Convenient Synthesis of Ruthenium(II) Dihydride Phosphine Complexes Ru(H)2(PP)2and Ru(H)2(PR3)x(x= 3 and 4)

A novel and convenient one-pot synthesis of ruthenium(II) dihydride phosphine complexes from the air-stable [RuCl 2 (COD)] x, the appropriate phosphine, and NaOH in sec-butyl alcohol under argon at 80 °C is reported. A series of chelating (dcpm, dcpe, dppe, dppb, dppp, dppf, and depe) and monodentate phosphine (PEt 3 and PPh 3 ) complexes have been synthesized using this methodology. The crystalline products are isolated in high yield. These dihydride complexes have been shown to be useful precursors to cationic dihydrogen hydride complexes, some of which exhibit significant activity as hydrogenation catalysts.