Binuclear paddle-wheel platinum(II) and platinum(III) complexes containing 4-methyl-4H-1,2,4-triazole-3-thiol ligand: Synthesis, X-ray studies, and spectroscopic characterization

The complex [Pt-2(-mtrzt)(4)(mtrzt)(2)] (1) was synthesized from the reaction of a mixture of 4-methyl-4H-1,2,4-triazole-3-thiol (Hmtrzt) and ethylenediamine (en) with K2PtCl4 in CH3OH/H2O (2:1) as solvent. The complex [Pt-2(-mtrzt)(4)] (2) was synthesized by the same procedure as described for preparation of complex 1 but in the absence of ethylenediamine. Both complexes were characterized by elemental analysis, IR,H-1 NMR,C-13{H-1}NMR, UV-Vis, as well as luminescence spectroscopy and their structures were analyzed by single-crystal X-ray diffraction method. The X-ray structure determinations show that complexes of 1 and 2 have binuclear structures in a paddle-wheel fashion with Pt-Pt distances of 2.6628(7) and 2.7977(16)angstrom, respectively. In complex 1, each platinum(III) atom has a distorted octahedral coordination geometry with the sulfur atom and the second platinum subunit in axial positions and two nitrogen and two sulfur atoms in equatorial positions. Also, in complex 2, each platinum(II) atom has a distorted square-pyramidal coordination geometry with the second platinum subunit in axial position and two nitrogen and two sulfur atoms in equatorial positions. In addition, intermolecular CH<bold>N and CHS hydrogen bonds in </bold>1 and 2 as well as intermolecular anagostic CH<bold>Pt and CH interactions in </bold>2 are effective in the stabilization of the crystal packing of these complexes. [GRAPHICS] .