Photoinduced electron-transfer reactions between C-60 and cyclic disiliranes (c-R2Si-X-SiR2; X = SiR2, CH2, O, NPh, S)

Photoinduced electron-transfer reactions between various cyclic disiliranes (c-R2Si-X-SiR2; X = SiR2,CH2, O, NPh, and S) and photo-excited C-60 in pol ar PhCN solvent have been investigated by 532 nm laser photolysis with the observation of the transient absorption bands in the near-IR region. The tr ansient absorption band of the anion radical of C-60 (C-60(.-)) appeared at 1070 nm, accompanying the decay of the excited triplet state of C-60 (C-3( 60)*), showing that electron transfer takes place from c-R2Si-X-SiR2 to C-3 (60)*. The rates and quantum yields for electron transfer via C-3(60)* were compared with changing X. The final products in PhCN were identified as mo no-adducts and bis-adducts of R2Si-X-SiR2 with PhCN, but not with C-60.