Structure and bonding in the PtCO isoelectronic series

The equilibrium geometries and harmonic frequencies of PtXY, XY = CO, N₂, CN^- and NO⁺, in the ¹∑⁺ state have been calculated by the ab initio self-consistent field method with gradients using appropriate effective core potentials. An analogous analysis was also carried out on the free ligands for comparison purposes. The ligands are compared with respect to changes in X-Y bond lengths and stretch frequencies upon complexation, and Pt-XY bond lengths, stretch frequencies and bond energies. The calculated results for PtCO and PtN₂ are compared with matrix-isolated infrared spectra.