Time-resolved fluorescence of α-(9-anthryl)-ω-(1-naphthyl)-oligosilanes: intramolecular electronic energy and charge transfer through π–π and σ–π interactions

The photophysical properties of a series of α,ω-diaryloligosilanes: (9-anthryl)-(SiMe2)n-(1-naphthyl) (1–4, and 6), n=1, 2, 3, 4, and 6, were investigated. For n⩾2, the intramolecular exciplex emission was observed in cyclohexane. For the stationary and the time-resolved fluorescence (TR-FL) measurements, the excitation of the naphthyl moiety showed a very efficient intramolecular energy transfer to the anthryl moiety, thus only fluorescence from the anthryl moiety was observed. In the case of 4 and 6, a charge-transfer (CT) emission was observed in acetonitrile. Then TR-FL of 6 revealed that the intramolecular-energy transfer from the naphthyl to anthryl moieties is faster than the CT.