C60-exTTF-C60 dumbbells : cooperative effects stemming from two C60s on the radical ion pair stabilization

The presence of a second C60 cage in C60-exTTF-C60 triads [exTTF = 9,10-bis(1,3-dithiol-2-ylidene)-9,10-anthraquinone] has beneficial effects on the stabilization of the radical ion pair formed upon irradiation in comparison with the related C60-exTTF dyad. Although C60-exTTF-C60 ensembles show no electronic interaction between the electroactive units in the ground state, their irradiation leads to C60•--exTTF•+-C60 species with lifetimes on the order of 600 ns in benzonitrile; these lifetimes are twice those determined for the analogous C60-exTTF dyad.