Photoinduced electron and energy transfer processes in fullerene C-60-metal complex hybrid assemblies

The electron and energy accepting properties of fullerene C-60 can be readily exploited upon the selection of suitable donating species to construct supramolecular assemblies which display photoinduced electron and/or energy transfer processes. In this account we focus on the use of transition metal complexes in the role of the electron/energy donor, in particular we discuss the photophysical properties of some fullerene hybrid systems containing tris(2,2'-bipyridine)ruthenium(II), (2,2'-bipyridine)rhenium (1) or bis(1,10-phenanthrolinc)copper(l) subunits that we have investigated over the years. In fullerene hybrid dyads with Ru(II) and Re(l) complexed moieties, electron transfer is observed at room temperature in both cases, while it is blocked at 77 K in the former case. For multicomponent arrays (rotaxane, dendrimers, helicates) with Cu(l)-bisphenanthroline moieties, quenching by electron/energy transfer of the MLCT excited states of the metal complexed moiety is always found. When excitation is addressed to the carbon cage, photoinduced processes occurs when methanofullerenes are involved, but not with bismethanofullerenes.