Charge-transfer complex formation and photo-induced electron-transfer reaction of dibenzo-7-silabicyclo[2.2.1]hepta-2,5-dienes

Article abstract of DOI:10.1016/S0040-4020(96)01076-9

Dibenzo-7-silabicyclo[2.2.1]hepta-2,5-dienes (1a, 1b) are excellent electron donors because of effective σ-π conjugation between the orbitals of C-C π bonds and Si-C σ bonds. Some of their donor properties are demonstrated by the reactions with some electron accepters. When 1a and 1b are mixed with tetracyanoethylene, facile formation of charge-transfer complexes was observed. In the 2,4,6-triphenylpyrylium tetrafluoroborate-sensitized photoreaction of 1b, the corresponding difluorosilane and anthracene were obtained in good yields. The structural and electronic features of radical cation 1a^+. were provided by semiempericaI molecular orbital calculation. In addition, the structure of 1a in crystals was determined by X-ray crystallography and compared with that obtained by the calculation.