Synthesis,characterization, antimicrobial,and nuclease activity studies of some metal Schiff-base complexes

A Schiff base (L) is prepared by condensation of cuminaldehyde and L-histidine, and characterized by elemental analysis, IR, UV-Vis, ¹H-NMR, ¹³C-NMR, and mass spectra. Co(II), Ni(II), Cu(II), and Zn(II) complexes of this Schiff-base ligand are synthesized and characterized by elemental analysis, molar conductance, mass, IR, electronic spectra, magnetic moment, electron spin resonance (ESR), CV, TG/DTA, powder XRD, and SEM. The conductance data indicate that all the complexes are 1 : 1 electrolytes. IR data reveal that the Schiff base is a tridentate monobasic donor, coordinating through azomethine nitrogen, imidazole nitrogen, and carboxylato oxygen. The electronic spectral data and magnetic measurements suggest that Co(II) and Ni(II) complexes are tetrahedral, while Cu(II) complex has distorted square planar geometry. XRD and SEM show that Co(II), Cu(II), and Zn(II) complexes have crystalline nature, while the Ni(II) complex is amorphous and the particles are in nanocrystalline phase. The in vitro biological activities of the synthesized compounds were tested against the bacterial species, Escherichia coli, Bacillus subtilis, Pseudomonas aeruginosa, and Staphylococcus aureus; and fungal species, Aspergillus niger, Aspergillus flavus, and Candida albicans by the disc diffusion method. The biological study indicates that complexes exhibit more activity than the ligand. The nuclease activity of the ligand and its complexes are assayed on CT DNA using gel electrophoresis in the presence and the absence of H₂O₂. The Cu(II) complex shows increased nuclease activity in the presence of an oxidant when compared to the ligand, Co(II) and Ni(II) complexes.     

Synthesis,characterization and biological studies of Co(II), Ni(II), Cu(II) and Zn(II) complexes with pyrral-l-histidinate

The Schiff base ligand, pyrral-l-histidinate(L) and its Co(II), Ni(II), Cu(II) and Zn(II) complexes were synthesized and characterized by elemental analysis, mass, molar conductance, IR, electronic, magnetic measurements, EPR, redox properties, thermal studies, XRD and SEM. Conductance measurements indicate that the above complexes are 1:1 electrolytes. IR data show that the ligand is tridentate and the binding sites are azomethine nitrogen, imidazole nitrogen and carboxylato oxygen atoms. Electronic spectral and magnetic measurements indicate tetrahedral geometry for Co(II) and octahedral geometry for Ni(II) and Cu(II) complexes, respectively. The observed anisotropic g values indicate the presence of Cu(II) in a tetragonally distorted octahedral environment. The redox properties of the ligand and its complexes have been investigated by cyclic voltammetry. Thermal decomposition profiles are consistent with the proposed formulations. The powder XRD and SEM studies show that all the complexes are nanocrystalline. The in vitro biological screening effects of the synthesized compounds were tested against the bacterial species, Escherichia coli, Bacillus subtilis, Pseudomonas aeruginosa and Staphylococcus aureus; fungal species, Aspergillus niger, Aspergillus flavus and Candida albicans by the disc diffusion method. The results indicate that complexes exhibit more activity than the ligand. The nuclease activity of the ligand and its complexes were assayed on CT DNA using gel electrophoresis in the presence and absence of H₂O₂.     

Synthesis,characterization and biological studies of some Co(II), Ni(II) and Cu(II) complexes derived from indole-3-carboxaldehyde and glycylglycine as Schiff base ligand

The Schiff base ligand derived from indole-3-carboxaldehyde(indal) and glycylglycine(glygly) were synthesized and characterized by elemental analysis, IR, electronic spectrum, ¹H NMR and mass spectrum. Co(II), Ni(II) and Cu(II)–indal-glygly Schiff base complexes were synthesized and characterized by elemental analysis, molar conductance, IR, electronic spectra, magnetic measurements, ESR, electrochemical studies, TGA, DSC analysis, XRD and SEM. Conductance measurements indicate that the above complexes are 1:1 electrolytes. IR spectral data show that the ligand is tridentate and the binding sites are azomethine nitrogen, peptide nitrogen and carboxylato oxygen atoms. Electronic spectral measurements indicate tetrahedral geometry for Co(II) and Ni(II) complexes and square planar geometry for Cu(II) complex. Magnetic measurements show weak ferromagnetic behaviour for Co(II) and Ni(II) complexes and paramagnetic behaviour for Cu(II) complex. ESR spectral data shows the ionic link between metal and the Schiff base ligand. The metal complexes are found to be stabilized in the unusual oxidation states of the metal ion during electrolysis. Thermal analysis of the complex indicates that the decomposition takes place in three steps. IR and thermal studies indicate that the fourth position would be occupied by a water molecule in complexes. XRD shows that the complexes have the crystallite size of 31, 40 and 67 nm, respectively. The surface morphology of the complexes was studied by SEM. The antimicrobial activity of the ligand and its complexes were screened by Kirby Bayer Disc Diffusion method. DNA cleavage studies were performed for metal–Schiff base complexes in presence of hydrogen peroxide as oxidant.     

New metal(II) complexes with ceftazidime Schiff base

Complexes of Co(II), Ni(II) and Cu(II) with the Schiff base (LH) derived from ceftazidime and salicylaldehyde were synthesized. The proposed structures of the new metal complexes based on the results of elemental analyses, molar conductivity, IR, DRUV and ¹H NMR spectra, effective magnetic moment and thermal analysis were discussed. The surface morphology of Schiff base and metal complexes was studied by SEM. The composition of the metal complexes was ML₂, where L is the deprotonated Schiff base ligand and M = Co(II), Ni(II) and Cu(II). IR spectral data indicated the Schiff base ligand being bidentately coordinated to the metallic ions with N and O atoms from azomethine and phenolic groups. All the complexes have square-planar geometry and are nonelectrolytes. The thermal analysis recorded that TG, DTG, DTA and DSC experiments confirmed the assigned composition and gave information about the thermal stability of complexes in dynamic air atmosphere. Theoretical investigation of the molecular structure of Schiff base ligand and its complexes was studied using programs dedicated to chemical modeling and quantomolecular calculation of chemical properties. The newly synthesized complexes were tested for in vitro antibacterial activity against selected Gram-negative and Gram-positive bacterial strains, and they exhibited an antibacterial activity superior to that of the Schiff base ligand.     

Synthesis, spectroscopic, antimicrobial, DNA binding and cleavage studies of some metal complexes involving symmetrical bidentate N, N donor Schiff base ligand

The Schiff base ligand, N,N′-bis-(4-isopropylbenzaldimine)-1,2-diaminoethane (L), obtained by the condensation of 4-isopropylbenzaldehyde and 1,2-diaminoethane, has been used to synthesize the complexes of the type [ML₂X₂] [M = Co(II), Ni(II) and Zn(II); X = Cl and OAc]. The newly synthesized ligand (L) and its complexes have been characterized on the basis of elemental analyses, mass, ¹H and ¹³C-NMR, molar conductance, IR, UV–vis, magnetic moment, CV and thermal analyses, powder XRD and SEM. IR spectral data show that the ligand is coordinated to the metal ions in a bidentate manner. The geometrical structures of these complexes are found to be octahedral. Interestingly, reaction with Cu(II) ion with this ligand undergoes hydrolytic cleavage to form ethylenediamine copper(II) complex and the corresponding aldehyde. The antimicrobial results indicate that the chloro complexes exhibit more activity than the acetato complexes. The complexes bind to CT–DNA by intercalation modes. Novel chloroform soluble ZnL₂Cl₂ complex exhibits tremendous antimicrobial, DNA binding and cleaving properties.     

Synthesis and characterization of Co(II), Ni(II), Cu(II) and Zn(II) complexes of tridentate Schiff base derived from vanillin and DL-alpha-aminobutyric acid

Co(II), Ni(II), Cu(II) and Zn(II) complexes of the Schiff base derived from vanillin and dl-alpha-aminobutyric acid were synthesized and characterized by elemental analysis, IR, electronic spectra, conductance measurements, magnetic measurements, powder XRD and biological activity. The analytical data show the composition of the metal complex to be [ML(H(2)O)], where L is the Schiff base ligand. The conductance data indicate that all the complexes are non-electrolytes. IR results demonstrate the tridentate binding of the Schiff base ligand involving azomethine nitrogen, phenolic oxygen and carboxylato oxygen atoms. The IR data also indicate the coordination of a water molecule with the metal ion in the complex. The electronic spectral measurements show that Co(II) and Ni(II) complexes have tetrahedral geometry, while Cu(II) complex has square planar geometry. The powder XRD studies indicate that Co(II) and Cu(II) complexes are amorphous, whereas Ni(II) and Zn(II) complexes are crystalline in nature. Magnetic measurements show that Co(II), Ni(II) and Cu(II) complexes have paramagnetic behaviour. Antibacterial results indicated that the metal complexes are more active than the ligand.     

Designing,Structural Elucidation and Comparison of the Cleavage Ability of Metal Complexes Containing Tetradentate Schiff Bases 1

New N₂O₂ donor type Schiff bases have been designed and synthesized by condensing acetylaceto-4-aminoantipyrine/acetoacetanilido-4-aminoantipyrine with 2-amino benzoic acid in ethanol. Solid metal complexes of the Schiff bases with Cu(II), Ni(II), Co(II), Mn(II), Zn(II), VO(IV), Hg(II) and Cd(II) metal ions were synthesized and characterized by elemental analyses, magnetic susceptibility, molar conduction, FAB Mass, IR, UV-Vis., ¹H NMR, and ESR spectral studies. The data show that the complexes have a composition of the ML type. The UV-Vis., magnetic susceptibility, and ESR spectral data of the complexes suggest a square planar geometry around the central metal ion, except for VO(IV) complexes, which have square-pyramidal geometry. The redox behavior of copper and vanadyl complexes has been studied by cyclic voltammetry. The nuclease activity of the above metal complexes shows that the complexes cleave DNA through redox chemistry. In the presence of H₂O₂, all the complexes are capable of cleaving calf thymus DNA plasmids, in order to compare the cleavage efficiency of all metal complexes in the two different ligand environments. In this assay, Cu(II), Ni(II), Co(II), and Zn(II) exhibit more cleavage efficiency than other metal ions. This article was submitted by the authors in English.     

Elaborated spectral,modeling, QSAR,docking, thermal,antimicrobial and anticancer activity studies for new nanosized metal ion complexes derived from sulfamerazine azodye

New azodye ligand (H₂L) and its relative Cr(III)-, Mn(II)-, Fe(III)-, Co(II)-, Ni(II)-, Cu(II)-, Zn(II)- and Cd(II)-nanosized complexes were prepared. A new synthesized compounds were characterized using spectral (mass, IR, UV–Vis, XRD, and ESR) and analytical (elemental, molar conductance, thermal and magnetic moment measurements) tools. Infrared spectra showed that the ligand behaves as a monobasic bidentate, coordinating with central atoms through carbonyl oxygen and α-hydroxyl group. The geometrical structures of Cr(III) and Fe(III) complexes were found to be in octahedral configuration, whereas Mn(II), Co(II), Ni(II), Cu(II), Zn(II) and Cd(II) complexes have tetrahedral forms. XRD patterns reflect an amorphous appearance of all investigated complexes. TEM images showed nanosized particles and identical distribution over the complex surface. Molecular modeling for the drug ligand and its metal ion complexes were performed using Gaussian09 program to assert on their structural formulae. Some essential parameters were extracted using HOMO and LUMO energies. AutoDock tools 4.2 was used to simulate the interaction process with infected cell proteins to expect the experimental pathway. The inhibition activity of drug ligand and its metal ion complexes was evaluated towards different types of bacteria and fungi through in vitro antimicrobial activities. The antitumor activities of all compounds are straightened towards human liver carcinoma (HEPG2) cell lines. Fe(III) and Co(II) complexes exhibited IC₅₀ of 2.90 and 4.23 µg mL^?1, respectively, which means they are more potent anticancer drug than the standard (doxorubicin, IC₅₀ = 4.73 µg mL^?1). Therefore, the two complexes may consider promising anticancer drugs.

     

Synthesis, spectral characterization of Schiff base transition metal complexes: DNA cleavage and antimicrobial activity studies

A new series of transition metal complexes of Cu(II), Ni(II), Co(II), Mn(II), Zn(II), VO(IV), Hg(II) and Cd(II) have been synthesized from the Schiff base (L) derived from 4-aminoantipyrine, 3-hydroxy-4-nitrobenzaldehyde and o-phenylenediamine. Structural features were obtained from their elemental analyses, magnetic susceptibility, molar conductance, mass, IR, UV-Vis, ¹H NMR and ESR spectral studies. The data show that these complexes have composition of ML type. The UV-Vis, magnetic susceptibility and ESR spectral data of the complexes suggest a square-planar geometry around the central metal ion except VO(IV) complex which has square-pyramidal geometry. The redox behaviour of copper and vanadyl complexes was studied by cyclic voltammetry. Antimicrobial screening tests gave good results in the presence of metal ion in the ligand system. The nuclease activity of the above metal complexes shows that Cu, Ni and Co complexes cleave DNA through redox chemistry whereas other complexes are not effective.     

Preparation,Structural characterization and DNA binding/cleavage affinity of new bioactive nano‐sized metal (II/IV) complexes with oxazon‐Schiff's base ligand

A novel oxazon‐Schiff's base ligand named (E)‐3‐(2‐(4‐(diethylamino)‐2‐hydroxybenzylidene)hydrazineyl)‐2H‐benzo[b][1,4]oxazin‐2‐one (HL) has been synthesized in addition to its nano‐sized divalent and tetravalent Mn (II), Co (II), Ni (II), Cu (II), Zn (II) and Pt (IV) complexes. The structures and geometries of the synthesized compounds have been confirmed using the different analytical and spectroscopic tools such as elemental analysis, uv–vis., IR, HR‐MS, ¹H NMR, ESR, TGA, XRD, EDX, TEM, SEM, AFM, magnetic and molar conductivity measurements. The elemental analyses confirm 1 M: 2 L stoichiometry of the type [PtL₂].2Cl and [ML₂] (M = Mn (II), Co (II), Ni (II), Cu (II) and Zn (II)). The FT‐IR spectral studies illustrated that the ligand bind to the metal ions through the phenolic hydroxy oxygen, azo methine nitrogen carbonyl oxazin oxygen. The spectral tools; UV–Vis, ligand field parameters and ESR in addition to the magnetic moment measurements confirmed octahedral geometry around the metal centres. The absence of coordinated or hydrated water complexes were confirmed by thermal analysis data of the complexes. The electron transfer reactions for the complexes have been studied by cyclic voltammetry. XRD, SEM, TEM, and AFM images confirmed nano‐sized particles and homogeneous distribution over the complex surface. The mode of binding of the complexes with DNA has been performed through electronic absorption titration and viscosity studies. The reaction between the metal complexes and DNA were studied by DNA cleavage. In general, MCF‐7 cell were least sensitive to the tested compounds and all compounds were considerably more toxic to the studied cancer cell lines than to the normal cell line HepG‐2. The binding mode of the compounds and DNA was preferably via intercalation. In addition, these results were confirmed based on theoretical studies . Finally, a linear and exponential correlation between interaction constant (K_b) and IC₅₀ for two human cancer cell was observed.     

Synthesis,structural, spectroscopic,biological and catalytic activity of Co(II), Ni(II) and Cu(II) complexes of benzilic hydrazide (BH)

Co(II), Ni(II) and Cu(II) chloro complexes of benzilic hydrazide (BH) have been synthesized. Also, reaction of the ligand (BH) with several copper(II) salts, including NO₃ ^?, AcO^?, and SO₄ ^? afforded metal complexes of the general formula [CuLX(H₂O) _n ]·nH₂O, where X is the anion and n = 0, 1 or 2. The newly synthesized complexes were characterized by elemental analysis, mass spectra, molar conductance, UV–vis, IR spectra, magnetic moment, and thermal analysis (TG/DTG). The physico-chemical studies support that the ligand acts as monobasic bidentate towards metal ion through the carbonyl and hydroxyl oxygen atoms. The spectral data revealed that the geometrical structure of the complexes is square planar for Cu (II) complexes and tetrahedral for Co(II) and Ni(II) complexes. Structural parameters of the ligand and its complexes have been calculated. The ligand and its metal complexes are screened for their antimicrobial activity. The catalytic activities of the metal chelates have been studied towards the oxidative decolorization of AB25, IC and AB92 dyes using H₂O₂. The catalytic activity is strongly dependent on the type of the metal ion and the anion of Cu(II) complexes.     

Phenoxo-bridged symmetrical homobinuclear complexes derived from an “end-off” compartmental ligand, 2,6- bis [5′-chloro-3′-phenyl- 1H -indole-2′-carboxamidyliminomethyl]-4-methylphenol

A compartment ligand 2,6-bis[5′-chloro-3′-phenyl-1H-indole-2′-carboxamidyliminomethyl]-4-methylphenol was prepared and homobinuclear phenol-bridged Cu(II), Ni(II), Co(II), Zn(II), Cd(II), Hg(II), Fe(III), and Mn(II) complexes have been prepared by the template method using the precursors 2,6-diformyl-4-methylphenol, 5-chloro-3-phenylindole-2-carbohydrazide and metal chlorides in 1 : 2 : 2 ratio, respectively. The complexes were characterized by elemental analyses, conductivity measurements, magnetic susceptibility data, IR, NMR, FAB mass and ESR spectra, TGA, and powder XRD data. Cu(II), Co(II), Zn(II), Cd(II) and Hg(II) complexes exhibit square pyramidal geometry whereas Ni(II), Mn(II), and Fe(III) complexes are octahedral. Low magnetic moment values for Cu(II), Ni(II), Co(II), Fe(III), and Mn(II) complexes show antiferromagnetic spin-exchange interaction between two metal centers in binuclear complexes. The ligand and its complexes were tested for antibacterial activity against Escherichia coli and Staphyloccocus aureus, and antifungal activity against Aspergillus niger and Candida albicans.     

Bioactivity of some divalent M(II) complexes of penicillin based Schiff base ligand: Synthesis,spectroscopic characterization,and thermal study

A series of four novel metal complexes of Co(II), Ni(II), Cu(II) and Zn(II) were synthesized from Schiff base derived from amoxicillin (AMX) and picolinaldehyde (PC2). The ligand and metal complexes were fully characterized by physical and spectral techniques such as elemental microanalysis, conductivity, FT-IR, ¹H & ¹³C NMR, UV–vis, mass spectra, EPR, magnetic moment measurement, TGA/DTA, PXRD and antibacterial activity study. The spectroscopic study revealed 1:2 metal ligand ratio and coordination sites in the ligand for metal ions were evaluated by analysis of the spectral results. The surface morphology of the complexes was evaluated by SEM analysis. Molar conductivity implies non-electrolytic nature of the complexes. UV–vis. spectral study nicely supports octahedral geometry for Co(II) and Zn(II) complexes and tetrahedral geometry for Cu(II) complex. The kinetic parameters were extracted from Coats-Redfern equation. The PXRD study revealed nano-crystalline nature of Co(II), Ni(II) & Cu(II) complexes and amorphous nature of Zn(II) complex. The proposed geometry of the complexes was optimized by MM2 calculation supported in Cs-ChemOffice Ultra-11 program. The ligand and metal complexes were screened for antibacterial potency against four human pathogenic clinical strains of bacteria and the data revealed their promising antibacterial activity.     

Synthesis,Spectral Characterization,Antitumor, Antioxidant,and Antimicrobial Studies of New Potential ONS Schiff Base Complexes

Novel Co(II), Ni(II), Cu(II), and Zn(II) complexes derived from 2‐aminopyridine‐3‐thiol and 4‐oxo‐4H‐chromene‐3‐carbaldehyde were synthesized and characterized by spectroscopic (IR, ¹H NMR, UV–vis, ESR, and MS) and other analytical methods. Molar conductance data and magnetic susceptibility measurements provide evidence for the monomeric and monobasic nature of the complexes. The molar conductance measurement of the complexes in DMSO corresponds to their non‐electrolytic nature. All the complexes are of high‐spin type. On the basis of the different spectral studies, the six‐coordinated geometry may be assigned for all the complexes. IR spectral studies indicate the binding sites of the ligand with the metal ion. The Schiff base acts as tridentate ligand coordinated through deprotonated thiolic (SH) sulfur, azomethine (─CH═N─) nitrogen, and carbonyl (−C═O) oxygen atoms. The ligand field parameters were calculated for Co(II) and Ni(II) complexes and their values were found to be in the range reported for an octahedral structure. The data show that the complexes have an ML₂‐type composition. The activation thermodynamic parameters are calculated using the Coast–Redfern, Horowitz–Metzger (HM), Piloyan–Novikova (PN), and Broido equations. The X‐ray diffraction data suggest a triclinic system for all compounds. Different surface morphologies were identified from SEM micrographs. Human tumor cell lines A427 (lung cancer cell line), LCLC‐103H (large cell lung cancer), SISO (uterine adenocarcinoma), and 5637(human bladder carcinoma) grown in RPMI‐1640 medium were elevated. The biological screening data show that the complexes show growth inhibitory activity against various microorganisms. The octahedral geometry of the complexes is confirmed using density functional theory (DFT) from DMOL³ calculations, electronic and magnetic moment measurements, ESR, and ligand field parameters.     

Synthesis,spectral, bioactivity,and NLO properties of chalcone metal complexes

A series of metal(II) complexes ML and ML₂ [where M?=?Cu(II), Co(II), Ni(II), Zn(II), Mn(II), Cd(II), and VO(II); L?=?2-hydroxyphenyl-3-(1H-indol-3-yl)-prop-2-en-1-one (HPIP)] have been prepared and characterized by elemental analysis, magnetic susceptibility, molar conductance, IR, UV-Vis, NMR, Mass, and ESR spectral studies. Conductivity measurements reveal that the complexes are non-electrolytes, except VO(II) complex. Spectroscopy and other data show square pyramidal geometry for oxovanadium and octahedral geometry for the other complexes. Redox behavior of the copper(II) and vanadyl complexes has been studied with cyclic voltammetry. Antimicrobial activities against several microorganisms indicate that a few complexes exhibit considerable activity. The nuclease activity shows that the complexes cleave DNA. All synthesized compounds can serve as potential photoactive materials as indicated from their characteristic fluorescence properties. The second harmonic generation efficiency of the ligand is higher than that of urea and KDP.     

Co(II), Ni(II), Cu(II), and Zn(II) complexes of 4-aminoantipyrine-derived Schiff base. Synthesis,structural elucidation,thermal, biological studies,and photocatalytic activity

The Schiff base ligand was prepared from 4-aminoantipyrine, acetamide, and m-phenylenediamine. Metal salts used for the synthesis of these complexes are Co(II), Ni(II), Cu(II), and Zn(II) acetates. The elemental analysis results are in accordance with proposed formula assigned to these complexes. In the IR spectra, the imine band is shifted to a lower wave number in the complexes. UV spectra and magnetic susceptibility measurements proposed square planar geometry for Co(II), Ni(II), and Cu(II) complexes and tetrahedral geometry for Zn(II) complex. The grain size of the metal complexes was estimated by the Scherrer formula using powder XRD. In the present study, the ligand and its metal complexes are found to be nanocrystalline. Thermal decomposition pattern is in agreement with the proposed formula of the complexes. Irreversible redox behavior of the complex was identified by cyclic voltammetric analysis. The photocatalytic activity of the synthesized complexes are high under UV-spectra using methylene blue dye. DNA studies reveal that the synthesized complexes exhibit both DNA cleavage and DNA binding properties. Antibacterial and antifungal activities were done by the minimum inhibitory concentration (MIC) method. Anticancer activity shows that Cu(II) complex has the highest cytotoxic effect in SK-MEL-28 cell line.     

Mass, EPR, IR and electronic spectroscopic studies on newly synthesized macrocyclic ligand and its transition metal complexes

Manganese(II), cobalt(II), nickel(II) and copper(II) complexes have been synthesized with a new tetradentate ligand viz. 1,3,7,9-tetraaza-2,4,8,10-tetraketo-6,12-diphenyl-cyclododecane (L) and characterized by the elemental analysis, molar conductance measurements, magnetic susceptibility measurements, mass, ¹H NMR, IR, electronic and EPR spectral studies. The molar conductance measurements of the complexes in DMF correspond to be nonelectrolytic nature for Mn(II), Co(II) and Cu(II) while 1:2 electrolytes for Ni(II) complexes. Thus, these complexes may be formulated as [M(L)X₂] and [Ni(L)]X₂ (where M = Mn(II), Co(II) and Cu(II) and X = Cl⁻ and NO₃⁻).On the basis of IR, electronic and EPR spectral studies an octahedral geometry has been assigned for Mn(II) and Co(II) complexes, square-planar for Ni(II) whereas tetragonal for Cu(II) complexes. The ligand and its complexes were also evaluated against the growth of bacteria and pathogenic fungi in vitro.     

Transition Metal Complexes of Dis(thiosemicarbazone): Synthesis and Spectral,and Antifungal Studies

Mn(II), Co(II), Ni(II), and Cu(II) complexes have been synthesized with benzil bis(thiosemicarbazone) (L) and characterized by elemental analyses, molar conductance measurements, magnetic susceptibility measurements, thermogravimetric studies, infrared (IR), electronic, and electron paramagnetic resonance (eEPR) spectral studies. The molar conductance measurements of the complexes in DMF correspond to the non-electrolytic nature of the complexes. Thus these complexes may be formulated as [M(L)X₂] (where M = Mn(II), Co(II), Ni(II), Cu(II) and X = Cl^? and NO₃ ^?). On the basis of IR, electronic, and EPR spectral studies, an octahedral geometry has been assigned for Mn(II), Co(II), and Ni(II) complexes, whereas a tetragonal geometry for the Cu(II) complexes is presumed. The free ligand and its metal complexes were tested against the phytopathogenic fungi (i.e., Rhizoctonia baticola, Alternaria alternata) in vitro.     

Synthesis,characterization, anti‐inflammatory and analgesic activity of transition metal complexes of 3‐[1‐(2‐hydroxyphenyl) ethylideamino]‐2‐phenyl‐3,4‐dihydroquinazolin‐4(3H)‐one

A new quinazolinone derivative, 3‐[1‐(2‐hydroxyphenyl)ethylideamino]‐2‐phenyl‐3,4‐dihydroquinazolin‐4(3H)‐one ( LH ) was synthesized by the condensation of 2‐hydroxyacetophenone‐2‐aminobenzoylhydrazone and benzaldehyde. The cyclization to form 1,2‐dihydroquinazolinone was confirmed by IR, 1D and 2D HETCOR studies. Coordination compounds of Co(II), Ni(II), Cu(II) and Zn(II) of LH were synthesized and characterized using various physico‐chemical studies like stoichiometric, conductivity, magnetic moment measurements and spectral techniques such as IR, NMR, UV‐vis and EPR spectroscopy. The elemental analysis and thermal studies suggested a general stoichiometry [M(HEPDQ)Cl] for all the complexes. A four‐coordinate geometry was assigned to all the complexes. The complexes along with the parent ligand were screened for their anti‐inflammatory activity, using carrageenan‐induced rat paw edema, and for their analgesic activity by Eddy's hot plate method. The activity of the ligand was enhanced on complexation with metal ions. This enhanced activity was attributed to the increased lipophilic nature of the complexes. Notable anti‐inflammatory activity was observed for Ni(II), Cu(II) and Zn(II) complexes. The analgesic activity of the ligand was greater than the standard at 60 min. and at a 10 mg kg⁻¹ dose, whereas the activity of Ni(II) and Cu(II) complexes at 10 mg kg⁻¹ dose was comparable with the standard used. Copyright © 2011 John Wiley & Sons, Ltd.     

Green synthesis of biologically active transition metal nanoparticles containing novel Schiff base via catalyst free hydrothermal reaction: Structural,biological and morphology study

Novel cobalt, nickel and copper complexes were synthesized by regular reflux method and nano sized Co(II), Ni(II) and Cu(II) metal complexes were synthesized by a facile hydrothermal method using green solvent at various temperatures without the addition of any capping agent. The structural characterization was done by magnetic susceptibility, molar conductance, elemental analysis, thermal analysis, FT‐IR, ¹H NMR, ¹³C NMR, ESI mass, UV–Visible analysis. The morphology and size of the nano metal complexes were determined using FE‐Scanning electron microscopy, powder X‐ray diffraction data and atomic force microscopic techniques. All the spectral and analytical results reveal 1:2 metal to ligand ratios having [ML₂(H₂O)₂] stoichiometry, here M=Co(II), Ni(II) and Cu(II), L=deprotonated ligand. The non‐electrolytic nature of the compound was confirmed by molar conductance experiment. The synthesized Schiff base and its metal complexes (7, 8 and 9) were tested for their biological activity. All the tested compounds exhibit decent anticancer and DNA cleavage activity and copper complex shows better activity results than other tested compounds.