Fluorescence behaviour of pyrene substituted tri- and hexa-silanes

The absorption and emission spectra of pyrene substituted tri- and hexa-silanes are reported. σ (SiSi)→π*(pyrene) charge-transfer fluorescence is observed for 1-(1-pyrenyl) tridecamethylhexasilane but not for 1-(1-pyrenyl) hepta-methyltrisilane. This is explained by the difference in oxidation potential of the tri- and hexa-silane chain. The emission of the bichromophoric systems 1,6-di (1-pyrenyl) dodecamethylhexasilane and 1-(4-N,N-dimethylanilino)-6-(1-pyrenyl) dodecamethylhexasilane is mainly determined by the σ→π* charge transfer. 1,3-di-(1-pyrenyl) hexamethylhexasilane and 1-(4,N,N-dimethylanilino)-3-(1-pyrenyl) hexamethyltrisilane show respectively excimer and exciplex emission. © 1991.