Why do cationic hydridoiridium(III) complexes with beta-aminophosphane ligands favour the transfer hydrogenation of ketones over the direct "H2-hydrogenation"? - a computational approach

Density functional theory and ab initio molecular orbital calculations show that the observed inability of cationic hydridoiridium(III) complexes with beta-aminophosphane ligands to catalyse the direct hydrogenation of carbonyl compounds with dihydrogen ("H2-hydrogenation") in contrast to their ruthenium(II) equivalents is due to the inability of H2 to displace a coordinated solvent molecule from an intermediate hydrido complex.