Preparation and Spectroscopic Studies of Cadmium(II), Zinc(II),Mercury(II) and Vanadium(IV) Chelates Azo Ligand Derived from 4-Methyl-7-hydroxycoumarin

The present paper demonstrates the synthesis and characterization of some transition elements complexes derived from (E)-7-hydroxy-6-((4-methoxyphenyl)diazenyl)-4-methyl-2H-chromen-2-one. The ligand was prepared in the general route of azo dyes by coupling the diazonium salt of 4-methoxyaniline with 4-methyl-7-hydroxycoumarin in sodium hydroxide 10% (w/v) solution. The azo ligand was identified on the basis of elemental analyses, MS, H-NMR and FT-IR spectra. The products of complexes with the new azo dye were isolated by the direct reactions of the metal chlorides of cadmium(II), zinc(II), vanadium(IV) and mercury(II) ions with the alkaline solution of free ligand to afford the colored in the following formulas, complexes[ML2]2H2O formula, M=Cd(II) and Zn(II). However the vanadium(IV) complex was square pyramid in [VOL2]SO42H2O chemical formula. As well as the tetrahedral environment was suggested for mercury(II) complex in formula [HgL2]. The time and mole ratio factors were studied to obtain the optimized conditions of metal complexes formations and the observed data investigated the deprotonation of the azo-dye at pH to range (7–7.5) with 30 min as time of reaction to get pure metal chelates. The TG-DSC study confirmed the thermal stability of complexes at a wide range of average heating in inert gas of analysis and the results observed from loss weight percent investigated the proposed structures of the prepared metal complexes.

Homogeneous or heterogeneous electrocatalysis: Reinvestigation of a cobalt coordination compound for water oxidation

A cobalt coordination compound with azo-ligand linkers combined with linked bisulfonate moieties has been argued to be an efficient catalyst for oxygen-evolution reaction (OER) (Dalton Trans., 2017, 46, 16321). In...

Nano-Azo Ligand and Its Superhydrophobic Complexes: Synthesis, Characterization, DFT, Contact Angle, Molecular Docking, and Antimicrobial Studies

Metal complexes of the 2,2'-(1,3-phenylenebis(diazene-2,1-diyl))bis(4-aminobenzoic acid) diazo ligand (H2L) derived from m-phenylenediamine and p-aminobenzoic acid were synthesized and characterized by different spectral, thermal, and analytical tools. The H2L ligand reacted with the metal ions Cr(III), Mn(II), Fe(III), Co(II), Ni(II), Cu(II), Zn(II), and Cd(II) as 1 : 1 stoichiometry. All complexes displayed an octahedral geometry according to the electronic and magnetic moment measurements. The IR spectra revealed the binding of the azo ligand to the metal ions via two azo nitrogen atoms and protonated carboxylate O in a neutral tetradentate manner. Both IR and 1H NMR spectra documented the involvement of the carboxylate group without proton displacement. The thermal studies pointed out that the complexes had higher thermal stability comparable with that of the free ligand. SEM images revealed the presence of the diazo ligand and its Cd(II) complex in a nanostructure form. The contact angle measurements proved that the Cd(II) complex can be considered as a superhydrophobic material. The molecular and electronic structure of H2L and [Cd(H2L)Cl2].H2O were optimized theoretically, and the quantum chemical parameters were calculated. The biological activities of the ligand, as well as its metal complexes, have been tested in vitro against some bacteria and fungi species. The results showed that all the tested compounds have significant biological activities with different sensitivity levels. The binding between H2L and its Cd(II) complex with receptors of the crystal structure of S. aureus (PDB ID: 3Q8U), crystal structure of protein phosphatase (PPZ1) of Candida albicans (PDB ID: 5JPE), receptors of breast cancer mutant oxidoreductase (PDB ID: 3HB5), and crystal structure of Escherichia coli (PDB ID: 3T88) was predicted and given in detail using molecular docking.