Spectroscopic characterization, thermogravimetric, dft and biological studies of some transition metals complexes with mixed ligands of meloxicam and 1,10 phenanthroline

Abstract

A series of biologically active complexes were prepared using meloxicam (H2mel) and 1,10-phenanthroline monohydrate (Phen) as ligands. The compositions of all complexes were elucidated by infrared, electronic absorption and 1H NMR spectroscopy, elemental analyses, magnetic moments, conductance and TG-DTG measurements. The analytical and spectroscopic data revealed that H2mel acts as a mono basic bidentate ligand binding through the oxygen of the amide and nitrogen of the thyizol groups, whereas Phen is coordinated through the two nitrogen atoms with slightly distorted octahedral geometry. The geometries of ligands and complexes were studied using density functional theory to predict properties of materials carried out using the hybrid density functional B3LYP level of theory. All studied complexes can be characterized as chemically soft with respect to the H2mel where η varied from 0.053 eV for Fe(III) complex to 0.089 eV for Zn(II) complex and σ varied from 11.236 to 18.868 eV, while η and σ for H2mel are 0.14 and 7.14 eV, respectively. The antibacterial activities of the ligands and metal complexes have been tested and the data showed that the complexes are significantly active against some bacterial species compared with H2mel.