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

Abstract

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 [PtCl 2(CH 3CN) 2] affords a series of square-planar Pt(II) complexes with formula [PtCl 2( NN′)] ( NN′ = deae ( 1); deat ( 2)), [PtCl 2(bdmae)] ( 3), or [PtCl(ddae)]Cl ( 4). Treatment of complex 4 in the presence of AgBF 4 in CH 2Cl 2/methanol (3:1) gives [PtCl(ddae)](BF 4) ( 5). These Pt(II) complexes have been characterised by elemental analyses, conductivity measurements and IR, 1H, 13C{ 1H}, and 195Pt{ 1H} NMR spectroscopies. The 1H 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.