Molecular structure and vibrational assignments of bis(4-aminopent-3-en-2-onato)copper(II): A detailed density functional theoretical study

Bis(4-aminopent-3-en-2-onato) copper(II), Cu(APO)2, was synthesized and its total X-ray crystallographic data were determined. The molecular structure and vibrational spectra of this compound were investigated by means of density functional theory (DFT) calculations at the B3LYP level using 6-31G**, 6-311G*, and 6-31++G* basis sets, and the results were compared with the experimental data. For comparison, the geometrical parameters and vibrational wavenumbers of Cu(APO)2 were also calculated at the HF and MPW1PW91 levels using mixed basis sets (GEN), 6-311+G* for the Cu atom and 6-31G** for all the other atoms. All of the measured IR and Raman bands were interpreted in terms of the calculated vibrational modes. The scaled theoretical frequencies and the structural parameters were in good agreement with the experimental data.