THEORETICAL-STUDY OF THE INTERACTION OF THE TI ATOM WITH CO2 - CLEAVAGE OF THE C-O BOND

The interaction of s(2)d(2) and s(1)d(3) Ti atoms with the CO2 molecul e has been studied using density functional theory at the gradient-cor rected level. The ground state Ti inserts with no energy barrier into a CO bond resulting in an OTiCO insertion product. The intrinsic react ion coordinate for the insertion process has been defined and the reac tion mechanism has been investigated by analyzing various structures a long this path. The singlet and triplet states of the final product ar e very close in energy. The comparison of the predicted vibrational fr equencies and isotopic shifts for both states with those from matrix i solation infrared data reveals that the insertion product formed in lo w-temperature argon matrix corresponds to singlet state OTiCO. Ti(CO2) complexes in various coordination modes have also been located on the triplet and quintet potential energy surfaces, from which the triplet state (0,0) coordination mode is the most stable one lying, however, about 30 kcal/mol above the OTiCO molecule.