ASYMMETRIC ELECTRON-TRANSFER FROM A CHIRAL RUTHENIUM COMPLEX DONOR TOAN ATROPISOMERIC CHIRAL 2,2'-BIPYRIDINE ACCEPTOR

We report asymmetric light-induced electron transfer (ET) in water in the system (A)-Ru(methylvinylbipyridine)(3)(2+)/(+)- and '-tetramethyl ene-2,2'-bipyridine-3,3'-dicarboxylic acid at pH greater than or equal to 5 (zwitterionic form). This reaction is activation controlled; Del ta G degrees was made nearly zero by manipulation of molecular structu re, pH, and solvent. Then reverse ET to the excited donor occurs which renders the quenching reaction asymmetric. The asymmetry of ET is sma ll as expected for high-DK solvents. From our results we infer that ch iral recognition takes place in a diastereomeric exciplex.