Synthesis, X-ray crystal structure and NMR characterisation of mononuclear Pd(II) and Pt(II) complexes of didentate ligands with NN′-donor set

Two new 3,5-dimethylpyrazolic derived ligands that are N1-substituted by diamine chains, 1-[2-(diethylamino)ethyl]-3,5-dimethylpyrazole (L1) and 1-[2-(dioctylamino)ethyl]-3,5-dimethylpyrazole (L2) were synthesised. Reaction of the ligands, L1 and L2, with [MCl2(CH3CN)2] yielded [MCl2(L)] (M = Pd(II), Pt(II)) complexes. These complexes were characterised by elemental analyses, conductivity measurements, IR, 1H, 13C{1H} and 195Pt{1H} NMR spectroscopies. The crystal structure of [PdCl2(L1)] was determined by single-crystal X-ray diffraction methods. The structure consists of mononuclear units. The Pd(II) atom is coordinated by a pyrazolic nitrogen, an amine nitrogen and two chlorine atoms in a cis disposition. In this structure, C–H⋯Cl, C–H⋯H–C and C–H⋯C–H intermolecular interactions have been identified.

Graphical abstractTwo new N-alkylamino-3,5-dimethylpyrazole ligands (L1 and L2) were synthesised and their reactions with [MCl2(CH3CN)2] were studied yielding [MCl2(L)] (M = Pd(II), Pt(II)) complexes with a simple mononuclear square-planar structure. These ligands are coordinated to Pd(II) and Pt(II) by a nitrogen atom of the pyrazole ring and a nitrogen atom of the amine. The metal atom finishes its coordination with two chlorine atoms in a cis disposition.Figure optionsDownload full-size imageDownload as PowerPoint slide