Photophysical and photochemical processes of poly(methylphenylsilane) functionalized with pendant p-nitroazobenzene groups

The synthesis of poly(methylphenylsilane) functionalized with pendant p-nitroazobenzene groups (PMPS-azo) has been carried out, and their photophysical and photochemical processes have been studied. The fluorescence quantum yields of PMPS-azo decrease with an increase of the amounts of the pendant p-nitroazobenzene groups. The picosecond fluorescence decay kinetics of PNIPS-azo was interpreted in terms of not only the energy transfer, but also the electron transfer from the Si-Si main chain to the pendant p-nitroazobenzene group. The evidence for intramolecular electron transfer was provided by the formation of the radical anion of the pendant trans-p-nitroazobenzene group upon steady-state photolysis of PMPS-azo at 77 K.