Coordination chemistry of higher oxidation states. Part 21. Platinum-195 NMR studies of platinum(II) and platinum(IV) complexes of bi- and multi-dentate phosphorus, arsenic and sulphur ligands

Abstract

195-Platinum NMR spectra are reported for a series of complexes of bidentate ligands [Pt(LL)X 4] (X=Cl, Br; LL=diphosphine, diarsine, dithioether, diselenoether), [Pt(Me 2PCH 2CH 2PMe 2) 2X 2]X 2, [Pt( o-C 6H 4(AsMe 2) 2) 2X 2]X 2, and for the Pt(II) analogues. The trends in chemical shifts δ(Pt) and 1 J(PtP), 1 J(PtSe) coupling constants are discussed, and used to establish the nature of the solution species obtained by oxidation of Pt(II) complexes of some multidentate phosphorus and arsenic ligands. The [Pt(LL)I 4] materials are shown to exist as [Pt II(LL)I 2] in dimethylsulphoxide solution, but [Pt( o-C 6H 4(AsMe 2) 2) 2I 2] 2+ is a genuine Pt(IV) iodo-complex.