Synthesis, Crystal Structures, and Some Properties of S-Bridged Pt(II)-M(III) (M = Co, Rh) Dinuclear Complexes with Square-Planar and Octahedral Geometries

Abstract

Abstract A novel dinuclear complex [{Pt(bpy)}{Co(aet)2(en)}]3+ (bpy = 2,2′-bipyridine; aet = 2-aminoethanethiolate; en = ethylenediamine) (1) composed of square-planar and octahedral geometries was obtained by a substitution reaction of [Ni{Co(aet)2(en)}2]4+ with [PtCl2(bpy)]. The reactions of fac(S)-[M(aet)3] (M = CoIII, RhIII) with [PtCl2(bpy)] also gave a similar type of S-bridged dinuclear complexes [{Pt(bpy)}{M(aet)3}]2+ (M = CoIII (2), RhIII (3)). The crystal structures of complexes 1, 2, and 3 were determined by X-ray crystallography. All of the Co and Rh atoms in 1, 2, and 3 take approximately octahedral geometry. The Pt atoms in 1, 2, and 3 are coordinated by two N atoms in bpy and two S atoms from C2-cis(S)-[Co(aet)2(en)]+ or [M(aet)3] unit, and all of them take square-planar geometry. fac(S)-[Co(aet)3] is structurally converted into a mer(S)-[Co(aet)3] unit during the course of producing a [{Pt(bpy)}{M(aet)3}]2+-type dinuclear complex, although fac(S)-[Rh(aet)3] retains its structure. These complexes were characterized on the basis of the electronic absorption, CD, and 13C NMR spectra, together with cyclic voltammetry.