SUPRAMOLECULAR CHEMISTRY FOR LIGHT

CAPTURE AND CONTROLLED ENERGY &

CHARGE TRANSFER

Henrique E. TomaInstituto de Química - USP

Workshop Bioen – 25/10/2009

CHEMICAL SOLAR ENERGY

TODAY

A. Fujishima and K. Honda, Nature, 1972, 238, 37.

back contact

thin film

SnO2/Metal

n

p

Si, CdTe,

CuIn(As)

Se

PHOTOVOLTAIC CELLS

SEMICONDUCTOR ORGANIC

DONOR

(POLYMER)

ACCEPTOR

(FULLERENE)

DYE CELLSPHOTOELECTROCHEMICAL

DYE /

ELECTROLYTE

SEMICONDUCTOR

(TiO2)

Supramolecular Concepts

Jean-Marie Lehn (Nobel Prize, 1987)

Molecules can be put together in order to work in a cooperative way,

exchanging information, energy and functionality. This is the route

chosen by the biological systems for performing high complexity tasks,

far beyond the chemistry of individual molecules.

+

Chemistry Supramolecular Chemistry

Performing molecular recognition,

Signaling (semiochemistry),

Precise sequencing on time, space, and energy,

Transporting, storing and exchanging

information,

Self-assembling and self-organizing,

Amplification (catalysis)

Performing energy conversion, and

Collisional

Statistics

Organized

CHEMISTRYSUPRAMOLECULAR

CHEMISTRY

Random

MOLECULAR NANOTECHNOLOGY

Supramolecular Approach to

Nanotechnology

Synthesis from atoms

and molecules

Molecular building blocks

Assembly

Nanostructured materials

Functional

materialsDevices

Coatings

Transducers

photon pump catalysis

electronics electron transfer

H.E.Toma, K. Araki, Prog. Inorg. Chem. 2009, 56, 379-485

3.1 nm

Supramolecular Porphyrins: 3

Yield highly homogeneous, stable,

functional self-assembled films

N

N N

N

N

NN

N

M Ru3+

Ru3+

Ru3+

Ru3+ Ru3+

Ru3+

Ru3+

Ru3+

Ru3+

Ru3+

Ru3+

Ru3+

Supramolecular Porphyrins

Properties can be modulated by changing the redox states

and electronic properties of the peripheral complexes

N

N N

N

N

NN

N

M Ru3+

Ru4+

Ru3+

Ru4+ Ru3+

Ru3+

Ru4+

Ru3+

Ru3+

Ru4+

Ru3+

Ru3+

N

N N

N

N

NN

N

M Ru2+

Ru3+

Ru3+

Ru3+ Ru3+

Ru2+

Ru3+

Ru2+

Ru3+

Ru3+

Ru3+

Ru2+

N

N N

N

N

NN

N

M Ru4+

Ru4+

Ru3+

Ru4+ Ru3+

Ru4+

Ru4+

Ru4+

Ru3+

Ru4+

Ru3+

Ru4+

Cit.-c

oxidase

Cit.

P-450

4

5

•ARAKI, K.; TOMA, H. E., Supramolecular

porphyrins as electrocatalysts,, Macrocyclic

Metal Complexes, Springer, 2006.

MULTI-ELECTRON TRANSFER

CATALYSIS

Mimicking cytochrome-C Oxidase

in 4e reduction of dioxygen.

N2

O2

H2O2 / H2O

O2 / H2O

rotating disc voltammetry cyclic voltammetry

rotating ring disc voltammetry

N

N N

N

Ru

Cl

N

N

NN

N

N

N

N

RuClN

N

N

N

Ru

Cl

N

N

NN

RuClNN

N

N

M

M(3-TRPyP)

I

O

C

C

C

C

C

C

C

C

C

C

C

C

O H

C

C

C

C

C

C

O

C

C

C

C

C

C

Cl

iodosobenzene

+ cyclohexane

+ PhIO

cyclohexanol (32%)

cyclohexanone (9%)

chlorocyclohexane(3%)

Cyclo-hexane oxydation

by Mn(3TRPyP)

Toma, Nunes et al, J.Catalysis 2005

MODELING CYTOCHROME P-450 ACTIVITY

K

+PhIO

k2

k-2

k3 fast

( AB)

(D)

Vectorial Energy Transfer of ZnTBipyP{Ru(dmbipy)2}4

Araki, Toma, Losco, Engelman, J.Photochem.Photobio, 2001

A) Pure compound in ethanol, B) In the presence of 0.3 M imidazole

HN N

Rubipy emission

porphyrin

emission

. ORGANIC PHOTOVOLTAICS

. PHOTOELECTROCHEMICAL

CELLS

. ELECTROCHROMIC DEVICES

. SENSORS

. LOGIC GATES /ELECTRONIC DEVICES

LIGHT

ELECTRONS

MOLECULAR DEVICES

Self-Assembled Films

Molecular Interfaces

1. Coating/Deposition

2. Electrostatic Assembly

3. Electropolimerization

4. Intercalation into lamelar films

ELECTRO-OPTICAL

Mediator/Electrolyte

conducting g

lass

H.E.Toma, K. Araki, Prog. Inorg. Chem. 2009, 56, 379-485

Red

Ox

Electrochemical response

of ferrocyanide ions at

a TRP modified electrode

Electrochemical response

of ferrocyanide ions at a

Pt bare electrode

Electrochemical response

of ferrocyanide ions at

a TRP modified electrode

RuII -RuIII

V

V

Ref AuxWork

i

Nitrite

Sulfite

Supramolecular ChemSensors for Food & Beverages and Drugs

Vitamine C

Sensorial probe

potentiostat/galvanostat

flow injection

analysis

4 USP patents

BC

BV

DYE PHOTOELECTROCHEMICAL

CELLS

red

ox

red

ox

e -

S

S*

h

e -

e-

N3 DYE

L = L’= NCS-

0.13%

88 %

TiO2 Macro

Nanocrystalline

TiO2

TiO2

IPCE % = I (amp/cm2) x 1240 (eV/nm) x 100

P(W/m2) x l(nm)

IPCE = Incident Photon to Charge Carrier Efficiency

Improving the light

harvesting in the

650-900 nm domain

is one of the greatest

challenges faced by

present day research in

DSC field.

Grätzel, 2009

Challenge 1

New, Better Dyes

N N

NN

N

N

N

NRu

Cl

N

N

NN

Ru

Cl

N

NN

N

RuCl

N

NN

N

RuCl

N

N

NN

M+

+

+

+

400 450 500 550 600 6500

5

10

15

20 (a)

Ab

sorb

an

ce (

A.U

)

IPC

E (

%)

l (nm)

0,0

0,5

1,0

1,5Soret

MLCT

TiO2

electronic spectrum

SUPRAMOLECULAR DYES

Weak anchoring of

porphyrin decreases

IPCE

Photoinjection from

the porphyrin and

ruthenium sites

NOGUEIRA, A. F. ; FORMIGA, A.LB. ; WINNISCHOFER, H. ;

TOMA, H. E. .Photochem. & Photobio. Sci., 3, 56-62, 2004

NOGUEIRA, A. F. ; FURTADO, O. ; FORMIGA, A.L.B. ;

TOMA, H. E. . Inorganic Chemistry, 43,. 396-398, 2004

TiO2

?

N

N

Ru

N

NN

N Cl

Ru

N

NN

N Cl

COOH

COOH

HOOC

OOC

OOC

HOOC

COOH

COOH

TiO2

mononuclear

binuclear

SUPRAMOLECULAR EFFECTS CAN IMPROVE IPCE

Challenge 2 : New mediators/electrolytes for improving the yield and DV

Challenge 4– Better porous materials

Challenge 4 - Minimizing corrosion, improving stability,

solid electrolytes, ionic liquids

Challenge 5 – Better understanding of the surface/liquid chemistry

Confocal Raman Microscope

Petrobras Grant

Confocal Raman Images showing the rutile/anatase distribution on a nanocrystalline P25 film,

10x10 μm wide, 75x75 points, monitoring the intensity of the (A) 398 cm–1 and (B) 448 cm-1 bands.

Raman spectra of the (a) anatase rich and (b) rutile rich domains are shown in (C). The plot of

Raman scattering intensity at (a) 398 and (b) 448 cm–1 bands, along the cross-section lines in (A)

and (B), are shown in (D).

Parussulo ALA, Bonacin JA,Toma SH, Araki K,Toma HE, Langmuir, 25, 11269-11271, 2009

TitaniumDioxide Nanoparticles

Probing rutile and anataseby ConfocalRaman Microscopy

TiO2 PHOTOACTION

2H2O

H2+

2OH-2OH-

1/2O2+ H2O

Nano TiO2

Prêmio NanoEurope-2006

JA Bonacin, SH Toma

K Araki, HE Toma 2006

16

Patente PI 0.702.995-0

catalyst

PHOTOELECTROCHEMICAL WATER SPLITTING CELL

WATER OXIDATION

T.J.Meyer, Accounts, 2010

E(V) = 0.2 – 0.59 pH

E(V) = 1.2 – 0.59 pH

E(V)= 1.6–0.59pH

PCET in ruthenium

clusters

III,III,II / III,III,III / IV,III,III / IV,IV,III

O2

pH > 9

pH

Toma et al,

Fotossíntese

Artificial –

Produção de

energia química

através da luz

Gust,Moore&Moore

Univ.Arizona, 1997

tríade fotônica – promove

a separação de cargas

através da luz

CE920 nm = DA/DQ = 190 cm2 /C

3X better than WO3 or paraquatTiO2

COLORATION EFFICIENCY

current

Fermi level

MOLECULAR LOGIC GATES

Type III - Photo-electrochemical

Ox /

Red

Eo

ITO

COND.

BAND

VALENCE

BAND

LFO Furtado, ADP Alexiou, L Gonçalves, HE Toma, K Araki

TiO2 Based Light Driven XOR/INH Logic Gates

Angew.Chemie, 2006, 45, 3143. - Patente PI 0.701.301-9 19

I3-/I-

CHEMICAL SOLAR ENERGY

TODAY

Muito obrigado!

recombination

kCR1: (ms -ns)

TiO2

EF

electron injection, kinj

50 %: <150 fs; 50 %: 1,2 ± 0,2 ps

D+/D*

D+/D

h

I3-/I

-

reduction

100 ns ([I-])

kCR2

Counter-electrode

IPCE % = I (amp/cm2) x 1240 (eV/nm) x 100

P(W/m2) x l(nm)

IPCE = Incident Photon to Charge Carrier Efficiency = LHE..

DYE PHOTOELECTROCHEMICAL CELL

I (amp/cm2)

P(W)

LHE (light harvesting energy)= capacidade absorção de luz

= eficiência de coleta de elétrons no eletrodo

= Rendimento quântico de injeção de elétrons

= kinj /( kinj + kr + knr )

ocsc

mm

th

max FFVI

VI

P

P

%100ÁreaaIrradiânci

max

P

V

+resistor

A

EFICIÊNCIA GLOBAL

ISC

Vm

Im

SURFACE PLASMON RESONANCE SPECTROSCOPY

ASSEMBLING HETERO-HYBRID NANOFILMS

J.J.Santos,Toma,Araki et al, 2009

50

40

30

20

10

0

Cu

rre

nt

(A

x1

0-6

)

0.60.40.20.0-0.2

Potential / V vs SHE

ascorbic

acid

10-5 M

a) [(CN)5FeIII

(bpz)RuII(bpz)Ru

II(bpy)2Cl]

(bpz)

h

b)

c)

d) [(CN)5FeIII

(bpz)RuII(bpz)Ru

III(bpy)2Cl]

(bpz-)

[(CN)5FeII(bpz)Ru

II(bpz)Ru

III(bpy)2Cl]

(bpz)

e) [(CN)5FeII(bpz)Ru

III(bpz)Ru

II(bpy)2Cl]

(bpz)

[(CN)5FeII(bpz)Ru

II(bpz)Ru

III(bpy)2Cl]

(bpz)

f)

kb

kc

kd

ke

[(CN)5FeIII

(bpz)RuIII

(bpz)RuII(bpy)2Cl]

*

(bpz

-)

[(CN)5FeIII

(bpz)RuIII

(bpz)RuII(bpy)2Cl]

*

(bpz-)

[(CN)5FeIII

(bpz)RuIII

(bpz)RuII(bpy)2Cl]

*

(bpz-)

[(CN)5FeIII

(bpz)RuII(bpz)Ru

III(bpy)2Cl]

(bpz-)

[(CN)5FeII(bpz)Ru

III(bpz)Ru

II(bpy)2Cl]

(bpz)

[(CN)5FeII(bpz)Ru

II(bpz)Ru

III(bpy)2Cl]

(bpz)

kf

[(CN)5FeIII

(bpz)RuII(bpz)Ru

II(bpy)2Cl]

(bpz)

DE (ED*/D - ERu(p)III/II) = 1.80 - 1.14 = 0.66 V

DE (EFeIII/II-ED+/D

*) = 0.70 + 0.09 = 0.79 V

DE (EFeIII/II - Ebpzo/-) = 0.70 + 0.37 = 1.07 V

DE (ERu(c)III/II - ERu(p)III/II) = 2.08 - 1.14 = 0.94 V

DE (ERu(p)III/II - EFeIII/II) = 1.14 - 0.70 = 0.44 V kf = 1.7 x 106 s-1

Photoinduced electron transfer - triad

system

RuN

N

N

N N

N

N

N

N

N

N

N

RuN

N

N

Cl

N

FeCN

CN

CN

CN

CN

IIIII

II

TOMA, H. E.; CAMERA, S. G.

J.Photochem.Photobio: A, 151, 57-65,

2002.

Co(III)/Co(II): 0,162 M Co(II)(dbbip)22+; 0,018 M Co(III)(dbbip)2

3+ em

etileno carbonato/acetonitrila (60:40)

- Menor densidade de corrente

de troca no contra-eletrodo

- Densidade de corrente de

troca no FTO é duas vezes

maior

- Limitações de transporte de

massa

Grätzel, M. et al. Coord. Chem. Rev., 248 (2004) 1447

1.4 nm

3.05 nm

2.29 nm

Optimized geometries (A, C = top view), (B, D = lateral view) for the 4-H2TPtPyP and 3-H2TPtPyP species, respectively.

Supramolecular Porphyrins: 2

The peripheral complexes dictate new stereochemical properties

Citocromo C Oxidase

oxygen-active site of

Bovine CitC-oxidase

Ion Pairing

+

Electrostatic and -stacking Assembly of Tetraruthenated/tetrasulphonated

Porphyrin Films

Dip-Coating

Electronic spectra

of multiple bilayers

Cytochrome P-450

OH

R

Cytochr.P450

O

R

C H

C

OH

N

N O

RXH +R'CHO

R X -C H 2R '

X =O , S o r N R " 2

R –S –R '

SR'

R

O

C

R'R

O

CR'

R

S

C

NH2

R

NOH

C

NH2

R O