Synthesis and characterization of ruthenium(II) complexes based on diphenyl-2-pyridylphosphine and their applications in transfer hydrogenation of ketones

Abstract Synthesis and characterization of the ruthenium complexes [RuH(CO)Cl( κ 1 - P -PPh 2 Py) 2 (PPh 3 )] ( 1 ) and [Ru(CO)Cl 2 ( κ 1 - P- PPh 2 Py)( κ 2 - P–N -PPh 2 Py)] ( 2 ) containing diphenyl-2-pyridylphosphine (PPh 2 Py) are described. Spectral and structural data suggested linkage of the PPh 2 Py in κ 1 -P bonding mode in 1 and both the κ 1 -P and κ 2 -P–N bonding modes in 2 . The complex 1 reacted with N , N -donor bases viz., ethylenediamine (en), N , N ′-dimethyl-(ethylenediamine) (dimen), 1,3-diaminopropane (diap), 2,2′-bipyridine (bipy), 1,10-phenanthroline (phen) and di-2-pyridylaminomethylbenzene (dpa) to afford cationic complexes of formulation [RuH(CO)( κ 1 - P -PPh 2 Py) 2 (N-N)] + ( 3 – 8 ) [N-N = en, 3 ; dimen, 4 ; diap, 5 ; bipy, 6 ; phen, 7 ; and dpa, 8 ], which have been isolated as their tetrafluoroborate salts. The complexes under investigation have been characterized by elemental analyses, spectroscopic and electrochemical studies. Molecular structures of 2 , 3 , 6 , and 8 have been determined by single crystal X-ray diffraction analyses. Further, the complexes 1 – 8 act as effective precursor catalyst in transfer hydrogenation of acetophenone/ketones in basic 2-propanol.