Synthesis of new platinum(II) compounds with several bidentate and tridentate nitrogen-donor ligands.: Structural analyses by 1H, 13C{1H} and 195Pt{1H} NMR spectroscopy and X-ray crystal structure

The reaction of the N-alkylaminopyrazole (NN') ligands 1-[2-(ethylamino) ethyl]-3,5-dimethylpyrazole(deae), 1-[2-(tert-butylamino) ethyl]-3,5-dimethylpyrazole (deat), or (NN'N)ligands bis[(3,5-dimethylpyrazolyl) methyl] ethylamine (bdmae) and bis[(3,5-dimethylpyrazolyl) ethyl] ethylamine (ddae) with [PtCl2(CH3CN)(2)] affords a series of square-planar Pt(II) complexes with formula [PtCl2(NN')] (NN' = deae (1); deat (2)), [PtCl2(bdmae)] (3), or [PtCl(ddae)] Cl (4). Treatment of complex 4 in the presence of AgBF4 in CH2Cl2/ methanol (3: 1) gives [PtCl(ddae)](BF4) (5). These Pt(II) complexes have been characterised by elemental analyses, conductivity measurements and IR, H-1, C-13{H-1}, and Pt-195{H-1} NMR spectroscopies. The H-1 NMR spectroscopic studies of the complexes prove the rigid conformation of the ligands when they are complexed. The solid-state structure of complex 1 was determined by single crystal X-ray diffraction methods. The deae ligand is coordinated through the N-pz and N-amino atoms to the metallic centre, which completes its coordination with two chlorine atoms in cis disposition. (C) 2008 Elsevier B.V. All rights reserved.