MICROWAVE ASSISTED SYNTHESIS, SPECTRAL AND ANTIBACTERIAL INVESTIGATIONS ON COMPLEXES OF Co (II) WITH AMIDE CONTAINING LIGANDS (original) (raw)
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1995
Five new complexes of cobalt(II) have been synthesised by the interaction of fluphenazine (FPH) with cobalt(II) chloride, bromide, perchlorate, acetate or sulphate. The complexes which have been found to possess a stoichiometric composition of [Co(C22H26F3N3OS)(H2O)(2)X(2)] have been characterised for their purity with the help of elemental studies, conductivity and magnetic measurements. An octahedral structure has been proposed based on thermal, electronic and IR spectral data. The new complexes-have been tested in vitro for their antimicrobial activity against Alternaria alternata, Aspergillus flavus, Escherichia coli and Staphylococcus aureus. The antibacterial activity of the cobalt(II) complexes against E. coli and S. aureus increases in the order: sulphate > chloride > perchlorate.
2015
Chemistry Research Laboratory, Department of Chemistry, Bharatiya Vidya Bhavan's Hazarimal Somani College of Arts and Science, Kulapati K. M. Munshi Marg, Chowpatty, Mumbai-400 007, India E-mail : shrees.rathod@gmail.com Manuscript received online 05 July 2014, accepted 06 February 2015 Copper(II) complexes containing mixed ligands, Schiff bases (L<sub>1</sub> = (2-carboxyphenyl)-pyridine-2-ylethyleneamine and L<sub>2</sub> = 5-NO<sub>2</sub> -(2-carboxyphenyl)-pyridine-2-ylethyleneamine) and 1,10-phenanthroline has been synthesized by conventional and microwave methods. These copper(II) complexes have been characterized by elemental analysis, molar conductance, magnetic moment, <strong>IR</strong>, <strong>UV</strong>-Visible spectra and thermal analysis. The copper(II) complexes are green and brownish green colored and stable in air. On the basis of these spectral studies, it is revealed that all the complexes exhibit...
European journal of medicinal …, 2008
The ligands 2-(N-(X-pyridyl)carbamoyl)pyridine (X ¼ 2, 3 or 4 for HL 1 eHL 3 , respectively) and 2,6-bis(N-(Y-pyridyl)carbamoyl)pyridine (Y ¼ 2, 3 or 4 for H 2 L 4 eH 2 L 6 , respectively) in their mono-and di-deprotonated forms have been used to synthesize kinetically stable cobalt(III) compounds [Co(L 1e3 ) 3 ] (1e3) and Na[Co(L 4e6 ) 2 ] (4e6), respectively. The Co(III) ion is in octahedral environment and is surrounded by three bidentate ligands in complexes 1e3 and two tridentate ligands in complexes 4e6. Ligands coordinate the cobalt center via amidic-N and pyridine-N centers forming a 5-membered chelate ring. Complexes 1e6 have thoroughly been characterized by the various spectroscopic analyses ( 1 H NMR, 13 C NMR, UVevis, IR, mass), elemental analysis, and conductivity measurement. All complexes have been assayed for in vitro antimicrobial activity against clinically isolated resistant strains of Pseudomonas, Proteus, Escherichia coli and standard strains of Pseudomonas aeruginosa (MTCC 1688), Shigella flexneri (MTCC 1457), Klebsiella planticola (MTCC 2272). All cobalt compounds show mild to moderate activity. However, complexes [Co(L 1 ) 3 ] (1) and Na[Co(L 4 ) 2 ] (4) were found to have potent activity against standard and pathogenic resistant bacteria used in the study. Their MIC ranged from 2.7 to 187 mg/ml. In vitro toxicity tests demonstrated that all complexes were less cytotoxic than that of gentamycin on HEK cell lines and the results reveal that these complexes can act as potent antimicrobial agents.
Synthesis, Spectroscopic and Antimicrobial Studies of Co(II), Ni(II), Cu(II) and Zn(II) Complexes
The Schiff base was synthesized by condensation of 2-hydroxy-1-naphthaldehyde with 3aminobenzoic acid in 1:1 molar ratio. The Schiff base ligand formed complexes with Co (II), Ni (II), Cu (II) and Zn (II) acetate via mechanochemical synthesis. The synthesized compounds were characterized by solubility test, thermal analysis, FT-IR, powder x-ray diffraction, molar conductance measurement, magnetic susceptibility and elemental analysis. The Schiff base has a melting point of 190 o C. The decomposition temperature of complexes was found to be in the range 289-302 o C. The Schiff base and its metal (II) complexes were soluble in DMF, DMSO and sparingly soluble in acetonitrile, chloroform, diethyl ether and insoluble in n-hexane which indicate the polar nature of the synthesized compounds. The IR spectral analysis of the free Schiff base shows a band at 1622 cm-1 , assigned to v(C=N) stretching vibrations. This band was shifted in the spectra of complexes (1607-1633 cm-1), indicating coordination of the Schiff base to the metal ion through the azomethine group. The molar conductance of complexes determined are in the range 9.51-14.87 Ohm-1 cm 2 mol-1 which indicate the non-electrolytic nature in DMF. Magnetic susceptibility measurements of Co (II), Ni (II) and Cu (II) complexes exhibit a magnetic moment in the range 1.25-3.08 BM. The values correspond to square-planar geometry. The magnetic moment value of Zn (II) complex indicates a diamagnetic behaviour. The elemental analysis of the complexes for C, H and N determined showed that the observed and the calculated percentages of the elements are in good agreement.
Biointerface Research in Applied Chemistry
The complexes of tailor made ligands with life essential metal ions may be an emerging area to answer the problems of multi drug resistance (MDR). Some novel Schiff base metal complexes of Co(II), Ni(II) and Cu(II) derived from 4-chlorobenzylidene-2,6-dichloro-4-nitroaniline (CDN) 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, magnetic susceptibility, 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. FAB-mass and thermal data show degradation pattern of the complexes. 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 Schiff base and metal complexes show a good activity against the bacteria; E. coli, S. aureus, S. fecalis and fungi A.niger, T. polysporum, C. albicans. The antimicrobial results also indicate that the metal complexes are better antimicrobial agents as compared to the Schiff base. Abstract Keywords: microwave synthesis; N donor; thermal analyses; XRD; biological activity 1. INTRODUCTION_______________________________________________
Journal of Chemistry
Some new Schiff base metal complexes of Co(II), Ni(II) and Cu(II) derived from 4-chlorobenzylidene-2-aminothiazole (CAT) and 2-nitrobenzylidene-2-aminothiazole (NAT) 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, magnetic susceptibility, thermal, electrical conductivity and XRD analysis. The complexes are coloured and stable in air. nalytical data revealed that all the complexes exhibited 1:2 (metal:ligand) ratio with oordination number 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. 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
The present report pertains to synthesis and combined experimental-DFT studies of a series of four novel mixed-ligand complexes of cobalt(II) of the general composition [Co(dha)(L)(H2O)2], where dhaH ¼ dehydroacetic acid, LH ¼ b-ketoenolates viz., o-acetoacetotoluidide (o-aatdH), o-acetoacetanisidide (o-aansH), acetylacetone (acacH) or 1-benzoylacetone (1-bac). The resulting complexes were formulated based on elemental analysis, molar conductance, magnetic measurements, mass spectrometric, IR, electronic, electron spin resonance and cyclic voltammetric studies. The TGA based thermal behavior of one representative complex was evaluated. Molecular geometry optimizations and vibrational frequency calculations have been performed with Gaussian 09 software package by using density functional theory (DFT) methods with B3LYP/LANL2MB combination for dhaH and one of its complexes, [Co(dha)(1-bac)(H2O)2]. Theoretical data has been found in an excellent agreement with the experimental results. Based on experimental and theoretical data, suitable trans-octahedral structure has been proposed for the present class of complexes. Moreover, the complexes also showed a satisfactory antibacterial activity
Bioinorganic Chemistry and Applications, 2012
Two new heterocyclic Schiff bases of 4-amino-5-mercapto-3-H/propyl-1,2,4-triazole and 5-nitrofurfuraldehyde [HL 1-2 ] and their cobalt, nickel, copper, and zinc complexes have been synthesized and characterized by elemental analyses, spectral (UV-Vis, IR, 1 H NMR, Fluorescence, and ESR) studies, thermal techniques, and magnetic moment measurements. The heterocyclic Schiff bases act as bidentate ligands and coordinate with metal ions through nitrogen and sulphur of the thiol group. The low molar conductance values in DMF indicate that the metal complexes are nonelectrolytes. The magnetic moments and electronic spectral data suggest octahedral geometry for the Co(II), Ni(II), and Zn(II) complexes and square planar for Cu(II) complexes. Two Gram-positive bacteria (Staphylococcus aureus MTCC 96 and Bacillus subtilis MTCC 121), two Gram-negative bacteria (Escherichia coli MTCC 1652 and Pseudomonas aeruginosa MTCC 741), and one yeast, Candida albicans, were used for the evaluation of antimicrobial activity of the newly synthesized compounds.
Synthesis and Study of Cobalt Complexes
Journal of emerging technologies and innovative research, 2020
The origin of the name Cobalt is thought to stem from the German kabold for "evil spirits or goblins", who were superstitiously though to cause trouble for mines, since the cobalt minerals continued arsenic that injured their health and the cobalt ores did not yeild metals when treated using the normal methods. Metal ion complexes are playing an increasing role in the development of antimicrobials. In this research paper we study the antimicrobial properties of cobalt coordination complexes in oxidation state 3+. All complexes are found active when screen for their antimicrobial activity In UV-Vis spectrophotometeric study it is found that the, Hexamine cobalt (III) chloride absorbs at 240nm, Hexanitro cobaltate (III) absorbs at 228nm and hexanitro Co(III) absorbs at 222nm. Thermogravimetric analysis of Co(III) complex of Hexamine cobalt (III) chloride show mass at 80°c to 100°c is due to water lattice weight losses upon decomposition point shows thermal stability. In sodi...
Synthesis, molecular geometry, spectroscopic studies and thermal properties of Co(II) complexes
Applied Organometallic Chemistry, 2018
Co(II) complexes (1-4) were prepared and characterized by elemental analyses, infrared spectra, spectral studies, magnetic susceptibility measurements, X-ray diffraction analysis and thermogravimetric analysis (TGA). The X-ray diffraction patterns of Co(II) complexes were observed many peaks which indicate the polycrystalline nature. The thermodynamic parameters were calculated by using Coats-Redfern and Horowitz-Metzger methods. The bond length, bond angle and quantum chemical parameters of the Co(II) complexes were studied and discussed. The Co(II) complexes were tested against various Gram-positive bacteria, Gram-negative bacteria and fungi. It was found that the Co(II) complex (1) has more antifungal activity than miconazole (antifungal standard drug) against P. italicum at all concentration. The Co(II) complex (2) has more antibacterial activity than the penicillin against K. pneumoniae at all concentration. The interaction between Co(II) complexes and calf thymus DNA show hypochromism effect. The relationship between the values of HOMO-LUMO energy gap (ΔE) and the values of intrinsic binding constant (K b) is revealed increasing of HOMO-LUMO energy gap accompanied by the decrease of K b .