Synthesis, spectroscopic characterisation, thermal analysis, DNA interaction and antibacterial activity of copper(I) complexes with N, N′- disubstituted thiourea

copper(I) complexes Cu(4MTU)2Cl (2), Cu(4MTU) (B)Cl (3), Cu(6MTU)2Cl (5) and Cu(6MTU) (B)Cl (6) where 4MTU = 1-Benzyl-3-(4-methyl-pyridin-2-yl)-thiourea (1) and 6MTU = 1-Benzyl-3-(6-methyl-pyridin-2-yl)-thiourea (4), B is a N,N-donor heterocyclic base, viz. 1,10-phenanthroline (phen 3, 6), were synthesized, characterized by various physico-chemical and spectroscopic techniques. The elemental analysis suggests that the stoichiometry to be 1:2 (metal:ligand) for 2, 5 1:1:1 (metal:ligand:B) for 3, 6. X-ray powder diffraction illustrates that the complexes have crystalline nature. IR data coupled with electronic spectra and molar conductance values suggest that the complex 2, 5 show the presence of a trigonal planar geometry and the complex 3, 6 show the presence of a tetrahedral geometry about the Cu(I) centre. The binding affinity towards calf thymus (CT) DNA was determined using UV-Vis, fluorescence spectroscopic titrations and viscosity studies. These studies showed that the tested phen complexes 3, 6 bind moderately (in the order of 105 M-1) to CT DNA. The complex 2, 5 does not show any apparent binding to the DNA and hence poor cleavage efficiency. Complex 3, 6 shows efficient oxidative cleavage of plasmid DNA in the presence of H2O2 involving hydroxyl radical species as evidenced from the control data showing inhibition of DNA cleavage in the presence of DMSO and KI. The in vitro antibacterial assay indicates that these complexes are good antimicrobial agents against various pathogens. Anti-bacterial activity is higher when thiourea coordinates to metal ion than the thiourea alone. © 2015 Elsevier B.V

“In Vitro Antimicrobial Activity and DNA Cleavage Studies: Synthesis and Characterization of Novel M(II) Complexes with O, N, O donor Schiff Base Ligand Derived from Phenylpropanehydrazide”

Three new ternary complexes of general formulation [M(L)n] (1–3), where L=N`-(5-chloro-2-hydroxybenzylidine)-3- phenylpropanehydrazide; n=2;M= Cu, Ni, Zn, complexes are synthesized, characterized by various physicochemical and UV-Vis, FTIR, 1H NMR and ESI-MS spectroscopic methods. The Cyclic voltammetry show a quasi-reversible cyclic voltammetric response due to one electron Cu(II)/Cu(I) reduction near 100 mV (versus SCE) in DMF–0.1 M KCl. All the compounds were screened for their in-vitro antibacterial activity against Gram positive and Gram negative bacterial strains. Among them, Cu complex showed good activity against all microbes. The copper complex shows moderate chemical nuclease activity in the presence of MPA as a reducing agen

Synthesis and Chemical Nuclease Activities of Copper (II) and Ni (II) Complexes of 4-Chloro-2-(pyridine-3-Yliminomethyl) Phenol Schiff Bases

This communication describes a procedure to synthesize a novel Schiff base ligand4-chloro-2-(pyridine-3-yliminomethyl) phenol and its transition metal complexes of Cu(II) and Ni(II)and its characterization by physiochemical techniques such as elemental, FTIR,UVVisible, 1 H-NMR, Mass spectra and cyclic voltammetry. Further, the ligand was structurally characterized by X-ray crystallography and is found to be planar suitable for DNA studies. The complexes were screened for their in-vitro antimicrobial activity using various strains of gram positive and gram negative bacteria- Bacillus mycoides, Bacillus subtilis, Escherichia coli, Micrococcus luteus, Proteus mirabilis, Pseudomonas aeruginosa and Yersinia enterocolitica. The Schiff base ligand showed higher antibacterial activity than the ligand coordinated to either of the metal ion copper or nickel. The DNA cleavage studies of the complexes have been investigated and both the complexes showed extensive cleavage of DNA. However, Cu(II) complexes showed better cleavage activity compared to Ni(II) complex

In vitro antimicrobial activity and DNA cleavage studies: synthesis and characterization of novel M(II) complexes with tridentate [ONO] donor Schiff base ligand derived from phenylpropane hydrazide

Three new ternary complexes of general formulation [M(L)​n] (1-​3)​, where L = N'-​(5-​chloro-​2-​hydroxybenzylidine)​-​3-​phenylpropane hydrazide; n = 2; M = Cu, Ni, Zn, complexes are synthesized, characterized by various physicochem. and UV-​Vis, FT-​IR, 1H NMR and ESI-​MS spectroscopic methods. The Cyclic voltammetry show a quasi-​reversible cyclic voltammetric response due to one electron Cu(II)​/Cu(I) redn. near 100 mV (vs. SCE) in DMF-​0.1 M KCl. All the compds. were screened for their in-​vitro antibacterial activity against Gram pos. and Gram neg. bacterial strains. Among them, Cu complex showed good activity against all microbes. The copper complex shows moderate chem. nuclease activity in the presence of MPA as a reducing agent

Synthesis, Crystal Structure, Antioxidant, Antimicrobial, and Mutagenic Activities and DNA Interaction Studies of Ni(II) Schiff Base 4-Methoxy-3-Benzyloxybenzaldehyde Thiosemicarbazide Complexes

Three new Ni(II) square planar complexes of 4-methoxy-3-benzyloxybenzaldehyde thiosemicarbazide(4m3BTSC) having polypyridyl bases of general formulation [ML2] (1) and [MLB] (2, 3), where L = 4m3BTSC and B is N,N-donor heterocyclic bases, namely, 1,10-phenanthroline (phen, 2), 2,2′-bipyridine (bpy, 3), are synthesized and characterized. The free radical scavenging assay results showed that complex 1 possesses significant activity when compared to complexes 2 and 3. The biological studies showed that the ligand and its complexes exhibited significant and different biological activities and also the prepared compounds are nonmutagenic. They may be potential commercial antioxidants because of their nonmutagenic and nontoxic nature. The DNA interaction of the new complexes is evaluated by absorption, emission, and melting temperature methods, and the results suggested that the binding affinity of the complexes increases with the presence of planar ligand in the molecule. The nickel (II) complexes with planar phenanthroline bases show moderate DNA binding and cleavage ability

Oxidative DNA cleavage, cytotoxicity and antimicrobial studies of l-ornithine copper (II) complexes

New ternary copper (II) complexes, Cu(l-orn)(B)(Cl)(Cl·2H 2O) (1-2) where l-orn is l-ornithine, B is an N,N-donor heterocyclic base, viz. 2,2â²-bipyridine (bpy, 1) and 1,10-phenanthroline (phen, 2), were synthesized and characterized by various spectroscopic techniques. Complex 2 is characterized by the X-ray single crystallographic method. The complex shows a distorted square-pyramidal (4 + 1) CuN 3OCl coordination sphere. Binding interactions of the complexes with calf thymus DNA (CT-DNA) were investigated by UV-Vis absorption titration, ethidium bromide displacement assay, viscometric titration experiment and DNA melting studies. Complex 2 shows appreciable chemical nuclease activity in the presence of 3-mercaptopropionic acid (MPA). The complexes were subjected to in vitro cytotoxicity studies against carcinomic human alveolar basal epithelial cells (A-549) and human epithelial (HEp-2) cells. The IC 50 values of 1 and 2 are less than that of cisplatin against HEp-2 cell lines. MIC values for 1 against the bacterial strains Streptococcus mutans and Pseudomonas aeruginosa are 0.5 mM. © 2012 Elsevier Ltd. All rights reserved

Oxamido binuclear copper (II) complexes: Synthesis, crystal structure, DNA interaction and antibacterial studies

Four binuclear copper (II) complexes Cu(oxpn)Cu(B)2+ (2-5) bridged by N, Nâ²-bis3-(methylamino) propyl oxamide (oxpn), where, B is N, N-donor heterocyclic bases (viz. 2,2â²-bipyridine (bpy, 2), 1,10-phenathroline (phen, 3), dipyrido3,2-d:2â²,3â²-fquinoxaline (dpq, 4) and dipyrido3,2-a:2â²,3â²-cphenazine (dppz, 5) are synthesized, characterized by different spectroscopic and single crystal X-ray data technique. The phen (3) and dpq (4) complexes were structurally characterized by X-ray data analysis. Their DNA binding, oxidative cleavage and antibactirial activities were studied. The dpq (4) and dppz (5) complexes are avid binders to the Calf thymus DNA (CT-DNA). The phen (3), dpq (4) and dppz (5) complexes show efficient oxidative cleavage of supercoiled DNA (SC DNA) through hydroxyl radical (OH) pathway in the presence of Mercaptopropionic acid (MPA). © 2013 Elsevier Ltd. All rights reserved

Novel ligand 1-Benzyl-3-(4-ethyl-pyridin-2-yl)-thiourea and Cu (I) complexes: DNA interaction, antibacterial and thermal studies

The new ligand 1-Benzyl-3-(4-ethyl-pyridin-2-yl)-thiourea (1), and two copper(I) complexes Cu(4ETU)2Cl (2), Cu(4ETU)(B)Cl (3) where 4ETU=1-Benzyl-3-(4-ethyl-pyridin-2-yl)-thiourea, B is a N,N-donor heterocyclic base, viz. 1,10-phenanthroline (phen, 3), were synthesized, characterized by various physico-chemical and spectroscopic techniques. The elemental analysis suggests that the stoichiometry to be 1:2 (metal:ligand) for 2 and 1:1:1 (metal:ligand:B) for 3. PXRD analysis provides the crystalline nature of the metal complexes. IR data coupled with electronic spectra and molar conductance values suggest that the complex 2 shows the presence of a trigonal planar geometry and the complex 3 shows the presence of a tetragonal geometry about the Cu(I) centre. Binding interactions of the complexes with calf thymus (CT) DNA have been investigated by absorption, emission, DNA thermal denaturation and viscosity studies. The phen complex displays significant binding propensity to the CT DNA giving an order: 3 (phen) > 2. Complex 3 shows efficient oxidative cleavage of SC-DNA in the presence of H2O2 involving hydroxyl radical species as evidenced from the control data showing inhibition of DNA cleavage in the presence of DMSO and KI. The compounds were screened for their in vitro anti-bacterial activity using Gram-positive bacteria (Staphylococcus aureus, Bacillus subtilis, Micrococcus luteus) and Gramnegative bacteria (Esherichia coli, Pseudomonas aeruginosa, Klebsiella pneumonia). Complexes 2 & 3 exhibits higher antibacterial activity against Gram-positive bacteria than the Gram-negative bacteria. Antibacterial activity is higher when thiourea coordinates to metal ion than the thiourea alone. The thermogram of complex 2 exhibits single step and complex 3 exhibits two step decomposition behavior