Photoinduced charge transfer interaction between fullerene[60] and diphenylpolyenes in solution: evidence for photocycloaddition reaction

The charge transfer interaction between C60 and diphenylpolyenes, namely 1,4-diphenylbutadiene and 1,6-diphenylhexatriene, has been studied in benzene and benzonitrile solutions using transient absorption techniques with pico to microsecond time resolution. Polyenes form weak ground state charge transfer complexes with C60 in benzonitrile, but not in benzene. In benzonitrile the charge transfer complex undergoes charge separation on photoexcitation to form a contact ion-pair, which undergoes a fast charge recombination process. Diphenylpolyenes also interact with the excited triplet state of C60. The interaction of the polyenes with the excited states of C60 gives rise to a cycloaddition product.