A ruthenium(ii) bis(phosphinophosphinine) complex as a precatalyst for transfer-hydrogenation and hydrogen-borrowing reactions.

The 2-phosphinophosphinine 2-PPh2 -3-Me-6-SiMe3 -PC5 H2 (2) has been prepared and was shown to act as a κ2 -chelating ligand in cis-[RuCl2 (2)2 ] (4). Complex 4 was a competent precatalyst for the room temperature transfer hydrogenation of acetophenone (0.1 mol% 4 and 0.5 mol% KOt Bu) and the conversion of methanol/ethanol mixtures to the advanced biofuel isobutanol in 50% yield and 96% selectivity.