New Cu(II), Co(II), Ni(II) complexes with aroyl-hydrazone based ligand. Synthesis, spectroscopic characterization and in vitro antibacterial evaluation

A novel mixed-ligand antimycobacterial dimeric copper complex of ciprofloxacin and phenanthroline.

In this work, formation in the binary and ternary systems of the FeIII metal ion with gallic acid and glycine was investigated by means of potentiometry, conductometry, polarography, and UV−visible absorption spectroscopy techniques at 25 °C and in I = 0.10 mol·dm−3 NaNO3. The protonation equilibria of gallic acid and glycine were investigated and discussed. The acidity constants of gallic acid and glycine were determined and used for determining the stability constants of the binary and ternary complexes formed in the aqueous medium under the experimental conditions. The ternary complex formation was found to occur in a stepwise manner. The stability constants of these binary and ternary systems were calculated. The concentration distribution of the various complex species in solution was evaluated and discussed. The solid binary [FeIII−gallic acid] and ternary [FeIII−gallic acid−glycine] complexes were synthesized and characterized by elemental analysis, FT-IR, 1H NMR, and 13C NMR spectroscopy.

Iron Complexation Studies of Gallic Acid

Structural, spectral, electrochemical and DFT studies of two mononuclear manganese(II) and zinc(II) complexes

The interactions of ciprofloxacin (HCipro) with transition metals have been investigated. Two types of complexes, [M(Cipro)(OAc)(H2O)2] · 3H2O (M = MnII, CoII, CuII or CdII) and [M(Cipro)(OAc)] · 6H2O (M = NiII or ZnII), were obtained and characterized by physicochemical and spectroscopic methods. The i.r. spectra of the complexes suggest that the ciprofloxacin behaves as a monoanionic bidentate ligand. In vitro antibacterial activities of the HCipro and the complexes were tested.

Synthesis and antibacterial activity of metal complexes of ciprofloxacin

The heterocyclic hydrazones constitute an important class of biologically active drug molecules. The hydrazones have also been used as herbicides, insecticides, nematocides, redenticides, and plant growth regulators as well as plasticizers and stabilizers for polymers. The importance of the phenolic quinolyl hydrazones arises from incorporating the quinoline ring with the phenolic compound; 2,4-dihydroxy benzaldehyde. Quinoline ring has therapeutic and biological activities whereas, phenols have antiseptic and disinfectants activities and are used in the preparation of dyes, bakelite and drugs. The present study is planned to check the effect of the counter anions on the type and geometry of the isolated copper(II)- complexes as well as the ligational behavior of the phenolic hydrazone; 4-[(2-(4,8-dimethylquinolin-2-yl)hydrazono)methyl] benzene-1,3-diol; (H2L). A phenolic quinolyl hydrazone (H2L) was allowed to react with various copper(II)- salts (Cl‾, Br‾, NO3‾, ClO4‾, AcO‾, SO42-). The reactions afforded dimeric complexes (ClO4‾, AcO‾ ), a binuclear complex (NO3‾ ) and mononuclear complexes (the others; Cl‾, Br‾, SO42-). The isolated copper(II)- complexes have octahedral, square pyramid and square planar geometries. Also, they reflect the strong coordinating ability of NO3‾, Cl‾, Br‾, AcO‾ and SO42- anions. Depending on the type of the anion, the ligand showed three different modes of bonding viz. (NN)0 for the mononuclear complexes (3, 4, 6), (NO)- with O- bridging for the dimeric complexes (1, 5) and a mixed mode [(NN)0 + (NO)- with O- bridging] for the binuclear nitrato- complex (2). The ligational behavior of the phenolic hydrazone (H2L) is highly affected by the type of the anion. The isolated copper(II)- complexes reflect the strong coordinating power of the SO42-, AcO‾, Br‾, Cl‾ and NO3‾ anions. Also, they reflect the structural diversity (octahedral, square pyramid and square planar) depending on the type of the counter anion.

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The ligational behavior of a phenolic quinolyl hydrazone towards copper(II)- ions

Cobalt(II) and copper(II) complexes of benzoyl and salicoyl hydrazones derived from β-diketones were synthesized and characterized by elemental and thermal analysis, conductance and ir studies. The hydrazones behave either as monobasic bidentate or dibasic tridentate ligands towards the metal cations. EPR and visible spectra show that the cobalt(II) complexes are tetrahedral while the copper(II) complexes are either tetragonally distorted octahedra or square planar. Magnetic measurements indicated some association between neighbouring molecules.

Cobalt(II) and Copper(II) Complexes with Benzoyl and Salicoyl Hydrazones Derived from β-Diketones

Three hydrazones (oximic: MHQ; ketonic: BHQ and phenolic: AHQ) bearing the quinoline moiety were prepared and characterized. Their dissociation constants as well as their stability constants with some transition, lanthanide and actinide metal ions have been investigated potentiometrically in 75% (v/v) dioxane-water at 303K. Also, stability constants of cobaloximes in 75% (v/v) solvent-water (solvent = dioxane, isopropanol, ethanol and methanol) as well as in 75, 70, 65, 60 and 55% (v/v) ethanol-water at 303K were evaluated. A linear regression analysis was used to evaluate the stability constants in the aqueous medium. Irving-Williams order for stability is not strictly obeyed.

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Gaber A. El‐Inany

Papers

The ligational behavior of a phenolic quinolyl hydrazone towards copper(II)- ions

Cobalt(II) and Copper(II) Complexes with Benzoyl and Salicoyl Hydrazones Derived from β-Diketones

Complexation of some hydrazones bearing the quinoline ring: potentiometric studies

Spectroscopic studies on 2-[2-(4-methylquinolin-2-yl)hydrazono]-1,2-diphenylethanone molecule and its metal complexes.

Polarography of metal-gallic complexes