Influence of molecular oxide cages on metal carbonyls

A series of DFT calculations have been performed on mononuclear d(6) metal tricarbonyls supported on molecular oxide cages. The molecular cages were chosen both as models for phosphate, silicate, and aluminosilicate surfaces and because experimental data is available for a few of these molecular complexes. By systematically varying the nature of the oxide surface, qualitative estimates of metal carbonyl geometry, relative metal-CO bond strengths, and predictions of the shifts in C identical withO stretching frequencies upon changes in oxide basicity have been determined for a range of transition metals. Although most of the calculated trends correlate with expectations, additional insights into some of the bonding characteristics of these systems were obtained.