[Todos] Miercoles 9 de mayo 13 .00 hs - Seminario DQIAQF/INQUIMAE

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Seminarios DQIAQF - INQUIMAE, miercoles 9 de mayo - 13 hs.

Aula de Seminarios INQUIMAE - DQIAQF
Facultad de Ciencias Exactas y Naturales
Ciudad Universitaria - Pab. 2  -  Piso 3

Transferencia de electrones en sistemas híbridos nanopartículas-centros
redox.
David J Schiffrin,
Chemistry Department, University of Liverpool, UK

Hexanethiolate gold monolayer-protected clusters (C6-MPCs) with an average
core diameter of 1.8 nm and a capacitance of 0.6 aF were synthesised by a
two-phase method. The clusters were functionalised with
(6-ferrocenyl)-1-hexanethiol by a place exchange reaction at different
molar ratios. The average number of ferrocene centres per cluster
determined by 1H NMR were 10, 7 and 4. DPV and CV measurements for cluster
solutions in 0.1 M TBAPF6/Tol:AN (2:1) showed clearly the response of the
Fc+/Fc redox couple and of Quantized Double Layer (QDL) charging events of
the gold core. A transition from single to multiple electron transfer
response for the
redox couple was observed as the number of ferrocene units per cluster was
increased. The distances between the redox moieties have been estimated
considering a homogeneous distribution of the redox sites on the
nanoparticle ligand shell. In all the cases the inter-ferrocene average
separation is too large to observe self-exchange reactions and the most
likely electron transfer pathway is by fast rotational diffusion. The
oxidation of the ferrocene groups results in an electrostatic
switching-off of electron transfers between the electrode and the
nanoparticle core.