Synthesis and Structure of Platinum (II) Complexes with Dithiodiethylamine

Abstract

The interaction of dithiodiethylamine (cystamine) (L1) with platinum compounds in non-aqueous and aqueous media has been studied. It was shown that in aqueous solutions the disulfide bond L1 cleaves with the subsequent coordination of platinum of the resulting β-mercaptoethylamine (mercamine, LH). Depending on the reaction conditions, binuclear complexes of the composition [Рt2(LН)2С14] with bridging chlorine or sulfur atoms or [Рt2L2С12] with bridging chlorine atoms are formed. An X-ray structural analysis of the complex [Рt2(LН)2С14] (I) was carried out. Crystals of I are rhombic, at 20°С а = 17.283(1), b = 9.987(1), с = 8.0187(9) Å; R = 0.030. Molecule I is a binuclear complex in which platinum atoms are linked by a pair of bridging thiolate ligands (-SСН2-СН2-МН3+). The Рt2S2 metal cycle is bent along the sulfur-sulfur line, so that the dihedral angle between the coordination planes of platinum atoms is 138 °. The S-S distance, equal to 2.909 (1) Å, is noticeably shorter than the double van der Waals radius of the sulfur atom (3.60 Å). Carrying out the reaction in benzene makes it possible to obtain the complex (L1Н2)[РtХ4] (X = С1, Вг) with the retention of the sulfur-sulfur bond in the ligand. The structure of the complexes is confirmed by the data of IR spectroscopy.