A quantum chemical ab initio study of the interaction between Co+ and Ni+ ions with CO2 and N2O

Coordinations of monocations of Co+ and Ni+ to CO2 and N2O were calculated using the CCSD(T) method and 6-31G(3d, f) basis sets for C, N, and O atoms, and Stuttgart's pseudopotentials for metal cations. The strongest interaction (125.1 kJ/mol) was found for Co+-N2O when the ion is bound to the nitrogen end of the oxide, establishing the linear complex in the tripler state (3 Delta). The coordination of Ni+ to the same N-end of N2O has a very similar stabilization. The ground state symmetry of the linear Ni+-N2O complex is (2) Sigma(+). The interaction energy of the metal cations with the oxygen end of NO is more than 40 kJ/mol weaker than with the nitrogen end of the molecule. The linear structure of the ions bound to the oxygen of carbon dioxide are more stable than similar structures of metal-ion oxygen-ended N2O. Stabilization energies of Co+-CO2 and Co+-N2O in quintet states are more than 25 kJ/mol smaller than the corresponding energies in triplets, and a similar relationship holds in the case of Ni+-CO2 and Ni+-N2O. (C) 1998 Elsevier Science B.V.