Interfacial Supramolecular Assemblies
and Electron Transfer Dynamics
Prof. Robert Forster
National Centre for Sensor Research
Biomedical Diagnostics Institute
Dublin City University
Ireland
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Molecular Self-
Nano- and Assembly Electron Transfer
Microelectrodes Dynamics
UNI-NANOCUPS
Interfacial
Luminescence
Molecular Switches
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Training in Techniques
Electrochemical
•Microelectrode fabrication and characterisation
•Cyclic voltammetry
•Chronoamperometry
•AC Impedance
Spectroscopy
•Raman Microscopy
•Luminescence (Solution, solid, interfacial)
•Transient emission spectroscopy
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Exchanges and Visits
BIRMINGHAM
•Surface active metal complexes (J. Phys. Chem. Publication,
Phys. Chem. Chem. Phys. publication imminent)
WARWICK
•Personnel – Dr. Paolo Bertoncello (J. Phys. Chem. Publication)
•Materials – electrodes
DEMOKRITOS
•Materials – surface active CDs
KASSEL
•Personnel – Rodica Morarescu
AMSTERDAM
•Planned visit by Pablo Contreras (Raman Microscopy)
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MOLECULAR SELF-ASSEMBLY:
SH
Spontaneously Adsorbed Monolayers
SH
CH2
CH2
Diffusional N
N
N
N
N
N
Co
mass transport N
Co
N N N
SH
N N CH2
SH
N
CH2 N N
CH2 Co
SH CH2 N N
S
CH2 S N
CH2
Surface N N
S
adsorption N
N
Co
N
N
N
Co
N
N N
kinetics N
N
CH2
S
CH2
S
ELECTRODE
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Adsorption Dynamics
200
1 min
150 5 min
20 min
180 min
100 10 min
50
i/nA
0
-50
-100
-150
-200
-0.7 -0.5 -0.3 -0.1 0.1 0.3
E vs Fc/Fc+
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Concentration Dependence
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Adsorption Isotherm
2.00E+05
(Cb / G ) / cm
1.60E+05 y = 1E+10x + 17705
R2 = 0.9978
1.20E+05
8.00E+04
s S S S
4.00E+04
0.00E+00 Gold-Thiol Bond 100 kJ mol-1
0.0E+00 3.0E-06 6.0E-06 9.0E-06 1.2E-05
[Co(ttpy)2]2+ / M
Gsat = 1x10-10 mol cm-2
Gads = 32.8±1.5 kJmol-1
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Thiolated Ruthenium 2,2´-Bipyridine Monolayers
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Cyclic Voltammetry
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Luminescence Properties
90000
Intensity / A.U.
80000
70000
60000
50000
40000
30000
20000
10000
0
500 550 600 650 700 750
/ nm
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Cyclodextrins Substituted on Primary Rim
S
n = 1, 2, 6
DCU, DEM
( )n
HS
NH NH NH
N N N
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Blocking & Backfilling
Blocking of 1mM [Fe(CN)6]3-/4- at a modified Pt
Bare electrode
Surface
g-CD-py2
0.0001
0.00008 Thiol backfilling C6
0.00006 thiol backfilling with
Current density (A.cm-2)
admantyl inject
0.00004
0.00002
0
-0.00002
-0.00004
-0.00006
-0.2 -0.1 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7
-0.00008
Potential (V) verses Ag/AgCl
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Electron Transfer
Heterogeneous
Electron Transfer
Glass Body
Electrode
Electron Cross-
Exchange
Glass Body
High Speed Voltammetry
ko = 0.9±0.1x104 s-1
Adsorption Dynamics and Electrochemical and Photophysical Properties of Thiolated
Ruthenium 2,2'-Bipyridine Monolayers Bertoncello, P.; Kefalas, E. T.; Pikramenou, Z.; Unwin, P.
R.; Forster, R. J. J. Phys. Chem. B.; 2006; 110(20); 10063-10069.
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ACKNOWLEDGEMENTS
•Almut Czap (ER)
•Elena Campagnoli
•Martin Sjodin
•ESR Claudio Zuliani to join in June!!!
•European Union, Science Foundation Ireland,
Enterprise Ireland, Higher Education Authority.
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