Photoinduced processes of newly synthesized bisferrocene- and bisfullerene-substituted tetrads with a triphenylamine central block

Photoinduced electron transfer processes of two newly synthesized tetrads with a triphenylamine (TPA) as central building block, to which bisfullerenes (C60) and bisferrocenes (Fc) are covalently connected, have been studied. One of them has a TPA linked with one C60 moiety and two ferrocene moieties C60–TPA–(Fc)2 and another tetrad has a TPA linked with two C60 moieties and one ferrocene unit (C60)2–TPA–Fc. The photophysical properties of (C60)m–TPA–(Fc)n have been investigated by applying the picosecond time-resolved fluorescence and nanosecond transient absorption techniques in both polar and nonpolar solvents. The charge separation process via the excited singlet state of the C60 moiety of the C60–TPA–(Fc)2 is more efficient than that of the (C60)2–TPA–Fc. It is found that the ratio of Fc-donor to C60-acceptor affects charge separation efficiency via the excited singlet state of the C60 moiety.