Cleavage mode of benzyltributylstannane radical cations produced in photoinduced electron transfer

Cleavage of metal-carbon bond of benzyltributylstannane radical cation produced in photoinduced electron transfer from benzyltributylstannane to 10-methylacridinium ion occurs to give benzyl radical rather than benzyl cation, resulting in formation of 9-benzyl-10-methyl-9,10-dihydroacridine selectively in dehydrated acetonitrile. In the presence of water, however, 10-methyl-9,10-dihydroacridine is also formed via electron transfer from benzyl radical to the dihydroacridine radical cation produced by protonation of acridinyl radical following the initial photoinduced electron transfer.