Six new derivatives of ciprofloxacin compounds and their copper(II) complexes were synthesized, characterized by spectroscopic methods (ultraviolet–visible [UV–vis], Fourier transform infrared [FTIR], nuclear magnetic resonance [NMR], mass spectrometry [MS], and electron paramagnetic resonance [EPR]), and tested for antibacterial activities against gram‐negative and gram‐positive bacteria. The data showed that ciprofloxacin derivatives act as bidentate ligands and the metal ions coordinate through the pyridone carbonyl and the carboxylate oxygen atoms. Tetragonally distorted octahedral ligand fields were assumed for all complexes based on their spectral studies. Copper(II) complexes of the synthesized ciprofloxacin derivatives revealed higher antibacterial activities against gram‐positive and gram‐negative bacterial species than the parent ciprofloxacin antibiotic. Furthermore, three‐dimensional quantitative structure–activity relationship (3D‐QSAR) models were evaluated by studying 30 antibiotic compounds of the quinolone class. Density function theory (DFT) calculations were applied to evaluate the optimized geometrical structures using the B3LYP method and 6‐311G(d,p) basis set. The 3D‐QSAR study revealed that there are eight optimum parameters that give the best predictive modulation with good reliability (R2 = 0.996, F = 12.004, sigma = 0.426). In silico molecular docking was also performed on the derivatives, and the results revealed the presence of two types of interactions between the Escherichia coli and the derivatives, H‐bonding and Van der Waals interactions, and an effective inhibition at the docked site.

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A series of ruthenium (II) complexes derived from the reaction between cis-bis (2,2 0 -bipyridine) dichloro ruthenium (II) dihydrate and enaminone derivatives of ciprofloxacin were synthesized and fully characterized using elemental analysis, cyclic voltammetry and different spectroscopic techniques (Uv-vis, FTIR, NMR, mass spectroscopy, and X-ray photoelectron spectrometry (XPS)). The isolated compounds were tested for their antibacterial and antifungal activities against gram-negative and gram-positive bacteria. The FTIR data revealed that ciprofloxacin derivatives act as bidentate ligands through the pyridone carbonyl and the carboxylate oxygen atom. The UV-visible data showed that the charge transfer CT band is blue shifted upon the coordination of the ciprofloxacin derivatives compared to the CT band of the parent complex. The XPS results revealed the characteristic peaks of Ru 3p3/2 and Ru 3p1/2 as well as Ru 3d5/2 and Ru 3d3/2 , which confirmed the assembly of the ruthenium (II) ciprofloxacin derivative complexes. Cyclic voltammetry data showed that the ciprofloxacin enaminone derivatives have a similar reduction potential for the Ru (II)/Ru (III) redox couple, and it revealed that the coordination of the ruthenium (II) ion altered the redox property of the ligands and enhanced their electron transfer rate. The electrochemical and the UV-visible results suggest that the ciprofloxacin derivative ligands are π-acceptor ligands. Further, the complexes showed higher antibacterial activities than the parent ciprofloxacin antibiotic and did not show antifungal activities among the tested fungi strains.

Efficient Highly Stereoselective Synthesis of Olefinic Macrocyclic Crown-Formazans with the Z-Configuration via Ring-Closure Metathesis.-Ring closing metathesis of 1,5-bis-Oallyloxyphenylformazanes of type (I) afford Z-olefinic 15-membered ring macrocyclic crown-formazanes (II) with good selectivity.-(IBRAHIM, YEHIA A.; BEHBEHANI, HAIDER; IBRAHIM, MAHER R.; ABRAR, NADA M.; Tetrahedron Lett. 43 (2002) 39, 6971-6974; Dep. Chem., Fac. Sci., Univ.