Theoretical studies on vibrational spectra of some mixed carbonyl-halide complexes of Osmium(II)

Abstract

The vibrational spectra of Os(CO)62+ and some of its mixed carbonyl-halide complexes, cis-Os(CO)2X42−, fac-Os(CO)3X3− and Os(CO)5X+ (X=F, Cl, Br and I), have been systematically investigated by ab initio RHF and density functional B3LYP methods with LanL2DZ and SDD basis sets. The calculated vibrational frequencies of complexes Os(CO)62+, cis-Os(CO)2X42− and fac-Os(CO)3X3− are evaluated via comparison with the experimental values. In infrared frequency region, the C–O stretching vibrational frequencies calculated at B3LYP level with two basis sets are in good agreement with the observed values with deviations less than 5%. In the far-infrared region, the B3LYP/SDD method achieved the best results with deviations less than 9% for Os–X stretching and less than 8% for Os–C stretching vibrational frequencies. The vibrational frequencies for Os(CO)5X+ that have not been experimentally reported were predicted.