Vibrational assignments and structure of bis(3-amino-1- phenyl-2-buten-1-onato)copper(II) complex

•The vibrational spectra of Cu(APBO)2 are measured.•All calculations were performed at the UB3LYP/6-311G(d) level.•By using DFT calculations, the vibrational band frequencies were fully assigned.•Theoretical and experimental results suggest stronger M-O/N in ketoamines than diketones.

The bis(3-amino-1-phenyl-2-buten-1-onato)copper(II) complex, Cu(APBO)2, has been characterized by ab initio calculations and vibrational spectroscopic techniques. The geometry optimization are performed at the UB3LYP level using 6-311G(d) and 6-311+G(d,p) basis sets. The vibrational frequencies were calculated at the UB3LYP/6-311+G(d,p) level. Furthermore, to include the relativistic effects on the core electrons of Cu atom, the optimization and vibrational frequencies were recalculated at the UB3LYP level with 6-311G(d,p) basis set for all atoms but the Cu atom, whose basis set was LanL2DZ and CEP-31G, with their corresponding pseudopotential. The scaled theoretical frequencies and the structural parameters are in excellent agreement with the experimental data. HOMO–LUMO energies and natural charges over chelated ring atoms of Cu(APBO)2 and Cu(APO)2 are also compared.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slide