Specific interactions between phosphorus compounds and carbon dioxide: Ab initio approach

Abstract

The optimized structures of several complexes of phosphorus containing compounds and CO 2 in the gas phase were determined theoretically. The Gaussian 03 computer software package was used to perform the ab initio computations, including Hartree–Fock (HF/6-31+G(d)) and density functional theory (B3LYP/6-31 +G(d)). At the same level of calculation, the binding energy between CO 2 and phosphorus containing compounds was calculated. The binding energies for CO 2–trialkyl phosphate complexes increased with the number of alkyl groups attached to the phosphorus. Harmonic infrared frequencies were calculated for the CO 2 bending mode ( ν 2) in the various complexes. The appearance of a second peak in the CO 2 bending mode ( ν 2) at lower wavenumber verified the strong interaction between CO 2 and phosphorus containing compounds. The results of the ab initio computations were in good agreement with data previously reported.