epoxy alcohol, with various substituted aniline
nucleophiles. The 3,4-epoxy alcohol substrate was synthesized in a three step-process.
The products were characterized by NMR analyses.
References
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181(6), 1249–1270.
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Org. Chem. 2016, 2016(7), 1367–1379.
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66 - Urea-linked Polymerization of Primary Amino
Porphyrin Complexes in Mild Conditions with CO2
Caitlin Dao1, Billy Deng1, Maryam Abdinejad1, Bernie Kraatz1, Xiao-an Zhang1
1University of Toronto
The N-C bonds that can be formed from capturing carbon dioxide (CO2) with amine
solutions lead to the production of urea derived intermediates, compounds, and
polymers for potential applications in various industries such as electropolymerized films,
photonic materials, and chemical sensors. Using amino porphyrins, we demonstrated
selective synthesis of urea-derivative polymers from respective mono- and cis- amino
porphyrin complexes, wherein product yields were selectively generated by altering gas
flow and reaction times at room temperature.
Compared to traditional syntheses of polyureas involving the toxic chemical phosgene,
we present a catalyst-free and relatively rapid synthesis as a low-cost and
environmentally-conscious alternative that can be performed under mild conditions.
69 - Investigation of Protein Folding, Aggregation and
Substrate Binding Sites Using High Resolution Mass
Spectrometry
Jeremy Wong1, Rebecca Jockusch1
1University of Toronto
Misfolded proteins can cause protein aggregation and cluster formation, which ultimately
may lead to amyloid fibrils as an end product. Amyloid fibrils and protein cluster (plaque)
formation are associated with several neurodegenerative diseases including
Parkinson’s, Alzheimer’s and Huntington’s diseases. Over the past 150 years, extensive
research efforts have been poured into studying the mechanisms of amyloid fibril and
plaque formation. Some recent studies suggest that, at least for Alzheimer’s disease, the
toxic species is not the insoluble end products, but smaller soluble oligomers composed
of a number Ab monomers. It would be useful to develop methods to study the early
stages of protein aggregation and, in particular, how putative drugs affect early stages of
the aggregation process. Here, protein aggregation is studied using Mass Spectrometry
(MS). With the development of soft ionization techniques such as electrospray ionization
(ESI), it is possible to bring big biological molecules such as proteins and their
complexes into the gas intact. Compared to other conventional methods of studying
protein aggregation, MS is advantageous due to the minimal sample prep required,
small amount of sample required, and the ability to distinguish different oligomeric
species based on mass.
71 - Poly(norbornene) Dopamine Polymer Electrode for
Lithium Storage
Luke Kyne1, Bryony McAllister1, Tyler Schon1, Dwight Seferos1
1University of Toronto
Organic polymers are environmentally-sustainable and inexpensive alternatives to
metal-based electrodes used in modern energy storage devices. Among these, catechol-
dervied pendant polymers have been synthesized as precursors to polymeric ortho-
quinones, which have high charge-storing capabilities. In this work, a poly(norbornene)
backbone with dopamine pendant groups was synthesized for use as a cathode material
in lithium-ion batteries. This two-step, semi-synthetic methodology was effective in
minimizing reaction complexity while maximizing yield. The polymer is observed to have
high operating voltage and capacity in a lithium-ion battery system, making the electrode
material favorable for use in industrial applications. Electronic properties were optimized
when combined with Super P carbon black and polyvinylidene difluoride, before
being deposited on aluminum foil and thoroughly characterized via electron
microscopy. This new material represents an important contribution to the current array
of organic polymer electrodes, and further advances the field of renewable, high-
performance energy storage technology.
73 - Application of Reductive Transposition in the
Synthesis of Pancratistatin
Nolan Nardangeli1, Ringaile Lapinskaite1, Tomas Hudlicky1
1Brock University
The synthetic approach towards pancratistatin, an anticancer compound from the
Amaryllidaceae family of plants, will be presented. The chemoenzymatic process from
m-dibromobenzene will be described, along with the route from natural narciclasine,
producing compound 4. The proposed common intermediate, 2-epi-7-
methoxynarciclasine 4, is envisioned as the key intermediate for the application of a
reductive transposition strategy to the synthesis of pancratistatin.
74 - Mild Metal Mediated Cyclization of a Thiourea to a
Substituted 2-Aminobenzothiazole
Zachary Schroeder1, Lana Hiscock1, Louise N. Dawe1
1Wilfrid Laurier University
Benzothiazoles are a highly sought and privileged scaffold for their frequent
bioactivity.1,2,3 The use of expensive metals, such as palladium and ruthenium coupled
with the disposal of halogenated materials resulting from the use of halide leaving
groups, present drawbacks to previous reported syntheses.4,5 Herein, the use of
stoichiometric copper(II) or gold (III) to induce the cyclization of substituted thiourea in an
aryl C-H bond breaking reaction will be presented.6 Benzothiazoles were confirmed
through NMR, IR and X-ray crystallography. Extension of this work to achieve the same
transformation, using Fe(III) salts, could provide access to benzothiazole products in a
green and highly tunable way, with promising versitility.7
(1) Ali, R. et al. J. Chem. 2013, 2013, 1–12.
(2) Seth, S. Antiinflamm. Antiallergy. Agents Med. Chem. 2015, 14 (2), 98–112.
(3) Sharma, P. C. et al. J. Enzyme Inhib. Med. Chem. 2013, 28 (2), 240–266.
(4) Sharma, S. et al. Org. Lett. 2016, 18 (3), 356–359.
(5) Joyce, L. L. et al. Org. Lett. 2009, 11 (13), 2792–2795.
(6) Schroeder, Z. W. et al. Acta Crystallogr. Sect. C Struct. Chem. 2017, 73 (11), 905–
910.
(7) Shang, R. et al. Chem. Rev. 2017, 117 (13), 9086–9139.
75 - Total Synthesis of (-)-Oxycodone
Jared Thomson1, Tyler Bissett1, Prof. Tomas Hudlicky1
1Brock University
An approach towards the total synthesis of (-)-oxycodone will be presented. Key steps
include a Suzuki cross coupling of A- and C-ring fragments, an Arndt-Eistert
homologation, an intramolecular Friedel-Crafts cyclization and a proposed stereospecific
oxidative dearomatization step, inspired by a previous synthesis1, to install the key C-14
hydroxyl group. The aim of the project is to provide a shorter, more efficient synthetic
pathway towards (-)-oxycodone.
(1) Kimishima, A.; Umihara, H.; Mizoguchi, A.; Yokoshima, S.; Fukuyama, T. Org. Lett.,
2014, 16, 6244-6247.
77 - Nickel-Catalysed Aminations of Diaryl Ethers
Alethea Lee1, Chad Orsini1, Sophie Rousseaux1
1Department of Chemistry, University of Toronto
Aryl-amines and N-aryl heterocycles are widely employed as building blocks in synthetic
molecules and pharmaceutical agents.1 Over the past decade, various metal-catalyzed
cross-coupling reactions have been developed as valuable tools for the construction of
C(sp2)-N bonds.2,3,4 Nickel represents an economical and sustainable cross-coupling
approach as a more earth-abundant transitional metal. 5,6 We have developed a Ni-
catalyzed coupling of a naturally derived aryl ether from the plant source – lignin, with
various aniline derivatives in good yields. As the second most abundant biopolymer on
earth, lignin, along with its high content of aromatic groups, serves as an ideal candidate
for a renewable feedstock in the synthesis of aromatic compounds.7 This presentation
will focus on the amine substrate scope of the reaction as well as approaches on the
functionalization of by-products in such reaction.
(1) Cho, S. H.; Kim, J. Y.; Kwak, J.; Chang., S. Chem. Soc. Rev. 2011, 40, 5068.
(2) Hartwig, J. F. Acc. Chem. Res. 2008, 41, 1534.
(3) Surry, D. S.; Buchwald, S. L. Angew. Chem. Int. Ed. 2008, 47, 6338.
(4) Evano, G.; Blanchard, N.; Toumi, M. Chem. Rev. 2008, 108, 3054.
(5) Chirik, R.; Morris, R. Acc. Chem. Res. 2015, 48, 2495.
(6) Dunetz, J. R.; Fandrick, D.; Federsel, J. Org. Process Res. Dev. 2015, 19, 1325.
(7) Kärkäs, M. D.; Matsuura, B. S.; Monos, T. M.; Magallanes, G.; Stephenson, C. J.
Org. Biomol. Chem. 2016, 14, 1853.
89 - Optical biosensing of oligonucleotide modified gold
nanoparticles by induced DNA disassembly
Nicholas Colombo1, Gurbrinder Ghotra1, Jennifer Chen1
1York University
Gold (Au) nanoparticles (NPs) participate in a broad range of applications from
bioimaging, clinical diagnosis to therapy, due to their water-solubility, drug-loading
capacity, and capability of surface-modification, however they can easily aggregate in
solution and have potential biotoxicity, which can limit their applications.1 In this work, Au
NPs are used as probes for colorimetric optical biosensing of nucleic acids to increase
signal intensity, sensitivity, and specificity. Au NPs were functionalized with sequence 1
and sequence 2 with varying density using a diluent DNA. Target DNA-210 is an analog
of miRNA-210, which is a micro RNA biomarker that is overexpressed in cells affected
by cardiac disease or cancer. Kinetics of self-assembly and disassembly
of oligonucleotide modified Au NPs were monitored using UV-visible spectrophotometry.
The absorbance ratio at 526nm versus 650nm was monitored over time during the
disassembly induced by target DNA-210, and then monitored during the temperature
induced denaturation disassembly. The effect of surface density of the oligonucleotides
on the assembly and disassembly process was examined to compare efficiency
of assembly and disassembly. Lastly, urea-page electrophoresis was used to quantitate
the density of the linker and diluent sequences on the nanoparticles.
94 - Exploring and optimizing sulfenate alkylation
reactions for applications in natural product synthesis
Adam Riddell1, Adrian Schwan1
1University of Guelph
One of the compounds responsible for the aroma of a crushed or heated shiitake
mushroom is a sulfur-containing 7 membered ring known as lenthionine. Lenthionine is
made by an enzymatic process that occurs when the mushroom is crushed causing
lentinic acid to be converted to lenthionine.1 Synthesizing lentinic acid would be
advantageous for artificially creating the scent or flavour of a shiitake mushroom.
Utilizing a sulfenate approach to synthesize lentinic acid would provide a highly versatile
method which requires no subsequent oxidation of the sulfurs. Sulfenate anions
(RSO⁻ M+) are the conjugate base of sulfenic acids and have value in the synthesis of
desired sulfoxides due to the prochirality of sulfur and their potential in stereoselective
reactions. The Perrio and Schwan groups have developed methods for generating these
highly reactive sulfenate anions in situ which can then be reacted with a variety of
electrophiles such as alkyl halides.2,3 The primary investigation of this work will involve a
building block analysis of how best to synthesize the sulfur-carbon backbone of lentinic
acid using various sulfenate anions and electrophiles. Subsequent work will focus on
increasing the rate at which these investigated reactions take place.
1 Yasumoto, K.; Iwami, K.; Mitsuda H. Agric. Biol. Chem. 1971, 35, 2070-2080.
2 Caupène, C.; Boudou, C.; Perrio S.; Metzner P. J. Org. Chem. 2005, 70, 2812-
2815. 3 Singh S. P.; O’Donnell J. S.; Schwan A. L. Org. Biomol. Chem. 2010, 8, 1712-
1717.
95 - Preparation of Various β‑ Amino Iodides and
Bromides for Alternative Synthetic Approaches to
Sulfenate Substitution
Nolan Frame1
1University of Guelph
N-Protected-Β-amino sulfoxides have found plentiful use as organocatalysts, chiral
ligands, and precursors in biologically active compounds. 1 The current synthetic
approach to Β-amino sulfoxides involves the reaction of sulfenates with amino iodides or
bromides and the use of tert-butyloxycarbonyl (BOC) as the primary protecting group.
Previous investigations by Söderman and Schwan utilizing N-BOC protected Β-amino
iodides and arenesulfenates provided yields of 71-92% with diastereomer ratios
averaging 9:1. 2 This research explores and extends the variety of N-protected Β-amino
iodides and bromides to react with sulfenates. Primary investigations will involve large,
polar protecting groups to maintain specific chirality in the α-carbon to the amine group
in addition to inducing sulfur stereogenicity through steric hindrance and charge
stabilization of the sulfenate counterion.
1. Otocka, S.; Kwiatkowska, M.; Madalińska, L.; Kiełbasiński, P. Chemical Reviews
2017, 117 (5), 4147–4181.
2. J. Org. Chem. 2013, 78, 1638−1649
104 - Synthesis of Cyano-substituted carbene-stabilized
phosphorus(I) cations
Erica Dionisi1, Justin F. Binder1, Tricia Breen Carmichael1, Charles L.B.Macdonald1
1University of Windsor
There are an increasing number of phosphorus(I) compounds appearing in literature due
to interest in their fundamental properties and potential applications.1,2 Macdonald’s
group has developed a versatile synthetic approach for the generation of carbene-
stabilized PI compounds using an easily prepared phosphorus(I) transfer agent.3,4 Little
attention, however, has been paid to the effect of incorporating electron withdrawing
groups on these cations. We report a streamlined method for the synthesis of cyano-
substituted NHC-stabilized P(I) salts from triphosphenium triflate and in situ generated
carbenes. Structures created in the synthetic pathway were isolated and characterized
by IR, NMR and XRD techniques. There is potential for future work using these
molecules for studies of self-assembled monolayers, with the possibility of using the
cyano-substituents as a handle for characterization or post modification with interesting
functional groups.
1. B. D. Ellis and C. L. B. Macdonald, Coordination Chemistry Reviews., 2007, 7, 936-
973
2. J. F. Binder, S. C. Kosnik and C. L. B. Macdonald, Chem. Eur. J., 2018, 24, 3556-
3565
3. B. D. Ellis and C. L. B. Macdonald, Inorg. Chem., 2006, 45, 6864–74
4. E. L. Norton, K. L. S. Szekely, J. W. Dube, P. G. Bomben and C. L.
B. Macdonald, Inorg. Chem., 2008, 47, 1196–203
108 - Development of a Next Generation Covalent MRI
Tag Based on Manganese Porphyrin
Keith Tang1, Edmond Wong1, Xiao-an Zhang1
1University of Toronto
Magnetic resonance imaging (MRI) is a non-invasive technique that provides detailed
morphological, physiological, and functional information. However, this technique is often
limited by low sensitivity, thus contrast agents (CAs) are applied to enhance tissue
contrast and improve sensitivity (characterized by longitudinal relaxivity - r1). While
conventional CAs lack molecular specificity, development of a molecular MRI tag for
conjugation with diseases-targeted ligand, i.e. antibody, have the potential to improve
specificity. Clinically approved gadolinium (Gd) based CAs have several drawbacks
which include Gd-toxicity, low stability, and suboptimal sensitivity. However, new
manganese(III) porphyrin (MnP) CAs developed by us have shown high relaxivity at
clinical magnetic fields, high stability, and lower toxicity of Mn than Gd. The design of our
porphyrins were developed in-part based on the Solomon-Bloembergen-Morgan model
by optimizing molecular tumbling rate to increase r1. Earlier MnPs containing sulfonate
groups developed in our group have high r1 at clinically relevant fields, however suffer
from large bulky phenyl groups inducing unwanted hydrophobic interactions lowering
target specificity and solubility. Herein we report the development of a novel MnP,
MnTriCP-PhNH2 containing small polar carboxylate groups and its conjugation to a
polymer backbone for use as a covalent MRI tag.
MnTriCP-PhNH2 was successfully synthesized, using a step-wise di-pyrrolemethane
strategy. The structure is fully characterized by NMR, UV-vis, ESI-MS, HPLC, and Mn-
atomic absorption spectra. The preliminary results on protein conjugation will be
discussed. Next steps are to quantitatively measure the r1 relaxivity at low and high
magnetic field strengths and to identify the in vivo imaging potential.
116 - The secondary structure and membrane
association of the M2- subdomain of TOC159, a protein
of the chloroplast outer membrane
Neil Jurkiewicz1, Dr. Matthew Smith1
1Wilfrid Laurier University
On the Chloroplast outer envelope lies the Translocon at the outer envelope membrane
of the chloroplast (TOC complex) which translocates pre-proteins into the chloroplast.
The core of the TOC complex is formed by two GTPase receptors, Toc159 and Toc-34,
and a β-barrel channel protein Toc-75. Toc159 contains 3 domains one of which is the
M-domain which associates with the membrane; however the nature of the association
with the membrane is unknown. Secondary structure prediction analysis of the M-
domain revealed a sub-domain (called M2) that is rich in β-strands, that also aligns with
a known β-helix protein. This led to the hypothesis that the M2 sub domain forms a β-
helix which is involved in membrane association. Our research is aimed at identifying the
secondary structure of the M2 sub-domain of Toc159 (Toc159Mβ) using circular
dichroism (CD) by first purifying the recombinant his-tagged Toc159Mβ using affinity
chromatography. The purified Toc159Mβ will be analyzed with CD to measure its
secondary structure content. Surface plasmon resonance (SPR) will be used to test the
ability of Toc159Mβ to associate with membranes. Determining the secondary structure
and testing the membrane association of Toc159Mβ will advance our understanding of
intracellular trafficking to organelles and also gain a better understanding of atypical
membrane-protein association.
120 - Synthesis of Supramolecular Vanadate Receptors
– Structural Mimics of Vanadium Haloperoxidase
Kit Adriano1, Lana Mikhaylichenko1, Xiao-An Zhang1
1University of Toronto
Vanadium haloperoxidases are natural enzymes which can catalyze halogenation of
organic substrates. These enzymes utilize vanadium in the form of vanadate as a
cofactor along with hydrogen peroxide to perform the reaction. This on-going study
extends upon the results of a previous work (Zhang and Woggon, 2005) where a
structural mimic of vanadium haloperoxidase was successfully synthesized. The
supramolecular compound showed binding preference for pyrovanadate (V2O74-) and
compound-vanadate complex was found to catalyze bromination of activated C-H bonds.
This work aims to synthesize another structural mimic of the enzyme albeit with binding
preference to monovanadate (HVO42-) instead of pyrovanadate to mirror the natural
enzyme. Extending the previous work, four novel basket-shaped guanidinium receptors
were attempted to be synthesized containing the tripodal ligand tris(2-aminoethyl)amine.
Four different moieties where introduced at each N-terminal of the tripodal ligand:
benzene, propane, pentane and dodecane. Thiourea derivatives for the four moieties
were successfully synthesized while only the dodecyl moiety has been successfully
transformed into its guanidinium derivative, as confirmed by ESI-MS and NMR
spectroscopy. Analyses employed in the previous work (Zhang and Woggon, 2005) such
as 51V-NMR and 1H-NMR are currently being used to characterize the binding between
guanidinium receptor and the vanadate in aqueous and organic solutions.
123 - Remarkably High Stabilities of MnTCP: A Non-Gd
Extracellular MRI Contrast Agent
Naixin Zhao1, Henry Tieu2, Xiao-an Zhang3
1Department of Chemistry, 2Department of Physical and Environmental Science,
Department of Chemistry, 3Department of Physical and Environmental Science,
Department of Chemistry and Department of Biological Sciences, University of Toronto
Scarborough, Toronto, Ontario, Canada
Magnetic resonance imaging (MRI) is a high resolution, noninvasive imaging technique
widely applied in clinical diagnoses. By administering paramagnetic contrast agents, the
sensitivity and image contrast can be significantly improved. Gadolinium-based contrast
agents (GBCAs) are most popular for current clinical MRI scans. However, reports had
been pointed out the release and accumulation of toxic GdIII ions could occur from these
GBCAs, due to the low kinetic stability of Gd-complex. We develop of manganese(III)
porphyrins (MnP) as alternative Gd-free contrast agents. Mn(III) porphyrins have higher
sensitivity under high magnetic field, higher stability and lower toxicity. One of the
designed porphyrins is MnTCP, the first MnP-based extracellular agent. Here we
investigate the stability of MnTCP under various conditions. We designed the
experimental conditions to test under different pH, temperature, chelate and metal ions.
We chose five different metals, zinc, copper, iron, calcium, and magnesium as possible
replacements of manganese in MnTCP and monitored for over two months.
Measurements were made using UV-Visible spectroscopy because porphyrins exhibit an
unique spectra with high intensity Soret band and low intensity Q bands. HPLC was
applied as supplementary method when necessary. Preliminary results show no
significant changes for MnTCP. No metal dissociation or transmetallation was observed
up to 10X the metal concentrations. However, decreases in the Soret band was
observed in all iron concentrations. There was no indication of trans-metallated
porphyrin signal but may be caused by precipitation of the porphyrin from solution. In
conclusion, we demonstrated the high stability and kinetic inertness of MnTCP.
128 - Synthesis and Characterization of Mn(I) Complexes
for Asymmetric Polar Bond Reduction
Max Olson1, Karl Demmans1, Robert H. Morris1
1University of Toronto
The catalytic and asymmetric reduction of ketones to produce enantiopure alcohols is of
great importance to the flavour, fragrance, and fine chemicals industries. Currently,
many of the most active catalysts for such transformations are based on expensive and
toxic platinum group metals. The Morris group has focused on the development
of asymmetric direct hydrogenation (ADH) and asymmetric transfer hydrogenation (ATH)
catalysts that incorporate cheap, earth-abundant, and non-toxic metals including iron,
cobalt, and manganese. Currently under development are a class of chiral
manganese(I) complexes incorporating the PNP tridentate pincer ligands seen in
previous reports by the Morris group on iron(II)-based hydrogenation catalysts.
Described herein are strategies for their synthesis and characterization as well
as preliminary results for their activity in transfer hydrogenation.
131 - Determining the Calcium Bound Structure of
Daptomycin
Nour Mashmoushi1, Ryan Moreira1, W. Scott Hopkins1
1University of Waterloo
Daptomycin is a calcium-dependent cyclic lipopeptide used in treating infections caused
by gram-positive bacteria, including skin infections from methicillin-resistant and
vancomycin-resistant bacteria. Its bactericidal capacity is dependent on its binding to
calcium. While it is a relatively new drug, there have been documented cases of
nonsusceptibility to the antibiotic in patients. Since its 3D structure and action
mechanism are not yet well understood, finding ways to modify the lipopeptide to
prevent bacterial resistance is a difficult task. This research project aims at
experimentally and computationally identifying structural characteristics of the
daptomycin that help in binding calcium. Daptomycin can be modified at different amino
acid sites with different affinities to calcium and studied to understand calcium binding.
Using differential mobility spectrometry, daptomycin and its analogues are analyzed to
determine their clustering behavior and hence, structural conformations. In addition,
computational studies are performed to determine the most energetically-stable
conformers of the calcium-bound and unbound analogues in solution and gaseous
states. Calculations to determine the most favourable conformation of the calcium-bound
structure will provide a greater insight into the role of calcium in the action mode of
daptomycin will be acquired.
133 - Crystallization of a Putative Polysaccharide Lyase
TDE0626 from Treponema denticola
Vasu Patel1, Michael D. L. Suits1
1Wilfrid Laurier University
The “red-complex” is a consortia of bacteria, consisting of Treponema
denticola, Tannerella forsythia, and Porphyromonas gingivalis, that are associated with
the progression of periodontitis. T. denticola produces virulence factors that facilitate
infection and tissue damage. The open reading frame TDE0626 from T. denticola was
identified to be up-regulated during dense co-culture via transcriptome analysis.
Bioinformatics analysis suggests TDE0626 to be a putative polysaccharide lyase
enzyme comprised of a parallel β-helix fold. Four crystallization conditions for TDE0626
have been identified using sitting drop and hanging drop protein crystallization methods.
Optimization of these conditions could lead to the production of diffraction-quality
crystals for structural determination. Characterizing the structure and function would aid
in elucidating the role of TDE0626 in T. denticola.
136 - Characterization of a GH88 Family Glucuronyl
Hydrolase from Tannerella forsythia
Peter Nguyen1, Dr. Michael Suits1
1Wilfird Laurier University
Polymicrobial complexes that cause periodontal disease form biofilms that make
treatment difficult. Tannerella forsythia is a member of the red complex; a group of
bacteria implicated with advanced periodontal disease. A number of virulence factors
are expressed by T. forsythia that aid in the proliferation of periodontal disease. One
such pathway degrades chondroitin sulfate A, a carbohydrate component of connective
tissue. Using fluorophore assisted carbohydrate electrophoresis, and bioinfomatics,
some functional characterization of BFO2285, a putative unsaturated glucuronyl
hydrolase was found to be inactive on sulfated chondroitin due to a lack of three
conserved residues on GH88 family hydrolases specific for sulfate group binding.
138 - Synthesis and Characterization of Novel Copper(I)
and Nickel(II) Complexes with a Tetradentate
Bis(amino)-Bis(N-heterocyclic carbene) (CNNC) ligand
Nina Farac1, Kai Yang Wan1, Elvira Bergen1, Robert H. Morris1
1University of Toronto
N-heterocyclic carbene (NHC) ligands have become known as a promising alternative to
phosphine ligand-based transition metal catalyzed processes as NHC ligands provide a
σ-donor strength comparable or greater than that of a phosphine with potentially less
toxic effects. An important application of NHC-metal complexes is in the field of
asymmetric catalysis, mainly asymmetric hydrogenation for the production of
enantiomerically pure alcohols and amines, which are essential intermediates in the
synthesis of pharmaceuticals, fragrances, and agrochemicals. Herein, a tetradentate
bis(amino)-bis(NHC) (CNNC) ligand – ‘a-a-CNNC’ – was prepared in high yield by a
simple Schiff base condensation between glyoxal solution and two equivalents of an
earlier reported enantiopure (S,S)-[Ph-Ph-KaibeneH]PF6 proligand rendering the
bis(imino) analog, which was then followed by a reduction with sodium borohydride to
give the desired bis(amino) form. This bis(amino)-bis(NHC) proligand, with the molecular
formula [(S,S,S,S)-H3C-NC3H3N-CHPhCHPh-NHCH2CH2NH-CHPhCHPh-NC3H3N-
CH3](PF6)2, when reacted with a slight excess of potassium bis(trimethylsilyl)amide,
produces the corresponding tetradentate NHC-NH-NH-NHC ligand (a-a-CNNC). In the
presence of copper(I) starting material CuI, a novel CuI(a-a-CNNC) complex can be
prepared and characterized by nuclear magnetic resonance spectroscopy (NMR) and
elemental analysis (EA). A novel nickel(II) complex was additionally prepared, [Ni(a-a-
CNNC)](PF6)2, but only partially characterized with NMR and requires further
purification.