Synthesis, chemical properties, and electrochemical behavior of a Pt(II) complex bearing a benzenediamide-derived ligand

The reaction of [PtCl2(cod)] (cod = 1,5-cyclooctadiene) with Ph-Ph′-Ph′(2,3-NH2)-Ph′-Ph (LH2) (Ph = phenyl; Ph′ = p-phenylene; Ph′(2,3-NH2) = p-phenylene-2,3-diamine) gave a new platinum(II) complex bearing a π-conjugated Ph-Ph′-Ph′(2,3-NH)-Ph′-Ph (L, Ph′(2,3-NH) = p-phenylene-2,3-diamide) ligand, [Pt(L)(cod)], with the liberation of 2 HCl. The X-ray structure determination of the complex confirmed the coordination of the ligand to the platinum center in an o-benzenediamide form. The cyclic voltammogram of the complex showed reversible two-step [Pt-bda]0/[Pt-sqdi]+ and [Pt-sqdi]+/[Pt-bqdi]2+ redox couples (bda = o-benzenediamide, sqdi = o-semiquinone diimine, bqdi = o-benzoquinone diimine).