Synthesis and characterisation of new pyrazole-phosphinite ligands and their ruthenium(II) arene complexes

The new potentially bidentate pyrazole-phosphinite ligands [(3,5-dimethyl-1H-pyrazol-1-yl)methyl diphenylphosphinite] (L) and [2-(3,5-dimethyl-1H-pyrazol-1-yl)ethyl diphenylphosphinite] (L 2) were synthesised and characterised. The reaction of L-1 and L-2 with the dimeric complexes [Ru(eta(6)-arene)Cl-2](2) (arene = p-cymene, benzene) led to the formation of neutral complexes [Ru(eta(6)-arene)Cl-2(L)] (L = L-1, L-2) where the pyrazole-phosphinite ligand is kappa(1)-P coordinated to the metal. The subsequent reaction of these complexes with NaBPh4 or NaBF4 produced the [Ru(eta(6)-p-cymene)Cl(L-2)][BPh4] and [Ru(eta(6)-benzene)Cl(L-2)][BF4] compounds which contain the pyrazole-phosphinite ligand kappa(2)-P, N bonded to ruthenium. All the complexes were fully characterised by analytical and spectroscopic methods. The structure of the complex [Ru(eta(6)-p-cymene)Cl(L-2)][BPh4] was also determined by a X-ray single crystal diffraction study. (c) 2005 Elsevier B.V. All rights reserved.