Synthesis and spectroscopic studies of ruthenium complexes with poly(pyrazol-1-yl) methane ligands. Crystal structure of [RuCl(cod)(tpzm)]Cl·EtOH [cod = cycloocta-1,5-diene, tpzm = tris(pyrazol-1-yl)methane]

Abstract

Neutral six-co-ordinate complexes of Ru^II, [RuCl₂(btpzm)(cod)]1 and [RuCl₂(btpzm)(cod)]2 with bis(pyrazol-1-yl)methane (bpzm) or bis (5-trimethylsilylpyrazol-1-yl)methane (btpzm) were synthesised from [{RuC₂(cod)}_n](cod = cycloocta-1,5-diene) and the corresponding ligand. Complex 1 reacts with LiBEt₃H to give the hydride [RuH(Cl)(bpzm)(cod)]3. The reactitivity of 2 allowed the synthesis of the new complex [RuCl₂(btpzm)₂]·0.5thf 4(thf = tetrahydrofuran) with two bidentate btpzm ligands. The reaction of [{RuCl₂(cod)}_n] with the tris(pyrazol-1-yl)methane ligand (tpzm) yielded the six-co-ordinate cationic complex [RuCl(cod)(tpzm)]Cl·-EtOH 5. Finally, the reaction of [RuCl₃(tpzm)] with both pyridine and triethylamine afforded [RuCl₂(py)(tpzm)]6. Spectroscopic data are provided for all these compounds. The crystal structure of compound 5 has ben determined by X-ray diffraction methods: monoclinic, space group P2₁/c, with a= 9.330(2), b= 15.579(4), c= 15.667(4)Å, β= 97.79(2)° and Z= 4. The structure has been solved from diffractometer data by direct and Fourier methods and refined by full-matrix least squares to R= 0.0414 for 3362 observed reflections. It consists of complex cations, chloride anions and ethanol molecules of solvation linked by strong hydrogen bonds. The ruthenium is approximately octahedrally co-ordinated to one tridentate tpzm ligand, one chloride ion and two η²-CC olefinic groups of the cod ligand.