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SUPRAMOLECULAR CHEMISTRY FOR LIGHT
CAPTURE AND CONTROLLED ENERGY &
CHARGE TRANSFER
Henrique E. TomaInstituto de Química - USP
Workshop Bioen – 25/10/2009
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
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
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
Nano TiO2
Prêmio NanoEurope-2006
JA Bonacin, SH Toma
K Araki, HE Toma 2006
16
Patente PI 0.702.995-0
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
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-
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 )
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
Ion Pairing
+
Electrostatic and -stacking Assembly of Tetraruthenated/tetrasulphonated
Porphyrin Films
Dip-Coating
Electronic spectra
of multiple bilayers
Recommended