Binuclear platinum(II) complexes bridged by pyridine-2-thiolate and related ligands. Synthesis and crystal structure

Abstract

Bis(ethylenediamine)di-µ-pyridine-2-thiolato-diplatinum(II) chloride trihydrate (1), bis(ethylenediamine)di-µ-4-methylpyridine-2-thiolato-diplatinum(II) chloride dihydrate (2), and di(µ-2-aminoethyl 2-pyridyl sulphide)-bis[chloroplatinum(II)] chloride trihydrate (3) were synthesized and their structures investigated by means of X-ray crystallography. The binuclear complexes (1) and (2) have the head-to-head configuration in which planar PtN₂S₂ and PtN₄co-ordination spheres face one another with Pt ⋯ Pt distances of 3.083(1)Å, in (1) and 3.101(1)Å, in (2). The two co-ordination spheres are slanted against one another and twisted about the Pt ⋯ Pt axis, the interplanar and the torsion angles being 31.0(3) and 32.6(3)° in (1) and 31.9(2) and 34.3(2)° in (2). In complex (3) two planar PtN₂SCl co-ordination spheres bridged by two pyridine-2-thiol segments have an eclipsed conformation; the interplanar and torsion angles [17.9(4) and 3.4(2)°] are much less than those of (1) and (2). The complex is of the head-to-tail isomer and has an approximate two-fold axis perpendicular to the Pt ⋯ Pt axis. The Pt ⋯ Pt distance is 2.956(1)Å. Both of the head-to-head dimers in (1) and (2) form a centrosymmetric pair of the dimers in the solid state, the PtN₂S₂co-ordination planes of the respective dimers being in contact with one another. The interdimer Pt ⋯ Pt distance is 3.613(1)Å in (1) and 3.726(2)Å in (2).