Spectral, thermal stability and antibacterial studies of copper, nickel and cobalt complexes of N-methyl-N-phenyl dithiocarbamate

Copper(II), cobalt(II) and nickel(II) bis(N-methyl-N-phenyl dithiocarbamate) complexes having the general formula [M{S2CN(MePh)}2] (where M = Cu, Co and Ni) have been prepared and characterized by spectral and thermal analysis. The IR spectra suggest that coordination of dithiocarbamate (DTC) occurred through the two sulfur atoms in a symmetrical bidentate fashion. The electronic spectra, conductance measurement and magnetic moment analysis support the proposed geometry for the electronically dilute complexes. The results of the thermal analysis showed that after dehydration, a one-step decomposition pattern leading to the formation of respective metal sulfide as the end-product occurred. The results are consistent with the proposed composition of the complexes. The in vitro antibacterial activity of the complexes was investigated against strains of gram-negative Escherichia coli, Klebsiella oxytoea and Pseudomonas aureginosa, and gram-positive Bacillus cereus, Staphylococcus aureus and Protues mirabilis. The antibacterial activity of the complexes compared favorably with that of streptomycin and augmentine against S. aureus and B. cereus. The cobalt complex had the best antibacterial activity against the test compounds with inhibitory zone range of 11–14.5 m

Research and Reviews: Journal of Chemistry Synthesis, Spectroscopic and Antibacterial Properties of Some Metal (II) Mixed Ligand Complexes of Riboflavin and 2,2'-Bipyridine

ABSTRACT Mixed ligand complexes of Riboflavin (L) and 2,2'-Bipyridine (L 1 ) with Mn(II), Fe(II), Co(II), Ni(II), Cu(II) and Zn(II) ions were synthesized and characterized by, infrared and electronic spectroscopies, room temperature magnetic moments, melting points and conductance measurements. The % metal analysis confirmed that the complexes analyzed as [MX2(L)(L 1 )] where X = Cl/(CH3CO2)/SO4. Infrared spectra data confirmed that coordination is via the imine nitrogen and carbonyl oxygen atoms of the riboflavin, and the nitrogen atoms of the 2,2'-bipyridine molecules respectively. The room temperature magnetic moment and electronic spectra data indicated that all the metal(II) complexes were octahedral, and the Mn(II), Fe(II), Co(II) and Ni(II) complexes showed high spin low spin octahedral equilibrium. The conductance measurements of all the metal(II) complexes in water and DMSO showed that the complexes were all covalent. Interestingly, the invitro antibacterial studies of these metal(II) complexes, riboflavin and 2,2'-bipyridine against Bacillus cereus, Escherichia coli, Proteus mirabilis, Pseudomonas aeruginosa, Klebsiella oxytoca and Staphylococcus aureus showed that none of the bacteria was sensitive to the former two compounds, with the exception of Proteus mirabilis which had activities of 20.0 mm and 13.0 mm against the Cu(II) complex and riboflavin. In contrast, all the bacteria were sensitive to 2, 2'-bipyridine, just like Augmentine, although with higher inhibitory zones range of 24.0-47.0 mm proving its potential as a broad spectrum antibacterial agent

Syntheses, characterization, and antimicrobial properties of nickel(II) dithiocarbamate complexes containing NiS₄ and NiS₂PN moieties

<p>Three Ni(II) dithiocarbamate complexes, [Ni(buphdtc)₂] (<b>1</b>), [Ni(buphdtc)(PPh₃)(NCS)] (<b>2</b>) and [Ni(buphdtc)(PPh₃)(NC)] (<b>3</b>) (where bu = butyl and ph = phenyl), were synthesized and characterized by elemental analysis, UVvis, and FTIR spectroscopies. Complexes <b>1</b> and <b>2</b> were further characterized by single-crystal X-ray structural analysis. The single-crystal X-ray structural analysis indicates a slightly distorted square planar geometry. In <b>2</b> and <b>3</b>, the influences of the auxiliary ligands (PPh₃, NCS, and NC) on their steric and electronic properties were observed. Thermal studies of the complexes showed decomposition starting at 250–300 °C, leading to formation of nickel sulfide phases around 400 °C. The complexes were screened against some bacteria strains, <i>Staphylococcus aureus</i>, <i>S</i><i>treptococcus pneumoniae</i>, <i>Bacillus subtilis</i>, <i>Escherichia coli</i>, <i>K</i><i>lebsiella oxytoca</i> and <i>P</i><i>seudomonas aeruginosa</i>, and two fungi species, <i>A</i><i>spergillus niger</i> and <i>F</i><i>usarium oxysporum</i>. The complexes showed moderate-to-strong antimicrobial potentials, with [Ni(buphdtc)₂] (<b>1</b>) displaying the best antimicrobial activity. Fluconazole and streptomycin were used as reference drugs for antifungal and antibacterial assays, respectively.</p

Synthesis, DFT Calculation, and Antimicrobial Studies of Novel Zn(II), Co(II), Cu(II), and Mn(II) Heteroleptic Complexes Containing Benzoylacetone and Dithiocarbamate

Heteroleptic complexes of zinc(II), copper(II), manganese(II), and cobalt(II) of the types [MLL′(H2O)2]·nH2O and [MLL′]·nH2O have been synthesized using sodium N-methyl-N-phenyldithiocarbamate (L) and benzoylacetone (L′). The metal complexes were characterized by elemental analysis, electrical conductance, magnetic susceptibility, infrared (IR), and UV-visible spectroscopic studies. The electrical conductance measurements revealed the nonelectrolytic nature of the synthesized complexes. The results of the elemental analyses, magnetic susceptibility measurements, and electronic spectra inferred that the Zn(II) complex adopted a four-coordinate geometry while the Co(II), Cu(II), and Mn(II) complexes assumed octahedral geometries. The IR spectra showed that the metal ions coordinated with the ligands via the S- and O-donor atoms. The geometry, electronic, and thermodynamic parameters of the complexes were obtained from density functional theory (DFT) calculations. The spin density distributions, relative strength of H–bonds, and thermodynamic parameters revealed that the order of stability of the metal complexes is Mn Zn. The agar diffusion methods were used to study the antimicrobial activity of the complexes against two Gram positive bacteria (S. aureus and S. pneumoniae), one Gram negative bacterium (E. coli), and two fungi organisms (A. niger and A. candida) and the complexes showed a broad spectrum of activities against the microbes