Copper(II) mixed-ligand complexes with fluoroquinolones and an N-donor co-ligand: Structures and biological application

Cu(II) mixed-ligand complexes of the type [Cu(ofx)(bipym)(CH3OH)]center dot ClO4 center dot H2O and [Cu(cpx)(bipym) (NO3)]center dot NO3 center dot 2H(2)O, where ofx = ofloxacin ([9-fluoro-3-methyl-10-(4-methyl-1-piperazinyl)-7-oxo-2,3-dihydro-7H-[1,4]oxazino[2,3,4-ij]quinoline-6-carboxylic acid]), cpx = ciprofloxacin ([1-cyclopropyl-6-fluoro-4-oxo-7-(1-piperazinyl)-1,4-dihydro-3-quinoline carboxylic acid hydrochloride]) and bipym = 2,2'-bipyridylamine, have been synthesized and characterized by elemental analysis, spectroscopic techniques (UV-Vis and FTIR), electron spin resonance (ESR), electrospray ionization spectrometry (ESI-MS), thermal analysis (TG/DTA), conductance measurements, melting point and single-crystal X-ray diffraction (SCXRD). X-ray crystallographic analysis reveals that both complexes belong to the monoclinic system, with the space group P21/n for 1 and P21/c for 2. The geometry of the Cu(II) ion is a distorted square-pyramidal coordination environment in both complexes and the complexes are considerably air-stable in the solid-state and in solution. The results of the thermal analysis show that the complexes are stable at room temperature. The antimicrobial and antimycobacterial activities of the newly synthesized complexes were tested on (H37RV) and both Gram(+) and Gram(-) microorganisms in comparison to the parent ligands. (C) 2020 Elsevier Ltd. All rights reserved.