Coordination Complexes Of Co Research Articles

Synthesis, Characterization, UTI and Antibacterial Activity of Schiff Base, (E)-2-(decan-2-ylidene) hydrazine-1-carboxamide Co2+, Mn2+ and Fe3+Metal Complexes

Novel coordination complexes of Co, Mn and Fe with Azomethine (E)-2-(decan-2-ylidene) hydrazine-1-carboxamide have been synthesized and studied using elemental analysis (C, H, N), FT-IR, 1HNMR, 13 CNMR, XRD and Mass spectroscopy as well as thermal studies. The Schiff base has octahedral geometry and functions as a tridentate ONS donor ligand. The antimicrobial action of the Azomethine ligand and complexes was investigated towards Staphylococcus aureus, Escherichia coli and fungi C. albicans and A. fumigatus. Microbial pathogens invading the urinary tract produced urinary tract infections, they can cause a variety of clinical symptoms as well as potentially fatal sequelae. The current research focus on the growth of a novel antimicrobial agent towards E. coli, P. aeruginosa, K. pneumoniae bacteria.

Synthesis and characterization of cobalt(II) complexes with bidentate Schiff base ligand

The coordination complexes of Co(II) have been prepared from bidentate Schiff base. The Schiff base ligand was synthesized by the condensation of 4- hydroxy-3-methoxybenzaldehyde and 2-aminobenzhydroxamic acid in an alcoholic medium at room temperature. The ligand and cobalt (II) complexes were characterized by elemental analysis, molar conductance, electronic spectra, IR spectra, NMR spectra, electrical conductivity and magnetic susceptibility. The cobalt (II) complexes are colored and stable in air. In the metal complexes, the metal -ligand ratio was found to be 1:2. A sharp band at 1630 cm-1 is characteristics of the azomethine group present in the Schiff base ligand. This band was shifted to lower frequency (1605 – 1620 cm-1) in all the cobalt complexes, indicating the coordination of the azomethine nitrogen to the metal ion in complexes. The ν(N-OH) stretching vibration of the ligand obtained at 1080 cm-1 was raised up by 10-40 cm-1 in the complexes suggesting the deportation of (N-OH) hydrogen and coordination of hydroxy imino nitrogen atom in the bond formation with the Co(II) ions. The molar conductivity data of the complexes in DMF solution indicates that they are of non-electrolytic nature. On the basis of elemental analysis, magnetic susceptibility and electronic spectral data, geometry of complexes was proposed to be octahedral.

Synthesis, characterization and H2 adsorption performances of polymeric Co(II) and Ni(II) complexes of pyrazine-2,3-dicarboxylic acid and 1-vinylimidazole

We studied the synthesis and characterization of polymeric coordination complexes of Co(II) and Ni(II) ions with pyrazine-2,3-dicarboxylic acid and 1-vinylimidazole. The e lemental analysis, infrared spectroscopy, powder X-ray diffraction, magnetic susceptibility, thermal analysis and X-ray single crystal techniques were used in the characterization. The X-ray single crystal analysis suggests that the pyrazine-2,3-dicarboxylato ligand acts as a bridging ligand through the oxygen atoms of the carboxylate groups and the nitrogen atoms on the pyrazine ring. The 1-vinylimidazole ligand behaves as a monodentate ligand via the ring nitrogen atom. Further, the H2 adsorption studies were carried out at 75 K for various increasing pressures and the highest H2 adsorption performances for Co(II) and Ni(II) complexes were estimated as 2.66 and 2.99 wt% at 87 bar. The theoretical calculations using the crystal data were also performed to determine the voids in the structure of Co(II) complex.

Transition metal complexes of 2-(2-(1H-benzo[d]imidazol-2-yl)hydrazono)propan-1-ol: Synthesis, characterization, crystal structures and anti-tuberculosis assay with docking studies

Transition metal coordination complexes of Co(II), Ni(II), Cu(II) and Zn(II) with a newly designed ligand, 2-(2-(1H-benzo[d]imidazol-2-yl)hydrazono)propan-1-ol have been synthesized and characterized using various spectro-analytical techniques. The molecular structures of Co(II), Cu(II) and Zn(II) complexes are determined by single-crystal X-ray diffraction method. The metal to ligand stoichiometry has been found to be 1:2 in the case of Cobalt(II), Nickel(II) and Zinc(II) whereas 1:1 in the case of Copper(II) complex. The newly synthesized ligand and complexes have been assessed for their growth inhibiting potencies against H37Rv strain of Mycobacterium tuberculosis. The copper and cobalt complexes have emerged to be potent in vitro growth inhibitors of H37Rv. All the complexes are inhibiting the growth of other tested common microbial flora to a significantly lesser extent, making them selective towards H37Rv in the preliminary analysis. The consensus scores obtained by the docking studies of the molecules to the target protein enoyl acyl carrier protein reductase of M. tuberculosis H37Rv are in good agreement with the obtained MIC values.

Synthesis, Characterization and Biological Activity of Schiff Base Metal Complexes

New coordination complexes of Co, Ni and Zn with Schiff base bis ((4-phenylpyrimidin-2-yl)(((2-thioxo-1, 2dihydroquinolin-3-yl)methylene)hydrazono)methoxy) have been synthesized and characterized by several techniques using elemental analysis (C, H, N), IR spectra and 1HNMR spectra. The new Schiff base has been synthesized by the reaction of 4-phenylpyrimidine-2-carbohydrazide and 2-thioxo-1, 2dihydro quinoline-3carbaldehyde. The Schiff base behaves as tridentate ONS donor ligand and exhibited octahedral geometry. The Schiff base ligand and complexes were tested for their antibacterial activity against Staphylococcus aureus, Escherichia coli and Proteus vulgaris to assess their inhibiting potential. In screening medium was nutrient agar and biological screening were performed by employing cup plate method. Antibacterial activity of the ligand and its metal complexes is compared with the standard drug ciprofloxacin. In this series Co (II) complexes showed high antibacterial activity and the other complexes showed moderate antibacterial activity against different bacteria.

SYNTHESIS, CHARACTERIZATION, IN VITRO ANTIMICROBIAL, ANTHELMINTIC AND DOCKING STUDIES OF NEW 2-[(E)-{[4-(1H-1,2,4-TRIAZOL-1 YLMETHYL)PHENYL]IMINO} METHYL]PHENOL, AND THEIR COMPLEXES WITH 3D METAL IONS

<p><strong>Objective: </strong>The main objectives of this research work is the synthesis and characterization of biologically potential triazole ring containing the Schiff base legend and their transition metal complexes, followed by screenings of their antimicrobial and anthelmintic activity the results of antimicrobial activity were compared with docking scores.</p><p><strong>Methods: </strong>The<strong> </strong>coordination complexes of Co(II), Cu(II), Fe(III) and Zn(II) with Schiff base derived ligand 4-(1<em>H</em>-1,2,4-triazol-1-ylmethyl) aniline and substituted aldehydes have been synthesized. The complexes are characterized by elemental analysis, conductivity measurements, electronic, IR, and <sup>1</sup>H NMR spectral data. The synthesized compounds were also screened <em>In vitro</em> antimicrobial activity was carried out according to diffusion method by using agar and potato dextrose agar at 100, 500 and 700 mg/ml concentrations in DMF.<strong> </strong>HEX 8.0<strong> </strong>programmers were used to perform the docking experiments on <em>nucleotide </em>of <em>S. typhi </em><em>at</em> as ligand [PDB: 3B6O].</p><p><strong>Results: </strong>Schiff base ligand and their transition metal complexes were studied for antimicrobial activity as well as docking. The results of both studies concluded that 4a, 4c and 4d compounds are more active in minimum inhibition concentration (30μg/ml) against <em>Staphylococcus aureus</em> (<em>S. aureus), Salmonella typhi (S. typlei)</em> bacteria and <em>Penicillium chrysogenum</em> (<em>P. Crysogenum) </em>fungi. The compounds showed highest docking score (-257.47,-275.61 and-280.17 respectively) with the secondary structure of the alpha-amylase with a nucleotide from <em>s. typhi</em> in the solid model. In the study of anthelmintic activity among these three compounds, 4d compound exhibits more activity compared with the standard.</p><strong>Conclusion: </strong>The compounds 4a, 4c and 4d were found to be more promising pharmacological activity this observation may promote a further development of this triazole group of compounds which may lead to better pharmacological profile than standard drugs. <p> </p>

Synthesis, Characterization and Study of Antibacterial Activity of a New Schiff Base Ligand and Its Complexes with Co(II), Ni(II), Cu(II), Cd(II) and Hg(II) Metal Ions

Some coordination complexes of Co(??), Ni(??), Cu(??), Cd(??) and Hg(??) are reacted in ethanol with Schiff base ligand derived from of 2,4,6- trihydroxybenzophenone and 3-aminophenol using microwave irradiation and then reacted with metal salts in ethanol as a solvent in 1:2 ratio (metal: ligand). The ligand [H4L] is characterized by FTIR, UV-Vis, C.H.N, 1H-NMR,13C-NMR, and mass spectra. The metal complexes are characterized by atomic absorption, infrared spectra, electronic spectra, molar conductance, (C.H.N for Ni(??) complex) and magnetic moment measurements. These measurements indicate that the ligand coordinates with metal (??) ion in a tridentate manner through the nitrogen and oxygen atoms of the ligand, octahedral structures are suggested for these complexes. Antibacterial activity of the ligand [H4L] and its complexes are studied against (gram positive) and (gram negative) bacteria [Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Bacillus]. The proposed structure of the complexes using the program, Chem office (2006) and the general formula has been given for the prepared ligand complexes K2[M(H2L)2].

Synthesis, Characterization and Study of Antibacterial Activity of a New Schiff Base Ligand and Its Complexes with Co(II), Ni(II), Cu(II), Cd(II) and Hg(II) Metal Ions

Some coordination complexes of Co(??), Ni(??), Cu(??), Cd(??) and Hg(??) are reacted in ethanol with Schiff base ligand derived from of 2,4,6- trihydroxybenzophenone and 3-aminophenol using microwave irradiation and then reacted with metal salts in ethanol as a solvent in 1:2 ratio (metal: ligand). The ligand [H4L] is characterized by FTIR, UV-Vis, C.H.N, 1H-NMR,13C-NMR, and mass spectra. The metal complexes are characterized by atomic absorption, infrared spectra, electronic spectra, molar conductance, (C.H.N for Ni(??) complex) and magnetic moment measurements. These measurements indicate that the ligand coordinates with metal (??) ion in a tridentate manner through the nitrogen and oxygen atoms of the ligand, octahedral structures are suggested for these complexes. Antibacterial activity of the ligand [H4L] and its complexes are studied against (gram positive) and (gram negative) bacteria [Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Bacillus]. The proposed structure of the complexes using the program, Chem office (2006) and the general formula has been given for the prepared ligand complexes K2[M(H2L)2].

Conductivity Studies of Schiff Base Ligands Derived from O-Phenylenediamine and Their Co(II) and Zn(II) Complexes

The coordination complexes of Co(II) and Zn(II) with Schiff bases derived from o-phenylenediamine and substituted 2-hydroxybenzaldehyde were prepared All compounds were characterized by Fourier transform infrared (FTIR) spectroscopy and Nuclear magnetic resonance (NMR) spectroscopy elemental analyzers. They were analyzed using impedance spectroscopy in the frequency range of 100Hz-1 MHz. LI and L2 showed higher conductivity compared to their metal complexes, which had values of 1.3 7 x 10-7 and 6.13 x 10-8 S/cm respectively.

Conductivity Studies of Schiff Base Ligands Derived from O-Phenylenediamine and Their Co(II) and Zn(II) Complexes

The coordination complexes of Co(II) and Zn(II) with Schiff bases derived from o-pheny/enediamine and substituted 2-hydroxybenza/dehyde were prepared All compounds were characterized by Fourier transform infrared (FTIR) spectroscopy and Nuclear magnetic resonance (NMR.) spectroscopy elemental analyzers. They were analyzed using impedance spectroscopy in the frequency range of 100 Hz - 1 MHz. L1 and L2 showed higher conductivity compared to their metal complexes, which had values of 1.3 7 x 10-7 and 6.13 x 10-8 S/cm respectively.

Theoretical and experimental studies on three new coordination complexes of Co(II), Ni(II), and Cu(II) with 2,4-dichloro-6-{(E)-[(5-chloro-2 sulfanylphenyl)imino]methyl}phenol Schiff base ligand.

Three mononuclear coordination complexes of Co(II), Ni(II), and Cu(II) have been synthesized from 2,4-dichloro-6-{(E)-[(5-chloro-2-sulfanylphenyl)imino]methyl}phenol ligand (H 2 L) obtained by simple condensation reaction of 3,5-dichloro-2-hydroxybenzaldehyde and 2-amino-4-chlorobenzenethiol and characterized by elemental analysis, spectral (FT-IR, electronic, and (1)H-NMR), molar conductance, thermal, SEM, PXRD, and fluorescence studies. The PXRD analysis and SEM-EDX micrographs show the crystalline nature of complexes. The domain size and the lattice strain of synthesized compounds have been determined according to Williamson-Hall plot. TG of the synthesized complexes illustrates the general decomposition pattern of the complexes. The ligand exhibits an interesting fluorescence property which is suppressed after complex formation. The Co(II) complex adopted a distorted octahedral configuration while Ni(II) and Cu(II) complexes showed square planar geometry around metal center. The geometry optimization, HOMO-LUMO, molecular electrostatic potential map (MEP), and spin density of synthesized compounds have been performed by density functional theory (DFT) method using B3LYP/6-31G and B3LYP/LANL2DZ as basis set. Graphical abstract Three new coordination complexes of Co(II), Ni(II) and Cu(II) with 2,4-dichloro-6-{(E)-[(5-chloro-2 sulfanylphenyl)imino]methyl}phenol Schiff base ligand.

Cobalt lawsone complexes: searching for new valence tautomers

Bi-stable molecular systems presenting valence tautomerism are associated with the development of new functional materials, which can be used for applications in organic electric conductors, optoelectronic and molecular magnetic devices. The properties of these materials can be adjusted with slight chemical changes and can be induced by external stimuli. Typical examples of valence tautomer compounds are coordination complexes of Co and o-dioxolene ligands, notably quinone like ones. In the search for a new class of cobalt complexes presenting valence tautomerism we report herein the synthesis and characterization of five new coordination compounds of cobalt and 2-hydroxy-1,4-naphthoquinone (lawsone or shortly Law). Complexes [Co(Law)2(im)2]·C6H5CH3 (1), [Co(Law)2(py)2]·CH3OH (2), [Co(Law)2(phen)]·(C4H8O)2 (3), [Co(Law)2(2,2-bpy)]·C6H5CH3 (4) and [Co(Law)2(2,2-bpy)] (5) were synthesized and fully characterized by X-ray diffraction and EPR techniques in a wide range of temperatures and under illumination. Despite presenting similar molecular and geometry packing of the valence tautomer complexes of cobalt and o-dioxolenes, neither structural nor electronic evidence of valence tautomerism could be found in the Co and lawsone complexes.

Synthesis, spectroscopic, electrochemical and biological studies of novel Schiff base complexes derived from 4-(3-ethoxy-2-hydroxybenzylideneamino)-N-(pyridin-2-yl)benzenesulfonamide

Novel coordination complexes of Co(II), Ni(II) and Cu(II) have been synthesized from 4-(3-ethoxy2-hydroxybenzylideneamino)-N-(pyridin-2-yl)benzenesulfonamide (ESSP) Schiff base derived from sulfapyridine and 3-ethoxysalicylaldehyde. The nature of bonding and the structural features of the Schiff base and its complexes have been deduced from elemental analysis, molar conductance, magnetic susceptibility measurements, IR, 1H NMR,13C NMR, UVVis, cyclic voltammetry, fluorescence and EPR spectral studies. The spectral data of the complexes have revealed bidentate coordinating nature of the Schiff base through azomethine nitrogen atom and phenolic oxygen. The Schiff base and its metal complexes were screened for their antimicrobial activity. The complexes showed enhanced antimicrobial activity as compared to uncomplexed Schiff base.

Microwave Induced Synthesis And Characterization Of Semiconducting 2-thiophenecarboxaldehyde Metal Complexes

The coordination complexes of Co(II), Ni(II) and Cu(II) derived from 2-thiophenecarboxylidene-3-chloro-4-fluoroaniline (TCC) and 2-thiophenecarboxylidene-4-fluoroaniline (TCF) have been synthesized by conventional as well as microwave methods. These compounds have been characterized by elemental analysis, FT-IR, FAB-mass, molar conductance, electronic spectra, ESR, thermal, magnetic susceptibility, electrical conductivity and XRD analysis. The complexes are coloured and stable in air. Analytical data revealed that all the complexes exhibited 1:2 (metal:ligand) ratio with the coordination 4 or 6. FAB-mass and thermal data show degradation pattern of the complexes. The thermal behavior of metal complexes shows that the hydrated complexes loses water molecules of hydration in the first step; followed by decomposition of ligand molecules in the subsequent steps. The crystal system, lattice parameter, unit cell volume and number of molecules in unit cell in the lattice of complexes have been determined by XRD analysis. XRD patterns indicate crystalline nature for the complexes. The solid state electrical conductivity of the metal complexes has also been measured. Solid state electrical conductivity studies reflect semiconducting nature of the complexes.

Microwave synthesis, spectral, thermal, and antimicrobial activities of some transition metal complexes involving 5-bromosalicylaldehyde moiety

Article history: Received May 30, 2012 Received in Revised form June 23, 2012 Accepted 12 July2012 Available online 14 July 2012 The coordination complexes of Co(II), Ni(II) and Cu(II) derived from 5-bromosalicylidene-3,4dimethylaniline (BSMA) and 5-bromosalicylidene-3,4-dichloroaniline (BSCA) have been synthesized by conventional as well as microwave methods. These compounds have been characterized by elemental analysis, FT-IR, molar conductance, electronic spectra, H-NMR, FAB-mass, ESR, magnetic susceptibility, electrical conductivity and thermal analysis. The complexes are coloured and stable in air. Analytical data revealed that all the complexes exhibited 1:2 (metal: ligand) ratio with coordination number 4 or 6. IR data shows that the ligand coordinates with the metal ions in a bidentate manner through the phenolic oxygen and azomethine nitrogen. FAB-mass and thermal data show degradation pattern of the complexes. Solid state electrical conductivity studies reflect semiconducting nature of the complexes. The Schiff base and metal complexes show a good activity against the Gram-positive bacteria; Staphylococcus aureus and Gram-negative bacteria; Escherichia coli and fungi Aspergillus niger and Candida albicans. © 2012 Growing Science Ltd. All rights reserved.

Synthesis, spectroscopic, thermal and antimicrobial studies of Co(II), Ni(II), Cu(II) and Zn(II) complexes with Schiff base derived from 4-amino-3-mercapto-6-methyl-5-oxo-1,2,4-triazine

Coordination complexes of Co(II), Ni(II), Cu(II) and Zn(II) with Schiff base derived from syringaldehyde and 4-amino-3-mercapto-6-methyl-5-oxo-1,2,4-triazine have been synthesized. These complexes have been characterized by elemental analysis, magnetic moment, spectroscopic (IR, Electronic, 1H NMR, ESR) and thermogravimetric analysis. Magnetic and spectral data suggest octahedral geometry for Co(II), Ni(II) and Zn(II) complexes and square planar for Cu(II) complexes. The presence of coordinated water in metal complexes was confirmed by thermal and IR data. The Schiff base and its metal complexes have been screened for antibacterial (Pseudomonas aeruginosa, Bacillus subtilis, Escherichia coli, Staphylococcus aureus) and antifungal activities (Aspergillus niger, A. flavus). A comparison is made between activities of complexes with Schiff base and with the standard antibiotics.

2D parallel interpenetration of [ M2(bpp) 4X4] [ M, Fe(II)/Co(II); bpp, 4,4′-trimethylenedipyridine; X, SCN −, SeCN − and N 3−] complexes: Pseudohalide-dependent conformation of bpp

Three coordination complexes of Co(II)/Fe(II) with 4,4′-trimethylenedipyridine (bpp) and pseudohalides (SCN −, SeCN − and N 3 −) have been synthesized. The complexes have been characterized by X-ray single crystal structure determination. They are isomorphous having 2D layers in which two independent wavy nets display parallel interwoven structures. Pseudohalide binds metal centers through N terminal and occupies the trans axial positions of the octahedral metal coordination environment. Pseudohalide remains pendant on both sides of the polymeric layer and help the stacking through hydrogen bonding. The conformation of bpp in the interpenetrated nets is observed to be dependent on the choice of pseudohalide.

Infrared evidence for the presence of Superoxide in a Co(III)-ATP complex used for the labeling of nucleotide in binding sites of ATPases

The inert coordination complexes of Co(III) and ATP are used as dead end inhibitors to determine enzyme mechanisms. Conclusive infrared evidence for the presence of superoxide ion in a Co(III)-ATP complex is presented. The superoxide is displaced by monovalent anions such as cyanide. The presence of superoxide explains the biological reactivity of the inert Co(III) complex.