Stereoselective Photoinduced Electron Transfer of Zinc Myoglobin with Optically Active Viologens

The excited triplet state of zinc myoglobin was preferentially quenched by (S,S)-isomers of optically active viologens, 1,1′-bis(1-phenylethylcarbamoylmethyl)-4,4′-bipyridimum (OAV2+) and 1,1′-bis(1-(1-naphthyl)ethylcarbamoylmethyl)-4,4′-bipyridinium (NOAV2+) ions: kq((S,S)-)/kq((R,R)-) = 1.5 for NOAV2+ and 1.3 for OAV2+ at 25 °C and an ionic strength of 0.02 mol dm−3.