Structures, preparation and catalytic activity of ruthenium cyclopentadienyl complexes based on pyridyl-phosphine ligand

Ruthenium complexes [(η5-C5H5)Ru(κ1-P-PPh2Py)(PPh3)Cl] (1) and [(η5-C5H5)Ru(κ2-P-N-PPh2Py)(PPh3)]+ (1a) containing diphenyl-2-pyridylphosphine (PPh2Py) are reported. Coordinated PPh2Py in the complex [(η5-C5H5)Ru(κ1-P-PPh2Py)(PPh3)Cl] (1) exhibits monodentate behavior. In presence of NH4PF6 in methanol at room temperature it afforded chelated complex [(η5-C5H5)Ru(κ2-P,N-PPh2Py)(PPh3)]+ (1a). Further, 1 reacted with various species viz., CH3CN, NaCN, NH4SCN and NaN3 to afford cationic and neutral complexes [(η5-C5H5)Ru(κ1-P-PPh2Py)(PPh3)L]+ and [(η5-C5H5)Ru(κ1-P-PPh2Py)(PPh3)L] [L = CH3CN (1b); CN− (1c); N3− (1d) and SCN− (1e)] and it’s reaction with N,N-donor chelating ligands dimethylglyoxime (H2dmg) and 1,2-phenylenediamine (pda) gave cationic complexes [(η5-C5H5)Ru(κ1-P-PPh2Py)(κ2-N-N)]PF6 [κ2-N-N = dmg (1f) and pda (1g)]. The complexes 1–1g have been characterized by physicochemical techniques and crystal structures of 1, 1a, 1c, 1e and 1f have been determined by single crystal X-ray analyses. Catalytic potential of the complex 1 has been evaluated in water under aerobic conditions. It was observed that the complex 1 selectively catalyzes reduction of aldehyde into alcohol.

Complex [(η5-C5H5)Ru(PPh3)2Cl] on reaction with diphenyl-2-pyridylphosphine (PPh2Py) afforded mono [(η5-C5H5)Ru(k1-P-PPh2Py)(PPh3)Cl] (1) and bis-chelated complex [(η5-C5H5)Ru(k2-P,N-PPh2Py)(PPh3)]+ (1a). Complex 1 effectively catalyze reduction of aldehydes/substituted aldehydes into corresponding alcohol in the presence of HCOONa in water under aerobic conditions.Figure optionsDownload as PowerPoint slide