Synthesis, spectroscopic, structural characterization, thermal analysis, kinetics, biological evaluation of non-steroidal anti-inflammatory drug diclofenac zirconium (IV) solvates (L) (L = H2O, DMF, Py and Et3N)

Abstract

There are four new solid complexes of [ZrO(dic)2L].nH2O, where L = water (H2O), dimethylformamide (DMF), pyridine (Py) and triethylamine (Et3N) were prepared. The isolated complexes have been characterized with physicochemical and spectroscopic techniques (IR, UV–Vis. and 1HNMR spectroscopes) as well as thermal analyses. The results supported the formation of the complexes and indicated that diclofenac reacts as a bidentate ligand bound to the Zr (IV) ion through the amino nitrogen and one carboxylato oxygen. The kinetics parameters were calculated using Coats–Redfern and Horowitz–Metzeger methods. The diastereoisomers of each complex has been studied by using the density functional theory (DFT) at the B3LYP/CEP-31G level of theory. All complexes are cis-conformers (cis-N or cis-O) conformers except the Et3N complex existed in trnas conformer as trnas-O. The Py and DMF complexes more polarized than ligand while the H2O and Et3N complexes less polarized than ligand. The energy gap ΔE (0.144eV) for H2O complex is greater than ligand and others complexes, while the ΔE for others complexes (0.112–122eV), so the electronic transition within these complexes is easier than H2O complex and free ligand. All complexes are soft (η = 0.056–0.061) except H2O complex is hard (η = 0.072). The ligand and their metal complexes were also evaluated for their antibacterial activity against several bacterial species, such as Bacillus Subtilis (B. Subtilis), Staphylococcus aureus (S. aureus), Nesseria Gonorrhoeae (N. Gonorrhoeae), Pseudomonas aeruginosa (P. aeruginosa) and Escherichia coli (E. coli).