Synthesis, Characterisation, and X‐ray Crystal Structure of New NiII, PdII, and PtII Complexes of Tridentate Pyrazole‐Based Ligands with an NOS‐Donor Set

Abstract

AbstractTreatment of the ligands 1‐(3‐thia‐5‐hydroxypentyl)‐3,5dimethylpyrazole (thpd) and 1‐(3‐thia‐6‐hydroxyhexyl)3,5‐dimethylpyrazole (thhd) with [PdCl2(CH3CN)2], [PtCl2(CH3CN)2], and NiCl2·6H2O produces the complexes [MCl2(L)] [M= Pd, L = thpd (1), thhd (2); M = Pt, L = thpd (3), thhd (4); M = Ni, L = thpd (5), thhd (6)], which have been characterised by elemental analyses, conductivity, IR, electronic spectra, and NMR spectroscopy (when possible). The crystal structures of 2, 3, and 4, determined by single‐crystal X‐ray diffraction, each consist of discrete [MCl2(L)] units. Each MII atom is coordinated by the pyrazolyl nitrogen and the thioether sulfur from the ligand and two cis chloride ions in a square‐planar geometry. Crystallisation of [NiCl2(thpd)] in non‐anhydrous alcohols yields [NiCl(H2O)2(thpd)]Cl ([7]Cl), the crystal structure of which was determined by single‐crystal X‐ray diffraction to reveal nickel atoms coordinated by two water molecules, one chloride ion and one thpd ligand (coordinating via all three donor atoms, N, S, and O) in a skew‐trapezoidal bypyramid (distorted octahedral) geometry. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)