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ABSTRACT. Some new transition metal complexes of ciprofloxacin-imine derived from ciprofloxacin and ophenylenediamine were synthesized and characterized on the basis of melting point, magnetic moment, conductance measurements, elemental analysis, infrared, UV/Vis, nuclear magnetic resonance spectroscopy, mass spectra as well as thermal analyses. The data indicate that the ligand acts as tetradentate chelate bound to the metal ions through the deprotonated carboxylate and the azomethine group. The ligand as well as their metal complexes was also evaluated for their antibacterial activity against several bacterial strains such as Staphylococcus aureus, Bacillus subtilis, Escherichia coli and Pseudomonas aeruginosa and also, fungicidal activity aganist Candida albicans and Aspergillus fumigatus were tested. It was found that the metal complexes are more antibacterial as compared to uncomplexes ligand and no antifungal activity observed for ligand and their complexes. Also, this study showed that the ciprofloxacin-imine is more antibacterial as compared to ciprofloxacin alone.

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A new series of Fe (III), Co (II), Zn (II), Y (III), Zr (IV) and La (III) complexes derived from the novel ligand 4‐(4‐Isopropyl phenyl)‐2‐oxo‐6‐phenyl 1,2‐dihyropyridine‐3‐carbonitrile (L) were synthesized and characterized. The mode of bonding of L and geometrical structures of their metal complexes were elucidated by different micro analytical and spectral methods (FT‐IR,UV–visible,1H NMR and Mass spectra) as well as thermal analysis (TG and DTG), and differential scanning calorimetry (DSC). The results of analytical and spectroscopic equipments revealed that L acts as bidentate through nitrogen of carbonitrile group and oxygen of keto group. The conductivity measurement results deduced that these chelates are electrolyte with 1:2 for Co (II), Zn (II), and Zr (IV) and 1:3 for Fe (III), Y (III), and La (III). The results of magnetic moment measurements supported paramagnetic for some complexes (Fe (III), Co (II) and Cu (II)) and diamagnetic phenomena for the other complexes (Y (III), Zr (IV) and La (III)). Thermodynamic parameters such as energy of activation E*, entropy ΔS*, enthalpy ΔH* and Gibss free energy ΔG* were calculated using Coats‐Redfern and Horowitz‐Metzeger methods at n = 1 or n#1. Some results of bioactivity tests for ligands and their metal complexes were recorded against Gram‐positive, Gram‐negative bacteria and antifungal. The complexes showed significant more than free ligand.

The coordination of CIP-en (N,N'-ethylene (bis 1-cyclopropyl-6-fluoro-4-oxo-7-(piperazine-1-yl)-quinoline-3-carboxylic acid) towards Cr(III), Mn(II), Fe(III), Co(II) and Ni(II)ions has been investigated. The elemental analysis, melting point, molar conductivity, magnetic properties, infrared, UV-Vis, mass, 1 H NMR spectra and thermal analysis studies were used to characterize the complexes. TGA and DTG have been applied to study the compositions of the compounds. The measured molar conductance values indicate that the complexes are electrolytes in nature. The biological activities of the complexes were assayed against several bacterial strains.

ABSTRACT. The interaction of titanium (IV), yttrium (III), zirconium (IV), palladium (II) and cerium (IV) with deprotonated enrofloxacin leads to the formation of the neutral or cationic mononuclear complexes. The isolated solid complexes have been characterized with physicochemical and spectroscopic techniques and thermogravimeteric analyses. The spectroscopic data indicate that the enrofloxacin ligand is on the deprotonated mode acting as bidentate ligand coordinated to the metal ions through the ketone oxygen and a carboxylato oxygen and the metal ions completed the coordination number with water molecules. The thermal decomposition mechanisms proposed for enrofloxacin and their metal complexes were discussed. The activation energies, E * , enthalpies, ∆H * , entropies, ∆S * and Gibbs free energies, ∆G * , of the thermal decomposition reactions have been derived from thermogravimetric (TG) and differential thermogravimetric (DTG) curves, using Coats-Redfern (CR) and Horowitz-Metzeger (HM) methods. The antimicrobial activity has been evaluated against six different microorganisms.

Mononuclear Co(II), Cu(II), Y(III), Zr(IV), La(III), and U(VI) complexes of 2‐[(2‐hydroxybenzylidene)‐amino]‐benzoic acid (H2L) ligand in presence of 1,10‐phenanthroline (Phen) were synthesized and characterized by elemental analysis, spectroscopic techniques (IR, UV–vis, and 1H‐NMR), X‐ray powder diffraction and magnetic measurements. The results prove that H2L acts with the mentioned metal salts as a bidentate ON donor ligand and Phen as an NN donor ligand. The calculated bond length and force constant F(UO) in the uranyl complex are 1.732 Å and 708.90 nM−1, respectively. The electronic spectra and the magnetic susceptibility data support the octahedral geometry for the mononuclear Co(II), Y(III), Zr(IV), La(III), and U(VI) complexes and square‐pyramidal geometry for the Cu(II) complex. Thermogravimetric analysis was performed to determine the thermal stability of the synthesized compounds. The kinetic parameters, that is, the activation energy (E*), pre‐exponential factor (A), entropy of activation (ΔS*), enthalpy of activation (ΔH*) and free energy of activation (ΔG*), of the thermal degradation process were evaluated using Coats–Redfern (C–R) and Horowitz–Metzger (H–M) methods for all the complexes, and the best fit results could be obtained. In the present work, all the synthesized complexes showed nematicidal activity against the root knot nematode (Meloidgyne javanica) by inhibiting egg hatching and causing larval mortality of second‐stage juveniles.

String of vanadium (IV), zirconium (IV), palladium (II), platinum (IV) and uranium (VI) chelates of 2‐cyano‐2‐[(2‐nitrophenyl)hydrazono]thioacetamide (Cnphta) were prepared and characterized by physicochemical, spectroscopic and thermal analyses. The formulae of the isolated solid complexes were assigned as [VO(Cnphta)2(H2O)]SO4 ⋅ 5H2O (1), [ZrO(Cnphta)2(H2O)]Cl2 ⋅ 4H2O (2), [Pd(Cnphta)2]Cl2 (3), [Pt(Cnphta)2Cl2]Cl2 (4) and [UO2(Cnphta)2](NO3)2 ⋅ 5H2O (5). The infrared assignments clearly showed that Cnphta ligand coordinated as a bidentate feature through the hydrazono nitrogen and the thioacetamide nitrogen for V(IV), Zr(IV) and U(VI) but displayed different behavior for Pd(II) and Pt(IV). Results of the molar conductivities measurements showed that the metal complexes were electrolytes in contrast with Cnphta ligand. The interpretation, mathematical analysis and evaluation of kinetic parameters were also carried out. In addition, the studied ligand and its new chelates were tested for their antimicrobial activity against some human or phytopathogenic microorganisms. The new metal complexes explicated promising antibacterial activity against all tested bacteria especially Staphylococcus aureus and Bacillus subtilis. Regarding the antifungal activity, all metal complexes were able to inhibit the mycelium growth of both tested pathogenic fungi. In particular Zr(IV) and Pt(IV) complexes showed the highest significant fungicidal effect against A. fumigatus similar to positive control.