Photoinduced electron transfer of dialkynyldisilane-linked zinc porphyrin-[60]fullerene dyad

A zinc porphyrin-fullerene dyad with a disilane as a sigma-conjugated linker has been newly synthesized to evaluate the electron transfer ability of the oligosilane chain. Its photoinduced processes have been studied using the time-resolved fluorescence and absorption measurements. Photoexcitation of the dyad causes the energy and/or electron transfer from the excited singlet state of the ZnP to C-60 moiety in polar solvents. The charge separation takes place as a final step in the excited-state process to yield the radical-ion pair with a radical cation on the zinc porphyrin and a radical anion on the fullerene, similar to other porphyrin-fullerene dyads. Its lifetime has been estimated to be 0.43-0.52 mu s on the basis of the decay rate of the fullerene radical anion in polar solvents.