Half-sandwich η6-benzene Ru(II) complexes of pyridylpyrazole and pyridylimidazole ligands:: Synthesis, spectra, and structure

New series of half-sandwich ruthenium(II) complexes supported by a group of bidentate pyridylpyrazole and pyridylimidazole ligands [(eta(6)-C6H6)Ru(L-2)Cl][PF6] (1), [(eta(6)-C6H6)Ru(HL3)Cl][PF6] (2), [(eta(6)-C6H6)Ru(L4)Cl][pF(6)] (3), and [(eta(6)-C6H6)Ru(HL5)Cl][PF6] (4) [L-2, 2-[3-(4-chlorophenyl)pyrazol-1-ylmethyl]pyridine; HL3, 3-(2-pyridyl)pyrazole; L-4, 1-benzyl-[3-(2'-pyridyl)]pyrazole; HL5,2-(1-imidazol-2-yl)pyridine] are reported. The molecular structures of 1-4 both in the solid state by X-ray crystallography and in solution using H-1 NMR spectroscopy have been elucidated. Further, the crystal packing in the complexes is stabilized by C-H... X (X = Cl and pi), N-H center dot center dot center dot Cl, and pi-pi interactions. (c) 2006 Elsevier B.V. All rights reserved.