Synthesis of New PdII Complexes Containing Thioether−Pyrazole Hemilabile Ligands − Structural Analysis by 1H and 13C NMR Spectroscopy and Crystal Structures of [PdCl2(bddo)] and [Pd(bddo)](BF4)2 [bddo = 1,8-Bis(3,5-dimethyl-1-pyrazolyl)-3,6-dithiaoctane

Abstract

Treatment of the ligands 1,6-bis(3,5-dimethyl-1-pyrazolyl)-2,5-dithiahexane (bddh), 1,7-bis(3,5-dimethyl-1-pyrazolyl)-2,6-dithiaheptane (bddhp), 1,8-bis(3,5-dimethyl-1-pyrazolyl)-3,6-dithiaoctane (bddo) and 1,9-bis(3,5-dimethyl-1-pyrazolyl)-3,7-dithianonane (bddn) with [PdCl2(CH3CN)2] produces [PdCl2(L)] or [Pd2Cl4(L)] complexes, depending on the stoichiometry. Treatment of the complexes [PdCl2(bddo)] and [PdCl2(bddn)] with AgBF4 gives [Pd(bddo)](BF4)2 and [Pd(bddn)](BF4)2. These PdII complexes have been characterised by elemental analyses, conductivity measurements, IR and 1H and 13C NMR spectroscopy where possible. The X-ray structures of the complexes [PdCl2(bddo)] and [Pd(bddo)](BF4)2 have been determined. In [PdCl2(bddo)] the thioether−pyrazole ligand is coordinated through the azine nitrogen atoms to the metal atom, which completes its coordination with two chloride ions in a trans disposition. In [Pd(bddo)](BF4)2 the metal atom is tetracoordinated by the two thioether sulfur atoms and the two azine nitrogen atoms of the pyrazole rings. Complexes [PdCl2(bddo)] and [PdCl2(bddn)] were obtained again when the complexes [Pd(bddo)](BF4)2 and [Pd(bddn)](BF4)2 were heated under reflux in a solution of Et4NCl in CH2Cl2/MeOH (1:1). (© Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002)