Pd(II) complexes containing N-alkyl-3-pyridine-5-trifluoromethyl pyrazole ligands: Synthesis, NMR studies and X-ray crystal structures

摘要

Palladium [PdCl2(L)] complexes with N-alkylpyridylpyrazole derived ligands [2-(5-trifluoromethyl-1H-pyrazol-3-yl)pyridine (L-1), 2(1-ethyl-5-trifluoromethyl-1H-pyrazol-3-yl)pyridine (L-2), 2-(1-octyl-5-trifluoromethyl-1H-pyrazol-3-yl)pyridine (L), and 2-(3-pyridin2-yl-5-trifluoromethyl-pyrazol-1-yl)ethanol (L-4) were synthesised. The crystal and molecular structures of [PdCl2,(L)] (L = L-2, L-3, L-4) were resolved by X-ray diffraction, and consist of monomeric cis-[PdC](2)(L)] molecules. The palladium centre has a typical square-planar geometry, with a slight tetrahedral distortion. The tetra-coordinate metal atom is bonded to one pyridinic nitrogen, one pyrazolic nitrogen and two chlorine ligands in cis disposition. Reaction of L (L-2, L-4) with [Pd(CH3CN)(4)](BF4)(2), in the ratio 1M:2L, gave complexes [Pd(L)](2)(BF4)(2). Treatment of [PdCl2(L)] (L = L-2, L-4) with NaBF4 and pyridine (py) and treatment of the same complexes with AgBF4 and triphenylphosphine (PPh3) Yielded [Pd(L)(py)(2)](BF4)(2) and [Pd(L)(PPh3)(2)](BF4)(2) complexes, respectively. Finally, reaction of [PdCl2(L)] with 1 equiv of AgBF4 yields [PdCI(L-4)](BF4). (c) 2006 Elsevier B.V. All rights reserved.