M. Suzuki et al., SUBSTITUENT EFFECT OF 1,4-BENZENEDICARBONITRILES AS SENSITIZERS ON THE PHOTOINDUCED ELECTRON-TRANSFER REACTIONS IN ALCOHOL, Bulletin of the Chemical Society of Japan, 70(9), 1997, pp. 2269-2277
In the photosensitized electron transfer reaction of 6,6-diphenyl-1,4-
dioxaspiro[4.5]decane in methanol (MeOH), the quantum yield is increas
ed by the use of 2-methylbenzene-1,4-dicarbonitrile (2-methyl-BDC) or
2,5-dimethylbenzene-1,4-dicarbonitrile (2,5-dimethyl-BDC) as compared
to that by the use of 1,4-benzenedicarbonitrile (BDC), though the exci
ted methyl-substituted BDCs have lower reduction potentials than the e
xcited BDC. Detailed study on this substituent effect reveals that the
electron transfer between MeOH and the excited BDC occurs to some ext
ent. By the use of methylated BDCs, electron transfer between the exci
ted sensitizers and MeOH is suppressed enough due to its lower reducti
on potential. Some typical photoinduced electron transfer reactions in
alcohol proceed more efficiently by the use of 2-methyl-BDC or 2,5-di
methyl-BDC instead of BDC.