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Dallas-Fort Worth Section of the American Chemical Society

51st Annual Meeting-in-Miniature

Saturday, April 21, 2018

Technical Program and

Abstract Booklet

Organized by The Department of Chemistry

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Table of Contents Important Information 3

Map 4

Program at a Glance 5

Sessions Schedules 6

Session 1: Undergraduate Research I 13

Session 2: Undergraduate Research II 31

Session 3: Biological Chemistry 47

Session 4: Computational Chemistry 64

Session 5: Inorganic and Analytical Chemistry 80

Session 6: Organic Chemistry and Polymers I 98

Session 7: Organic Chemistry and Polymers II 114

Program Schedule

7:30 – 7:45am Check-in 7:45 – 9:15am Round 1 9:15 – 9:30 am Coffee Break 9:30 – 11:00am Round 2 11:00 – 11:15am Coffee Break 11:15 – 1:00pm Round 3 1:00 – 2:00pm Lunch Reception 2:00 – 3:15pm 1st Annual Biehl Lecture: Professor K. C. Nicolaou 3:15 – 4:00pm Awards Ceremony

Session Locations

Session 1: Undergrad I FOSC 152 Session 2: Undergrad II FOSC 157 Session 3: Biological Hyer 204 Session 4: Computational DLSB 110 Session 5: Inorganic FOSC 127 Session 6: Organic I FOSC 123 Session 7: Organic II FOSC 133

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Important Information 1. The meeting will be held on Saturday, April 21 at the Department of Chemistry at Southern Methodist University (3215 Daniel Ave, Dallas, TX 75205). Sessions will be located in Fondren Science Building (FOSC), Dedman Life Sciences Building (DLSB), and Hyer Hall (Hyer). See the blue outlines on the map on the next page for locations of these buildings. Please stop by the registration desk located on the 1st floor of Fondren Science Building to pick up your name tag. 2. Parking will be available in the Airline Garage at the corner of Daniel Ave and Airline Blvd and the Heroy Lot on Daniel Ave. See the red outlines on the map on the next page for locations of these parking lots. Parking in these locations is free on weekends. 3. DART riders can get off at Mockingbird Station. The SMU Express (Route 768) is free to everyone and will take passengers from Mockingbird Station to the SMU Bishop bus stop. See the red outlines on the map on the next page. The shuttle schedule can be found here: https://www.dart.org/riding/mustangexpress.asp. 4. Each room will be equipped with a projector, PC computer, and VGA cable. Please be sure to bring any adapters you may need if you plan to use your own computer. We also recommend backing up a PDF version of your talk onto a flash drive. Please arrive 15 minutes before your session begins to load your talk or test your computer. 5. Please stick to the allotted 15-minute time slot and leave 3–5 minutes for questions. 6. If you are unable to present at the scheduled time please notify alippert@smu.edu and igarciabosch@smu.edu as soon as possible.

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smu.edu

Registration and Sessions

ParkingParking

ComputationalSession

BiologicalSession

Mockingbird StationPickup for free SMU Shuttle (768)

SMU BishopSMU Shuttle (768)

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Session 1: Undergraduate Research I (Biochemistry, Inorganic and Analytical Chemistry)

Session Chairs: Prof. Patty Wisian-Neilson, SMU

Prof. Micael Lattman, SMU

Location: FOSC 152

Time Activity Speaker

7:30 – 7:45 Registration and coffee - 7:45 – 8:00 Session 1- Speaker 1 Tyler C. Rozanitis (SMU) 8:00 – 8:15 Session 1- Speaker 2 Sydney Schmitt (SMU) 8:15 – 8:30 Session 1- Speaker 3 Kevin Huynh (UT Dallas) 8:30 – 8:45 Session 1- Speaker 4 Thomas Howlett (UT Dallas) 8:45 – 9:00 Session 1- Speaker 5 Parsa V. Shamloo (UT Dallas) 9:00 – 9:15 Session 1- Speaker 6 Abigail Lewis (UT Dallas) 9:15 – 9:30 Coffee Break - 9:30 – 9:45 Session 1- Speaker 7 Brianna Royer (UT Dallas) 9:45 – 10:00 Session 1- Speaker 8 Ahmad Hamza (UT Dallas) 10:00 – 10:15 Session 1- Speaker 9 Zachariah Malik (UT Dallas) 10:15 – 10:30 Session 1- Speaker 10 Sanjana Ravi (UT Dallas) 10:30 – 10:45 Session 1- Speaker 11 Nhan Khuu (UT Dallas) 10:45 – 11:00 Session 1- Speaker 12 Cong-Bao Phan (UT Dallas) 11:00 – 11:15 Coffee Break - 11:15 – 11:30 Session 1- Speaker 13 D. Zometa (Abilene Christian U.) 11:30 – 11:45 Session 1- Speaker 14 Delroy A. Daley (UNT) 11:45 – 12:00 Session 1- Speaker 15 D. Martinez (Abilene Christian U.) 12:00 – 12:15 Session 1- Speaker 16 Frida Verdin (Texas Wesleyan) 12:15 – 12:30 Session 1- Speaker 17 Nathanael Lutz (Baylor University) 12:30 – 12:45 Session 1- Speaker 18 Chayton Creswell (UT Dallas) 12:45 – 13:00 Break before lunch -

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Session 2: Undergraduate Research II (Organic Chemistry and Polymers)

Session Chairs: Prof. Nimali Abeykoon, UTD

Prof. Hong Wang, UNT

Location: FOSC 157

Time Activity Speaker 7:30 – 7:45 Registration and coffee - 7:45 – 8:00 Session 2- Speaker 1 Mackenzie Young (SMU) 8:00 – 8:15 Session 2- Speaker 2 Nimmy Babu (UT Dallas) 8:15 – 8:30 Session 2- Speaker 3 Ganesa Parmar (UT Dallas) 8:30 – 8:45 Session 2- Speaker 4 Gino Occhialini (UT Dallas) 8:45 – 9:00 Session 2- Speaker 5 Lauren McCaghren (UT Dallas) 9:00 – 9:15 Session 2- Speaker 6 Lana Tuong (UT Dallas) 9:15 – 9:30 Coffee Break - 9:30 – 9:45 Session 2- Speaker 7 Arimilli Bhargav S (UT Dallas) 9:45 – 10:00 Session 2- Speaker 8 Mai N. Nguyen (UT Dallas) 10:00 – 10:15 Session 2- Speaker 9 Ashif Karedath (UT Arlington) 10:15 – 10:30 - - 10:30 – 10:45 Session 2- Speaker 10 Marcela Torres (UNT) 10:45 – 11:00 Session 2- Speaker 11 Sara Tuck (Tarleton State U.) 11:00 – 11:15 Coffee Break - 11:15 – 11:30 Session 2- Speaker 12 A. Thomas (Austin College) 11:30 – 11:45 Session 2- Speaker 13 C. Mills (Tarrant County C. S. C.) 11:45 – 12:00 Session 2- Speaker 14 Sam Kaiser (Texas A&M) 12:00 – 12:15 Session 2- Speaker 15 Matthew Tran (Austin College) 12:15 – 12:30 Session 2- Speaker 16 Anh-Thu Pham (Austin College) 12:30 – 12:45 Break before lunch - 12:45 – 13:00 Break before lunch -

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Session 3: Biological Chemistry Session Chairs: Prof. Brian Zoltowski, SMU

Prof. Jiyong Lee, UTD

Location: Hyer 204

Time Activity Speaker 7:30 – 7:45 Registration and coffee - 7:45 – 8:00 Session 3- Speaker 1 Robert Green (SMU) 8:00 – 8:15 Session 3- Speaker 2 Nischal Karki (SMU) 8:15 – 8:30 Session 3- Speaker 3 Aditi Nagar (SMU) 8:30 – 8:45 Session 3- Speaker 4 N. Akhavantabib (UT Dallas) 8:45 – 9:00 Session 3- Speaker 5 Candace E. Benjamin (UT Dallas) 9:00 – 9:15 Session 3- Speaker 6 Jenifer Calvo (UT Dallas) 9:15 – 9:30 Coffee Break - 9:30 – 9:45 Session 3- Speaker 7 Maria Castaneda (UT Dallas) 9:45 – 10:00 Session 3- Speaker 8 Zhuo Chen (UT Dallas) 10:00 – 10:15 Session 3- Speaker 9 Hsichuan Chi (UT Dallas) 10:15 – 10:30 Session 3- Speaker 10 Fatemeh Khashami (UT Dallas) 10:30 – 10:45 Session 3- Speaker 11 Chao Long (UT Dallas) 10:45 – 11:00 Session 3- Speaker 12 Christopher Parish (UT Dallas) 11:00 – 11:15 Coffee Break - 11:15 – 11:30 Session 3- Speaker 13 Jasmine N. Tutol (UT Dallas) 11:30 – 11:45 Session 3- Speaker 14 Qing Wang (UT Dallas) 11:45 – 12:00 Session 3- Speaker 15 Monira Obaid (UT Arlington) 12:00 – 12:15 Session 3- Speaker 16 Philip M. Palacios (UT Arlington) 12:15 – 12:30 Session 3- Speaker 17 Aisha Fahim (TCU) 12:30 – 12:45 Break before lunch - 12:45 – 13:00 Break before lunch -

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Session 4: Computational Chemistry

Session Chairs: Prof. Steven Nielson, UTD

Dr. Marek Freindorf, SMU

Location: DLSB 110

Time Activity Speaker 7:30 – 7:45 Registration and coffee - 7:45 – 8:00 Session 4- Speaker 1 Nassim Beiranvand (SMU) 8:00 – 8:15 Session 4- Speaker 2 Feng Wang (SMU) 8:15 – 8:30 Session 4- Speaker 3 Malgorzata Z. Makos (SMU) 8:30 – 8:45 Session 4- Speaker 4 Sadisha Nanayakkara (SMU) 8:45 – 9:00 Session 4- Speaker 5 Dineli Ranathunga (UT Dallas) 9:00 – 9:15 Session 4- Speaker 6 Alexandra M. Shamir (UT Dallas) 9:15 – 9:30 Coffee Break - 9:30 – 9:45 Session 4- Speaker 7 Li Shen (SMU) 9:45 – 10:00 Session 4- Speaker 8 Shariq Haseen (UT Arlington) 10:00 – 10:15 - - 10:15 – 10:30 Session 4- Speaker 9 Yavuz S. Ceylan (UNT) 10:30 – 10:45 Session 4- Speaker 10 Arshad Mehmood (TCU) 10:45 – 11:00 Session 4- Speaker 11 Catherine A. Moulder (UNT) 11:00 – 11:15 Coffee Break - 11:15 – 11:30 Session 4- Speaker 12 Ilia Ponomarev (UT Arlington) 11:30 – 11:45 Session 4- Speaker 13 E. A. Vázquez-Montelongo (UNT) 11:45 – 12:00 Session 4- Speaker 14 Niraj Verma (SMU) 12:00 – 12:15 Session 4- Speaker 15 Seth Yannacone (SMU) 12:15 – 12:30 Session 4- Speaker 16 Hongyu Zhou (SMU) 12:30 – 12:45 Break before lunch - 12:45 – 13:00 Break before lunch -

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Session 5: Inorganic and Analytical Chemistry

Session Chairs: Prof. Isaac Garcia-Bosch, SMU

Dr. Joshua Tully

Location: FOSC 127

Time Activity Speaker

7:30 – 7:45 Registration and coffee - 7:45 – 8:00 Session 5- Speaker 1 K. Rajabimoghadam (SMU) 8:00 – 8:15 Session 5- Speaker 2 K. A. Benavides (UT Dallas) 8:15 – 8:30 Session 5- Speaker 3 Alexander T. Brown (UT Dallas) 8:30 – 8:45 Session 5- Speaker 4 Jonathan Buford (UT Dallas) 8:45 – 9:00 Session 5- Speaker 5 Shaobo Li (UT Dallas) 9:00 – 9:15 Session 5- Speaker 6 Jason Lin (UT Dallas) 9:15 – 9:30 Coffee Break - 9:30 – 9:45 Session 5- Speaker 7 G. I. Ashok Kumar (UNT) 9:45 – 10:00 Session 5- Speaker 8 Juan P. Vizuet (UT Dallas) 10:00 – 10:15 Session 5- Speaker 9 Christopher E. Ozigagu, (UNT) 10:15 – 10:30 Session 5- Speaker 10 Weiland Ashley (UT Dallas) 10:30 – 10:45 Session 5- Speaker 11 Muthappan Asokan (UNT) 10:45 – 11:00 Session 5- Speaker 12 Melissa Wunch (UT Dallas) 11:00 – 11:15 Coffee Break - 11:15 – 11:30 Session 5- Speaker 13 Samantha M. Brewer (TCU) 11:30 – 11:45 Session 5- Speaker 14 J. Caperton (UNT) 11:45 – 12:00 Session 5- Speaker 15 D. Parasar (UT Arlington) 12:00 – 12:15 Session 5- Speaker 16 Seunga Kim (Texas A&M) 12:15 – 12:30 Session 5- Speaker 17 Tengteng Lyu (Texas A&M) 12:30 – 12:45 Session 5- Speaker 18 Darrell D. Mayberry (UNT) 12:45 – 13:00 Break before lunch -

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Session 6: Organic Chemistry and Polymers I

Session Chairs: Prof. David Son, SMU

Prof. Alex Lippert, SMU

Location: FOSC 123

Time Activity Speaker 7:30 – 7:45 Registration and coffee - 7:45 – 8:00 Session 6- Speaker 1 Avichal Vaish (SMU) 8:00 – 8:15 Session 6- Speaker 2 Rachel Trammell (SMU) 8:15 – 8:30 Session 6- Speaker 3 Rajesh Kumar (SMU) 8:30 – 8:45 Session 6- Speaker 4 Lucas Ryan (SMU) 8:45 – 9:00 Session 6- Speaker 5 Shashini Diwakara (UT Dallas) 9:00 – 9:15 Session 6- Speaker 6 A. Durand-Silva (UT Dallas) 9:15 – 9:30 Coffee Break - 9:30 – 9:45 Session 6- Speaker 7 Hamilton Lee (UT Dallas) 9:45 – 10:00 Session 6- Speaker 8 Soheil Malekpour (UT Dallas) 10:00 – 10:15 Session 6- Speaker 9 Masoumeh Tajik (UT Dallas) 10:15 – 10:30 Session 6- Speaker 10 Ravi P. Singh (UT Arlington) 10:30 – 10:45 Session 6- Speaker 11 Raymond P. Welch (UT Dallas) 10:45 – 11:00 Session 6- Speaker 12 Lawton Seal II (UT Arlington) 11:00 – 11:15 Coffee Break - 11:15 – 11:30 Session 6- Speaker 13 Hiep Nguyen (UT Arlington) 11:30 – 11:45 Session 6- Speaker 14 Charles Ochoa (TCU) 11:45 – 12:00 Session 6- Speaker 15 Whitney K. Cosey (UT Dallas) 12:00 – 12:15 Break before lunch S. Aguirre-Medel (UT Arlington) 12:15 – 12:30 Break before lunch - 12:30 – 12:45 Break before lunch - 12:45 – 13:00 Break before lunch -

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Session 7: Organic Chemistry and Polymers II

Session Chairs: Prof. Nick Tsarevsky, SMU

Prof. Mihaela Stefan, UTD

Location: FOSC 133

Time Activity Speaker 7:30 – 7:45 Registration and coffee - 7:45 – 8:00 Session 7- Speaker 1 Caleb Bunton (SMU) 8:00 – 8:15 Session 7- Speaker 2 Jian Cao (SMU) 8:15 – 8:30 Session 7- Speaker 3 Maha Aljowni (SMU) 8:30 – 8:45 Session 7- Speaker 4 Weiwei An (SMU) 8:45 – 9:00 Session 7- Speaker 5 Stephen M. Budy (SMU) 9:00 – 9:15 Session 7- Speaker 6 R. Jayawickramage (UT Dallas) 9:15 – 9:30 Coffee Break - 9:30 – 9:45 Session 7- Speaker 7 M. Dharmarwardana (UT Dallas) 9:45 – 10:00 Session 7- Speaker 8 Chamaal Karunaweera (UT Dallas) 10:00 – 10:15 Session 7- Speaker 9 Vasanthy Karmegam (UT Dallas) 10:15 – 10:30 Session 7- Speaker 10 Michael A. Luzuriaga (UT Dallas) 10:30 – 10:45 Session 7- Speaker 11 Parham Asgari (UT Arlington) 10:45 – 11:00 Session 7- Speaker 12 Enrique Barragan (UT Arlington) 11:00 – 11:15 Coffee Break - 11:15 – 11:30 Session 7- Speaker 13 T. Avullala (UT Arlington) 11:30 – 11:45 Session 7- Speaker 14 U. sree Dakarapu (UT Arlington) 11:45 – 12:00 Break before lunch Juan Garcia (UT Dallas) 12:00 – 12:15 Break before lunch - 12:15 – 12:30 Break before lunch - 12:30 – 12:45 Break before lunch - 12:45 – 13:00 Break before lunch -

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Session 1: Undergraduate Research I (Biochemistry, Inorganic and Analytical Chemistry)

Functional tunability of clock-regulating protein ZEITLUPE

Tyler C. Rozanitis, Hailee Browne, Brian D. Zoltowski* Department of Chemistry, Southern Methodist University, Dallas, TX

75275, United States

Division: Biochemistry E-mail: trozanitis@smu.edu; hbrowne@smu.edu Category: Undergraduate Plants, fungi, and animals utilize a 24 hour (circadian) clock to measure and respond to environmental factors. Many clock regulating proteins accomplish this via blue-light activation of a Light, Oxygen, Voltage (LOV) domain. ZEITLUPE (ZTL) in Arabidopsis thaliana utilizes its LOV domain and a Flavin cofactor (FMN) to respond to blue light and transition between the day and evening cycles of the circadian clock via degradation of TIMING OF CAB EXPRESSION 1 (TOC1). By tuning the functionality of ZTL with controlled point mutations, the circadian clock and its regulated processes can be manipulated. The change in functionality of ZTL is determined by taking kinetic measurements after photo-bleaching to measure the photochemical reversion rate from the light to the dark state. A mutant library of biologically functional and non-functional mutants has been created through this method. This mutant library hopes to be used as tool in optogenetics by altering LOV domain containing proteins, tuning the blue-light fluence sensitivity of A. thaliana, and helping to better understand the photochemical reversion mechanism of ZTL.

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Interaction Studies of Circadian Clock Proteins to Elucidate Their Effect on Glucose Metabolism in Mammals

Sydney Schmitt, Shannon Swisher, Brian Zoltowski* Department of Chemistry, Southern Methodist University

Division: Biological chemistry E-mail: slschmitt@smu.edu Category: Undergraduate The synchronization of cellular and physiological activity with changes in environmental stimuli is facilitated by circadian clock systems, which are defined by three main elements: input, oscillator, and output. The core oscillation mechanism maintains a 24-hour rhythm and works to link environmental inputs to a diverse array of outputs. A known regulator of this oscillatory system in mammals is cryptochrome (CRY), which works to periodically bind to and degrade from the main oscillatory proteins CLOCK and BMAL1. This contributes to the periodicity of the mammalian circadian rhythm. Recent research has shown that misalignment of the core oscillator with environmental stimuli leads to aberrant outputs with significant health consequences, such as metabolic irregularities such as diabetes. The structural nature of CRY’s protein-protein interaction with human glucocorticoid receptor NR3C1 is explored through cloning the respective protein constructs into a two-hybrid vector system. Fluorescence assay in the presence of small molecule inhibitors dimethylsulfoxide, dexamethasone, and CRY inhibitor KL001 yields quantitative data on the frequency of construct interaction. Results have shown modulated interaction effects by these small molecules. These studies will lead to the design of constructs suitable for identifying the minimal interaction domain between hCRY and hNR3C1, and will be extended to other CRY:construct interaction systems.

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Implication of Disulfides in the Solvent Stability of Qb Virus Like Particles

Kevin Huynh, Jeremiah J. Gassensmith* Department of Biochemistry and Chemistry, University of Texas at Dallas

Division: Biochemistry E-mail: Kevin.Huynh1@utdallas.edu Category: Undergraduate

Viruses are instinctively resilient biomolecules uniquely crafted to hold sensitive packages and deliver their payload to specific destinations. Characteristically resistant in nature, they lack a metabolism of their own, and they have, as-a-result, acclimated to their environment by scavenging resources in biological environments or usurping a host’s metabolic machinery for survival constantly under evolutionary pressures1. Stripping the viruses of the genomic identity that codes for their infectious qualities leaves us with the empty proteinaceous capsids known as virus-like-particles that offers an opportunity of increasing functionality on exposed cysteine residues interspersed along the particle’s capsids in alternative drug delivery approaches. Our recombinant viral capsids were soluble in water, but we needed to pinpoint its solubility in co-organic solvents that can dissolve different two-carbon maleimide compounds. To investigate the stability of structural disulfide bonds on phage Q!, we characterized the viral particles immersed in iterative gradients of co-organic solvents and identified the structural integrity and solubility limits. We quantified the size of viral capsids using dynamic-light-scattering instrumentation every 0, 12, and 24-hour time frames and found the loss of structural stability in concentrations of co-organic solvent: 15% ACN, 20% THF, 40% DMSO, and 50% DMF. Future studies will focus on characterizing stability limits of viral capsids with reduced thiol groups and ‘rebridge’ the functional handles with two-carbon backbone maleimide based compounds soluble in co-organic solvents within bioconjugation-conditions to harness its increasing functionality.

1. Steinmetz NF. Viral nanoparticles in drug delivery and imaging. Mol Pharm 2013, 10:1–2.

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Encapsulation of Iron Nanoparticles with Holmium-Based Materials for Targeted Cancer Therapy

Thomas Howlett, Juan P. Vizuet, Jason Lin, Kenneth J. Balkus* Department of Chemistry and Biochemistry, The University of Texas at

Dallas Division: Inorganic E-mail: ThomasHowlett@verizon.net Category: Undergraduate Holmium-166 (166Ho) is an effective radionucleotide for cancer therapy that is produced by neutron-activation of the 100% natural abundant Holmium-165 isotope. 166Ho has a half-life of 26.8 hours, emits both β- particles and γ photons, which can be used for cancer treatment and imaging respectively. 166Ho systems have shown to be effective in cancer therapy but there are challenges in the delivery and localization methods. Recently, our research group has developed Holmium-based Metal-Organic Frameworks (Ho-MOFs). The properties of these materials, such as defined porosity and high surface area, complements 166Ho therapy with the advantage of loading different radiosensitizers. To improve the targeting and localization we propose the encapsulation of superparamagnetic iron nanoparticles within the Ho-MOFs. The first step is the synthesis of iron nanoparticles. Size is key in cancer therapy applications, so ferrofluids are prepared as they give reliable size control. To encapsulate the nanoparticles, we propose the direct addition of the nanoparticles into the Ho-MOF synthesis. In order to improve encapsulation, the modification of the surface of the nanoparticles is also investigated. The growth of the Ho-MOF around the nanoparticles is followed through electron microscopy (SEM, TEM), infrared spectroscopy and powder x-ray diffraction.

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Lanthanum-Templated Hollow Carbon Nanorods for Electric Double Layer Capacitor

Parsa V. Shamloo, Alexander T. Brown, Zijie Wang, Kenneth J. Balkus* University of Texas at Dallas, Department of Chemistry & Biochemistry

Division: Inorganic E-mail: pvs150030@utdallas.edu Category: Undergraduate The development of graphitic carbon with high surface area is desired for supercapacitor energy storage. Electrically conductive and high surface area carbons advantageously lead to a higher energy density in supercapacitors. We have synthesized a carbon material via a lanthanum-catalyzed chemical vapor deposition. La(OH)3 nanorods were used as a template and catalyst for the synthesis of graphitic carbon at 600 °C. The structure was comprised of hollow carbon nanorods with broken ends, forming an interconnected tubular network. A surface area of 771 m2/g indicates that both the interior and exterior of the hollow carbon nanorods are accessible. The carbon was further characterized by transmission electron microscopy, scanning electron microscopy, powder X-ray diffraction, and Raman spectroscopy. An electric double layer capacitor (EDLC) cell was constructed with the templated carbon using the ionic liquid electrolyte, 1-ethyl-2-methylimidazolium bis(trifluoromethylsulfonyl)imide (EMIM-TFSI). Subsequently, the symmetric electrochemical cell was tested for electrochemical properties. The specific capacitance was 128 F/g at 10 mV/s, the energy density was 55 Wh/kg, and the power density was 1700 W/kg at 1 A/g. The cell retained 89 % capacitance after 5000 cycles.

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Synthesis of Holmium-based Metal-Organic Frameworks for Cancer Therapy

Abigail Lewis, Juan P. Vizuet, Dr. Kenneth Balkus Jr.* Department of Chemistry and Biochemistry, University of Texas at Dallas

Division: Inorganic E-mail: all170130@utdallas.edu Category: Undergraduate Holmium-166 (166Ho) can be generated from the 100% natural abundant Holmium-165 through neutron activation.166Ho emits both photons and β– particles, the latter with the potential of damaging cancer cell’s DNA. A suitable 166Ho carrier must have high Holmium content, be chemically/thermally stable, and have low toxicity. Metal-organic frameworks (MOFs) have properties, such as high surface area and porosity, that can benefit drug delivery and cancer therapy. By synthesizing Holmium-based MOFs, it is possible to exploit these properties to store radiosensitizer agents, such as Nitric Oxide (NO). Due to the gaseous nature of NO, a solid delivery system is needed. This can be achieved by reacting NO with a secondary amine to form a diazeniumdiolate. Thus, the desired MOF must contain secondary amine groups in its structure. These materials have the potential to improve current cancer therapy treatments due to the intrinsic properties of MOFs and the synergistic effect of NO and 166Ho. Proposed research will begin with the synthesis of a Ho-based MOF. Characterization of the material is done by single-crystal x-ray diffraction, surface area analysis, electronic microscopy (SEM, TEM), powder x-ray diffraction, infrared spectroscopy, and thermogravimetric analysis. After characterization, NO loading and release experiments will be performed.

19

13C NMR Spectroscopic Investigation of Glucose and Fructose Metabolism in Cancer Cells

Brianna Royer1, Christopher Parish1, Fatemeh Khashami1, Qing Wang1, and Lloyd Lumata1

1Department of Physics, The University of Texas at Dallas Division: Biological E-mail: bri_royer@aol.com Category: Undergraduate As cancer cells proliferate, there is an immediate need for high consumption of fuels and raw materials to sustain the rapid proliferation of these malignant cells. Foremost among these metabolic alterations is the Warburg effect which is characterized by high uptake of glucose and eventual overproduction of lactate in cancer cells. In this study, we have investigated the hyperdrive metabolism of two glycolytic NMR probes [1-13C] glucose and [1-13C] fructose in SfXL glioblastoma and PC-3 prostate cancer cells. The main goal of this study was to track the basic biochemistry of glucose and fructose in cancer cells due to the ubiquity of these two types of sugar in food and beverages. Our initial NMR results suggest that glucose is metabolized into lactic acid faster than fructose in cancer cells. This differences in metabolic rates and its possible impact upon cellular function and proliferation of prostate and glial cancer cells will be discussed in the context of the Warburg effect

20

Enhanced Techniques to Modify the Topology of Metal Organic Framework on Tobacco Mosaic Virus

Ahmad Hamza, Jeremiah J. Gassensmith* The University of Texas at Dallas, Department of Chemistry and

Biochemistry Division: Colloid and Surface Science E-mail: hxa150630@utdallas.edu Category: Undergraduate Attenuated vaccines or Virus Like Particles (VLPs) are used to improve the immune system against many strains of similar bioactive viruses. However, these VLPs are unstable at elevated temperatures and need to be kept refrigerated when transported from manufacture to supplier, a process known as the cold chain. In fact, approximately 80% of the cost for vaccines come from keeping them refrigerated. Our group has published a method to encapsulate tobacco mosaic virus (TMV) into a zeolitic imidazole framework 8 (ZIF-8). The TMV@ZIF-8 shows improved stability in conditions that normally denature the virus. When developing batches of TMV@ZIF small granules can sometimes appear in certain batches. The use of centrifugation can be an added step in purifying these TMV@ZIF. The goal of my project is to add centrifugation as a quick way to purify all these batches at once and verify using scanning electron microscopy (SEM). Further studies will be implemented by making small modifications to the current procedure to see the effect on topology. We also hope to show SEM, powder x-ray diffraction, and atomic force microscopy of the possible changed topologies.

21

MOF Encapsulation of live Tardigrada Zachariah Malik, Shaobo Li*, Jeremiah Gassensmith*

University of Texas at Dallas: Department of Chemistry and Biochemistry

Division: Physical Chemistry E-mail: zam170030@utdallas.edu Category: Undergraduate

Metal Organic Framework (MOF) encapsulation is an exciting field within nanotechnology and bio-engineering. This technology is applicable in storing materials in typically hostile conditions, for the MOF acts as a protective exoskeleton that permits the transport of vital nutrients. Following the successful encapsulation of the Tobacco Mosaic Virus (TMV) within ZIF-8, it follows that the next task is to encapsulate a living animal. Current progress is being made to encapsulate the Hypsibius Dujardini with ZIF-8. While preliminary data may suggest partial MOF formation along the surface of the animal, it remains to determine the viability of the specimen. MOF encapsulation is achieved via introduction of the Tardigrade to a precursor solution that contains 2-mthylimidazole at 1600mM and Zinc Diacetate at 20mM at equal volumes. The current procedure, however, appears to be toxic for animals, for example, animals demonstrate no activity upon immediate exposure to 2-methylimidazole, the ligand used for ZIF-8 synthesis. Animals also show an adverse response upon introduction to EDTA and NaOAc.

22

Synthesis of Silica Centipede Nanoparticles for Drug Delivery Purposes

Sanjana Ravi, Jason Lin, Kenneth Balkus Jr.* Department of Chemistry at The University of Texas at Dallas

Division: Inorganic E-mail: sxr162230@utdallas.edu Category: Undergraduate Today, most cancer patients are treated with nonspecific antitumor drugs that are distributed throughout the body following intravenous injections. These drugs attack both healthy and cancerous tissue, causing a weakened immune system, among many other effects. By using a wrinkled silica coated magnetic core, tumors can be directly targeted. While synthesizing wrinkled silica, silica structures, named centipedes were observed. These centipedes contain a smooth surface with legs protruding from the surface. Since the centipede has a width of 30 nm, the centipede can fit inside the pores of tumorous tissues and deliver chemotherapy drugs. This, along with its chemical and thermal stability makes it optimal for drug delivery purposes. The current synthesis for these centipedes is by using urea, cetylpyridinium bromide, water, cyclohexane and tetraethyl orthosilicate. Centipedes have not been been published prior to now, making them a topic of interest. With experimentation, we found that the pH was the determining factor that determined whether centipedes, hollow spheres or wrinkled silica were formed. Currently, we are working on coating polymers and other inorganic materials with centipedes for use in drug delivery. For example, we can coat magnetic cores with these centipedes to target tumors and make cancer treatment more effective.

23

Micro Lux Chants Nhan Khuu, Jeremiah Gassensmith*

Chemistry Department, University of Texas at Dallas Division: Biochemistry E-mail: ntk140040@utdallas.edu Category: Undergraduate Vibrio Fischeri is a bioluminescent bacterium belongs to the Vibrionaceae family. Vibrio Fischeri fluoresce at different light intensities at different growth stages. By recording time lapse photography of the Vibrio Fischeri bacteria growing at varying temperatures, we are attempting to create a sonification model to illustrate the life cycle of the bacteria. The sonification will use the light intensity as a direct indicator of the growth stage, and then map those intensities to different sound parameters. The goal would then be to discern which stage of the life cycle the bacteria are in by only listening to them over the duration of the time lapse. Vibrio Fischeri was incubated in a dark environment, and an incubator was used to control the temperature. A camera attached to a computer was set to take pictures of the bacteria plate every 30 seconds for 72 hours. Results showed that the more bacteria colonies fluoresce, the higher the intensity of the sounds were heard. Hence, we will start hearing some clicking sound at hour 6th, the most intense sounds between hour 12th-18th, and almost no sounds around hour 48th.

24

Extraction of Virus-like Particles through the Attachment of Poly(L-lysine) Iron Oxide Nanoparticles and 3,4-

Dibromofuran-2,5-Dione Cong-Bao Phan, Jeremiah J. Gassensmith*

Department of Chemistry and Biochemistry, University of Texas at Dallas Division: Biochemistry E-mail: cxp141430@utdallas.edu Category: Undergraduate The objective of this project is to investigate an alternative method to extracting Virus-like Particles (VLP) from a solution derived from Bacteriophage Q-Beta. The concept is that Poly(L-lysine) coated Iron Oxide Nanoparticles can be produced and have 3,4-Dibromofuran-2,5-Dione can be bound to the exterior of these nanoparticles. These particles have a magnetic property, and so tris(2-carboxyethyl)phosphine (TCEP) and these particles would be added in the procedure of Q-Beta VLP purification to extract VLP. The VLP would then be isolated from these magnetic particles by the addition of another sulfur.

25

A molecular octahedron containing twelve osmium atoms Diego F. Zometa, Dr. Greg Powell*

Department of Chemistry and Biochemistry, Abilene Christian University Inorganic division

Division: Inorganic E-mail: dfz15a@acu.eduCategory: Undergraduate Os3(CO)12, dodecacarbonyltriosmium(0), reacts with carboxylic acids to form diosmium sawhorse complexes with Os–Os single bonds. Our research group has previously explored reactions of Os3(CO)12 with dicarboxylic acids that produce dicarboxylato ligands, which link together two, three or four diosmium sawhorse units in one molecule. We turned our attention to tricarboxylic acids, but our initial efforts to make new compounds with trimesic (benzenetricarboxylic) acid failed. We finally discovered that the addition of small amounts tetrafluoroboric acid allowed Os3(CO)12 to react with trimesic acid to produce the first example of a compound in which six sawhorse units are linked together. X-ray crystallographic analysis revealed an octahedral molecular structure for this dodecanuclear osmium complex.

26

STRUCTURAL ANALYSIS OF A TUNGSTEN BASED HYDROGEN STORAGE MATERIAL

Delroy A. Daley, Brandon Allen, and Muhammed Yousufuddin* Life and Health Sciences Department, University of North Texas at Dallas

Division: Inorganic E-mail: delroy.daley21@gmail.com Category: Undergraduate The storage of hydrogen gas for use in fuel cells is an ongoing research effort. Metal complexes have been studied extensively for their ability to store hydrogen, although the release of stored hydrogen from metal complexes has been problematic. We describe here the synthesis and structural analysis of a tungsten based hydrogen storage material. The compound was synthesized based on the reported literature and characterized using X-ray Crystallography, a technique that determines molecular structure of a compound directly from X-ray diffraction from a single crystal of the compound. The molecular structure results show that the tungsten compound was able to trap 4 hydrogen atoms in a fascinating trapezoidal geometry around the tungsten metal. We will discuss the geometry around the tungsten metal and compare this compound to other similar complexes that have been reported.

27

Novel Methods for Surface Patterning DNA Curtains Dakotah Martinez, A. D. Robison

Department of Chemistry and Biochemistry, Abilene Christian University Division: Biochemistry E-mail: dsm13a@acu.edu Category: Undergraduate This research summarizes novel ways of developing reproducible microfluidic devices by careful cross-disciplined analysis. The purpose of the device is to prototype microfluidic devices for DNA double tethering, imaging, and the analysis of protein repair mechanisms qualitatively and quantitatively. This is done by inventing and designing programmable devices that facilitate the process of microfluidic device production based on designs similar to the operation of vinyl record players or by patterning nanoparticles with solenoid-induced magnetic fields. These methods are novel compared to the traditional “DNA curtain” methods and allow for structural analysis in an elongated, controlled position based on the Worm-Like Chain model of DNA. By using the Law of Cosines and some basic di erential concepts from calculus, both parametric equations and theoretical magnetic field equations were derived, allowing for the formation of two useful patterning mechanisms, one allowing the formation of microfluidic rivulets on the substrate that can be treated with PDMS and a lipid bilayer and one allowing the double tethering of DNA in a reproducible fashion. Through fluorescence microscopy, protein mechanisms will be analyzed thoroughly using advances in chemical and mathematical analysis to provide greater understanding of the physical phenomena by which DNA repair protein mechanisms operate.

28

Synthesis Methods for Au Nanoparticles Frida Verdin and Michael G. Weir*

Department of Chemistry and Biochemistry at Texas Wesleyan Fort Worth Division: Analytical/Nano E-mail: fverdin@txwes.edu Category: Undergraduate Gold nanoparticles (Au NPs) have been synthesized using different methods, with a variety of ligands preventing agglomeration either by stearics or electrostatics. Here we report our comparison of the synthesis of Au NPs with several ligands including citrates, thiols, and PAMAM dendrimers. The size and degree of agglomeration of these nanoparticles were characterized by ultraviolet-visible spectrophotometry and high-resolution transmission electron microscopy. UV-vis spectra show the instability of the NPs by changes in the background absorbance, and both the size and position of the plasmon band. HR-TEM was used to identify that Au NPs synthesized by the citrate method were initially 10 nm in diameter but showed agglomeration as soon as a week's time period and resulting in large aggregates of 20 nm NPs after three weeks. The dendrimer and thiol ligands resulted in NPs with an initial size under 10 nm. We have successfully synthesized Au NPs with different ligands and characterized the size and shape of these NPs. These experiments are necessary precursors for comparison of the electrocatalytic properties of these nanoparticles.

29

High Performance Liquid Chromatography Analysis of the Bioreductive Cleavage of Prodrug KGP372 to Its Effector

Anti-cancer Agent Combretastatin A-4 Nathanael Lutz, Cody Hamrick, Kadon Caskey, Tracy E. Strecker, Yifan

Wang, Matthew T. MacDonough, Kevin G. Pinney, and Mary Lynn Trawick*

Department of Chemistry and Biochemistry, Baylor University

Division: Biochemistry E-mail: Nathanael_Lutz@baylor.edu Category: Undergraduate Regions of hypoxia are common in cancerous tumors and contribute to chemotherapeutic treatment failure and cancer metastasis. Cell studies have demonstrated that NADPH cytochrome c P450 oxidoreductase (POR) is a major enzyme responsible for the activation of the nitrothiophene-containing prodrugs under hypoxic conditions. In cells with standard oxygen levels, any reduced prodrugs are spontaneously re-oxidized. The purpose of this research, collaborative with the Pinney Group at Baylor University, was to analyze the bioreductive cleavage of the prodrug KGP372 to the active anti-cancer agent combretastatin A-4 (CA4) by POR. To ensure hypoxia, the reaction solutions were flushed with nitrogen and incubated with the oxygen scavenging enzyme protocatechuate-3,4-dioxygenase (PCD) and its substrate protocatechuate (PCA). In addition to POR, PCA and PCD, the reactions contained NADPH, Triton X-100 to facilitate solubilization of the prodrug, and KGP372 in phosphate buffer (pH 7.4). Reactions were treated with acetonitrile and analyzed by reversed phase high-performance liquid chromatography (HPLC) using the following mobile phase: 55% acetonitrile/water (10 min), followed by a gradient (30 min) increasing to 95% acetonitrile/water (10 min). Using this method, CA4 and KGP372 standards were eluted from the column with retention times of 6.5 min and 24.0 min, respectively, and detected by absorbance at 254 nm and 300 nm. Standard curves were linear from 2.5-200 µM for both CA4 and KGP372. Reaction samples were analyzed by this method and demonstrated cleavage of the prodrug to CA4. (This study was supported by URSA and CPRIT).

30

Trimming the fat: Applications of lipid nanoparticle nucleotide therapies

Chayton Creswell, Jeremiah Gassensmith* Department of Biochemistry and Chemistry, University of Texas at Dallas

Division: Biochemistry E-mail: chayton.creswell@utdallas.edu Category: Undergraduate Lipid nanoparticles have caught the attention of a portion of the scientific community since their first report in 1964. As therapeutic agents, lipid nanoparticles grant the ability to generate targeted, biocompatible delivery systems that can be tuned to the needs of the therapy. However, the technology is not without flaws. This review examines the use of lipid-based nanoparticles used as a delivery system for various nucleotide based therapies with a focus on liposomes and presents potential future applications of lipid nanovesicles as carriers for genetic therapies as well as potential new methods of lipid nanoparticle formation and the implications of such methods.

31

Session 2: Undergraduate Research II (Organic Chemistry and Polymers)

Pyridine-substitution of Poly(alkyl/arylphosphazenes) Mackenzie Young and Patty Wisian-Neilson*

Department of Chemistry, Southern Methodist University

Division: Inorganic E-mail: mackenziey@mail.smu.edu Category: Undergraduate

Poly(alkyl/arylphosphazenes), [RR'PN]n, are inorganic polymers where both R and R' are directly attached to the phosphorus-nitrogen backbone by P–C bonds. Simple alkyl and aryl groups are attached in the monomer stage, prior to condensation polymerization of precursor Si–N–P small molecules. Like all polymers, changing the side-groups alters the properties of the resulting polymer system. This is exemplified by numerous studies on poly(methylphenylphosphazene), PMPP, 1, where the methyl group is readily modified by deprotonation-substitution reactions. This approach is used here to attach potentially bioactive pyridine groups to the phosphazenes backbone. Treatment of PMPP with BuLi gives an intermediate polymer anion, 2, which reacts with electrophiles allowing for incorporation of new functionality and subsequent alteration of properties of the polymeric materials. In this study, the electrophiles, 2-, 3-, and 4-pyridine carboxaldehyde were used to attach pyridine groups. The pyridine functionality offers a metal coordination site as well as potential antibacterial properties. The synthesis, characterization by NMR spectroscopy, filming properties, and potential applications of this new polymer system will be discussed.

3

21

P N

Ph

CH3

P N

Ph

CH2C OHH

N

x y

..

N C

O

H

_Li+

P N

Ph

CH3

P N

Ph

CH2x y

P N

Ph

CH3n

n-BuLi

P

CH2C OHH

N

4

P

CH2C OHH

N

5

32

Liquid crystalline structure exhibited in achiral poly(naphthyl octadecyl)carbodiimide

Nimmy Babu, Dr. Bruce M. Novak* Department of Healthcare Studies, University of Texas at Dallas

Division: Organic E-mail: babunimmy844@gmail.com Category: Undergraduate Liquid crystals are an intermediate phase of matter that tend to flow like liquids as well as possess some of the properties of solids as a result of the ordered arrangements of the molecules. The three common phases of liquid crystals that occur due to the differing order and alignment of its molecules are cholesteric, smectic, and nematic. Controlling the specific alignment of liquid crystals enable its application in modern technology and science. In this experiment, achiral poly(naphthyl octadecyl)carbodiimide or PNOC was synthesized and dissolved in four different solvents to produce 25wt% and 15wt% solutions. The solutions, at room temperature, were then observed under a polarized light microscope and the corresponding image and phase were recorded. The results showed that in chloroform, the 25wt% solution was in the smectic phase while the 15wt% solution was in the cholesteric phase. In addition, it was found that the 25wt% solution, when dissolved in toluene, was in the chiral smectic phase. However, when the solvent DCM was used, the 25wt% solution was present in a mixture of the cholesteric and chiral smectic phase. It can be concluded that different solvents affect the phase of liquid crystals at varying weight percentages.

33

Liquid Crystalline Structure of S – Poly(phenyl octadecyl)carbodiimide

Ganesa Parmar, Dr. Bruce Novak* Department of Chemistry and Biochemistry, University of Texas at Dallas

Category: Undergraduate E-mail: ganesaparmar@gmail.com Division: Organic Liquid crystal formation occurs as a state between the highly ordered solid state and the unordered liquid state. The molecules align in approximately the same direction which, depending on the type of order, can be characterized as three different types of phases: the smectic, nematic, or cholesteric phase. Furthermore, liquid crystals have many applications in engineering, science, and technology with the most common being liquid crystal displays or LCDs. In this experiment, various molecular weights of S – Poly(phenyl octadecyl)carbodiimide or PPOC (S) were synthesized and dissolved in chloroform in order to create 25wt% and 15wt% solutions. These solutions were observed using a polarized light microscope at room temperature and when heated to 400 C. Additionally, PPOC (S) at 15wt% was also observed while dissolved in THF. It was found that the 25wt% PPOC (S) stayed the same phase despite the difference in temperature while the 15wt% PPOC (S) changed phases.

34

Structural Approach to Predict the Formation of Well Ordered Boronate Ester Based Covalent Organic

Frameworks Gino Occhialini, Christina Thompson, Steven Nielsen, Ronald Smaldone* Department of Chemistry and Biochemistry, University of Texas at Dallas

Category: Undergraduate E-mail: Geo130030@utdallas.edu Division: PMSE/POLY 2d Covalent Organic Frameworks (COFs) are an emerging class of crystalline porous polymers with high surface area, tunable pore sizes, and diverse functionalization potential; because of these properties, COFs are positioned as ideal materials for gas storage and separation, catalysis, and capacitive energy storage. Due to these broad potential applications, it is highly desirable to design and optimize new materials. However, as of yet there is a significant deficit of robust design rules for monomers that self-assemble into crystalline structures. Herein we report a design methodology for predicting whether a given set of monomers will form COFs based upon systematic experimental and computational study. This approach is based upon low-cost computational simulations that are correlated with experimental knowledge of COF success/failure. Ultimately this work represents the exciting potential of refining knowledge of what COFs work prior to the labor of synthesis, thereby allowing the targeted synthesis of only structures that are predicted to form crystalline frameworks.

35

BTDA based polyimides for Gas Separation Membranes Lauren McCaghren, Chamaal Karunaweera, John P. Ferraris*

Department of Chemistry and Biochemistry The University of Texas at Dallas

Division: Polymers E-mail: lqm170030@utdallas.edu Category: Undergraduate For the past several decades research has been conducted on gas separation membranes with the goal of creating a process for membrane fabrication that is commercially viable. Many of these research studies are focused on synthesizing polymers suitable for the separations. Polyimides are a group of high performance polymers that can be used in separating gas pairs such as CO2/CH4 and CO2/N2. Blending polyimides with PBI has proven to be useful in separating H2/CO2, a hard-to-separate gas pair. However, polyimides synthesized using expensive dianhydrides such as 4,4' (hexafluoroisopropylidene)diphthalic anhydride (6FDA) need to be replaced with less expensive alternatives in order for the resulting polyimides to be commercially viable. 3,3',4,4'-Benzophenonetetracarboxylic dianhydride (BTDA) is one of the cheap alternatives that can be used in place of 6FDA. However, BTDA-based polyimides are less soluble in common organic solvents due to the planar nature of BTDA. We will be focusing on synthesizing soluble polyimides using BTDA and various diamines and diamine combinations. Further, the synthesized polymers will be used for membrane-based gas separation experiments.

36

Charge Mediated Cellular Uptake of Qβ VLPs Lana Tuong, Hamilton Lee, Dr. Jeremiah J. Gassensmith* Chemistry Department at the University of Texas at Dallas

Division: Organic E-mail: lht150230@utdallas.edu Category: Undergraduate Nanoparticles show promise in drug delivery systems. Despite this, a major limitation of therapeutic nanoparticle systems is inefficient cellular uptake of these surface-modified nanoparticles. Under the guidance of graduate student Hamilton Lee (Gassensmith Lab), we investigate cell uptake using virus-like particles (VLPs), specifically bacteriophage Qβ (Qβ). Among the many advantages of VLPs are their monodispersity and uniform functionality. We have previously demonstrated the inhibition of cell uptake of Qβ conjugates functionalized on the outer surface with negatively charged moieties. We now insert a switch allowing for stimulus-controlled change in charge and inhibition of cell uptake. We have developed a hydrazone-based switch to target acidic conditions. With the use of an acidic pH stimulus, the properties of hydrazones can be used to cleave off the negatively charged carboxylate group so the VLP can be taken up by the cell. Here, we focus on the synthesis and characterization of Qβ conjugates according to standard chemical and biochemical techniques. Through our research, we hope to be able to understand the role of charge in cellular uptake of VLPs to further progress the potential of the use of VLPs in drug delivery systems.

37

Thermoresponsive behavior in a novel family of single crystal alkoxyphenyl N-substituted naphthalene diimide derivatives Arimilli, Bhargav S1, Dharmarwardana, Madushani1, McCandless, Gregory

T1, Luzuriaga, Michael A1, Lee, Hamilton1, Gassensmith, Jeremiah J*1

1Department of Chemistry and Biochemistry, University of Texas at Dallas, Richardson TX 75080

Division: Organic E-mail: bhargav.arimilli@utdallas.edu Category: Undergraduate Thermochromic compounds, which change color in response to changes in temperature, are widely used in consumer products. Thermochromic properties of liquid crystalline and polymeric systems of naphthalene diimides (NDIs), a class of aromatic, electron-deficient n-type semiconductors, have been previously explored. However, the thermochromic properties of single crystal NDI systems have yet to be reported. In this study, we investigate the thermochromic properties of single crystal alkoxyphenyl N-substituted derivatives of NDIs. Our group previously reported that single crystals of one such NDI derivative – a butoxyphenyl-N-substituted NDI (BNDI) – exhibited thermochromic behavior. We were curious to see whether this behavior occurred in other derivatives within this family. Of the seven compounds evaluated, four were found to exhibit thermochromic properties. We report the thermochromism of pentoxyphenyl- (PNDI), heptoxyphenyl- (HNDI), nonoxyphenyl- (NNDI), and decoxyphenyl- (DNDI) substituted naphthalene diimides. Surprisingly, hexoxyphenyl- and octoxyphenyl- substituted NDIs did not display thermochromic properties. We also synthesized branched derivatives such as a 2-ethylhexylphenyl-substituted NDI, which also did not display thermochromic properties. Thermochromic properties were analyzed using hot-stage microscopy. Single crystals of alkoxyphenyl-substituted NDI derivatives were subsequently grown for single crystal x-ray diffraction (SXRD) analysis using chloroform. SXRD data was collected for the HNDI, NNDI, and DNDI derivatives at variable temperatures.

38

Carbon Electrode Materials through Blending of Immiscible Polymers

Mai N. Nguyen, Juan Alex Garcia, Kenneth J. Balkus, Jr., John. P. Ferraris* University of Texas at Dallas

Division: Analytical E-mail: mnn150230@utdallas.edu Category: Undergraduate Supercapacitors, or electrochemical double-layer capacitors are a widely used energy storage devices desired for their rapid energy delivery and potential for wide stable operating windows at extreme temperatures and pressures. These energy storage devices typically have lower energy capacities then those of some battery devices therefore the goal for many studies into supercapacitors is to improve the energy storage to make them comparable to higher energy storage devices. Two prominent techniques are the modification of the surface area using porogens and incorporation of redox materials for hybrid devices. Previous work has shown the varying degrees of immiscibility in polymer blends can provide different morphologies yielding mesoporosity high mesoporous quality in the resulting carbon fibers. The presented research proposes a facile preparation of carbon fibers from multi-component blends of polymers as opposed to synthesis of co-polymers. The resulting blends can be used in a simple process to incorporate metal oxides into carbon fiber electrode materials through blends of polyacrylonitrile and polystyrene with other sacrificial polymers readily able to complex with metals and metal oxides.

39

Synthesis of Silyl-End Capped Polystyrenes through Hydrogen Atom Transfer

Ashif Karedath, Parham Asgari, Apparao Bokka, Gyu Leem and Junha Jeon*

Department of Chemistry and Biochemistry, University of Texas at Arlington

Division: Organic Chemistry E-mail: ashif.karedath@mavs.uta.edu Category: Undergraduate Controlled polymerization systems resulting in the formation of low PDI polymers is highly sought after. Atom Transfer Radical Polymerization (ATRP) in the presence of a metal-ligand system has been a popular method to achieve these low PDI polymers. ATRP has also showed its non-exclusiveness towards different vinyl monomeric units. We have reported the radical polymerization of styrene initiated by hydrosilane and potassium tert-butoxide in the presence of 18-crown-6 ether. The polystyrene formed contains reactive silicon-end groups, which are useful for customization of properties of the inherently inert polystyrene. Primary, Secondary and tertiary silanes could be inserted in the end groups of the polystyrene compound allowing full customization of end groups. End group analyses were characterized by 1H/13C/29Si NMR and FT-IR spectroscopy. The primary metal-ligand system used was the potassium-18-crown-6 ether coupled complex. GPC results reported that Mn, Mw, Mz and PDI values of the polystyrene respectively were 5,800, 11,400, 22,000 and 1.54. This system opens the possibilities of creating copolymers in a more controlled manner by utilizing the reactive silyl end group.

40

CRYSTAL GROWTH AND STRUCTURE DETERMINATION OF IMIDAZOLE COMPOUNDS

CONTAINING ALLYLIC AZIDES Marcela Torres, Raakiyah Moore, Lorenzo M. Cruz, and Muhammed

Yousufuddin* Life and Health Sciences Department, University of North Texas at Dallas Division: Organic E-mail: marcelatorres947@yahoo.com Category: Undergraduate Allylic azide systems are fairly reactive making them attractive starting compounds to convert into amides. Our group has been collaborating with the Lovely research group at the University of Texas at Arlington to synthesize several azide containing imidazole compounds, grow their crystals, and determine the molecular structure using X-ray crystallography (a technique that uses X-ray diffraction from a single crystal of a compound to determine the structure of that compound). We report here the techniques our group has employed to grow crystals and determine structures along with the synthesis of such compounds.

41

Isolation of osajin from Osage orange and measurement of the Abraham hydrogen bonding acidity value by NMR

spectroscopy Sara Tucka, Margaret J. Rishera, Peter Bella, Michael H. Abrahamb, William

L. Whaleya* aDepartment of Chemistry, Geosciences & Physics, Tarleton State

University, Stephenville, TX 76401, bDepartment of Chemistry, University College of London, London, UK

Division: Organic E-mail: whaley@tarleton.edu Category: Undergraduate Osajin is a diprenylated isoflavone that is present at high concentrations in the fruit of Osage orange (Maclura pomifera). Most commercial preparations of this compound also contain a small amount of pomiferin which is also present in the fruit of Osage orange. These two compounds have similar structures, with pomiferin containing an additional oxygen atom that is not present in osajin. A chromatographic procedure for isolation of highly purified osajin was developed. Several medicinal activities have been reported for osajin; however, the absorption, distribution, metabolism and excretion (ADME) properties of this compound have not been investigated. The Abraham hydrogen bonding acidity (A) is an important physical parameter that is a measure of the ability of a compound to act as a hydrogen bond donor to solvent molecules that act as hydrogen bond acceptors. A method for determining A based on proton NMR spectroscopy was previously used to examine mono-hydroxy and di-hydroxy isoflavones. This same method was used to measure A for osajin; however, the resulting measured value of A was 0.61. This is significantly lower than for 4’-hydroxy-isoflavone (A=0.69). When the concentration of osajin was increased 4-fold in the NMR assay, the apparent value of A was reduced to 0.57. These results indicate that osajin self-associates in the deuterochloroform solvent resulting in a higher chemical shift value which translates to a lower value of A. Previously, evidence for self-association of osajin in aqueous micelles was cited. (This research was supported financially by The Welch Foundation Departmental Research Grant and the Tarleton Research Opportunity Program.)

42

Exploration of Metal-Templated Organogelators for use in Dye-Sensitized Solar Cells

AnnaBeth Thomas, Andrew J. Carr, Ph.D.* Department of Chemistry, Austin College

Division: Organic Chemistry E-mail: aethomas15@austincollege.edu Category: Undergraduate Interest in improving viability of dye-sensitized solar cells (DSCs) has driven recent research in examining metallogels as alternative charge-transfer mediums to traditional liquid electrolytes. Previous work by Carr et al found successful urea-based organogelators capable of forming thermoreversible gels in a variety of organic and inorganic solvents. In this study, urea-based organic compounds containing pyridyl groups L1 (3-{[3-(Hexadecyloxy)-4-methoxyphenyl]methyl}-1-[(4-pyridyl)methyl]urea) and L2 (3-{[3,5-Bis(hexadecyloxy)phenyl]methyl}-1-[(4-pyridyl)methyl]urea) were synthesized in moderate yield, and examined as potential ligands for eventual use in metallogeltion of liquid electrolytes in DSCs. Compound L1 successfully complexed to silver(I) in THF to form amorphous, transient gels. Compound L2 successfully complexed to silver(I) in a mixture of THF/octane and in octane to form strong, durable gels. Critical concentration experiments established the in situ metallogelators as capable of forming super-metallogels in octane:THF combination systems (less than 0.46 wt %, 2.16 mM). Experiments examining the metallogel formation between the aforementioned ligands and other metals such as copper(II) are currently being conducted.

Figure 1: Ligands L1 & L2, R = C16H33

NNH

NH

O

OR

OR

NNH

NH

O

ORO

L1 L2

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Spent Coffee Grounds as an Alternative Green Source of Biodiesel

Colleen Mills, Aima Ovai, Olga Papadopoulou, Martha Gilchrist* Department of Natural Science, Tarrant County College South Campus

Division: Green Chemistry E-mail: colleen.mills@my.tccd.edu Category: Undergraduate Burning fossil fuels contributes to climate change caused by excessive greenhouse gas emissions. Biodiesel, used as fuel, contributes minimal amounts of CO2 to the atmosphere. Triglycerides from corn, soybeans, and other crops are often used to produce biodiesel, but any triglyceride is a potential precursor. The production of coffee beverages generates a substantial amount of triglyceride containing waste. According to the international coffee organization 8 billion kilograms of coffee beans a year are produced. In this study we are investigating the potential use of landfill-bound spent coffee grounds (SCG) as viable source of biodiesel. SCG were air dried for two weeks and then extracted with hexane. The isolated coffee oil was transesterified with methanolic NaOH. The resulting biodiesel was extracted and analyzed by NMR spectroscopy, gas chromatography, infrared spectroscopy. Preliminary results agree with work by Misra et al. and Sharma et al. that spent coffee grounds are a feasible source for biodiesel.

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Catalytic Hydrothermal Liquefaction of Chlorella into Bio-Oil

Sam Kaiser and Ben Jang* Texas A&M University - Commerce Department of Chemistry Energy and

Fuels (ENFL) Division

Division: Biological E-mail: samuel.J.Kaiser@gmail.com Category: Undergraduate The purpose of this research is to effectively convert algae to bio-oil through hydrothermal liquefaction (HTL) with both homogeneous and heterogeneous catalysts. The selected biomass is a broken-cell wall algae powder of the genus, Chlorella. The carbon fixating properties of the biomass feedstocks could counteract, or neutralize, the amount of greenhouse gasses emitted when burning the resultant oils as fuel. Based on its carbohydrate/ protein content and lipid density, Chlorella was chosen for its potential to produce high yields of bio-oil with higher energy contents. The further study of catalytic effects on the hydrothermal liquefaction process has led to higher yields of oil in comparison to the non- catalyzed HTL process, with similar energy content of about 34 MJ/kg based on CHNO analysis and bomb calorimetry. Investigated catalysts include a homogeneous catalyst, Calcium Nitrate Ca(NO3)2, and a heterogeneous catalyst, Y Zeolite; both catalysts were tested at 1, 2, and 5% loadings across a temperature range of 275 to 350°C. The various bio-oil samples were compared by their yield after HTL, and analyzed via Gas Chromatography/Mass Spectrometer, as well as CHNOS and energy content analyses. The characteristics of the bio- oils will be summarized and discussed.

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Synthesis and gelation tests of 2,5 bis-urea organogel with C12 tails

Matthew Tran and Andrew Carr* Department of Chemistry, Austin College

Division: Organic E-mail: mtran16@austincollege.edu Category: Undergraduate Due to the demand for oil in the modern age, oil shipping and transportation is abundant. However, oil spills do occur, with current methods for remediation including oil dispersants or boom and skimmers. This leads to less oil available for human consumption or is expensive to use. An alternative to these methods is the usage of organogelators to solidify the oil to make it easier for retrieval. A compound that solidifies the oil is known as an organogelator. A class of gelators with 2 urea units has been studied and has been shown to gel organic solvents at superorganogelator concentrations (sub 1 w/w%). The presence of alkyl tails on the periphery of the molecule has been shown to aid in the gelation ability of these molecules. A derivative of the bis-urea molecule with tails on the 2 and 5 positions on the aromatic ring have been synthesized from 2,5 didodecoxybenzaldehyde, and critical concentrations have been determined in toluene (2 w/w%) and octane (1 w/w%). These gels set in hours unlike the 3,5 derivative that sets in 20 minutes or less. This increased time could be beneficial as it lends more time for mixing and dispersal into the oil before gelation.

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The Exploration of Aldol Condensation and Imination towards the Synthesis of Bisurea Organogelators

Anh-Thu Pham, *Dr. Andy Carr Chemistry, Austin College

Division: Organic Email: Atpham15@austincollege.edu Category: Undergraduate Thermoreversible organogelators’ practical applications vary from improving the safety and efficiency of oil transportation and clean up, to being a valuable tool in the medical industry. The utilization potential of thermoreversible organogelators entails further exploration of the chemistry. Preceding literature have found bis ureas organogelators with increasing alkyl tail lengths have increased the Van der Waals surface area in self-aggregation resulting in better and sturdier gels. We predicted the differing tail types would make the organogelator adept in gelling a more diverse array of organic solvents, both polar and nonpolar. Thus, we explored the aldol condensation and imination reaction. The aldol condensation products were difficult to isolate; once they were converted to urea, the organogelator failed to gel octane and toluene. The imine reaction’s product, once converted to urea, yielded a super organogelator. The super organogelator, made from the imine product, gelled octane and toluene at 0.35 weight % and 0.63 weight % respectively.

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Session 3: Biological Chemistry

Oxidative stress sensing mechanisms in ZEITLUPE Robert Green, Brian D. Zoltowski*

Department of Chemistry, Southern Methodist University Division: Biochemistry E-mail: robertg@smu.edu Category: Graduate Organisms have evolved to sense and adapt to daily and seasonal environmental ques to maximize their fitness through biological responses. Proteins containing Light, Oxygen, or Voltage (LOV) domains act at signaling nodes to integrate oxidative stress, metabolism and light into circadian, reproductive and stress pathways. In plants the ZEITLUPE (ZTL) family of blue-light photoreceptors are responsible for integrating these signals into circadian and photoperiodic responses by allosteric regulation. These mechanisms are likely conserved in plants, fungi and mammals but are still poorly understood. To better understand the allosteric mechanisms that allow ZTL signaling, we focused on residue G46 which is in close proximity to Q154, a residue involved in signal transduction. Mutating this residue to S46 forces Q154 to a buried conformation which mimics the light-state. This allows direct analysis of the light-driven global conformational response. Using chemical, biophysical, and in vivo approaches we have identified oxidative stress sensing mechanisms in ZTL that integrate environmental stress, light and circadian function.

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Elucidating the thermodynamics of LOV domain adduct formation in YtvA

Nischal Karki and Dr. Brian Zoltowski Department of Chemistry; Southern Methodist University

Division: Biological Chemistry E-mail: nkarki@smu.edu Category: Graduate Sun is the ultimate source of energy for almost all organisms on earth. As such, the ability to keep track of sunlight has evolved in most organisms for efficient mobilization and, in photosynthetic organisms, collection of energy. Many higher plants utilize a blue light sensitive protein domain to keep track of when to expect light and ensure efficient capture of light throughout the day. These proteins have a Light-Oxygen-Voltage-sensing domain (LOV domain) that binds flavin mononucleotide (FMN) non-covalently in its dark state and forms a covalent adduct between a conserved cysteine and FMN cofactor in its light state. This differentiation in light/dark state is utilized to conformationally alter the protein and relay the signal to effector domains. Adduct decay in the absence of light returns the protein to the dark conformation, allowing adaptation to changing levels of blue light. The light to dark recovery has been studied extensively in LOV domains from various organisms and the ability to tune the recovery rate using temperature, ionic environment, and point mutations. One such LOV-domain containing protein, expressed by Bacillus subtilis, is called YtvA. The kinetics of adduct decay of YtvA has been previously studied and the thermodynamics of the reaction characterized. The mechanism of adduct formation has also been studied extensively; however, the temperature dependence has not been characterized in detail. In this study, we demonstrate the quantum yield of light absorbance during adduct formation as a function of temperature. We verified our method by comparing the activation energy and enthalpy of activation during adduct decay to the literature which is 81.9kJ and 79.5kJ respectively. We hope to open the doorway to modulate the adduct formation by establishing an effective method to measure the quantum yields.

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Study of LOV domain chemistry of Brassica rapa and understanding their role in the crop productivity

Aditi Nagar, Dr. Brian D. Zoltowski* Department of Chemistry, Southern Methodist University, Dallas, TX.

Division: Biochemistry E-mail: aditin@smu.edu Category: Graduate Global population growth has posed an unprecedented demand for the agricultural and natural resources. The gap between the crop production and demand is extensive and is expected to grow in years to come. With this rate, the predicted requirement for the agricultural supply is anticipated to be doubled by the year 2050. Circadian rhythm is a 24-hour autonomous biological cycle and has been shown to play a critical role in the crop productivity. Plants being sessile employ several photoreceptor proteins which sense broad spectrum of light and facilitate the growth and development of the plant. In Arabidopsis thaliana, LOV domain proteins like Zeitlupe (ZTL), flavin binding kelch repeat F-box1 (FKF1) and LOV Kelch protein2 (LKP2) employ small molecule flavin chemistry to measure the day length and hence determine the flowering time and regulate the other circadian processes. This research, however, mainly focuses on studying LOV domain proteins of Brassica rapa (includes turnip, napa cabbage, Chinese cabbage, etc.) which is one of the major agricultural crops. The research employs several biophysical techniques to understand the architecture of LOV domain proteins and their chemistry. Hence thereby anticipated to assist in enhancing the productivity and will eventually facilitate in bridging that gap of supply and demand of major crops.

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Structural approach to study Rtt109-Vps75 interactions and dynamics in complex with histones H3 and H4

Noushin Akhavantabib, Dr. Sheena D’Arcy* Department of Chemistry and Biochemistry, University of Texas at Dallas

Division: Biochemistry and Structural Biology E-mail: nxa161130@utdallas.edu Category: Graduate Rtt109 is histone acetyltransferase that works in concert with histone chaperones Vps75 and Asf1 to acetylate multiple histone H3 residues in yeast. These histone modifications have shown essential role in maintaining genomic stability and DNA repair-coupled nucleosome assembly. Rtt109 has shown potential for therapeutic applications in Pneumocystis pneumonia associated with HIV and other immunosuppressing diseases. We optimized co-expression and purification of Rtt109-Vps75 in Escherichia coli using immobilized metal affinity and ion exchange chromatography. One challenge in studying the complex between Rtt109, Vps75, and histones H3-H4 is understanding the stoichiometry of the complex. Current crystal structures of Rtt109 and Vps75 show either a 1:2 or 2:2 complex. We determined the stoichiometry to be 1:2 (1 monomer of Rtt109 binds to a dimer of Vps75) using wild type and mutant proteins by utilizing Size Exclusion Chromatography coupled to Multi-Angle Light Scattering (SEC-MALS). Determining the crystal structure of the most homogenous and active complexes is currently under experimentation. The crystal structure will yield high-resolution structural information about the protein complex, an essential stepping stone in designing small molecules that interfere with Rtt109 activity.

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Figure 2: Confocal Images of RAW 264.7 cells incubated in Dulbecco’s Modified Eagle Medium with A) PBS B) Doxorubicin C) Qβ@AuNP D) Qβ(Dox)@AuNP. Each sample was imaged 2 hours after incubation and immediately after laser irradiation. The fluorescence Dox can be seen using the RFP filter.

Site Selective Nucleation and Growth of Gold Nanoparticles on the Pore Structures of a Virus

Candace E. Benjamin, Zhuo Chen, Blake A. Wilson, Peiyuan Kang, Na Li, Steven O. Nielson, Zhenpeng Qin, and Jeremiah J. Gassensmith*.

The University of Texas at Dallas – Chemistry Department Division: Biological Chemistry E-mail : ceb150230@utdallas.edu Category: Graduate Student Site specific delivery of drug molecules to target tissues provides a means for effective dosing while possibly reducing the adverse side effects often associated with systemic drug administration. To achieve this specificity in delivery, we have employed the

virus-like particle (VLP) Qβ as a proteinaceous drug carrier capable of release via precise external stimulus.

We have shown that this viral capsid is capable of holding upwards of 500 molecules of the anti-cancer drug Doxorubicin within its genetic material. Additionally, using gold’s natural affinity for sulfur, the VLP

provides a template for the facile synthesis of ~6 nm gold nanoparticles. The complete system allows for payload release upon stimulation by a single six nanosecond pulse green laser. We hypothesize that the laser energy is absorbed by the gold nanoparticles which is then converted to thermal energy that denatures the

protein capsid releasing the encapsulated Doxorubicin. This system denoted as Qβ(Dox)@AuNP has been tested in RAW 264.7 macrophages and have been shown to exhibit uptake and release such that a) the laser light itself does not harm cells and b)

when masked, cells containing Qβ(Dox)@AuNP only release Dox if present in the laser path of green laser.

Figure 1: Qβ possesses 32 pores, each either 1.5 or 3.0 nanometers in diameter, which are large enough to permit A) the diffusion of Doxorubicin into and out of the VLP; after loading, the pores are then B) capped by ~6 nm AuNPs grown in situ.

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Understanding metal selectivity in metallothionein-3 Jenifer Calvo1, Victor Lopez and Gabriele Meloni1*

1Department of Chemistry and Biochemistry The University of Texas at Dallas, Richardson, TX 75080, USA

Division: Biochemistry E-mail: Jenifer.Calvo@utdallas.edu Category: Graduate Metallothioneins (MTs) are small, cysteine-rich proteins capable of binding d10 metal ions with high affinity thereby playing major roles in metal storage and detoxification. Out of the four MT isoforms in mammals (MT-1/4), only MT-3, an isoform expressed in the brain, exhibits growth inhibitory activity and protects neurons from amyloid-β toxicity. Despite the conservation of all 20 cysteines which coordinate Zn(II) or Cu(I) in metal thiolate clusters in all isoforms, MT-3 show a copper-thionein character while MT-2 possess higher zinc selectivity - a feature that underlies MT-3 function. To understand this difference in metal selectivity, we used a spectroscopic approach to study rates of Cu(II) reduction and Cu(I) binding to MT-3 and MT-2 and reveal that Zn7MT-3 binds Cu(I) significantly faster than Zn7MT-2. Using competition assays with metal selective chelators, we show that Cu(I)4Zn4MT-3 possess a higher affinity for Cu(I) than MT-2, whereas Zn7MT-2 possess higher affinity for Zn(II) than MT-3. From mutational studies, we showed that the Thr-Cys-Pro-Cys-Pro motif unique in MT-3 is mainly responsible for its faster Cu(I)-binding kinetics and its metal selectivity bias for Cu(I). We revealed that the noncoordinating residues in MT-3 impart a unique metal selectivity and reactivity which are fundamental for its biological roles.

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Inhibition of Cancer Metastatic Progression: Targeting FOXC2 and the Epithelial Mesenchymal Transition

Maria Castaneda, Luxi Chen, Ruba Zein, Jiyong Lee* Department of Chemistry and Biochemistry, University of Texas at Dallas

Division: Biochemistry E-mail: Mxc117930@utdallas.edu Category: Graduate Student Patients diagnosed with cancer face two main challenges: chemoresistance and metastasis. A focus in solving these challenges has been on targeting the epithelial-mesenchymal transition (EMT). In order to halt and better understand EMT we have targeted the transcription factor FOXC2, required for the initiation and maintenance of EMT and acquisition of chemoresistance, hoping to lead in the development of a therapeutic agent for the treatment of metastatic cancers. We have isolated the first small molecule FOXC2 ligand using a one-bead-one compound screening method utilizing an alpha-helix mimetic library. In vitro assays on full-length FOXC2 as well as endogenously expressed FOXC2 have proven the specificity and affinity of the ligand. We have shown decrease in metastatic potential in both breast and prostate cancer through examination of cancer stem cell markers, EMT markers and transwell invasion assays. Current studies are on the ligand’s effect on FOXC2 transcriptional activity and mode of action. Preliminary data suggests the ligand is able to cause FOXC2 degradation through disruption of phosphorylation mediated translocation. As the first FOXC2 inhibitor this ligand will lead a new wave of cancer therapeutics targeting not only the primary tumor, but also metastatic sites and help in unraveling the initiation of metastasis.

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Dual Functionalized Bacteriophage Qβ as a Photocaged Drug Carrier

Zhuo Chen, Jeremiah J. Gassensmith*

Department of Chemistry and Biochemistry, The University of Texas at Dallas

Division: Biological E-mail: zhuo.chen1@utdallas.edu Category: Graduate Virus-like particles (VLPs) are proteinaceous nanoparticles that emerged to be robust and uniform platform for biomedical research. VLPs are derived from natural virus, which possesses highly repetitive and multivalent structures. Conjugations reactions have been utilized to functionalize the viral capsid and introduce therapeutic drugs, imaging agents and fluorescence tags, et al. In this work, bacteriophage Qβ VLP was used as a photocaged drug carrier for controlled drug release, which can be stimulated by UV irradiation. About 530 doxorubicin complexes with photo-linkers were attached on the surface of Qβ through CuAAC reaction, however, the conjugate tended to precipitate and cause cell death at higher concentration in dark. In order to increase the solubility and stability, thiol-dibromomaleimide chemistry was induced to functionalized the disulfides on Qβ with polyethylene glycol (PEG). The dual-functionalization of Qβ VLPs with PEG and doxorubicin resulted highly stable conjugate in media and negligible cytotoxicity before photo-stimulation, as well as highly controllable photorelease after activation.

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Computationally-guided engineering of genetically encodable fluorescent biosensors for cellular chloride

Hsichuan Chi, Paarth Kapadia, Jessica Lee, Jasmine N. Tutol, Faruck Morcos, and Sheel C. Dodani*

Department of Chemistry and Biochemistry, University of Texas at Dallas Division: Chemical Biology E-mail: Hsichuan.Chi@utdallas.edu Category: Graduate Genetically encodable fluorescent biosensors have revolutionized our ability to monitor ions in living cells. In this context protein-based biosensors to study cations in cellular signaling are well-developed and widely used but remain largely underexplored for anions due to the inherent challenge of anion binding in water. Along these lines, we have recently discovered that a single point mutation can convert fluorescent proton- pumping proteins called rhodopsins into turn-on fluorescent rhodopsin sensors for chloride, the most abundant biologically relevant anion. In this presentation, we will present a novel computationally-guided approach to improve the properties of these rhodopsin-based fluorescent chloride sensors for cellular imaging applications.

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Temperature Dependence of Proton NMR Relaxation Times at Earth’s Magnetic Field

Fatemeh Khashami1, Peter Niedbalski2, Christopher Parish1, David Clark1, Qing Wang1 and Lloyd Lumata1*

1Department of Physics, University of Texas at Dallas, 800 West Campbell Road, Richardson, TX 75080 USA

2Center for Pulmonary Imaging Research, Cincinnati Children’s Hospital Medical Center, 3333 Burnet Avenue, Cincinnati, OH 45229 USA

Division: Biochemistry E-mail: fxk160330@utdallas.edu Category: Graduate The earth’s magnetic field is highly uniform which is required for high-resolution nuclear magnetic resonance (NMR) spectroscopy. In this study, we have investigated the spin-lattice relaxation time (T1) of water-glycerol mixtures at earth's magnetic field (1700 Hz). The water proton T1s at different ratios of water-glycerol contents were measured at different temperatures ranging from -20 oC to 90 oC. Our results indicate that water proton T1 increases linearly with temperature, from ~2 s at 20 oC to ~6.6 s at 78.9 oC. However, the addition of high glycerol content as a mixture decreases the slope of this linear relationship and, in fact, disrupts the linearity of this behavior at low temperatures. A slight turnover of the T1 slope occurs at temperatures close to -20 oC which is indicative of the effect of changing correlation time. These results are discussed in light of the Bloembergen-Pound-Purcell (BPP) theory.

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Isolation of Breast Cancer Stem Cells via a synthetic binder Chao Long, Dr. Luxi Chen, Kha Andy Minh Tran, Prof. Dr. Jiyong Lee*

Department of Chemistry and Biochemistry, University of Texas at Dallas Division: Biochemistry E-mail: cxl135330@utdallas.edu Category: Graduate student Cancer stem cells (CSCs), also termed as tumor-initiating cells (TICs), are implicated in drug resistance, cancer metastasis and recurrence. A novel binder to CSCs might not only provide a chemical tool of studying CSC’s mechanism, but also a lead for imaging, diagnoses or therapies of targeting CSCs. Herein, a synthetic ligand CL-1-19-1(#1) that specifically binds to CSC subpopulation over non‐CSC subpopulations of breast cancer was identified via a high throughput cell‐based screening from one-bead-one-compound (OBOC) combinatorial peptoid library. #1 bound to CD24−/CD44+/ALDH+ CSC phenotype of MCF‐7 and MDA‐MB‐231 specifically. Our data has shown that #1‐immobilized beads can be utilized as a tool of isolating CSC population from breast cancer cells. The #1‐binding population demonstrated higher expressions of stemness‐associated transcription factors. Moreover, the #1‐binding population showed higher tumor growth rate in vivo, and cells from the tumors exhibited an increased expressions of CSC markers and migratory activity. In summary, CL-1-19-1 has been identified as the first synthetic binder of breast CSC.

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Tracking leucine metabolism in cancer cells via 13C NMR spectroscopy

Christopher Parish1, Peter Niedbalski2, Fatemeh Khashami1, Qing Wang1, Aya Cloyd1 and Lloyd Lumata1*

1Department of Physics, University of Texas at Dallas 2Center for Pulmonary Imaging Research, Cincinnati Children’s Hospital

Medical Center Division: Biochemistry E-mail: crp108020@utdallas.edu Category: Graduate Nuclear magnetic resonance (NMR) spectroscopy is relatively insensitive due to the weak magnetic moments of nuclei, especially those with low gyromagnetic ratio (γ) such as 13C (γ = 10.705 MHz/T). Fortunately, a technique known as dynamic nuclear polarization (DNP) enhances the NMR signals by transferring the much higher electron (γ = 28,000 MHz/T) polarization to nuclei. Furthermore, the invention of dissolution DNP in 2003 has expanded DNP’s large signal enhancement (more than 10,000-fold) to the biomedical realm. Significantly, dissolution DNP allows real-time tracking of metabolism via labeling the relevant substrate with 13C. This study examined the real-time cancer cell enzyme kinetics involved in the metabolism of [1-13C] alpha-ketoisocaproate [!-KIC] into [1-13C] leucine and vice versa. Results of in vitro conventional 13C NMR of cell extracts and hyperpolarized 13C NMR of living cancer cells will be discussed in the context of biochemical kinetics and possible diagnostic application.

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Genetically Encodable Fluorescent Sensors for Probing Cellular Chloride

Jasmine N. Tutol, Jessica Lee, Hsichuan Chi, Farah N. Faizuddin, Sameera S. Abeyrathna, Gabriele Meloni, and Sheel C. Dodani*

Department of Chemistry and Biochemistry, University of Texas at Dallas Division: Chemical Biology E-mail: Jasmine.Tutol@utdallas.edu Category: Graduate Chloride is the most abundant, biologically-relevant anion with concentrations ranging up to 100 mM inside the living cell. It is linked to numerous cellular functions including cell volume, pH regulation, cell division, muscle contraction, and neuroexcitation. Chloride transport dysregulation is also implicated in human disease such as cystic fibrosis, pancreatitis, and epilepsy suggesting that chloride levels could be a signal of cellular status. However, we lack a molecular level picture of how cells regulate inter/intracellular chloride dynamics in this context. Existing quinolinium/acridinium-based dyes and yellow fluorescent protein-based sensors can be a biocompatible approach for imaging cellular chloride, but these sensors turn-off in response to chloride and can be pH dependent, translating into high background emission, loss of spatial and temporal resolution, thus requiring rigorous controls. A turn-on fluorescent sensing approach can provide an alternative to the current state of the art but is largely underdeveloped. In this presentation, we will describe the development and applications of genetically encodable, rhodopsin-based turn-on fluorescent chloride sensors for studying cellular chloride dynamics.

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Magnetic Field-Dependent Lifetimes of Hyperpolarized 13C Spins at Cryogenic Temperature

Qing Wang1, Peter Niedbalski2, Christopher Parish1, Fatemeh Khashami1, Andhika Kiswandhi1, Lloyd Lumata1*

1Department of Physics, University of Texas at Dallas, 2Center for Pulmonary Imaging Research, Cincinnati Children’s Hospital

Medical Center

Division: biochemistry E-mail: qxw151230@utdallas.edu Category: graduate In recent years, dynamic nuclear polarization (DNP) has emerged as an important subset of the magnetic resonance field. While this takes several forms, the basic principle common to all flavors of DNP is that high polarization is transferred from electrons to nuclei, enabling drastic signal enhancements for many different nuclei. As DNP technology expands, new experiments not previously possible are brought to fruition. One avenue explored in this work is the study of the magnetic field dependence of relaxation times of 13C-labeled biomolecules at cryogenic temperatures. Using novel homebuilt DNP instrumentation, we could study relaxation times at 2 K for four different 13C-labeled biomolecules between 0.8 and 9 T. We found that, for each of the four biomolecules studied ([1-13C] pyruvate, [1-13C] Acetate, [1-13C] Glycine, and [1-13C] pyruvic acid), the T1 at 2 K had a power law dependence on magnetic field (! 1 = "#a) with " between 2.3 and 3.1. T1 also had a strong dependence on the concentration of biomolecule and the proximity of protons to 13C within the biomolecule. These considerations were used to create a data fit using a linear superposition of electronic and nuclear effects on relaxation, which gave good agreement with the data.

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lncRNA HOTAIR in immune response Monira Obaid and Subhrangsu S. Mandal*

Department of Chemistry and Biochemistry, University of Texas at Arlington

Division: Biological E-mail: monira.obaid@mavs.uta.edu Category: Graduate The mammalian immune system orchestrates innate and adaptive immune responses that are complex biochemical processes regulated by various protein and lipid mediators such as cytokines, chemokines, hormones, growth factors, and others. The emerging evidences suggest that non-coding RNAs (ncRNAs) play vital roles in regulation of immune responses. I am studying the functions of a long noncoding RNA (lncRNA), called HOTAIR (HOX antisense intergenic RNA) in the regulation of cytokine expression and immune response. HOTAIR is a 2.3 kb lncRNA which is well-known to play key roles in gene silencing. HOTAIR is overexpressed in variety of cancers. Here, we aim to explore potential roles of HOTAIR in immune response. Interestingly, we have found that expression of HOTAIR is induced in macrophages (immune cells) upon treatment with lipopolysaccharide (LPS). Knockdown of HOTAIR has reduced the LPS-mediated activation of critical cytokines (such as IL-6) and iNOS (inducible nitric oxide synthase) in macrophages. These observations suggest that HOTAIR plays crucial roles in cytokine signaling and immune response. Our mechanistic analyses show that HOTAIR regulates NF-κB activation and hence its down-stream targets such as cytokine expression.

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Single Amino Acid Substitution in MiaE shows unique shift in chemical reactivity towards aryl-N-amine Oxidation

Philip M. Palacios and Brad S. Pierce* Department of Chemistry and Biochemistry, University of Texas-Arlington

Inorganic Division

Division: Biochemistry (Inorganic) E-mail: Philip.Palacios@mavs.uta.edu Category: Graduate Non-heme enzymes have historically attracted considerable interest in the field of bioinorganic chemistry. This focus of research efforts is generally attributed to the vast number of functionally (and structurally) diverse enzymes identified throughout the biological kingdom and the versatility exhibited in chemical oxidations (mono- and dioxygenations, aliphatic desaturation) they initiate. Recently, two non-heme diiron enzymes, AurF and Cml I, were identified to catalyze the 6-electron oxidation of an aryl-amine substrate to produce an aryl-nitro product. With the notable substitution of a pendant water/hydroxide ligand for an additional His residue, the diiron coordination sphere for the aryl-N-oxygenase AurF is super imposable with that of the O2-dependent tRNA-monooxygenase, MiaE. In this work, the L199H active site variant of MiaE was produced to investigate the impact of Fe-site first coordination sphere in directing monooxygenase versus aryl-N-oxygenase chemistry. In addition to activity studies, a variety of spectroscopic techniques were utilized to (UV-visible, EPR, and Mössbauer) for comparison of the active site electronic structure to known aryl-N-oxygenase enzymes.

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Amplification of Salt-Induced Protein Diffusiophoresis by Varying Salt Nature

Aisha Fahim, Onfrio Annunziata* Department of Chemistry and Biochemistry Texas Christian University,

2800 S. University Drive, Fort Worth, TX 76129 (USA),

Division: Biological Email: aisha.fahim@tcu.edu Category: Graduate Diffusiophoresis is the migration of a relatively large particle (e.g., protein, polymer, nanoparticle) induced by a gradient of salt concentration. The salt-induced diffusiophoresis of lysozyme, a model protein, at pH 4.5 and 25 °C was examined as a function of salt concentration for three chloride salts: NaCl, KCl and MgCl2. Diffusiophoresis coefficients were theoretically extracted from experimental multicomponent diffusion data by applying irreversible thermodynamics. A selected mass-transfer process was theoretically examined to show that concentration gradients of MgCl2 produce significant lysozyme diffusiophoresis. The dependence of lysozyme diffusiophoresis on salt nature was theoretically examined and linked to protein charge. The effect of salt type on hydrogen-ion titration curves was experimentally characterized to understand the role of salt nature on protein charge. Our findings indicate that diffusiophoresis may be exploited for diffusion-based separation of proteins in the presence of salt concentration gradients and for the enhancement of protein adsorption onto solid surfaces relevant to biosensing applications.

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Session 4: Computational Chemistry

A new quantum chemical toolbox for structural biology – applied to the building blocks of DNA

Nassim Beiranvand, Elfi Kraka* Computational and Theoretical Chemistry Group (CATCO), Department

of Chemistry Division: Computational Chemistry E-mail: nbeiranvand@smu.edu Category: Graduate Deoxyribonucleotides are the building blocks of DNA that is vital for all living organisms and even plants. Deoxyribonucleotides consist of three major components: a sugar ring, a phosphate group and a nitrogenous base. The four deoxyribonucleotides differ according to the base attached to the deoxyribose sugar; deoxycytidine, deoxythymidine, deoxyadenosine, and deoxyguanosine. We have analysed the conformational energy and geometrical parameters of the deoxyribonucleotides along their conformational paths traced out by the 5-memberd sugar ring to understand the correlation between ring puckering and internal hydrogen bonding, which strongly contributes to the shape of the DNA determining its biological functions.We have used a combination of the Cremer-Pople Ring Puckering Analysis [1] and the Local Mode Analysis of Konkoli and Cremer, [2] which describe conformational processes at the quantum mechanic level. First results show that the global minima of all deoxyribonucleotides adapt a twist form of the sugar ring. The planar ring forms are less stable by about 5 kcal/mol.The Local mode analysis along the conformational path reveals that the number of H-bonds and their strength change during puckering process. While the global minima have 3 hydrogen bonds the envelope forms have at most 2 hydrogen bonds.

[1] Cremer,D; Pople.J; General definition of ring puckering coordinates, J.Am.Chem.Soc, 1975, 97 (6), 1354–1358. [2] Konkoli,Z;Cremer,D; A new way of analyzing vibrational spectra. I. Derivation of adiabatic internal modes, International Journal of Quantum Chemistry, 1998,67, 19.

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Mechanistic differences between class A β-lactamases and penicillin binding proteins revealed from molecular dynamics

simulations Feng Wang, and Peng Tao

Department of Chemistry, Southern Methodist University Division: Computational Chemistry E-mail: fengw@smu.edu Category: Graduate student β-Lactamases are the enzymes produced by bacteria to resist antibiotics such as penicillins and cephalosporins. The overuse of antibiotics leading to fast evolution of β-lactamases results in the antibiotics resistance posing a serious threat on the public health. The dynamical interactions between antibiotics and β-lactamases are essential for the function of β-lactamases and could facilitate the development of antibacterial drug design and investigating the catalytic mechanism of β-Lactamases. TEM-1 and TOHO-1 are classified into class A β-lactamases, which are the most common β-lactamases. Penicillin binding protein A (PBP-A) and DD-transpeptidase are penicillin binding proteins that are evolutionarily related to class A β-lactamases. Understanding the evolutionary relation between class A β-lactamases and penicillin binding proteins including dynamical properties may provide insight into functional differences among these enzymes. In this study, we carried out molecular dynamic (MD) simulations of TEM-1, TOHO-1, PBP-A and DD-transpeptidase, including reactant, intermediate and product states along the reaction pathway. We applied the conformational distributions and Markov states model analysis on the MD simulations. Our detailed analyses provide a new insight into interactions between antibiotics in different catalytic states and enzymes, leading to a novel view on the development of antibiotics and drug design.

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Trans Ligand Substitution in [NiFe] Hydrogenases: A Novel Method for Enhancing Hydrogen Production

Malgorzata Z. Makos, Marek Freindorf, Mansoor Khan, Elfi Kraka Computational and Theoretical Chemistry Group (CATCO)

Department of Chemistry, SMU, Dallas, Texas, USA Division: Computational E-mail: mmakos@smu.edu Category: Graduate [NiFe] hydrogenases are enzymes that contain an unusual bimetallic cluster centre being composed of nickel and iron. These enzymes provide energy to an organism and balance a redox potential of its cells by activating hydrogen. Several studies have shown that hydrogenases are able to serve as clean energy carriers or potential transportation fuel. In this work, we present two models of the [NiFe] hydrogenase active site, each containing two phosphine groups PH3 and a ligand L in a trans position relative to an active site of the bimetallic cluster. The ligand L is modified in our study in order to monitor the Fe-H and H-H bond strength, which is essential for cleavage of the hydrogen molecule in the enzyme catalytic activity.

The strength of the Fe-H and H-H bonds is determined in our study by the Konkoli−Cremer local mode model [1], and the covalent character of the Fe-H and H-H bonds is monitored by an energy density at the bond critical point, according to the Cremer-Kraka criterion [2]. We observe in our calculations that those ligands, which make the Fe-H bond weaker in both models (e.g., -CH3 or -NO2), make the H-H bond stronger. On the other hand, those ligands which make the Fe-H bond stronger in both models (e.g., NH3 or H2O), make the H-H bond weaker. [1] Zou, W.; Kalescky, R.; Kraka, E.; Cremer, D. Relating normal vibrational modes to local vibrational modes benzene and naphthalene. J. Chem. Phys. 2012, 137, 084114−084127. [2] Kraka, E.; Cremer, D. The Concept of the Chemical Bond; In Theoretical Models of Chemical Bonding.; Maksic, Z., Ed.; Springer Verlag: Heidelberg, Germany, 1990 Vol. 2 pp 453−542.

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A NEW WAY OF STUDYING CHEMICAL REACTIONS: A HAND-IN-HAND URVA AND QTAIM APPROACH

Sadisha Nanayakkara,Velmurugan Gunasekaran, and Elfi Kraka Computational and Theoretical Chemistry Group (CATCO), Department

of Chemistry, Southern Methodist University Division: Computational E-mail: snanayakkara@smu.edu Category: Graduate The Unified Reaction Valley Approach (URVA) [1] focuses on the close relation between reaction complex the reaction path it traces on the potential energy surface during a chemical reaction. The curving of the reaction path reflects all electronic changes taking place, e.g. curvature peaks are the locations where bonds are broken or formed. In the Quantum Theory of Atom-in-Molecule (QTAIM) Analysis [2], changes in the topological properties of electron density r(r) are used to monitor bond forming/breaking events. Two atoms forming a chemical bond are connected by a bond path, which disappears if the bond is broken. In the present work, we systematically compared these two approaches for a series of chemical reactions including the hydrogen migration in HN2+, the CH3 + H2 reaction as well as the Gold(I) catalyzed [3,3]-sigmatropic rearrangement of allyl acetate. In the close vicinity of a curvature peak indicating a significant change in the reaction complex, we could observe notable changes in the r(r) bond path too.

[1] Zou, W.; Sexton, T.; Kraka, E.; Freindorf, M.; Cremer, D.; A New Method for Describing the Mechanism of a Chemical Reaction Based on the Unified Reaction Valley Approach, Journal of Chemical Theory and Computation, 2016, 12(2), 650–663. [2] Bader, R.F.W.; Atoms in molecules, Accounts of Chemical Research, 1985, 18(1), 9–15.

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Molecular Dynamics Simulations of Glutathione coated Gold Nanoparticles

Dineli Ranathunga, Steven O. Nielsen* Department of Chemistry and Biochemistry, University of Texas at Dallas

Division: Physical (Theoretical) Email: dxr161130@utdallas.edu Category: Graduate Ligand coated gold nanoparticles have shown promise in many bio-medical applications such as cancer detection, clinical chemistry, biosensors and targeted drug delivery. Use of glutathione as the ligand has been shown to give a renal clearable fluorescent probe. Conjugation of organic dyes like tetramethyl-rhodamine (TAMRA) onto these luminescent gold nanoparticles has shown a pH dependent emission. The organization of the ligands on the gold surface can be affected by the pH and that could give rise to the pH dependent emission. Here we show a general method to prepare the ligand coated gold nanoparticles for study using molecular dynamics computer simulations and the effect of pH on the organization of the ligands on the gold surface. We determined that the distance between transition dipoles of TAMRA dimers on glutathione coated gold nanoparticles increases with increasing pH.

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Molecular Dynamics Simulations of Slippery Liquid Infused Surface (SLIPs)-inspired substrates for water harvesting

Alexandra M. Shamir, Steven O. Nielsen* Department of Chemistry and Biochemistry, University of Texas at Dallas

Division: Physical (Theoretical) Email: axs171632@utdallas.edu Category: Graduate In recent years, marked progress has been made in novel substrate design for water condensation and fog harvesting. It is desirable for these engineered surfaces to display high droplet nucleation and removal rates. Here we focus on the surface chemistry of these substrates by evaluating the influence of hydrophobic and hydrophilic functional groups on droplet nucleation through molecular dynamics computer simulations. We show that the presence of even a few hydrophilic functional groups can dramatically enhance the nucleation rate.

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A Novel Insight into Antibiotics Resistance From Enzyme Evolution — Quantitative Analysis of β-lactamases Catalytic

Mechanism Li Shen, Peng Tao*

Department of Chemistry, Southern Methodist University Division: Physical E-mail: shenl@smu.edu Category: Graduate The overuse of antibiotics and fast evolution of bacteria with drug resistance in recent years pose serious threat to public health. β-Lactamases are enzymes involved with antibiotics resistance. Understanding β-lactamases’ hydrolysis mechanism could offer a theoretical foundation to predict the evolution of β-lactamases and provide guidance to develop new generations of antibiotics. Representing enzymatic mechanisms as reaction pathways provides structural basis to investigate evolution of β-lactamases catalysis. In this project, catalytic reaction pathways of DD-transpeptidase, penicillin binding protein (PBP) A and two Class A β-lactamases were calculated by hybrid quantum mechanics and molecular mechanics methods within chain-of-states framework. The structures of different states along each pathway of different enzymes were compared and superimposed. The similarity among key structures of different enzymes at the same stage suggests that the reaction mechanism of catalysis is conserved among these evolutionarily correlated enzymes. It is also confirmed that Residue GLU166 in Class A β-lactamases is a crucial residue in β-lactamase catalysis mechanism.

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DFT study of surface transformations between α-cristobalite and stishovite

Shariq Haseen, Peter Kroll* Department of Chemistry and Biochemistry at University of Texas at

Arlington Division: Physical (Computational) E-mial: shariq.haseen@mavs.uta.edu Category: Graduate We investigate the displacive structural transformation between the silica (SiO2) polymorphs α-cristobalite and stishovite using density functional theory calculations. Stishovite is one of the hardest known oxides but can only be synthesized in miniscule quantities at high pressures. On the other hand, α-cristobalite is accessible in high yields and under mild conditions like in hydrothermal synthesis. Hence, detailed knowledge of the structural transformation from α-cristobalite to stishovite and vice versa explores new venues for the production of stishovite. We relate the structures of α-cristobalite and stishovite using a common space group of C2221. The energy profile for the transformation yields an activation energy of 1.24 eV/SiO2. The impact of surfaces, which are critical once seed crystals are used in experiments, are studied for hydroxylated (001), (100), and (110) surfaces of each system. We find that a presence of surfaces reduces the activation energy for the structural transformation and that an aqueous system, meaning surface contact with water, contributes to a further reduction of activation energies. Consequently, while it takes less energy to transform α-cristobalite to stishovite, it will also take less energy to transform stishovite to α-cristobalite—which impacts the thermal stability of small stishovite seed crystals.

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Direct anti-Markovnikov addition of water to olefin to synthesize primary alcohol: a DFT study

Yavuz S. Ceylan and Thomas R. Cundari * Department of Chemistry, CASCaM, University of North Texas, Denton,

TX Division: Inorganic Chemistry (Computational Chemistry) E-mail: yavuz.selim.ceylan@gmail.com Category: Graduate Anti-Markovnikov addition of water has been a long-standing goal in catalysis. The [Rh(COD)(DPEphos)]+ complex was found as a general and regioselective Group 9 catalyst for intermolecular hydroamination of alkenes. The reaction mechanism was thus adapted for intermolecular hydration of alkenes catalyzed by a [Rh(DPEphos)]+ catalyst, and studied by means of DFT calculations. Hydration of alkene pathways were analyzed for anti-Markovnikov and Markovnikov regioselectivity. Based on our results, the operating mechanism can be summarized as follows: styrene activation through nucleophilic attack of OH- of water to alkene with simultaneous proton transfer to a vacant coordination site on the Rh, which is then followed byformation of primary alcohol via a reductive elimination step. Also, the competitive reaction for the formation of phenylethane was observed through a b-elimination pathway followed by hydrogenation. The origin of the regioselectivity (Markovnikov vs. anti-Markovnikov) was analyzed by means of studying the molecular orbitals, natural charges, energy decomposition analysis and shown to be orbitally driven not charge driven. Exceptionally, upon activation of olefin moiety by Nu- attack, h2-alkene slipped to h1-fashion and regioselectivity outcome was found to be related to the degree of slippage.

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An Orbital-Overlap Complement to Atomic Partial Charge Arshad Mehmood and Benjamin G. Janesko*

Department of Chemistry & Biochemistry, Texas Christian University Division: Physical Chemistry (Computational) E-mail: arshad.mehmood@tcu.edu Category: Graduate Atomic partial charges obtained from computed wavefunctions are widely used for interpreting quantum chemistry simulations and chemical reactivities of molecules, solids, surfaces, and nanoparticles. In many cases partial charge alone gives an incomplete picture of reactivity: PhS- is a better nucleophile compared to PhO- in SN2 reactions with MeI, though PhO- has a more negative charge on the nucleophilic atom, the carbons of benzene and cyclobutadiene, or those of diamond, graphene, and C60, possess nearly identical partial charges and very different reactivities, deprotonated amides perform nucleophilic attack via the less negative nitrogen, rather than the more negative oxygen, in anionic cyclization of o-alkynyl benzamides, halide anions F-, Cl-, Brand I- have identical charges but different nucleophilicities, carbons in aromatic benzene and antiaromatic cyclobutadiene have nearly identical partial charges, but different reactivities. Our atomic overlap distance complements computed partial charges by measuring the size of orbital lobes that best overlap with the wavefunction around an atom. Compact, chemically stable atoms tend to have overlap distances smaller than chemically soft, unstable atoms. Combining atomic charges and overlap distances captures trends in aromaticity, nucleophilicity, allotrope stability, and substituent effects. Applications to recent experiments in organic chemistry (counterintuitive Lewis base stabilization of alkenyl anions in anionic cyclization), nanomaterials chemistry (facile doping of the central atom in Au7 hexagons) and selective binding of ligands in proteins illustrate this combination’s predictive power.

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A DFT Survey of the Effects of d-Electron Count and Metal Identity on the Activation and Functionalization of C−H

Bonds for Mid to Late Transition Metals Catherine A. Moulder and Tom R. Cundari *

Department of Chemistry, University of North Texas, Denton, TX Division: Inorganic Chemistry Division (Computational) E-mail: cam0601@unt.edu Category: Graduate The contribution of metal identity to the activation and functionalization of methane by a series of three-coordinate imide complexes is evaluated in silico for a 3-by-3 block of metals from Fe to Pt. Three mechanisms were studied: oxidative addition (OA) to the metal; hydrogen atom abstraction (HAA) by the imide nitrogen; and, [2+2] addition across the metal-imide bond. In no studied case, was a [2+2] mechanism preferred, perhaps suggesting this mechanism is largely (entirely?) the domain of d0 imides. There is a diagonal relationship within the nonet of metals studied in that OA is preferred for earlier, heavier (5d) members of the series, transitioning to an HAA mechanism for later, lighter (3d) imides. DFT indicates that important parameters in partitioning between HAA and OA mechanisms include the strength of the metal-imide π-bond, the ability of larger metals to accommodate increases in formal oxidation state and coordination number, and the soft acid/base compatibility of larger transition metals with soft hydride and methyl ligands. Published paper citation: Moulder, C. A.; Cundari, T. R. A DFT Survey of the Effects of D-Electron Count and Metal Identity on the Activation and Functionalization of C−H Bonds for Mid to Late Transition Metals. Isr. J. Chem. 2017 DOI: 10.1002/ijch.201700066.

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Developing ReaxFF potential for modeling silicon oxycarbide

Ilia Ponomarev, Peter Kroll* Department of Chemistry and Biochemistry, The University of Texas at

Arlington Division: Physical Chemistry E-mail: ilia.ponomarev@mavs.uta.edu Category: Graduate Amorphous silicon oxycarbide (a-SiCO) ceramics have a wide range of applications such as membranes for gas separation, radiation-tolerant materials, thermal barrier coatings, and as anodes in Li-ion batteries. Structure modeling and property calculations are beneficial for targeted synthesis of the materials with defined properties for specific applications. The reactive force field – ReaxFF – promises the accuracy of quantum-chemical calculations (level of Density Functional Theory, DFT) at significantly lower computational costs, which enables simulations of bigger systems for longer periods of time. However, current parameterizations of ReaxFF for Si-C-O interactions neither match DFT-computed enthalpy differences nor reproduce the kinetic stability of stoichiometric SiCO glass phases at high temperature. We develop new ReaxFF parameters using a library of DFT-computed data. The library includes experimentally observed SiO2 and SiC structures as well as more than 10,000 hypothetical crystalline SiCO structures. We, furthermore, included over 1,000 models of amorphous SiCO with a variety of different geometries and bonding situations. Based on this “Big Data” exploration, we are able to determine new parameter sets for the ReaxFF capable to model SiCO structures and obtain energies comparable to DFT results. Moreover, simulations retain amorphous SiCO glasses structure up to 1200 K, agreeing with experimental observation.

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Characterizing the nature of hydrogen bonds in pincer pyrazine Pd complexes with a quantum topological criterion

Erik Antonio Vázquez-Montelongo1,2, Jessica Lohrman3, Subhamay Pramanik 3, Victor W. Day3, Mark Alan Hix1,2, Kristin Bowman-James3*,

and G. Andrés Cisneros1,2* Department of Chemistry, University of North Texas

Division: Computational Chemistry, Physical E-mail: erikvazquezmontelongo@my.unt.edu Category: Graduate Dipalladium(II) complexes with pyrazine tetracarboxamide ligands possess a distinctive short hydrogen bonds (HBs) between the oxygen atoms of adjacent carboxamide groups, which are responsible for the unusual nature of these structures. The crystal structures of two of these complexes suggest that the strength of the HBs varies depending on the ligands. This work will present electron localization function (ELF), quantum theory of atoms in molecules (QTAIM) and non-covalent interaction (NCI) analyses to characterize the nature of these HBs. According to the ELF and NCI results, the strength of the hydrogen bonding interaction depends on the type of substituent group and counter ion present in the complex. Electron density and the Laplacian of electron density at the hydrogen bond critical point (HBCP) corroborate these findings. Details of the ELF, QTAIM and NCI calculations and analyses will be presented.

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Unfolding the mysteries of hydrogen bonding in water via artificial intelligence

Niraj Verma; Yunwen Tao; Elfi Kraka* Computational and Theoretical Chemistry Group (CATCO), Department

of chemistry, Southern Methodist University Division: Computational E-mail: nirajv@smu.edu Category: Graduate Student Understanding the underlying properties of water is an active field of study, contrary to the fact that water is the most abundant and common molecule on Earth. We are interested in the shape of water molecules, which is governed by the network of hydrogen bonds. We came across the point that water forms huge clusters of hydrogen bonded water molecules. These clusters are formed by various smaller clusters of prism, cage, bag, book, chair or boat type. We used classical force fields including TIP5P, TIP3P-FB, TIP4P-FB, TIP4P-ew and OPC water models for the simulation of 1000 water molecules. Also, by doing simulations with 5 different force fields, the results are more reliable and can serve as a benchmark at the same time. Each huge cluster was detected using a mean shift algorithm (commonly used in machine learning). The smaller clusters however were more challenging to investigate, as this requires additional information about the shape of the rings formed by the hydrogen bonds. To find and quantify the smaller clusters, we used artificial intelligence. This work could for the first time quantitatively elucidate the hydrogen bond properties of water in a big water cluster system

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Intramolecular Hydrogen Bonding in Neutral Histidine: Eliciting Bond Strength Using Local Vibrational Modes

Seth Yannacone, Daniel Sethio, Elfi Kraka* Computational and Theoretical Chemistry Group (CATCO), Department

of Chemistry, Southern Methodist University Division: Computational E-mail: syannacone@smu.edu Category: Graduate

L-Histidine (HIS) is one of twenty essential amino acids involved in biological processes, such as human growth and tissue repair. In physiological systems, HIS exists in equilibrium between two tautomeric forms which are stabilized by intramolecular hydrogen bonds (IMHBs). To understand the factors involved in this effect, we detailed the relative stability of 6 different HIS conformers in gas and liquid phases. Conformational stabilities in HIS were rationalized via local mode analysis, Natural Bond Orbitals (NBO), Quantum Theory of Atoms in Molecules (QTAIM), and Cremer-Kraka energy density (H($)) using the wB97XD/aug-cc-pVTZ, B3LYP/aug-cc-pVTZ, and DLPNO-CCSD(T)/aug-cc-pVTZ levels of theory. We found the initial HIS conformer and its enantiomer to be the most stable in terms of the aforementioned methods. Most notably, local mode force constants (ka), number of interactions, thermochemical properties, and NBO populations with respect to the IMHBs of interest correlate directly to structural stability and geometry conformations. Therefore, presence and character of the IMHB networks in HIS play a significant role in stabilizing HIS. Some of the more nuanced and underlying mechanisms behind this phenomenon include resonance stabilization, steric effects, and covalent character of the IMHBs. [1] Bermúdez, C.; Mata, S.; Cabezas C.; Alonso, J. L.; Tautomerism in Neutral Histidine, Angew. Chem. Int. Ed., 2014, 53, 11015 – 11018. [2] Peschke, M.; Blades, A. T.; Kebarle, P. J. Am. Chem. Soc., 2000, 122, 1492-1505.

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Developing Generalized Network and Community Analysis Methods for Perturbation System

Hongyu Zhou and Peng Tao Department of Chemistry, Southern Methodist University

Primary division: Computational Chemistry Email: hongyuz@mail.smu.edu Category: Graduate student The molecular dynamics simulation is widely used to investigate protein biological functions through the simulation of the protein internal dynamics. One popular way to examine the internal dynamics is the Dynamic Network Analysis method which treats residues as nodes and build the networks upon them [1]. The correlation metrics are commonly applied to describe the averaged correlated motion between each residue pair. This method is useful in the single state equilibrium simulation, but less significant in comparison between the simulations of two equilibrium states. From the ensemble point of view, the difference between two states are indeed the distribution difference. Allostery, one special case for protein functional changes due to external perturbation, can be interpreted by distribution and population shift between several states[2]. The influence of external perturbations can be measured by the changes of distributions for some key order parameters. In the current study, relative entropy (also known as Kullback-Leibler divergence) was used to measure the difference between two distributions. The dynamic networks analysis was further developed based on the relative entropy regarding with any two different trajectories. The pairwise alpha carbon distance was adopted as the order parameters. The distance with the highest distribution differences was selected, and the shortest path algorithm was applied to identify the possible propagation path of that distribution changes. Communities analysis could also be conducted in the current framework. In additional to the Girvan Newman Algorithm proposed in the original paper, the Kernighan Lin algorithm and a hybrid algorithm were also applied to identify the communities that could be conserved regarding with the particular perturbation. [1] Eargle, J.; Luthey-Schulten, Z. NetworkView: 3D display and analysis of protein· RNA interaction networks, Bioinformatics, 2012, 28.22, 3000-3001. [2] Kar, G., Keskin, O., Gursoy, A. and Nussinov, R. Allostery and population shift in drug discovery. Current opinion in pharmacology, 2010, 10(6), 715-722

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Session 5: Inorganic and Analytical Chemistry

Catalytic Aerobic Oxidation of Alcohols by Copper Complexes Bearing Redox-Active Ligands with Tunable H-

bonding Groups Khashayar Rajabimoghadam, Isaac Garcia-Bosch.

Department of Chemistry, Southern Methodist University Division: Inorganic E-mail: krajabimoghadam@smu.edu Category: Graduate In this research presentation, we describe the structure, spectroscopy and reactivity of 1st row metal complexes bearing bidentate redox-active ligands that contain H-bonding donor groups. These unsaturated tetracoordinate complexes are stabilized by intramolecular H-bonding interactions between the two ligand scaffolds and between the ligand H-donor and the metal center.1 Interestingly, the copper complexes were found to be able to undergo multiple oxidation-reduction processes associated with the metal ion (CuI to CuIII) and the o-phenyldiamido ligand (diamido, diiminato radical and diimine).2 Some of the copper(II) complexes could carry out the oxidation of alcohols to aldehydes or ketone using only O2 and at room temperature. Like in galactose oxidase, the copper(II) complexes are proposed to deprotonate and coordinate the alcohol substrate and be oxidized to form reactive copper ligand-radical species that oxidize the substrate.3

References: (1) Cook, S. A.; Borovik, A. S. Molecular Designs for Controlling the Local Environments around Metal Ions. Acc. Chem. Res. 2015, 48, 2407. (2) Broere, D. L. J.; Plessius, R.; van der Vlugt, J. I. New avenues for ligand-mediated processes - expanding metal reactivity using redox-active catechol, o-aminophenol and o-phenylenediamine ligands. Chem. Soc. Rev. 2015, 44, 6886. (3) Klinman, J. P. Mechanisms Whereby Mononuclear Copper Proteins Functionalize Organic Substrates. Chem. Rev. 1996, 96, 2541.

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The Interplay of Magnetic, Electrical, and Structural Properties of Ln2Fe4-xCoxSb5-yBiy (Ln = La, Ce; x < 1.2,

y < 0.3) Katherine A. Benavides, Sheng Li, Joseph V. Burnett, Bing Lv, Julia Y.

Chan* Department of Chemistry & Biochemistry - The University of Texas at

Dallas

Division: Inorganic E-mail: kxb141830@utdallas.edu Category: Graduate The interplay between localized and itinerant magnetic mechanisms is not yet fully understood and can have far-reaching ramifications in the fields of magnetism and quantum computing. I synthesized single crystals of Ln2Fe4-xCoxSb5-yBiy (Ln = La, Ce; x < 1.2, y < 0.3) to study the interplay of the two magnetic sublattices in the structure. I found that the magnetic susceptibility and electrical resistivities are highly dependent on Co concentration. In this presentation, I will discuss the synthesis and changes in structure as a function of Co concentration and present the emerging physical properties.

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Lanthanum-Based Nanostructures as Catalytic Templates for Nanocasted Carbons

Alexander T. Brown, Zijie Wang, Wijayantha Perera, Jason Lin, John P. Ferraris, Kenneth J. Balkus, Jr.*

Department of Chemistry & Biochemistry, The University of Texas at Dallas

Division: Inorganic E-mail: atb150230@utdallas.edu Category: Graduate The development of electrically conductive carbon with high surface area is a current need for improving the efficiency of electric double layered capacitors (EDLC). Nanocasting carbon from a lanthanum based nanostructures is a unique method to generate the high surface area and electrically conductive carbons. The focus of this study is to demonstrate various lanthanum-based nanostructures as sacrificial templates for the synthesis of nanocasted carbon. We have synthesized multiple carbon nanomaterials via a lanthanum-catalyzed chemical vapor deposition process. The structures LaCO3OH, La2CO3O2, and La(OH)3 were used as templates/catalysts for the synthesis of graphitic carbons. Microsphere flowers, hollow nanorods, and wrinkled mesoporous silica morphologies were template structures used to form the graphitic carbons. The templated carbons were characterized by transmission electron microscopy, scanning electron microscopy, powder X-ray diffraction, and raman spectroscopy. The hollow carbon nanorods were further tested for electrochemical performance. Subsequently, an EDLC cell was constructed with the hollow carbon nanorods as the electrodes with the ionic liquid electrolyte, 1-ethyl-2-methylimidazolium bis(trifluoromethylsulfonyl)imide (EMIM-TFSI). The electrochemical properties were measured and reported as: Specific capacitance of 128 F/g at 10 mV/s, energy density of 55 Wh/kg @ 1 A/g, and the power density was 1700 W/kg @ 1 A/g. The cell retained 89 % capacitance after 5000 cycles.

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TiO2 Nanotubes Decorated with Ruthenium-based Nanoparticles

Jonathan Buford, Kenneth J. Balkus* Department of Chemistry and Biochemistry, University of Texas at Dallas

Division: Inorganic E-mail: jxb110930@utdallas.edu Graduate Student This research focuses on depositing ruthenium-based nanoparticles on the surface of TiO2 nanotubes, with the intention of using these synthesized materials for photocatalysis. The inspiration for this project stemmed from an interest in predicting the band gap of the TiO2 nanotubes (3.0eV-3.2eV) after the band was bent by the ruthenium material. These TiO2 nanotubes are formed via a hydrothermal synthesis, while the ruthenium is introduced in the form of the salt RuCl3·nH2O. The Ruthenium ions are bound to the nanotubes cysteine as a linker. The concentration of linker in solution also helps to regulate the sizes of the ruthenium-based nanoparticles that are bound to the surface. Ruthenium nanoparticle attachment is accomplished with use NaOH or thiourea to yield RuO2 or RuS2 nanoparticles respectively. The synthesized TiO2 nanotubes with ruthenium-based nanoparticles are imaged with transmission electron microscopy and the crystalline structure is displayed via X-ray diffraction. In conclusion the TiO2 nanotubes decorated with ruthenium-based nanoparticles were formed and the research in the future will consist of changing the cysteine concentration to adjust size and use for photocatalytic purposes.

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Biomimetic Mineralization of ZIF-8 Templated by Anisotropic Virus Particles

Shaobo Li, Madushani Dharmarwardana, Raymond P. Welch, Yixin Ren, Christina M. Thompson, Ronald A. Smaldone, Candace E. Benjamin,

Alexandra M. Shamir, Steven O. Nielsen and Jeremiah J. Gassensmith* Department of Chemistry and Biochemistry, The University of Texas at

Dallas Division: Inorganic Chemistry E-mail: sxl132830@utdallas.edu Category: Graduate Metal organic frameworks (MOFs) are a family of coordination polymer that possess high surface area, well-developed porosity, broad variety of composition and capability of post-synthetic functionalization. In recent years, MOF-encapsulation has become a popular strategy to protect biological substances, such as enzymes, viruses, or even cells. The crystallized MOF chainmail could effectively prevent denaturation of the inlaid biological substances under harsh conditions (for example, high temperature or presence of organic solvents), yet small molecules that are suitable for the pore sizes are still allowed to travel through for catalysis, reactions or nutrients supply. Here, we present our investigation of crystallization of zeolitic imidazolate framework-8 (ZIF-8) with the presence of an anisotropic viral particle- tobacco mosaic virus (TMV). We will show the morphological control of the TMV@ZIF-8 composites with a systematic mechanism study that involves precursor properties and surface characteristics of viral particle. In addition, we will demonstrate the robust stability of the as-formed TMV@ZIF-8 core-shell bionanoparticles, which retain the rod-shaped morphology from boiling water and a series of organic solvents, and the permeable ZIF-8 shell that allows the diazonium coupling reaction to be performed on the encapsulated viral particle.

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Wrinkled Mesoporous Silica Coated Nanoparticles Jason Lin, Kenneth J. Balkus Jr.*

Chemistry and Biochemistry, University of Texas at Dallas Division: Inorganic E-mail: jxl140030@utdallas.edu Category: Graduate Since the discovery of ordered mesoporous silica by Mobil a variety of pore structures and morphologies have been reported. Wrinkled silica particles have pores that radiate from a central core. We have found by varying the synthesis conditions that the wrinkled silica can be converted to hollow spheres and centipede like structures as shown in Figure 1. The centipedes can be coated on a variety of oxide particles creating a hierarchical pore structure. Synthesis and characterization of these nanoporous materials will be presented.

[Fig.1] From left to right hollow sphere, wrinkled surface, and centipede

86

Comparative study of Chloride and Fluoride induced Al pad corrosion in wire bonded packaging assembly

Goutham Issac Ashok Kumar, Alexander Lambert, Joshua Caperton, Muthappan Asokan, William Yi, Oliver Chyan*

Department of Chemistry, Interfacial Electrochemistry and Materials Research Lab, University of North Texas

Division: Analytical E-mail : gouthamissac26@gmail.com Category: Graduate Bond pad corrosion is one of the common modes of corrosion failure in wire-bonded devices IC packaging. Most common source of this corrosion comes from the presence of halide ions contamination as (Cl-, F-, Br- etc.) However, the corrosion morphology and the severity varies from different ions contamination as the chemistry governing the corrosion differs from one ion to another. Our research is focused on key findings on corrosion of Aluminum bond pad due to chloride and fluoride contamination. Our central motivation is to identify this F- corrosion mechanism, so that it will help to develop a strategy to prevent it and study the comparison between Cl- and F- Corrosion using Micro-pattern corrosion screening technique, Wire-bonded device and other characterization technique. Striking contrasts in corrosion morphology observed during the chloride and fluoride corrosion were explained in the present work and will lead to better understanding of factors influencing the bond pad corrosion leading to the wire bond failure in IC packaging devices.

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Holmium-based metal-organic framework for gas separations and cancer therapy

Juan P. Vizuet, *Dr. Kenneth Balkus Jr. Department of Chemistry and Biochemistry, The University of Texas at

Dallas Primary Division: Inorganic E-mail: juan.vizuet@utdallas.edu Category: Graduate Metal-organic frameworks (MOFs) are highly ordered hybrid organic-inorganic materials with properties such as defined crystallinity, permanent porosity and high surface area. By carefully selecting the building blocks in a MOF, i.e. the metal cluster and the organic linker, it is possible to tailor the specific properties of these materials. Lanthanide based MOFs have interesting properties due to the nature of the metal node. Lanthanide ions have high coordination numbers and diverse coordination geometries, making it difficult to prepare porous materials. By binding solvent molecules to these ions, along with the organic linker, nonporous extended 3D structures are formed. The removal of the solvent molecules can lead to the formation of microporous framework materials with accessible free metal sites. The presence of accessible coordinatively unsaturated lanthanides in the framework which can act as Lewis acid sites, imparts the MOFs with properties suitable for diverse applications such as drug delivery, photoluminescence, chemical sensing, heterogenous catalysis and gas adsorption. The research to be presented focuses on the synthesis and characterization of Holmium based MOFs (Ho-MOFs) and their potential applications in gas separations and radiotherapy. The characterization of these materials is mainly done through single-crystal x-ray diffraction and scanning electron microscopy. Thermal stability is also tested through thermogravimetric analysis and powder x-ray diffraction.

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Sweet corrosion of Ni-Mo alloy coating in high salt and gas hydrate temperature environments

Christopher E. Ozigagu, Teresa D. Golden* Department of Chemistry, University of North Texas

Division: Analytical chemistry E-mail: ozigaguc@gmail.com Category: Graduate Gas hydrate formation and corrosion can cause serious safety and flow assurance problems. One aspect that has been given less attention is the contribution of gas hydrate formation conditions to corrosion. The aim of this work is to investigate the combined corrosion contribution of dissolved CO2 gas and high salt (high-chloride) produced water at gas hydrate formation temperature (5 ºC). Due to excellent corrosion resistance in aggressive environments, Ni-Mo alloy coatings are used as the test material. A new technique was used to conduct the immersion test. The immersion test solutions were sweet low-chloride (CO2 + 1 wt% salt + 5 oC) and sweet high-chloride (CO2 + ~24 wt% salt + 5 ºC) environments, respectively. After the immersion tests, as the salt concentration increased in the presence of CO2, there was a decrease in the corrosion resistance of Ni-Mo coating. Grazing angle XRD indicated broadening of the (111) reflection peak. SEM and EDX revealed a cracked surface morphology, and 2.23 wt % increase in oxygen content of the Ni-Mo coatings. This project will evaluate a new technique for corrosion testing of materials exposed to gas hydrate environment. Key words: Ni-Mo alloy, chloride salt, sweet corrosion, gas hydrate temperature

89

Crystal growth and characterization of bismuth-doped highly correlated Ce-based intermetallics

Weiland, Ashley; Chaparro, David G.; Chan, Julia Y.* Department of Chemistry and Biochemistry, The University of Texas at

Dallas Division: Inorganic E-mail: ashley.weiland@utdallas.edu Category: Graduate Ce-based intermetallic systems are magnetic due to Ce’s unpaired 4f electron. The introduction of heavy elements, such as Bi, into these systems can allow for fascinating changes to the properties. These properties have the opportunity to be even more exciting when considering the strong correlation of the orbitals and spins of electrons in Bi, specifically spin orbit coupling. We are motivated to find materials that have been predicted to host Dirac or Weyl fermions. Our strategy has been targeting specific structure types that have the potential to exhibit these exotic new topological physics. In this talk I will present the solid state flux synthesis used to grow single crystals.

90

Characterization of post-etch residue clean by chemical bonding transformation mapping

Muthappan Asokan, Cheng-Hsien Wu, Chih-Cheng Shih, Ting-Chang Chang, Oliver Chyan*

Department of Chemistry (Analytical Division), Interfacial Electrochemistry and Materials Research Lab, University of North Texas

Division: Analytical E-mail: amuthappan@ymail.com Category: Graduate The incorporation of porous low-k interlayer dielectrics in Cu interconnects to reduce RC time delays pose significant integration challenges. Replacing Si–O bonds with Si–C bonds to create low-k interlayer dielectrics with nanoscale porosity makes them more susceptible to damage caused by common patterning processes like reactive ion etching (RIE). To minimize dielectric damage and maintain accurate trench profile control, fluorocarbon plasma chemistries are used to deposit thin fluoropolymers on trench surfaces during the RIE etching step. Removal of this fluoropolymer layer after RIE requires prior knowledge about chemical bonding structure and nature of the film. Using Multiple Internal Reflection-Infrared Spectroscopy (MIR-IR) and associated IR spectroscopic techniques as a sensitive characterization tool (sub-3nm), we established Chemical bonding structure of model fluorocarbon polymer films deposited on trench structures patterned in porous low-k dielectric and evaluated the plasma induced dielectric damages on high aspect ratio trench patterns. In this paper, we investigated cleaning efficiency and associated dielectric damages during various wet and dry cleaning of post-etch residues on low-k dielectric trench lines by FTIR, XPS and SEM. In additional to dry plasma etch and wet cleaning chemistry, we explored UV-assisted clean and post-etch residue cleaning in supercritical CO2 and CF4 conditions.

91

Functionalization and Dispersion Stability of Graphene Materials for Corrosion Protection in 2K Epoxy and Urethane

Coating Systems Melissa Wunch, Samsuddin F. Mahmood, C.K. Kim, S.H. Lee, Y.S. Kim,

J.H. Park, and Duck Joo Yang* Department of Chemistry and Biochemistry, The University of Texas at

Dallas, Division: Inorganic E-mail: maw130430@utdallas.edu Category: Graduate Conventional barrier protection methods, such as zinc, can lead to high cost input to maintain the integrity of the ship or automobile from the environment. This led to research into graphene based materials due to their multifunctional properties, such as: hydrophobicity, barrier against molecules and ions, and high surface area. It is possible to take advantage of these multifunctional properties through inclusion in two component (2K) coating systems and testing for corrosion protection. This research looks at including graphene materials in a 2K Urethane coating system in order to observe their effects on hydrophobicity and corrosion protection. Amine (-NH2) and fluorine (-F) groups were introduced on the surface of the graphene in order to observe how they would affect dispersion stability, surface properties, and corrosion protection in a 2K urethane coating. Dispersion stability of graphene materials was performed in acrylic polyol and isocyanate (2K Urethane). Dispersions in acrylic polyol yielded prolonged stability of graphene in the solution. Introduction of these graphene materials has yielded a positive effect on corrosion protection and surface hydrophobicity. The figures below display corrosion results with fluorinated graphene in 2K urethane coating after immerstion in 3.5% NaCl for two months.

- 2K Urethane with F-G coating after 2-month immersion in 3.5% NaCl. As concentration of F-G increases the corrosion decreases.

0% F-G 4% F-G2% F-G1% F-G

- Estimated corrosion rate of 2K urethane coating with F-G after 2-month immersion in 3.5% NaCl.

92

Structural and electronic properties of high-spin iron tetra-azamacrocyclic complexes that increase direct C-C coupling

efficiency Samantha M. Brewer, Kayla N. Green*

Department of Chemistry and Biochemistry, Texas Christan University Division: Inorganic E-mail: samantha.brewer@tcu.edu Category: Graduate Six high-spin iron(III) tetra-azamacrocyclic complexes ([Fe3+L1(Cl)2]+, [Fe3+L2(Cl)2]+, [Fe3+L3(Cl)2]+, [Fe3+PyNMe3(Cl)2]+, [Fe3+Me2BCyclen(Cl)2]+, and [Fe3+Me2EBC(Cl)2]+) and two high-spin iron(II) complexes ([Fe2+CB-MePyCyclen(Cl)]+ and [Fe2+PyMeEBC(Cl)]+) were tested for the ability to couple phenylboronic acid and pyrrole to produce 2-phenylpyrrole. The highest catalytic yield was obtained using [Fe3+Me2BCyclen(Cl)2]+, due to the increased rigidity/topological constraint, optimal half-wave potential, and small Neq-Fe-Neq angle of the catalyst. Additionally, the need for two labile cis-coordination sites and a sacrificial oxidant was confirmed. Finally, comparison of catalytic yield to radical scavenging ability of [Fe3+L1(Cl)2]+, [Fe3+L2(Cl)2]+, and [Fe3+L3(Cl)2]+ supported that the C-C coupling of phenylboronic acid and pyrrole does not proceed through a radical pathway.

93

Application of Micropattern Corrosion Screening to Study Copper/Aluminum Bimetallic Corrosion Relevant to IC

Packaging M. Asokan, J. Caperton, Z. Thompson, O. Chyan, M.

University of North Texas, Department of Chemistry, Denton, TX Division: Analytical E-mail: josh.caperton@gmail.com Category: Graduate student In this paper, an efficient corrosion screening method using micro-pattern test structures for analyzing Aluminum bond pad corrosion in Cu wire bonded semiconductor assembly is discussed. Our proposed corrosion mechanism of Al bond pad in chloride ion environment demonstrated Cu/Al bimetallic contact greatly enhanced corrosion. GC-MS was used to identified hydrogen evolution was the main cathodic reaction that derived the observed rapid Al bond pad corrosion reaction. Cathodic polarization analyses showed selected inhibitors can raise the overpotential of hydrogen evolution and achieved effective corrosion prevention. External Reflection FTIR and SEM were used to characterize the chemical bonding and surface morphology of inhibitor coating to the Cu/Al bonding interface. The epoxy molded Cu wire bonded samples with inhibitor treatment were found to survive the harsh environment test and showed good resistance to chloride induced corrosion in standard IC packaging testing conditions.

94

Synthesis and Luminescence Properties of Multinuclear Copper-Based Complexes

Devaborniny Parasar and Dr. Rasika Dias* Department of Chemistry and Biochemistry, University of Texas at

Arlington. Division: Inorganic Chemistry E-mail: devaborniny.parasar@mavs.uta.edu Category: Graduate student Luminescence is the emission of light by a substance subjected to external stimuli or photons. There are several everyday products and processes like glow sticks, fluorescent paint, energy efficient lighting, road safety signs, finger print detectors and optical brighteners that exploit this phenomenon. Due to their high sensitivity and wide applicability, luminescent materials have attracted much attention of the scientific community in the recent times. We are also interested in these materials and have developed several new and brightly luminescent copper based pyrazole-alkyne complexes (PAC) that emit orange light when exposed to UV radiation. These light emitting molecules were characterized by X-ray and other techniques. By varying the stoichiometric ratio of the combining reagents, we can change the structure and geometry of the resulting complexes. We can also tune the luminescence properties of the copper-based PAC by changing the stoichiometry of the contributing reagents. These complexes show different colors when exposed to various chemicals. They show high promise for sensing applications.

95

Investigation of PdCeO2 solid solution catalysts for selective hydrogenation of acetylene

Seunga Kim, Wentao Xia, and Ben-W. -L. Jang* Department of Chemistry, Texas A&M University Commerce

Division: Inorganic Chemistry E-mail: skim12@leomail.tamuc.edu Category: Graduate student Palladium materials are well-known commercial catalysts for selective hydrogenation of acetylene in ethylene, but with relatively low selectivity. Recently, ceria has been demonstrated to show high selectivity and considerable activity for selective hydrogenation at high temperatures. The objective of this investigation is to develop ceria based Pd catalysts with high activity and high selectivity for the selective hydrogenation of acetylene in ethylene at lower temperatures by using the co-precipitation technique followed by post treatment procedures, such as calcination, reduction, etc. Pd-ceria catalysts with Pd loadings of 0.1-0.2% have been studied for reactions at the various temperatures, from 50℃ to 200℃, with various reduction conditions and calcination temperatures. According to the reaction results, the reduced samples showed relatively higher conversion at moderate temperatures. However, the selectivity of those catalysts were quite low. The results indicate that significant amount of Pd appeared on the catalyst surface which promoted over-hydrogenation of ethylene to ethane, resulting in low ethylene selectivity. According to the temperature programmed reduction results, when the calcination temperature increased the lower temperature peak shifted to lower temperatures, it suggests that calcination caused Pd to move to the catalyst surface which resulting in higher activity matching with reaction results. Hydrogen chemisorptions were used to characterize the catalysts and to relate them to the reaction performance of catalysts with the amount of H2 adsorbed. As the calcination temperature increases, the amount of H2 adsorbed also increases.

96

Study of the Loading, Calcination and Reduction Effects on Ceria Supported Pd Catalysts for Acetylene Selective

Hydrogenation Tengteng Lyu, Kai Li and Ben W.-L. Jang

Department of Chemistry, Texas A&M University-Commerce Division: Physical chemistry E-mail: tlv@leomail.tamuc.edu Category: Graduate Pd/CeO2 catalysts with 0.05% to 1% Pd loadings, are prepared via incipient wetness impregnation method for selective hydrogenation of acetylene in ethylene. The results at reaction temperatures of 50ºC to 200ºC with a H2/C2H2/C2H4 ratio of 3/1/99 and a space velocity of 60,000 cc/h/g show that catalytic conversion of acetylene increases with palladium loading while the selectivity decreases. Since calcination temperature is one of the factors which can affect the activity and selectivity of the catalysts, various calcination temperatures are investigated in this study, such as 450ºC℃ and 800ºC. With increasing calcination temperature, the acetylene conversion of catalysts without reduction decreases and the ethylene selectivity increases. Effect of reduction temperature of 250ºC is evaluated as well. The results indicate that reduction procedure does enhance the activity of these catalysts. However, their selectivity decreases dramatically. To probe surface characteristic changes, catalysts are characterized by in-situ Fourier Transform Infrared Spectroscopy of CO adsorption with various pretreatment procedures, including no reduction and combination of reduction and calcination. The results show that cationic Pd species existing on the surface of catalysts can be reduced by CO during CO adsorption. After reduction, however, some cationic Pd species still remain even with a reduction temperature of 250 oC. The characteristics of the catalysts are also measured using Atomic Absorption Spectroscopy, H2-chemisorption and Temperature Programed Reduction techniques. The results will be discussed and compared with the reaction results.

97

Synthesis and Resolution of Chiral Metal Clusters Darrell D. Mayberry, Vladimir N. Nesterov, and Michael G. Richmond*

Department of Chemistry – University of North Texas Division: Inorganic Email: darrell.mayberry@gmail.com Category: Graduate The reactions of the new diphosphines 1-[2-(diphenylphosphino)ethylthiol]-2-(diphenylphosphino)benzene (dppet) and 1-[2-(diphenylphosphino)ethoxy]-2-(diphenylphosphino)benzene (dppeo) with H2Ru3(µ3-S)(CO)9 were investigated. The chiral cluster products isolated from the aforementioned reactions are H2Ru3(µ3-S)(CO)6(µ3-dppet) (1), H2Ru3(µ3-S)(CO)7(µ-dppet) (2), and H2Ru3(µ3-S)(CO)7(µ-dppeo) (3). Clusters 1-3 were fully characterized by 1D and 2D NMR spectroscopy, and the solid-state structures of 1 and 3 were established by X-ray crystallography. The kinetics for conversion of 2 ® 1 and CO have been investigated by UV-vis spectroscopy, and the determined activation parameters [DHǂ = 23.1(1.4) kcal/mol and DSǂ = -18.6(3.9) eu] support an associative substitution mechanism. The resolution of the enantiomers of 1-3 was examined by HPLC using commercially available chiral columns. Preparative amounts of the resolved enantiomers of 3 were collected by preparative HPLC and the enantiomers were analyzed by circular dichroism spectroscopy. DFT calculations on the mechanism for catalytic hydrogenation of a prochiral alkene using these chiral clusters will be discussed.

98

Session 6: Organic Chemistry and Polymers I

Modification of Cis-1,4-Polybutadiene Using Hypervalent Iodine Compounds

Avichal Vaish, Hongzhang Han and Nicolay Tsarevsky* Department of Chemistry, Southern Methodist University, Dallas, TX

Division: Polymers E-mail: avaish@smu.edu Category: Graduate Hypervalent iodine(III) compounds with ArIL2 type structure (Ar = Aryl, L = Ligand, e.g., carboxylates) undergo hemolysis reactions, upon heating or irradiation, which yield iodoarenes and the radicals L·. In this work, a new hypervalent iodine compound, [bis(2-bromopropionyloxy)iodo]benzene, PhI(O2CCH(Br)CH3)2, was synthesized by reacting iodosylbenzene (PhIO) with 2-bromopropionic acid. The product was used as precursor of 2-bromoproponyloxy radicals (or the products of their decarboxylation, 1-bromoethyl radicals), which were employed to modify an unsaturated polymer, cis-1,4-polybutadiene, an elastomer with unique elastic properties and longstanding industrial scalability. The reaction afforded macromolecules with densely attached ATRP-initiating functionalities at the polymer backbone. The polybutadiene-derived macroinitiators were successfully used in grafting-from reactions via low-catalyst-concentration ATRP to produce polymer brushes. Alternative approaches yielding [bis(2-bromopropionyloxy)iodo]benzene, namely the in-situ reaction of PhIO with 2-bromopropionic acid or the ligand exchange reaction between (diacetoxyiodo)benzene and the same acid were also explored.

99

Cu – Directed sp2 Oxidations Under Benign Conditions Rachel Trammell, and Isaac Garcia-Bosch*

Department of Chemistry at Southern Methodist University Division: Inorganic Chemistry E-mail: rtrammell@smu.edu Category: Graduate Student Direct stereo- and regio-selective C-H bond functionalization is an extremely powerful synthetic tool for synthesis of organic molecules especially in the industry field. Current procedures for functionalization of sp2 systems include using a transition metal center such as palladium, rhodium, and ruthenium for C-H bond oxygenation of aromatic systems have shown to be effective site-selective hydroxylation catalysts, while copper has been a lesser explored metal. However, there is one example that uses copper for direct hydroxylation through deprotonative cupration, but the directing group is unable to detach from the system. Taking inspiration from Cu – dependent metalloenzymes, (e.g. PHM and DβH) our lab has developed a synthetic method that uses mild, cheap, and green reagents such as copper and O2/H2O2 to functionalize the β sp2 C-H bond on our aromatic systems. With our synthetic method, we have three specific features (ketone, amine, oxidant) that can be changed for stereo- and regio-selectivity, but also aids us in understanding the Cu/O2 cores of our systems and how metalloenzymes carry out C-H bond hydroxylation and applying it for more synthetic and industrial purposes. In this presentation, we describe our current findings on sp2 systems, as well as characterization for intermediate responsible for hydroxylation.

100

Synthesis of Functional Linear and Branched Polymers Utilizing Hypervalent Iodine Compounds

Rajesh Kumar and Nicolay V. Tsarevsky* Department of Chemistry, Southern Methodist University

Division: Polymers E-mail: rajeshk@smu.edu Category: Graduate Iodosylbenzene is a hypervalent iodine compound that reacts with various (pseudo)halides (TMS-(N3 or NCO) or K-(N3, OCN, and Br)) to yield unstable hypervalent iodine(III) compounds, PhIX2 (X = (pseudo)halide), that undergo rapid homolysis of the hypervalent I−X bonds and generate (pseudo)halide radicals. These radicals can initiate the polymerization of various vinyl monomers, forming linear polymers containing (pseudo)halide functionalities at the chain ends. For instance, azide terminated polymers were prepared using the PhIO-(TMS or K)N3 system that underwent click-type coupling reactions with dialkynes. Similarly, the (iso)cyanate terminated polymers were prepared using PhIO-TMSNCO that reacted with diamines to afford urea-type interchain links. The one-pot synthesis of highly branched polymers with numerous chlorine-terminated chain ends was accomplished by the copolymerization of vinyl monomers and crosslinkers in the presence of 1-chloro-1, 2-benziodoxol-3(1H)-one (ClBIO), which served both as initiator and a transfer agent. ClBIO was found to transfer Cl atoms to the propagating polymer chains very efficiently and therefore, during the copolymerization of vinyl monomers and crosslinkers, gelation was significantly delayed and, up to relatively high monomer conversions, soluble highly branched polymers were formed. The transfer coefficient for ClBIO with methacrylates was determined, and the effects of crosslinker and ClBIO concentrations on the outcome of the copolymerizations were systematically studied.

101

HyCL-3: A reaction based chemiluminescent probe for nitroreductase and hypoxia in vivo

Lucas Ryan and Alex R. Lippert* Department of Chemistry, Southern Methodist University

Primary Division: Organic Chemistry E-mail: luke@smu.edu Category: Graduate Hypoxia is the condition of low tissue oxygenation arises in disease states such as cancer and pulmonary disease. Hypoxia arises from solid tumors outgrowing their own vasculature. Hypoxia inducible factor 1a (HIF-1a) is a subunit of the HIF-1 heterodimer that is activated in hypoxic conditions. Its binding with HIF-1b affects a multitude of downstream targets including upregulation of reductive enzymes such as nitroreductase to suppress apoptosis and promote angiogenesis in the tumor micro-environment. Here, we present HyCL-3 as a chemiluminescent reporter for the detection of hypoxia in vivo. HyCL-3 contains a nitroaromatic reactive handle that is reduced under hypoxic conditions, causing self-immolative cleavage of the handle from the scaffold. This initiaties decomposition of the highly energetic dioxetane bond through chemically initiated electron exchange luminescence. HyCl-3 shows a dose-dependent response to NTR and NADH at physiological pH, and can detect tissue oxygenation in vitro. HyCL-3 is highly sensitive and selective, and will be applied for in vivo imaging of hypoxia.

102

Hexaphenylbenzene Covalent Organic Frameworks Shashini Diwakara, Ronald A. Smaldone*

Department of Chemistry and Biochemistry, The University of Texas at Dallas

Division: Organic Chemistry E-mail: sdd170030@utdallas.edu Category: Graduate Covalent organic frameworks (COFs) are a class of crystalline porous two or three-dimensional polymers which are synthesized under dynamic control. The dynamic interplay between noncovalent aromatic interactions and covalent bond formation contribute to control the structure and properties of two-dimensional COFs. These materials have a broad spectrum of potential applications in gas storage, catalysis and especially as components for electronic and conductive materials. Porous polymers made with hexaphenylbenzene (HEX) units have been reported previously by our group and others. This presentation will discuss new methods for designing COFs containing non-planar units through dipolar and hydrogen bonding interactions. Two monomers are synthesized through coupling of 3',4',5',6'-tetrakis(4-carboxyphenyl)-[1,1':2',1''-terphenyl]-4,4''-dicarboxylic acid followed by reduction or hydrolysis. HEX covalent organic frameworks containing boronate ester and imine linkages to achieve dipolar and hydrogen bonding interactions will be synthesized by polymerizing this monomer with 1,2,4,5-tetrahydroxybenzene or dialdehyde co-monomers, respectively.

103

Supramolecular Assemblies for 3D Printing Durand-Silva, Alejandra; Berry, Danielle R.; Lopez, Paola M.; Thompson,

Christina M., Smaldone, Ronald A.* Department of Chemistry and Biochemistry, The University of Texas at

Dallas Division: Supramolecular Chemistry E-mail: alejandra.durandsilva@utdallas.edu Category: Graduate student 3D-printing is a highly flexible processing technique that has recently attracted chemists towards the development of compatible materials with both the 3D-printing technique and the applications of the printed objects. A major issue for 3D printed objects is the low mechanical robustness they present due to the lack of interlayer adhesion. To address this problem, herein, we prepare poly-pseudorotaxanes, using polyethers and polyesters as linear molecules, and cyclodextrins are incorporated as macrocycles threaded onto the polymer to adapt its properties. We selected cyclodextrins to exploit their capability to be chemically modified in one or more of their multiple hydroxyl groups, thus providing functionality to incorporate a reversible chemical crosslinking and to overcome the low interlayer adhesion. Physical properties of the polymers can also be modified due to the changes in their conformation when cyclodextrins thread, for example, poly(L-lactic acid) (PLA) is a biodegradable polymer commonly used for fused-deposition modeling 3D-printing, but it also exhibits poor interfilament adhesion. The amorphous content of PLA is reported to be increased when it forms poly-pseudorotaxanes with methylated-β-cyclodextrin,1 thus, this reduction of crystallinity may lead to enhanced mechanical properties of the printed objects. This approach could be useful for other types of polymers and functionalized cyclodextrins. References: (1) Suzuki, T.; Ei, A.; Takada, Y.; Uehara, H.; Yamanobe, T.; Takahashi, K. Modification of Physical Properties of Poly(L-Lactic Acid) by Addition of Methyl-β- Cyclodextrin. Beilstein Journal of Organic Chemistry 2014, 10, 2997–3006.

104

pH Mediated Cell Uptake of Alkyl Carboxylate Functionalized Qβ VLPs

Hamilton Lee, Candace E. Benjamin, Chance M. Nowak, Kyle W. Murray, Lana H. Tuong, Raymond P. Welch, Zhuo Chen, Madushani

Dharmarwardana, Jeremiah J. Gassensmith*. The University of Texas at Dallas, Department of Chemistry and

Biochemistry Division: Organic E-mail: hxl154130@utdallas.edu Category: Graduate The surface charge of nanoparticles is known to affect their uptake by cells. However, additional properties may mediate the cell uptake of nanoparticles, given that other properties of nanoparticles known to affect cell uptake such as size and shape are controlled for. We have discovered that conjugating hexanoic acid derivatives onto bacteriophage Qβ virus-like particles (VLPs) largely inhibits their uptake by macrophages and HeLa cells. In addition, conjugating aryl carboxylate derivatives onto Qβ did not have the same effect. Furthermore, we have designed Qβ conjugate featuring a terminal hexanoic acid moiety connected by a hydrazone linker acting as a pH responsive switch. When the Qβ conjugate is treated with mildly acidic conditions, the hydrazone linker undergoes hydrolysis resulting in the release of the terminal hexanoic acid moiety and allowing the uptake of the Qβ conjugate by cells.

Figure 1: A) The VLP is designed such that cell uptake is permitted only under very specific conditions—like

within theacidicmicroenvironmentofa cancerous tumor.B)When RAW264.7macrophagesare incubated

withQβ,Qβ(GFP),andQβ(GFP)-6-Hexfor4hoursatconcentrationsrangingfrom10μMto60μM(corresponding

totheterminalmoietyassumingallcoatproteinswerefunctionalizedatleastonce)wefoundlargedifferences

incellularuptake.CelluptakeresultsusingQβcontaininggreenfluorescentproteingoinfromflowCTshowQβ

ofpopulationvs.GFPabsorbance intensityoverlaysfornativeQβandQβconjugates.Datacorrespondingto

nativeQβareshowninredforallplots.DatacorrespondingtoQβpositivecontrolsandconjugatesareshown

inblue.forallplots.

A)

105

Preparation of carbon metal oxide composites with channeled like morphology for supercapacitor applications

Soheil Malekpour, John P. Ferraris Department of Chemistry and Biochemistry, The University of Texas at

Dallas Division: Organic E-mail: Soheil.malekpour@utdallas.edu Category: Graduate Hybrid supercapacitors made of carbon – metal oxide composites are devices which can combine the advantages of both electric double layer capacitors and pseudocapacitors e.g. high energy density, high power density and high cyclibilty. Although there are many ways to make carbon – metal oxide composites, carbon nanofibers (CNFs) as high surface area carbon materials were used as matrix to host the metal oxides. Covering the carbon with metal oxides will cause a decrease in conductivity of the carbon material, hence encapsulating the metal oxides with CNFs is a way for achieving high performance system. It has been shown that blending two immiscible polymers at certain ratios, electrospinning and carbonizing them will lead to formation of carbon fibers with channeled morphology, in which the metal oxides can be placed. Two immiscible polymers of polyacrylonitrile (PAN) and polymethyl metacrylate (PMMA) were blended at 1:1 ratios and electrospun. Upon annealing PMMA degraded and left channels behind. Adding a metal precursor to the blend solution cause interaction of metal with PMMA, hence upon degradation of PMMA, metal oxides were left in the channels. The prepared carbon – metal oxide composites not only preserves the conductivity of carbon but also adds the pseudocapacitance of metal oxides to the system which leads to a material with enhanced performance.

106

Conjugated polymer blend precursors for carbon molecular sieve membrane

Masoumeh Tajik, John P. Ferraris* Department of Chemistry and Biochemistry, The University of Texas at

Dallas Division: Polymer Chemistry E-mail: Masoumeh.Tajikasl@utdallas.edu Category: Graduate Mixed matrix membrane has been developed for gas separation by incorporating the polymer precursor with inorganic material to takes advantage of the favorable properties of both inorganic and polymer membranes. Different inorganic additives have been used for fabrication of mixed matrix membranes such as zeolite, carbon nanotubes and metal organic frameworks. Among these, zeolitic imidazolate frameworks (a subclass of metal organic frameworks) have been attractive due to the presence of organic linker in the ZIF structure which provides better interaction with polymer compound. The selection of polymer precursor plays an important role in tailoring the pore structure and control the membrane morphology. It has been shown polymer blends can be used a precursor for this purpose. The phase separation of polymer blend can be compatiblized by adding ZIF-8. Furthermore, by pyrolyzing these membrane precursors under controlled atmosphere and unique temperature protocols, carbon molecular sieve membranes can be formed. Therefore, tailoring the properties of polymer precursor allows the property of CMSM to be tailored. 6FDA-DAM was synthesized by reaction of 4,4-(hexafluoroisopropylidene) diphthalic anhydride (6FDA)-based polyimides with 2,4,6- trimethyl-1,3-phenylenediamine (DAM). Two immiscible polymer blends of 6FDA-DAM with polybenzimidazole (PBI) using different ratio of ZIF-8 as a compatiblizer were prepared. The tunable pore size and domain distribution will have a significant effect on gas permselectivity.

107

Approach towards Total synthesis of Spirocalcaridine A and B.

Ravi P. Singh, and Carl J. Lovely* Department of Chemistry and Biochemistry, University of Texas at

Arlington, Arlington Division: Organic Chemistry E-mail: ravi.singh@mavs.uta.edu Category: Graduate Student During the last few years, our attention has been directed towards the total synthesis of two Leucetta alkaloids, spirocalcaridine A 3, and B 4 (Fig-1), which have unprecedented functionality and are claimed to be among the first examples of non-organometalic chiral aminoimidazoles isolated from Calcareous sponges. In our recent approach towards the total synthesis, we have reported a tandem oxidative amination− dearomatizing spirocyclization (TOADS) reaction of propargyl ureas for the rapid construction of spiro fused iminooxazoles. To our delight, the TOADS chemistry also worked well with propargyl guanidines (1) to provide the complete spiro heterocyclic framework (2) for the two target alkaloids. To complete the total synthesis, we only need to perform a double bond (between C4/C8) migration on compound 2 followed by removal of protecting group and oxidation across the migrated double bond (C4/C5). Unfortunately, the migration of the double bond to the desired position (between C4/C5) provided a significant roadblock and has forced us to explore an alternative strategy. Herein, we report an alternate strategy to complete the total synthesis of the two alkaloids spirocalcaridine A and B without migration of the double bond.

Fig-1

108

Immunoassay Investigation of Vaccine Carrier Stability Within ZIF-8 Encapsulation

Raymond P. Welch, Michael A. Luzuriaga, Shaobo Li, Jeremiah J. Gassensmith*

Department of Chemistry and Biochemistry, University of Texas at Dallas Division: Polymers E-mail: rpw031000@utdallas.edu Category: Graduate Proteinaceous drugs often require constant refrigeration, from production to patient administration. Refrigeration failure at any point leads to drug loss and increased costs. This is tricky in regions such as developing nations, remote areas, disaster areas, or warzones, where refrigeration can be difficult. Recent studies have shown that enzymes, antibodies, and virus particles can be encapsulated in a removeable ZIF-8 coordination polymer shell that provides thermal, mechanical, and chemical stability to the underlying proteinaceous material. The rod-shaped tobacco mosaic virus (TMV) can be used as a model carrier due to its 2130 identical coat proteins providing attachment points for functional handles to be installed along the virus surface or inside the central lengthwise pore. This study uses ELISA immunoassay to test the surface stability of TMV through encapsulation, stress (denaturing solvents and heat), and shell removal; for a given amount of virus, a damaged surface will bind less antibodies than an intact one. Also tested is the ability to infect plants through the process, and antibody production in mice against the encapsulated virus. We show that the shell provides protection against stress, TMV remains infectious, and mice produce antibodies longer while the virus is encapsulated.

109

Studies Toward the Total Synthesis of Terrazoanthines A-C Lawton Seal II and Dr. Carl Lovely*

Department of Chemistry and Biochemistry, The University of Texas at Arlington

Division: Organic Email: Lawton.seal@mavs.uta.edu Category: Graduate Abstract: Terrazoanthines A-C are a new family of 2-aminoimidazole alkaloids recently isolated and characterized from Terrazoanthus onoi, a species of marine invertebrates found off the coast of Ecuador. While various NMR spectroscopic techniques and HRESIMS were able to elucidate the overall structure, the absolute stereo configurations were assigned by comparing experimental 13C NMR data, and the use of theoretical ECD data. To date, no total synthesis of these molecules have been reported, nor any further evidence presented to support the assignments given to the stereo centers. Here we propose a synthetic route utilizing a key desymmetrizing step, which should allow access to all three molecules and further elucidation of their stereochemistry.

110

3,3’-of Functionalization of BINOL and various Biphenol compounds

Hiep Nguyen, Yuanda Hua, Parham Asgari, and Junha Jeon* Department of Chemistry and Biochemistry, University of Texas at

Arlington Division: Organic Chemistry E-mial: hiephoang.nguyen@mavs.uta.edu Category: Graduate Student Efficient syntheses of the 3,3’ bis-substituted BINOLs and other biphenol compounds can be achieved from dioxasilines, generated by a one-pot Ir-catalyzed ester hydrosilylation catalyzed with dialkyldihydrosilanes and reductive Rh-catalyzed ortho-C–H silylation, by exploiting nucleophilic ring-opening addition with a series of nucleophiles (e.g., Grignards reagents, organolithium reagents, and oxygen nucleophiles) as well as arylation by Hiyama-Denmark cross-coupling. Moreover, the 3,3’ bis-silyl BINOLs can also be triflated and subsequently subjected to the Au-catalyzed direct arylation to form a class of triflated 3,3’-bis-aryl BINOLs which can be subjected to the Ni-catalyzed cross-coupling conditions to provide 3,3’-functionalized BINAPs. These BINOLs and BINAPs derivatives can facilitate an enormous set of stereoselective reactions including various methods of carbon-carbon bond formation and catalytic heteroatom-transfer.

111

Synthetic methods toward hippadine and pratosine alkaloids Charles Ochoa, David Minter*

Department of Chemistry & Biochemistry, Texas Christian University Division: Organic E-mail: c.ochoa@tcu.edu Category: Graduate Hippadine and pratosine are lycorine-type pharmacologically active Amaryllidaceae alkaloids. Although several total syntheses of these natural products have been developed, most of the routes require prohibitively expensive materials and/or give low overall yields. Our current research involves the development of new synthetic methods starting with 6,7-disubstituted isoquinolines that should be suitable for preparing these alkaloids on a large scale using inexpensive materials. The key step in the synthetic scheme centers around an intramolecular de Mayo photocyclization that uses the reaction of the alkene in an isocarbostyril with a 1,3-diketone contained within a six-carbon functionalized tether on nitrogen. The resulting tricyclic system should contain a 1,5-diketone grouping, but these functions are masked in the form of a cyclic hemiketal. Nevertheless, a base-catalyzed aldol addition reaction affords the ABCD-ring system present in hippadine and pratosine. Dehydration of this product affords a β,γ-enone that can be transformed to a diene in two steps. Oxidation of the diene with DDQ affords the target natural products after simple chromatographic purification. This synthetic pathway circumvents the use of catalysts that are either expensive or contain metals such as palladium or iridium. Moreover, our method allows for the syntheses of analogs in high yields by modifying the tether group on nitrogen

112

Age reduction in carbon molecular sieve membranes formed from copper acetate/polybenzimidazole mixed-matrix

membranes Whitney K. Cosey, Kenneth J. Balkus Jr., John P. Ferraris, and Inga H.

Musselman* Department of Chemistry and Biochemistry, The University of Texas at

Dallas Division: Polymers E-mail: Wkc160030@utdallas.edu Category: Gradaute Polymer-based gas separation membranes have been studied over the last two decades due to their low cost and ease of manufacturing. While polymeric membranes are currently used commercially, they are limited by an inherent trade-off between selectivity and permeability. Carbon molecular sieve membranes (CMSMs) are not bound by this trade-off, and thus they surpass polymeric membranes in terms of permeability and selectivity due to the presence of micropores (7-20 Å) and ultramicropores (<7 Å), which can provide high flux and high selectivity, respectively. While several researchers focus on tailoring the pore aperture to improve performance, improving the stability of the CMSMs by reducing physical aging (i.e., the collapsing of pores) has yet to be addressed. Our group introduced “pillars” formed by metal cations into CMSMs to prevent the collapsing of micropores. Specifically, multivalent cations from copper acetate were incorporated into polybenzimidazole, a CMSM precursor polymer, to form pillars within the CMSMs following high temperature heating. Loadings of up to 15 wt% copper acetate in polybenzimidazole were achieved before polymer cross-linking prevented the formation of membranes. The CMSMs incorporating copper were more flexible than those fabricated from pure polybenzimidazole.

113

Contaminant Removal Using Porous Silicon Oxycarbide (SiCO) Materials

Susana Aguirre-Medel, Peter Kroll* Chemistry and Biochemistry Department at University of Texas at

Arlington

Division: Physical Chemistry E-mail: susana.aguirre-medel@mavs.uta.edu Category: Graduate Student The isolation of graphene in 2004 steered fields of research involving materials design and discovery. The hunt for “new” materials with exciting properties that could be “tailored” is a target of scientific and engineering research. We synthesize and tailor porous silicon oxycarbide (SiCO) materials, characterize their microstructural properties and examine their performance in environmental applications. We use the sol-gel method which involves hydrolysis and condensation reactions to obtain a cross-linked gel which is slowly dried at 45°C. In this process we obtain a porous material with up to 800 m2/g of BET specific surface area (SSA). We also characterize the nanoparticle size, pore size distribution, average pore size, and total porosity, using N2 sorption measurements. Porous SiCO materials are transformed via thermal treatment in controlled atmospheres into SiCO ceramics. We characterize the microstructural features of the material using SEM and TEM imaging. We use UV-Vis spectrophotometry to study the potential applications of these materials for environmental remediation. Porous SiCO materials display high adsorption percent towards methylene blue (75%) and methyl violet (49%) solutions in less than 5 minutes of reaction. SiCO materials’ potential for environmental remediation will be further understood by comparing these results to commercial materials available today in the market.

114

Session 7: Organic Chemistry and Polymers II

Silicone–based materials for controlled release drug delivery Caleb Bunton, Zahra Bassampour, Joseph V. Rose, David Y. Son*

Department of Chemistry, Southern Methodist University

Division: Polymers E-mail: cbunton@mail.smu.edu Category: Graduate Drug delivery devices have recently received a lot of attention with many diverse types of devices becoming available as powerful tools for researchers and medical practitioners. Material design plays a significant role in the quality and improvement of these devices with the control of drug delivery being at the forefront of design considerations. With this in mind, we have sought to design a non-biodegradable drug delivery device incorporating a material which will allow drug release rate control, and drug release vector control (directional drug release) with high loading capabilities, and proven biocompatibility. In this study, a selection of silicones has been utilized to produce a polymeric crosslinked material via hydrosilylation for drug delivery applications. Varying the chain length and/or mole % functionality of the selected silicones affords several material formulations with varying crosslink densities. Through the differences in crosslink density, drug delivery rate may be controlled. A model of drug delivery was produced with the use of Nile Red dye and studied via visible spectroscopy. Vector controlled release may also be achieved in much the same manner; using varying crosslink densities to mechanically control the route of drug release through the material with either multi-directional release, or uni-directional release possible. These polymeric crosslinked materials are highly efficacious in terms of dosage control, vector control, and bio-compatibility. Drug release rate increases with decreasing crosslink density and conversely, decreases with increasing crosslink density. Furthermore, release direction (vector) can be controlled through mechanical means.

115

A Chemiluminescent Probe for Cellular Peroxynitrite Using a Self-Immolative Oxidative Decarbonylation Reaction

Jian Cao, Weiwei An, Audrey G. Reeves and Alexander R. Lippert* Department of Chemistry, Southern Methodist University

Division: Organic E-mail: jianc@smu.edu (graduate student) Category: Graduate

Peroxynitrite (ONOO–) is a highly reactive oxygen species which has been recognized as an endogenous mediator of physiological activities like the immune response as well as a damaging agent of oxidative stress under pathological conditions. While its biological importance is becoming clearer, many of the details of its production and mechanism of action remain elusive due to the lack of available selective and sensitive detection methods. Herein, we report the development, characterization, and biological applications of a reaction-based chemiluminescent probe for ONOO– detection, termed as PNCL. PNCL reacts with ONOO– via an isatin moiety through an oxidative decarbonylation reaction to initiate light with high selectivity against other reactive sulphur, oxygen, and nitrogen species. PNCL has been applied for ONOO− detection in aqueous solution and live cells. Moreover, PNCL can be employed to detect cellular ONOO– generated in macrophages stimulated to mount an immune response with lipopolysaccharide (LPS). The sensitivity granted by chemiluminescent detection together with the specificity of the oxidative decarbonylation reaction provides a useful tool to explore ONOO– chemistry and biology.

116

Synthesis of anti-cancer drugs to inhibit P-gp pumping action

Maha Aljowni, Amila Nanayakkara, Pia Vogel, John Wise, Alexander Lippert* Department of Chemistry, Southern Methodist University

Division: Organic Chemistry E-mail: maljowni@smu.edu Category: Graduate student A problem with cancer treatment is that many cancers develop resistance to chemotherapeutic agents, causing them to fail to accumulate in resistant cancer cells long enough to have any effect. This is due to the overexpression of a plasma membrane protein called P-glycoprotein (P-gp). Generally, the role of P-gp is to protect the cells from any toxins or foreign substances by pumping these toxins (including chemotherapeutic drugs) out of the cell. I am collaborating with the Wise-Vogel laboratory at Southern Methodist University, who utilize a computer-generated model to predict the structures of P-gp inhibitors that inhibit the action of P-gp. These docking models find drug targets that slow the action of P-gp pumping, as well as help understand the underlying mechanism of how the protein effluxes toxins from the cell. My current research is focused on multiple drug analogues that are predicted to inhibit the P-gp protein based on their docking models. These are tested in cancer cell lines in combination with current chemotherapeutics to determine efficacy and strength of inhibition so that future chemotherapeutic drugs can work effectively in cells.

117

Development of a Chemiluminescent Probe for Nitroxyl Weiwei An, Jian Cao and Alexander R. Lippert*

Department of Chemistry, Southern Methodist University Division: Organic E-mail: wan@smu.edu Category: Graduate Nitroxyl (HNO) is a reactive nitrogen species related to nitric oxide that shows distinct therapeutic potential, including the possibility as a treatment method for heart failure. The one-electron reducing capacity can be seen in the reactions with metals or metalloproteins. The low H-NO bond strength implies that HNO could go through series redox reactions in biology systems. However, a clear understanding of endogenous HNO generation in mammalian systems remains sparse because of a lack of efficient HNO probes. To further understand the in vivo mechanism and endogenous pathways of nitroxyl, a chemiluminescent nitroxyl probe based on the spiroadamatane 1,2-dioxetane has been synthesized and characterized. This talk will discuss the development and applications of this probe.

118

Polyarylene polyimide synthesis, characterization, and imide optimization

Stephen M. Budy and David Y. Son* Department of Chemistry, Southern Methodist University

Division: Organic/Polymer E-mail: sbudy@smu.edu Category: Graduate A series of six Diels–Alder polyarylene polyimides were synthesized via traditional oil bath and microwave-assisted step-growth polymerization. Optimization of the diamine with six different anhydrides using a two-step polycondensation was accomplished. The imidization of the polyamic acids was chemically completed by treating with acetic anhydride and triethylamine. The polyarylene polyimides were soluble in a variety of solvents. By controlling polymerization ratios and/or times, either oligomer or polymer can be produced in high yields. Proton NMR and FTIR spectroscopy were used to monitor the polymerization. The polyarylene polyimides were characterized by 1H/13C NMR spectroscopy, ATR-FTIR spectroscopy, TGA, DSC, DMA, and GPC. Further work will involve scaling up the polymerization reactions and investigating cross-linked materials.

119

PAN-Lignin polymer blends as carbon fiber precursors for high performance supercapacitors Rangana Jayawickramage, John P. Ferraris*

Department of Chemistry, University of Texas at Dallas, Dallas, TX 75080

Division: Polymers (Electrochemistry) E-mail: Jrp130430@utdallas.edu Category: Graduate

Supercapacitors are energy storage devices that electrostatically store energy in the electrode and electrolyte interface. To enhance the capacitance, energy and power densities, it is very important to increase the surface area and pore volume in the carbon electrodes. A promising method to increase the surface area is spinning carbon precursor solutions into fibers followed by carbonization. Blending PAN with a relatively low-cost polymer will result in cost reduction and often improved performance. Due to its excellent spinnability and the final fiber properties, polyacrylonitrile (PAN) is commonly used as a carbon fiber precursor. Lignin is the second most abundant natural polymer and is less expensive compared to other polymer precursors of carbon electrodes. But neat lignin cannot be electrospun. We report new carbon fiber precursors for supercapacitor electrodes comprising electrospun PAN and lignin blended at different compositions. The as-spun fiber mats were subjected to thermal treatments. Conductivity, SEM, Raman, and surface area analysis were carried out to characterize the structure and morphology of the carbon electrode material. Coin cell supercapacitors were assembled and the performance was evaluated with electrochemical testing. A PAN: Lignin composite of 70:30 mass ratio yielded devices with 128 F/g specific capacitance where neat PAN showed 100 F/g.

120

Nitroxyl Modified Tobacco Mosaic Virus as a Metal-Free High-Relaxivity MRI and EPR Active Superoxide Sensor

Madushani Dharmarwardana,a† André F. Martins,a,e† Zhuo Chen,a Philip M. Palacios,d Chance M. Nowak,b Raymond P. Welch,a Shaobo Li,a Michael A. Luzuriaga,a Leonidas Bleris,b Brad S. Pierce,d A. Dean Sherry,a,e Jeremiah J.

Gassensmitha,c,* aDepartment of Chemistry and Biochemistry, University of Texas at Dallas Division: Organic E-mail: mxd110630@utdallas.edu Category: Graduate Superoxide overproduction is one of the major reason for multiple diseases in the human body. There are several superoxide sensors based on fluorescence imaging have been reported, yet the detection of superoxides in deep injured tissues is very challenging. Organic radical contrast agents (ORCAs) are capable of detecting superoxides as they reduced to magnetic resonance imaging (MRI)/ electron paramagnetic resonance (EPR) active form to MRI/EPR silent from. Herein, we report MRI and EPR active contrast agent prepared by conjugating the paramagnetic ORCA to the surface of rod shaped viral nano particle, tobacco mosaic virus (TMV). Our data confirm that ORCA-TMV conjugates are efficient T1 and T2 contrast agents at low field and show very high T2 enhancement at high field (9.4 T). We used the unique tube-like structure of TMV nanoparticle to develop a “quenchless” bimodal probe for of fluorescence and MRI/EPR imaging. The interior surface of TMV was functionalized with fluorescent dye for fluorescent imaging and quantification, and the exterior surface of TMV was functionalized with ORCAs for MRI/EPR imaging. Finally, we showed that the reduced ORCA-TMV do not re-oxidized from normal cellular respiration and detect enzymatically produced superoxide in biological fluids like serum.

121

Propylene/propane separation using carbon membranes derived from a cross-linkable polyimide precursor, 6FDA-

DABA Chamaal Karunaweera, Samitha Panangala, Inga H. Musselman, Kenneth J.

Balkus. Jr, John P. Ferraris* Department of Chemistry and Biochemistry, The University of Texas at

Dallas

Division: Polymer Chemistry E-mial: cxk140730@utdallas.edu Category: Graduate

Cryogenic distillation is the traditional process for propylene/propane separation and it is highly energy intensive. However, membrane-based gas separation is becoming more attractive due to its simplicity, which leads to lower energy and equipment costs and are being considered for numerous gas separations including C3 separation. Polymeric membranes, mixed matrix membranes (MMMs), facilitated transport membranes and carbon molecular sieve membranes (CMSMs) are among the major types of separation membranes used for propylene/propane separation. The first three are less attractive, mainly due to their drawbacks including plasticization, non-homogenous distribution of inorganic nanoparticles in the polymer matrix and poor chemical stability. Carbon membranes, on the other hand, lack these disadvantages and have the potential to be readily integrated in commercial separation plants. In this study, a cross-linkable polyimide, 6FDA-DABA is used as the precursor for CMSMs. Synthesis of high molecular weight 6FDA-DABA is described for the first time. Thermal cross-linking at temperatures above the glass transition temperature (Tg) of the polymer was utilized prior to the carbonization. Material characterization and gas permselectivities are reported for the CMSMs prepared under different conditions. A propylene/propane separation selectivity of 25 was obtained for the CMSM derived from the pre-crosslinked polymer precursor.

122

Linear and Star-like Functionalized Polycaprolactones Micellar Systems for Doxorubicin Delivery

Vasanthy Karmegam,1 Mihaela. C. Stefan1* Department of Chemistry and Biochemistry, University of Texas at Dallas

Division: Organic Chemistry E-mail: kxv131230@utdallas.edu Category: Graduate

The effective clinical application doxorubicin (DOX), a widely used anti-cancer therapeutic agent, is limited by its serious toxicity to healthy tissues, such as cardiotoxicity, by off-target DOX delivery and development of DOX resistance. The use of biodegradable polymeric micellar drug delivery system has shown potential as drug nanocarriers for controlled and enhanced drug delivery at the tumor site. In this work we aimed at reporting; (1) preparation and characterization of DOX-encapsulated polymeric micelles formulated with biocompatible and biodegradable linear and star-like amphiphilic diblock copolymer poly(γ-benzyloxy-ε-caprolactone)-b-poly{γ-2-[2-(2-methoxy-ethoxy)ethoxy]ethoxy-ε-caprolactone(PBCL-b-PMEEECL); (2) the improvements in the micelle stability at high dilution and drug loading capacity by increasing the number of branching points (3) evaluation of the cytotoxic effect to cancer cells in vitro. Branching plays a key role in micellar stability, size, and DOX loading abilities. Two-fold higher DOX loading was achieved in star compared to linear polymeric micelles. The enhanced stability and the smaller size (~100 nm) obtained in the star-like polymeric micelles are advantageous in the controlled DOX delivery at the tumor site. This DOX Micellar formulation has potential benefits in cancer treatment by minimizing associated side effects and expands the therapeutic window.

123

Biodegradable 3D Printed Microneedles for Transdermal Drug Delivery

Michael A. Luzuriaga and Jeremiah J. Gassensmith* The University of Texas at Dallas, Department of Chemistry and

Biochemistry

Division: Polymers E-mial: Mal161930@utdallas.edu Category: Graduate Student

Microneedle (MN) arrays are small protruding devices used for transdermal drug delivery. More specifically, dissolvable MNs are broken off in the skin to diffuse drugs into the blood stream; however, prototyping new designs is expensive and requires modification to the master template. Here, we propose a new microfabrication technique with a fused deposition modeling (FDM) 3D printer using thermoplastic materials such as polylactic acid. With 3D modeling software, various MN shapes can be designed and 15 MN arrays can be printed in approximately 40 minutes. The challenge of FDM 3D printing is fabricating needles in the micrometer size region needed owing to the low resolution of these printers. We were able to significantly improve the resolution by developing a chemical etching protocol post fabrication. Using scanning electron microscopy, we found our method reduced needle tip sizes to 57.71 ± 8.82 microns and they successfully broke off into porcine skin. We have also shown that these MNs have comparable mechanical strengths to currently fabricated MNs and can release drugs over time into skin. This process allows us to rapidly prototype new designs that can be used for transdermal drug delivery.

124

Hydrogen Atom Transfer from Hydrosilanes by Lewis Base Catalysis

Parham Asgari, Junha Jeon* Department of Chemistry and Biochemistry, University of Texas at

Arlington Division: Organic chemistry E-mail: Parham.asgari@mavs.uta.edu Graduate student Because of the importance of hydrogen atom transfer (HAT) in biology and chemistry, emerging interests in synthetic chemistry research are to develop new strategies of the HAT in a sustainable manner. In this project we describe our discovery on unprecedented, sustainable HAT process, without any use of transition metal catalysts, and report a mechanism involving Lewis base-catalyzed, complexation-induced HAT (LBCI-HAT), followed by highly selective cross-radical coupling. In this reaction, earth abundant, alkali metal Lewis base catalysts play a dual-role. They first served as a HAT initiator and subsequently a silyl radical protecting group for selective downstream processes. Experimental and computational studies support the proposed LBCI-HAT mechanism, where EPR study identified potassiated paramagnetic species and multistate density function theory revealed a high HAT character in the transition state. This new, efficient and sustainable HAT permits highly controlled access to either branch-selective hydrosilylation or polymerization of vinylarenes.

125

Novel Substitution and Oxidation Reaction of Organic Azides through Triazene Intermediates

Enrique Barragan, Alejandro Bugarin* Department of Chemistry and Biochemistry, University of Texas at

Arlington Division: Organic E-mail: horacio.barraganpeyrani@mavs.uta.edu Category: Graduate Student Novel reactivity for organic azides is reported herein. Through reaction with NHC precursors, organic azides were converted to the corresponding triazenes. These intermediates undergo substitution and oxidation reactions under mild, transition-metal free, catalytic acidic conditions. The transformations achieved include successful synthesis of aldehydes, ketones, ethers, and sulfides from azides through a common intermediate, thus contributing to the versatility of the azide functional group.

126

Room temperature C–C silyl insertion with hydrosilyl acetals Thirupataiah Avullala, Parham Asgari, Yuanda Hua, Apparao Bokka,

Shawn G. Ridlen, Kyung Suk Yum, Rasika Dias, and Junha Jeon * Department of Chemistry and Biochemistry, University of Texas at

Arlington, Arlington Division: Organic E-mail: thirupataiah.avullala@mavs.uta.edu Category: Graduate Student Catalytic carbon-carbon single bond activation processes are inarguably one of the least reactive “functional” groups. The robust nature of carbon-carbon single bonds presents a fundamental challenge to organometallic chemists. Furthermore, petroleum plays a significant role in our daily lives and the selective activation of carbon-carbon bonds is crucial for petroleum refining and transformation. The development of highly selective C–C s-bond hydrosilylation and dehydrogenative silylation of cyclopropanes with silyl acetal directing group is described. Specifically, cyclopropane system possessing silyl acetal directing group would effect directed C–C-bond activation/silyl insertion over proximal Csp2–H and Csp3–H bonds. In this work, we described the relay of Ir-catalyzed hydrosilylation of inexpensive and readily prepared cyclopropanoacetates which we prepared by Kulinkovich reaction, followed by Rh-catalyzed hydrogenative and dehydrogenative C–C bond silylation to provide dioxasilepines and dioxasilolanes via putative [6,4]-bicyclic fused cyclometallated intermediate. Subsequent dehydrogenative β-hydride elimination followed by reductive elimination would furnish dioxasilepines. Alternatively, in the presence of Rh-Tp catalyst observed hydrosilylative sequential reductive elimination to provide dioxasilolanes. We gained mechanistic insights into the two distinctive organocmetallic pathways. We applied the hydrogenative and dehydrogenative C–C s-bond silylation method on complex bioactive molecules such as estradiol.

127

Hydro-Silyl Acetal Directed Transition Metal Catalyzed Regio-specific Exo-dig Hydrosilylation Of Alkynes.

Udaya sree Dakarapu, Thirupataiah Avullala, and Junha Jeon* Department of Chemistry and Biochemistry, University of Texas at

Arlington Division: Organic Chemistry E-mail: udayasree.dakarapu@mavs.uta.edu Category: Graduate Student Over a decade, transition metal catalyzed alkyne hydrosilylation studies have been investigated for a long time and the search for regiospecificity still remains a challenge. Vinyl silanes and vinyl-substituted silanes are of high synthetic utility in manufacture of copolymer plastics, cross-linking agents, resins and cable insulators. We have developed a transition metal catalyzed regiospecific intramolecular hydrosilylation of alkynes utilizing silyl acetal group as directing group. This study involves acetal-directing groups, which are easily accessible and ready to install, in order to achieve stereo-defined alkenyl products. Iridium catalyzed hydrosilylation of acetate group in alkynyl acetate generates alkynyl silyl acetal, subsequent rhodium catalyzed alkyne hydrosilylation generates α-E-regio-isomer in an exo-syn pathway to furnish dioxasilinanes in good to excellent yields. Thus synthesized dioxasilinanes can efficiently provide a feasible and convenient synthetic route for various organic molecules via cross-coupling reactions. This operationally convenient, easily accessible directing groups protocol exhibits excellent and wide range of functional group tolerance.

128

A Hybrid Supercapacitor Electrode Material with Carbon and Heteropoly Acids

Juan Alex Garcia, Kenneth J. Balkus, Jr., John P. Ferraris* University of Texas at Dallas

Division: Organic Email: jag150630@utdallas.edu Category: Graduate Widespread development of alternative energy sources and improved energy infrastructure requires improved storage devices. To meet these demands, devices will need to possess high energy and power densities, high cyclability, and affordability. Typically, battery systems have high energy densities but low power densities for quick dispersions of energy. Electrochemical double-layer capacitors have high power densities but lack comparable energy densities. Work has been done to improve these energy densities by increasing voltage windows and capacitance. One such effort has been the development of hybrid capacitor devices utilizing surface capacitance and redox charge storage from microstructured metal oxides (e.g., Ru, Mn, V, Mo, W). The conductivity of these electrode material is limited by the loading of metal oxide materials due to the insulating nature of many metal oxides. The research to be presented utilizes a technique of in situ addition of metal oxides and metal oxide precursors at higher loadings without inhibiting conductivity while maintaining sufficient access to capacitive and redox charge storage. Electrospun carbon nanofibers prepared from blends of polyacrylonitrile with polystyrene derivatives have shown the ability to selectively shepherd metal oxides and precursors into the fibers to increase metal loadings while maintaining the conductivity of the carbon nanofiber electrode.