Conformation effect of oligosilane linker on photoinduced electron transfer of tetrasilane-linked zinc porphyrin–[60]fullerene dyads

A series of zinc porphyrin–[60]fullerene dyads linked by conformation-constrained tetrasilanes and permethylated tetrasilane have been synthesized for the evaluation of the conformation effect of the tetrasilane linkers on the photoinduced electron transfer. The excited-state dynamics of these dyads have been studied using the time-resolved fluorescence and absorption measurements. The fluorescence of the zinc porphyrin moiety in each dyad was quenched by the electron transfer to the fullerene moiety. The transient absorption measurements revealed that the final state of the excited-state process was a radical ion pair with a radical cation on the zinc porphyrin moiety and a radical anion on the fullerene moiety as a result of the charge separation. The charge separation and charge recombination rates were found to show only slight conformation dependence of the tetrasilane linkers, which is characteristic for the Si-linkages.

Graphical abstractZinc porphyrin–[60]fullerene dyads linked by conformation-constrained tetrasilane were synthesized to evaluate the conformation effect of the linkers on the photoinduced electron transfer. The excited-state dynamics studies demonstrate that the lifetimes of the fluorescence and the charge-separated state show little conformation dependence, which is a characteristic of the Si-linkages.Figure optionsDownload full-size imageDownload as PowerPoint slide