Cu(II) Complex of a Schiff Base Derived from Pyridoxal: Synthesis, Experimental Characterization, DFT Studies, and Aim Analysis

Abstract

A Cu(II) complex of the N,N′-dipyridoxyl(1,2-diaminobenzene) [=H₂L] Schiff base is newly synthesized. The complex is characterized experimentally and theoretically. The density functional theory methods are employed to calculate the optimized geometry along with the natural bond orbital analysis and the vibrational frequency analysis of the complex. The computed IR frequencies are in agreement with the experimental one, confirming the validity of the proposed geometry for the complex. In the optimized geometry of the octahedral complex, dianionic L^2– acts as a tetradentate ligand. Two azomethine nitrogen atoms and two phenolate oxygen atoms of the L^2– ligand occupy four square positions of the complex. Also, two methanol ligands are perpendicular to the square plane. The large energy gap between the frontier orbitals demonstrates the stability of the complex. The properties of the Cu–N and Cu–O bonds are investigated by the Atoms In Molecules analysis, too.