A bis-bipyridine osmium(II) complex with an N,S-chelating 2-aminoethanesulfinate: photoinduced conversion of an amine to an imine donor group by air oxidation.

Treatment of [Os(bpy)(2)Cl(2)] (bpy = 2,2'-bipyridine) with 2-aminoethanethiolate was accompanied by air oxidation to give [Os(2-aminoethanesulfinato-N,S)(bpy)(2)](+) ([1](+)), which was further oxidized by air to be converted into [Os(2-iminoethanesulfinato-N,S)(bpy)(2)](+) ([2](+)) under photoirradiation. Complex [2](+) was reverted back to [1](+) by treatment with BH(4)(-).