RUTHENIUM(II) HYDRIDE COMPLEXES OF 2,6-(DIPHENYLPHOSPHINOMETHYL)PYRIDINE

A series of PNP-ruthenium(II) complexes Ru(OCOMe)(2)(PNP) (1), Ru(OCOM e)(2)(PNP)(PPh3) (2), the monohydrides RuHX(PNP)(PPh3) (X = OCOMe (3); X = Cl (4)), and dihydride RuH2(PNP)(PPh3) (5) (PNP = 2,6-bis(dipheny lphosphinomethyl)pyridine) were synthesized and characterized by micro analysis as well as NMR, IR, and mass spectroscopies. The solution dyn amics of complex 1 were studied by variable-temperature H-1 and P-31{H -1} NMR spectroscopies. The crystal structure of RuHCl(PNP)(PPh3) (4) was determined by X-ray crystallography, showing that the PNP ligand c oordinates the Ru atom in a meridional mode. The hydride complexes RuH (OCOMe)(PNP)(PPh3) (3) and RuH2(PNP)(PPh3) (5) undergo deuterium excha nge reactions with CD3OD to give substitution of both the hydrides and PNP methylene protons by deuterium. The probable intermediates involv ed in these exchange processes are molecular dihydrogen complexes of R u(II).