Stereospecific interactions between dinuclear complex cations involving square-planar [Pt(II)(μ-S)2(bpy)] (bpy = 2,2′-bipyridine) frameworks derived from optically active octahedral Co(III) units with d- or l-penicillaminates

The racemic crystals containing two enantiomers, [Pt(bpy){Co(d-pen)2}]+ (bpy = 2,2′-bipyridine, pen = penicillaminate) and [Pt(bpy){Co(l-pen)2}]+, can be obtained when their aqueous solutions are mixed in equimolar amounts. In this crystals, two kinds of enantiomers are arranged alternately while overlapping the bpy planes, and the π electronic systems in [Pt(bpy){Co(d-pen)2}]+ (D) stereoselectively interact with those in [Pt(bpy){Co(l-pen)2}]+ (L).