Half-Sandwich Complexes with 4,7-Dihydroxy-1,10-phenanthroline:  Water-Soluble, Highly Efficient Catalysts for Hydrogenation of Bicarbonate Attributable to the Generation of an Oxyanion on the Catalyst Ligand

Half-sandwich Ru(II), Ir(III), and Rh(III) complexes with 4,7-dihydroxy-1,10-phenanthroline are highly efficient catalysts for hydrogenation of bicarbonate in alkaline aqueous solution without an amine additive. The generation of an oxyanion by deprotonation of the two hydroxy substituents on the catalyst ligand caused a dramatic enhancement of catalytic activity, due to its strong electron-donating ability, as well as imparting water solubility.