Ab initio studies of transition-metal dihydrogen chemistry

Examples of transition metal complexes containing dihydrogen ligands are investigated using ab initio electronic structure calculations employing effective core potentials. Calculated geometrical structures and relative energies of various forms of WL5(H2) complexes (L = CO, PR3) are reported, and the influence of the ligand on the relative stabilities of the dihydrogen and dihydride forms is studied. The possible intramolecular mechanisms for H/D scrambling are investigated in another d6 complex, Cr(CO)4(H2)2, where various polyhydride intermediates are possible. 8 refs., 6 figs., 1 tab