Synthesis, spectroscopic investigation and biological activities of copper(II) complex of 2-(2,4-difluorophenyl)pyridine: A combined theoretical and experimental study

This paper reports the synthesis, crystal structure determination and spectroscopic characterization of a new copper (II) complex, [CuCl2(dfpy)2] [dfpy: 2-(2,4-difluorophenyl)pyridine]. The Cu(II) complex crystallizes in triclinic space group P1¯ and the Cu(II) ion lies on a crystallographic inversion center. The Cu(II) ion is four-coordinated in a square planar geometry in which Cu(II) atom bound to the dfpy ligands' nitrogen atoms and chloride ions. Density Functional Theory (DFT) method with the B3LYP/6-31 + G (d, p) level has been used to obtain ground state geometry for the title complex. The experimental FT-IR spectrum of the Cu(II) complex has been analyzed and compared with theoretical data obtained by the B3LYP level of theory. The electronic transitions, HOMO-LUMO energies, chemical hardness, softness, and electronegativity have been explained using the time-dependent DFT (TD-DFT) method. The second-order interaction energies of the Cu(II) complex have been obtained from Natural Bond Orbital (NBO) analysis. The antimicrobial activities have been tested by using minimal inhibitory concentration method (MIC).