Collect. Czech. Chem. Commun. 2001, 66, 276-290

Identification and Characterization of Redox Sites in Supramolecular Systems and Their Relevance for the Design of Photoactive Devices. Ru(II)/C60-Based Donor-Acceptor Dyads

Maurizio Caranoa, Paola Ceronia, Michele Magginib, Massimo Marcaccioa, Enzo Mennab, Francesco Paoluccia,*, Sergio Roffiaa,* and Gianfranco Scorranob

a Dipartimento di Chimica "G. Ciamician", Università di Bologna, Via Selmi 2, 40126 Bologna, Italy
b Centro Meccanismi CNR, Dipartimento di Chimica Organica, Università di Padova, Via Marzolo 1, 35131 Padova, Italy


Two dyads consisting of a mononuclear or a dinuclear ruthenium complex covalently linked to a fullerenopyrrolidine through a rigid androstane spacer, have been prepared through azomethine ylide cycloaddition to C60. Electrochemical and photophysical studies revealed that ground-state electronic interactions between the dinuclear ruthenium chromophore and the fullerenopyrrolidine moiety are small. The redox series observed for the dyads correspond to the superimposition of the reduction patterns of the fullerene core and of the Ru(II)-bipyridine moieties. The results of the electrochemical investigation allow us to rationalize the photophysical behaviour of the two species by identifying the thermodynamically allowed and forbidden routes for the deactivation of the Ru-based metal-to-ligand charge transfer (MLCT) excited state.

Keywords: Electrochemistry; Ruthenium complexes; Fullerenes; Steroids; Bipyridines; Donor-acceptor systems; Cyclic voltammetry; Redox series; Supramolecular chemistry.

References: 31 live references.