.2,6 - Two Pyrazole Pyridine Ruthenium (ii) Complexes Of Rucl <sub> 2 </ Sub> (pph <sub> 3 </ Sub>) (me, <sub> 4 </ Sub> Bppy) Catalytic Ketone Hydrogen Transfer And Hydrogenation Reaction

Complex RuCl₂(PPh₃)(Me₄Bppy) [Me₄Bppy = 2,6-bis(3,5-dimethylpyrazol-1-yl)pyridine] was synthesized and its molecular structure was confirmed for the first time. Transfer hydrogenation and hydrogenation of ketones were carried out with the complex.The molecular structure of the complex RuCl₂(PPh₃)(Me₄Bppy) was confirmed by X-ray crystallographic study, correcting the mistaken structure assignment of the complex in the literature. In the solid state, the complex exhibits a neutral molecular structure in which Me₄Bppy acts as a planar N₃ ligand and the metal center is six-coordinated with the tridentate pseudo N₃ ligand, two chloride atoms and one PPh₃ ligand. A discrete CH₂Cl₂ molecule is accompanied as well. The two chloride ligands are nearly perpendicular to each other. One chloride and the phosphine ligand, and the other chloride and the pyridyl nitrogen atom are positioned anti, respectively. The PPh₃ ligand and its trans partner chloride atom are arranged on the two sides of the pseudo N₃ ligand plane.Transfer hydrogenation of ketones were efficiently carried out with the ruthenium(II) complex RuCl₂(PPh₃)(Me₄Bppy) in propan-2-ol in the presence of i-PrOK and 0.2 mol% of the catalyst at 82°C. The corresponding products were obtained in yields up to 100% with final TOF up to 6000 h^-1.The catalyst was also applied in the hydrogenation of ketones. Under mild conditions hydrogenation of ketones were achieved in yields up to 99%.