International Journal of Inorganic Chemistry
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Open Access journal
ISSN (Print) 2090-2026 - ISSN (Online) 2090-2034
Published by Hindawi [333 journals]
- Microwave-Assisted Synthesis and Characterization of [Rh2(OAc)4(L)2]
Paddlewheel Complexes: A Joint Experimental and Computational Study
Abstract: The synthesis of four rhodium(II) paddlewheel complexes bearing axial aromatic amines and coumarin ligands, with formula [Rh2(OAc)4(L)2] (L = NH2Mesityl (1), NH2Dip (2), NH2Couma (3), coumarin (4)), prompted by microwave irradiation, was carried out successfully. All of the complexes were characterized by the melting point, elemental analysis, NMR, IR, and UV/Visible spectroscopy. Additionally, the structure of complexes 1-2 and 4 was corroborated by single-crystal X-ray diffraction. Cyclic voltammetry, ESI-MS, and tandem MS analyses were carried out in compound 1 for gaining further insight into its stability. Finally, a DFT study shows that complexes 1–4 are the thermodynamic products, having as intermediates complexes 1′–4′ which, under our experimental conditions, cannot be isolated.
PubDate: Sun, 19 Mar 2017 00:00:00 +000
- Structural Prediction of
Using 31P NMR Spectroscopy
Abstract: The present paper reports the use of 31P NMR spectroscopy to predict the isomer structures of [bis4-methoxy-phenyl-[3-(4-methoxy-phenyl)-allylidene]-amino]-bis[triphenylphosphine]ruthenium(II), also known as bis(di-p-anisole)-1,4-azabutadiene-bis[triphenylphosphine]ruthenium(II), complexes. The complexation reaction was carried out under refluxing condition of (di-p-anisole)-1,4-azabutadiene (compound 1), triphenylphosphine (PPh3), and ruthenium chloride in the ratio of 2 : 2 : 1 for five hours. In addition, ruthenium(II) complexes were also characterized using FTIR and UV-Vis spectroscopy to support the formation of ruthenium(II) complexes. 31P NMR spectroscopic study on ruthenium(II) complexes suggested that there are three isomers present after the complexation reaction and all the ruthenium complexes demonstrate octahedral geometry.
PubDate: Thu, 10 Nov 2016 11:17:51 +000
- Synthesis and Study in Solution of a New Dansyl-Modified Azacryptand
Abstract: We report the synthesis of a new asymmetric azacryptand (L1), characterized by three p-xylyl spacers, one of which carries a dansyl side arm. The fluorescent sensor has been studied by potentiometric, UV-Vis, and emission studies in MeOH : water 3 : 2 mixture (0.07 M NaNO3), determining, in particular, the protonation constants of the free ligand and metal ion complexation equilibria. Interestingly, the obtained results revealed that the new receptor is fluorescent at neutral pH with a typical emission band of the dansyl group. Metal addition induced a partial quenching of the dansyl emission band; this behavior is more pronounced with Cu(II) that reduces the receptor’s emission by 60%. With all the studied cations, quenching follows the formation of a dimetallic complex. Similar studies on the model compound L2 confirmed that fluorescence quenching is mainly driven by a static mechanism, attributable to the formation of the inclusion dicopper complex [L1Cu2]4+. In order to test the stability of copper complexes under physiological conditions, spectrofluorimetric titrations with Cu(II) were performed in water buffered at pH = 8 (HEPES 0.07 M) and the values of binding constants, K11 and K12, were determined.
PubDate: Mon, 10 Oct 2016 16:11:26 +000
- Synthesis, Characterization, and Structural Assessment of Ni(II) Complexes
Derived from Bis(2-hydroxy-1-naphthaldehyde)succinoyldihydrazone
Abstract: The monometallic nickel(II) complexes [Ni(H2nsh)(A)2]·H2O (where A = water (H2O), (1); pyridine (py), (2); 2-picoline(2-pic), (3); 3-picoline(3-pic), (4); and 4-picoline(4-pic), (5)) and homobimetallic nickel(II) complexes [Ni2(nsh)(A)4]·H2O (where A = water (H2O), (6); pyridine (py), (7); 2-picoline(2-pic), (8); 3-picoline(3-pic), (9); and 4-picoline(4-pic), (10), resp.) have been synthesized in methanol from bis(2-hydroxy-1-naphthaldehyde)succinoyldihydrazone (H4nsh). The complexes have been characterized by elemental analyses, molar conductance, magnetic moment, and electronic and IR and TGA/DTA spectroscopic studies. The monometallic complexes (1) to (5) are found to have octahedral stereochemistry while complexes (6) to (10) are found to have distorted octahedral stereochemistry in which one of the Ni(II) centres is present in N2O2 coordination sphere and another Ni(II) centre is bonded to it through phenolate oxygen atoms via oxo-bridging.
PubDate: Thu, 31 Dec 2015 06:46:05 +000
- Synthesis, Crystal Structure, and Antimicrobial Properties of a Novel 1-D
Cobalt Coordination Polymer with Dicyanamide and 2-Aminopyridine
Abstract: A novel one-dimensional coordination polymer bis(2-aminopyridine)-μ-bis(dicyanamido) cobaltate(II) has been synthesized and characterized by elemental analyses and infrared and ultraviolet visible spectroscopies and the structure has been determined by single crystal X-ray diffraction. Co(II) ion in the complex is coordinated to two axial 2-aminopyridine ligands through the pyridine N-atom and four equatorial dicyanamide ligands to give a CoN6 slightly distorted octahedral coordination environment around the metal ion. The amino N-atom forms intrachain hydrogen bonds. Antimicrobial screening of the complex against eight pathogenic microorganisms (four bacteria and four fungi) isolated from humans, indicates that the complex is moderately active.
PubDate: Mon, 29 Jun 2015 08:21:19 +000
- Synthesis, Characterisation, Crystal Structure, and Antimicrobial and
Larvicidal Studies of [Cu(2,2′-bipy)2SO4]·3CH4N2O·2H2O
Abstract: A pentacoordinated mononuclear copper(II) complex, namely, bis(2,2′-bipyridine)sulphatecopper(II) urea trisolvate dihydrate, has been synthesised and characterised by molar conductance and UV-Vis and FTIR spectra. The structure of the complex was unambiguously confirmed by single crystal XRD. The complex crystallizes in monoclinic system, space group C2/c, with the values (4), (4), and (3) Å; °, °, and °; (2) Å3 and . The Cu(II) ion is coordinated to four nitrogen atoms of two bidentate 2,2′-bipyridine ligands (bipy) and by one oxygen atom of the sulphate group and displays distorted trigonal bipyramidal geometry. The crystal packing is stabilized by inter- and intramolecular hydrogen bonding. The Cu(II) complex was screened for antimicrobial activity against Staphylococcus aureus, Escherichia coli, Klebsiella pneumonia, Aspergillus niger, Aspergillus flavus, and Candida albicans. Larvicidal activity of the synthesized copper(II) complex was carried out against larvae of Culex quinquefasciatus and Anopheles subpictus.
PubDate: Thu, 29 Jan 2015 09:56:13 +000
- Thermal Decomposition Studies of Layered Metal Hydroxynitrates (Metal: Cu,
Zn, Cu/Co, and Zn/Co)
Abstract: Layered metal hydroxynitrates and mixed metal hydroxynitrates (copper/cobalt hydroxynitrates and zinc/cobalt hydroxynitrates at different mole ratios) were synthesized by hydrolysis of urea and metal nitrates at 140°C. Layered metal hydroxyl nitrates derive their structure from brucite mineral and generally crystallize in hexagonal and monoclinic phases. Isothermal decomposition studies of Cu2(OH)3(NO3), Co2(OH)3(NO3), Cu1.5Co0.5(OH)3(NO3), Cu1.34Co0.66(OH)3(NO3), Zn5(OH)8(NO3)2(H2O)2, Zn3.75Co1.25(OH)8(NO3)2(H2O)2, and Zn3.35Co1.65(OH)8(NO3)2(H2O)2 samples were carried out at different intervals of temperature and the structural transformations during the process were monitored using powder X-ray diffractograms. Biphasic mixture of metal hydroxynitrate/metal oxide is observed in case of cobalt/zinc based layered hydroxynitrates, while copper hydroxynitrate or copper/cobalt metal hydroxynitrate decomposes in a single step. The decomposition temperatures of layered metal hydroxynitrates and mixed layered metal hydroxides depend on the method of preparation, their composition and the nature of metal ion, and their coordination.
PubDate: Tue, 27 Jan 2015 10:06:49 +000
- Synthesis, Characterisation, and Biological Evaluation of Zn(II) Complex
with Tridentate (NNO Donor) Schiff Base Ligand
Abstract: The present paper deals with the synthesis and characterization of metal complex of tridentate Schiff base ligand derived from the inserted condensation of 2-aminobenzimidazole (1H-benzimidazol-2-amine) with salicylaldehyde (2-hydroxybenzaldehyde) in a 1 : 1 molar ratio. Using this tridentate ligand, complex of Zn(II) with general formula ML has been synthesized. The synthesized complex was characterized by several techniques using molar conductance, elemental analysis, FT-IR, and mass and 1HNMR spectroscopy. The elemental analysis data suggest the stoichiometry to be 1 : 1 [M : L]. The complex is nonelectrolytic in nature as suggested by molar conductance measurements. Infrared spectral data indicate the coordination between the ligand and the central metal ion through deprotonated phenolic oxygen, imidazole nitrogen of benzimidazole ring, and azomethine nitrogen atom. Spectral studies suggest tetrahedral geometry for the complex. The pure compound, synthesized ligand, and metal complex were screened for their antimicrobial activity.
PubDate: Mon, 05 Jan 2015 07:35:07 +000
- Macrocyclic Assembly: A Dive into the Pecking Order and Applied Aspects of
Abstract: To aid in knowledge of macrocyclic complexes and biomedical scientists, we are presenting here a review article with compilation of work done so far along in relation to macrocyclic ligands and their metal complexes. The metal ion chemistry of macrocyclic ligands has now become a major subdivision of coordination chemistry. This overview focuses on developments in design, synthesis, and self-assembly of metal-based architectures and ligands related to macrocyclic chemistry.
PubDate: Thu, 18 Dec 2014 00:10:09 +000
- Synthesis and Spectroscopic and Antimicrobial Studies of Schiff Base Metal
Complexes Derived from 2-Hydroxy-3-methoxy-5-nitrobenzaldehyde
Abstract: Two new series of copper(II) and nickel(II) complexes with two new Schiff base ligands 2-((2,4-dimethylphenylimino)methyl)-6-methoxy-4-nitrophenol and 2-((3,4-difluorophenylimino)methyl)-6-methoxy-4-nitrophenol have been prepared. The Schiff base ligands were synthesized by the condensation of 2-hydroxy-3-methoxy-5-nitrobenzaldehyde with 2,4-dimethylaniline or 3,4-difluoroaniline. The ligands and their metal complexes have been characterized by IR, 1H NMR, mass and electronic spectra and TG analysis. The Schiff base ligands and their metal complexes were tested for antimicrobial activity against Gram positive bacteria Staphylococcus aureus, and Streptococcus pyogenes and Gram negative bacteria Escherichia coli, and Pseudomonas aeruginosa and fungus Candida albicans, Aspergillus niger, and Aspergillus clavatus using Broth Dilution Method.
PubDate: Mon, 17 Nov 2014 08:22:46 +000
- Antimicrobial Studies of N-Heterocyclic Carbene Silver Complexes
Containing Benzimidazol-2-ylidene Ligand
Abstract: Seven novel 4-vinylbenzyl substituted N-heterocyclic carbene (NHC) silver complexes were synthesized from different benzimidazolium salts and silver (I) oxide in dichloromethane at room temperature. These new 4-vinylbenzyl substituted NHC silver complexes were characterized by spectroscopic (NMR, IR) and elemental analysis techniques. Using the agar dilution procedure, the antimicrobial activities of these synthesized new compounds were investigated against Gram (+)/(−) bacterial and fungal strains. These NHC silver complexes showed effective activities against Escherichia coli, Pseudomonas aeruginosa (Gram-negative bacterial strains), Enterococcus faecalis, Staphylococcus aureus (Gram-positive bacterial strains), and Candida tropicalis and Candida albicans (fungal strains).
PubDate: Mon, 10 Nov 2014 14:10:15 +000
- Characterization of Complexes Synthesized Using Schiff Base Ligands and
Their Screening for Toxicity Two Fungal and One Bacterial Species on Rice
Abstract: Coordination complexes with metal ions Cu(II), Ni(II), Co(II), Fe(III), Mn(II), Cr(III), and VO(II) with six ligands formed by condensation products using azides and aldehydes or ketones are characterized. Both the ligands and the complexes synthesized are characterized by C, H, N, Cl and metal analyses, IR, UV-Vis, TGA, and magnetic susceptibility for tentative structure proposal. Several of them are screened for their toxicity (i.e., physiological activity) against fungal species Rhizoctonia solani and Acrocylindrium oryzae and a bacterium, Xanthomonas oryzae on rice pathogens. The study shows that the observed physiological activity is enhanced for the metal complexes as compared to the simple metal salts or ligands, except in the case of L3 or HAEP ligand, where the free –OH and –NH2 groups on the ligand seemed to have inhibited the activity. It is also observed that the order of activity has a dependence on the increased atomic weight of the metal ion in use. In some cases, especially the VO(II) complexes, they are found to be better than the standards in use, both for the fungicides and for the bactericide.
PubDate: Thu, 18 Sep 2014 00:00:00 +000
- Novel Low Spin Mixed Ligand Thiohydrazide Complexes of Iron(III):
Synthesis, Spectral Characterization, Molecular Modeling, and
Abstract: Mixed ligand complexes of Fe(III) with aromatic thiohydrazides of general composition [Fe(acac)(L)2] have been synthesized and characterized (acac-acetylacetonate, L = bidentate uninegative aromatic thiohydrazide ligand, for example, thiobenzhydrazide, 2-hydroxythiobenzhydrazide, furan-2-thiohydrazide, and thiophen-2-thiohydrazide). The magnetic susceptibility data and the EPR spectra of these complexes suggested the formation of rhombically distorted low spin iron center (d5) in octahedral environment, which was also supported by the UV-vis spectral data of the complexes. Biological studies of these complexes also indicated that the iron-thiohydrazido complexes have superior antibacterial properties compared to the corresponding ligands.
PubDate: Wed, 17 Sep 2014 10:56:11 +000
- Synthesis, Spectroscopic, and Electrochemical Studies on Some New
Copper(II) Complexes Containing 2-[(Z)-Phenyl (Pyridine-2-yl) Methylidene]
AminoBenzenethiol and Monodentate Ligands
Abstract: Five new mononuclear copper(II) complexes, namely, [Cu(L)(ImH)]·ClO41; [Cu(L)(Me-ImH)]·ClO42; [Cu(L)(Et-ImH)]·ClO43; [Cu(L)(2-benz-ImH)]·ClO44; [Cu(L)(benz-ImH)]·ClO45, where HL = 2-[(Z)-phenyl (pyridine-2-yl) methylidene] amino benzenethiol; ImH = Imidazole; Me-ImH = Methy-limidazole; Et-ImH = Ethyl-imidazole; 2-benz-ImH = 2-methyl-benzimidazole; benz-ImH = benz-imidazole, have been synthesized and characterized by various physicochemical and spectroscopic techniques. Magnetic moments, electronic spectra, and EPR spectra of the complexes suggested a square planar geometry around Cu(II) ion. The synthesized HL ligand behaves as monobasic tridentate Schiff base bound with the metal ion in a tridentate manner, with N2S donor sites of the pyridine-N, azomethine-N, and benzenethiol-S atoms. The redox behaviour of the copper complexes has been studied by cyclic voltammetry. Superoxide dismutase activity of these complexes has been revealed to catalyse the dismutation of superoxide () and IC50 values were evaluated and discussed.
PubDate: Thu, 19 Jun 2014 12:20:19 +000
- Complexing Behaviour and Antifungal Activity of
and Related Ligand with Metal Ions
Abstract: The coordination complexes of bivalent metal ions with N-[(1E)-1-(1H-Benzimidazol-2-yl)ethylidene]morpholine-4-carbothiohydrazide (H2bmctz, H2L-1) and N-[(1E)-1-(1H-Benzimidazol-2-yl)(phenyl)methylidene] morpholine-4-carbothiohydrazide (H2bpmctz, H2L-2) were prepared and their neutral, monoanionic, and dianionic forms of ligands of compositions [M(H2L)X2] (M=, , , , , or , X=Cl− or Br−, and H2L=H2L-1 or H2L-2), [M(HL)2]nH2O where (M=, , , , or , H2L=H2L-1 or H2L-2, and n = 0 or 2), and [MLB]nB (M=, , , , or , B=H2O, Py, or -pic, n = 0 and n = 1 if B=H2O for Ni(II) and H2L=H2L-1 or H2L-2) have been characterised by magnetic susceptibility measurements, electrical conductance values, and spectral properties. The magnetic moment value of [M(HL2)] (M=, , or ) type complexes is consistent with high spin octahedral structure while those of [M(H2L)X2] (M=, , , , or , X=Cl− or Br−) possess five coordinated trigonal bipyramidal geometry. The adduct complexes [MLB]·nB (M=, or , B=H2O, Py, or -pic) are four coordinated planar and those of and complexes [MLB], (H2L=H2L-1 or H2L-2, B=H2O, Py or -pic) are tetrahedral. These ligands have been suggested to coordinate as tridentate (N N S) donor molecule in complexes of type [M(H2L)X2], [M(HL)2], and [MLB]. The antifungal activity of ligands and some of their metal complexes were studied and it was observed that metal complexes show higher activity than free ligand.
PubDate: Tue, 22 Apr 2014 06:16:48 +000
- Kinetics and Mechanism of the Oxidation of Naphthol Green B by
Peroxydisulphate Ion in Aqueous Acidic Medium
Abstract: The kinetics of the oxidation of naphthol green B (NGB3−) by peroxydisulphate ion has been carried out in aqueous acidic medium at of 700 nm, °C, and mol dm−3 (NaCl). The reaction shows a first-order dependence on oxidant and reductant concentration, respectively. The stoichiometry of the NGB— reaction is 1 : 2. Change in hydrogen ions concentration of the reaction medium has no effect on the rate of the reaction. Added cations and anions decreased the rate of the reaction. The results of spectroscopic and kinetic investigation indicate that no intermediate complex is probably formed in the course of this reaction.
PubDate: Tue, 25 Mar 2014 14:11:15 +000
- Solution Studies on Co(II), Ni(II), Cu(II), and Zn(II) Complexes of
Hexamethylenetetramine in Aqueous and Non-Aqueous Solvents
Abstract: Potentiometric studies in aqueous medium and spectrophotometric study in non-aqueous medium were used to understand the behavior of hexamethylenetetramine (HMTA) complexes. The protometric studies of HMTA enabled us to confirm that only one basic site of this ligand is protonated in acidic medium and this ligand is decomposed in acidic medium. In aqueous medium, only hexa-aqua complexes in which HMTA is present in the second coordination sphere forming H-bonds with hydrogen atoms of coordinated and uncoordinated water molecules are obtained. In non-aqueous solvents, HMTA coordinates to metal ions displaying diversity in the structures of the resulting complexes in which HMTA can either be monodentate, bridged bidentate, tridentate, or tetradentate.
PubDate: Mon, 03 Mar 2014 08:48:36 +000
- Synthesis, Spectral, Thermal, Electrochemical, and Biocidal Activity of
Tolyl/Benzyl Dithiocarbonates of Zinc(II)
Abstract: Tolyl/benzyl dithiocarbonates of zinc(II) [(CH3C6H4 and C6H5CH2OCS2)2Zn] have been synthesized in 1 : 2 molar ratio by the reaction of zinc chloride, ZnCl2, with sodium salts of tolyl/benzyl dithiocarbonates CS2Na, in aqueous medium. These complexes were further reacted with nitrogen and phosphorous donor ligands to obtain donor stabilized complex of the type [[(CH3C6H4 and C6H5CH2)OCS2]2Zn.nL], (L = Bipy, Phen for and PPh3, Py for ). These complexes were characterised by elemental analysis, mass, IR, and NMR (1H, 13C, and 31P) spectroscopies. The thermal analysis (TGA/DTA), cyclic voltammetry, and SEM have also been done. Distorted tetrahedral and octahedral geometries around the Zn(II) metal are proposed. These complexes have depicted potential antibacterial and antifungal activity.
PubDate: Tue, 24 Dec 2013 09:30:15 +000
- Crystal Structures and Magnetic Properties of Two New Cobalt(II) Complexes
with Triazole-Substituted Nitronyl and Imino Nitroxide Radicals
Abstract: Two new cobalt(II) complexes of formula [Co(hfac)2(NITphtrz) 1 and Co(hfac)2(IMphtrz) 2] have been prepared and characterized structurally [where NITphtrz = 4,4,5,5-tetramethyl-2-(2-phenyl-1,2,3-triazole-4-yl)imidazoline-1-oxyl-3-oxide and IMphtrz = 4,4,5,5-tetramethyl-2-(2-phenyl-1,2,3-triazole-4-yl)imidazoline-1-oxyl]. All of the complexes crystallize in an isomorphous triclinic space group with the Co(II) ion octahedrally coordinated via the bidentate chelating mode. The magnetic measurements show that two complexes exhibit antiferromagnetic interactions between the metal ions and the nitroxide radicals.
PubDate: Sun, 22 Dec 2013 14:19:04 +000
- Synthesis and Characterization of the Adducts of
Bis(O-ethyldithiocarbonato)copper(II) with Substituted Pyridines
Abstract: Monomeric five coordinated adducts of bis(O-ethyldithiocarbonato)copper(II) of general formula [Cu(C2H5OCS2)2(L)], [L = 2-, 3-, 4-methylpyridines and 2-, 3-, 4-ethylpyridines] have been synthesized and characterized by elemental analysis, i.r. and electronic spectroscopy, magnetic and conductivity measurements. Analytical results show that the adducts have 1 : 1 stoichiometry. The adducts were found to be paramagnetic and their magnetic moments at room temperature lie within the 1.81–1.94 B.M. range and this indicates the presence of one unpaired electron. All the adducts have distorted square pyramidal geometry.
PubDate: Sun, 22 Dec 2013 09:28:12 +000
- Synthesis, Electrochemical, Spectroscopic, Antimicrobial, and Superoxide
Dismutase Activity of Nickel (II) Complexes with Bidentate Schiff Bases
Abstract: Five new nickel (II) complexes, namely, [Ni(L1)2](ClO4)2(1); [Ni(L2)2](ClO4)2(2); [Ni(L3)2](ClO4)2(3); [Ni(L4)2](ClO4)2(4); [Ni(L5)2](ClO4)2(5), where L1 = benzoylhydrazide; L2 = N-[(1)-1-(2-methylphenyl)ethylidene]benzohydrazide; L3=N-[(1)-1-(4-methylphenyl)ethylidene]benzohydrazide; L4=N-[(1)-1-(2-methoxyphenyl)ethylidene]benzohydrazide; L5 = N-[(1)-1-(4-methoxy-phenyl)ethylidene]benzohydrazide, have been synthesized and characterized by various physicochemical and spectroscopic techniques. The synthesized complexes are stable powders, insoluble in common organic solvents such as ethanol, benzene, carbon tetrachloride, chloroform, and diethyl ether, and are nonelectrolytes. The magnetic and spectroscopic data indicate a distorted square planar geometry for all complexes. The superoxide dismutase activity of these complexes has been measured and discussed. Antibacterial and antifungal properties of these complexes were also tested.
PubDate: Thu, 19 Dec 2013 13:46:59 +000
- Characteristic Studies of Hexamethylene Diamine Complexes
Abstract: Preparation and chemical analysis of Mn(II), Fe(III), Co(II), Ni(II), and Zn(II) complexes with Schiff base L [o-HOC6H4CH:N(CH2)6N:CHC6H4OH-o] are the main tasks of this work. The octahedral (M2L2·nH2O·X) complexes in 1 : 1 M : L ratio (X = or Ac− group, L = ligand) were prepared by involving the hydroxylic group in ortho position. All complexes were characterized on the basis of elemental analysis, UV, IR, 1H NMR, Gc/Ms, thermogravimetric analysis, magnetic measurements, molar conductance, and electrical conductivity. The obtained data indicate that all the investigated compounds behave as semiconductor materials.
PubDate: Tue, 05 Nov 2013 09:52:21 +000
- Synthesis, Characterization, and Photophysical Studies of Some Novel
Ruthenium(II) Polypyridine Complexes Derived from Benzothiazolyl
Abstract: A series of five benzothiazolylhydrazone ligands 3a–3e and their seven novel Ru(II) polypyridine complexes 4a–4d, 5a, 5d, 5e of the type [Ru(N–N)2(L)]Cl2, where (N–N)2 is 2,2′-bipyridine (bpy)2 or 1,10-phenanthroline (phen)2 and (L) is ligands 3a–3e, have been synthesized and characterized by elemental analysis, IR, 1H NMR, electronic absorption, and emission spectral studies. The interpretation of the analytical data revealed that the ligands coordinate with the metal ion in a bidentate fashion through azomethine nitrogen and phenolic oxygen to form complexes. These ligands and complexes also exhibit absorption and luminescence properties.
PubDate: Wed, 02 Oct 2013 11:39:40 +000
- Effect of Ni Doping on the Growth and Properties of Mn-L-Histidine
Hydrochloride Monohydrate Crystals
Abstract: The main focus of this work had been to grow good quality crystals from amino acids and amino acid-based materials for nonlinear optics (NLO) applications. For the first time, a series of amino acid complexes doped with transition metal ions were grown in our laboratory from aqueous solutions by slow evaporation technique. Ni(II) ion doped Manganese L-Histidine hydrochloride monohydrate (Ni(II)-MnLHICl) crystals were grown on the same lines and were characterized by powder X-ray diffraction (XRD), optical absorption, electron paramagnetic resonance, and infrared absorption studies. From Powder XRD, the unit cell lattice parameters were calculated as nm, nm and nm. From electron paramagnetic resonance (EPR) spectra, isotropic “g” factor and spin hamiltonian parameter A all were calculated as 2.0439 and , respectively. From optical absorption studies, crystal field splitting value () and the interelectron repulsion parameters B and C were calculated for Ni2+ and Mn2+ as cm−1, cm−1, cm−1 and cm−1, cm−1, cm−1, respectively. The presence of various functional groups and the modes of vibrations were confirmed by FTIR studies.
PubDate: Sun, 08 Sep 2013 17:22:50 +000
- Nickel (II) and Iron (II) Complexes with Azole Derivatives: Synthesis,
Crystal Structures and Antifungal Activities
Abstract: Two new complexes of nickel (II) with 4-amino-3, 5-bis(pyridyl)-1, 2, 4-triazole (abpt) and iron (II) with 2-(3-phenyl-1H-pyrazole-5-yl) pyridine (phpzpy) have been synthesized and characterized by elemental analysis and IR spectroscopy. The crystal structures of the complexes have been determined by single crystal X-ray diffraction techniques. In the nickel and iron complexes, the ligands are coordinated through nitrogen atoms in bidentate manner. The ligands and their respective complexes have been tested for their antifungal activity against Aspergillus niger, Aspergillus flavus, and Candida albicans. From the study, the complexes showed enhanced activities against the tested organisms compared to the ligands.
PubDate: Mon, 26 Aug 2013 16:07:34 +000
- Zn (II) and Cu (II) Halide Complexes of Poly(propylene amine) Dendrimer
Analysed by Infrared and Raman Spectroscopies
Abstract: Two nondestructive and complementary spectral methods as infrared and Raman spectroscopies have been used for characterizations of poly(propylene amine) dendrimers comprising 1,8-naphthalimide units in the dendrimer periphery and their metal complexes with Cu2+ at Zn2+ ions.
PubDate: Mon, 22 Jul 2013 09:48:06 +000
- Synthesis, Characterization, and Biological Studies of Binuclear
Copper(II) Complexes of
Abstract: Four novel binuclear copper(II) complexes [1–4] of (2E)-2-(2-hydroxy-3-methoxybenzylidene)-4N-substituted hydrazinecarbothioamides, (OH)(OCH3)C6H4CH=NNHC(S)NHR, where R = H (L1), Me (L2), Et (L3), or Ph (L4), have been synthesized and characterized. The FT-IR spectral data suggested the attachment of copper(II) ion to ligand moiety through the azomethine nitrogen, thioketonic sulphur, and phenolic-O. The spectroscopic characterization indicates the dissociation of dimeric complex into mononuclear [Cu(L)Cl] units in polar solvents like DMSO, where L is monoanionic thiosemicarbazone. The DNA binding properties of the complexes with calf thymus (CT) DNA were studied by spectroscopic titration. The complexes show binding affinity to CT DNA with binding constant () values in the order of 106 M−1. The ligands and their metal complexes were tested for antibacterial and antifungal activities by agar disc diffusion method. Except for complex 4, all complexes showed considerable activity almost equal to the activity of ciprofloxacin. These complexes did not show any effect on Gram-negative bacteria, whereas they showed moderate activity for Gram-positive strains.
PubDate: Thu, 11 Jul 2013 13:41:12 +000
- Synthesis and Characterization of Heteronuclear Copper(II)-Lanthanide(III)
Complexes of N,N′-1,3-Propylenebis(Salicylaldiminato) Where
Lanthanide(III) = Gd or Eu
Abstract: Three complexes, namely, [Cu(salbn)] (1), [Cu(salbn)Gd(NO3)3·H2O] (2), and [Cu(salbn)Eu(NO3)3·H2O] (3) where salbn = N,N′-1,3-propylenebis (salicylaldiminato) have been synthesized and characterized by elemental analyses, ICP-AES, IR, UV, NMR, MS, EDX, powder XRD, and EPR spectroscopies. The EDX results suggest the presence of two different metal ions in heteronuclear complexes (2) and (3). The ligand(salbn), complex (1), and complex (3) crystallize in triclinic system while complex (2) crystallizes in monoclinic system. The EPR studies suggest that [Cu(salbn)] complex is tetragonally coordinated monomeric copper(II) complex with unpaired electron in the orbital and spectral features that are the characteristics of axial symmetry while complex (2) in DMF solution at liquid nitrogen temperature exhibits an anisotropic broad signal around g ~ 2.03 which may suggest a weak magnetic spin-exchange interaction between Gd(III) and Cu(II) ions. The fluorescence intensity of Eu(III) decreased markedly in the complex (3).
PubDate: Tue, 28 May 2013 08:51:02 +000
- Synthesis, Spectroscopic, and Magnetic Studies of Mono- and Polynuclear
Schiff Base Metal Complexes Containing Salicylidene-Cefotaxime Ligand
Abstract: Metal complexes of a Schiff base ligand derived from cefotaxime and salicylaldehyde were prepared. The salicilydene-cefotaxime ligand (H2L) and mononuclear [M(L)] (M(II) = Co, Ni and Cu), dinuclear [Ag2(L)(OAc)2], and tetranuclear metal complexes [M4(L)(OH)6] (M(II) = Ni, Cu) were characterized on the basis of analytical, thermal, magnetic, and spectral studies (IR, UV-visible, 1H NMR, 13C NMR, and EPR). The electronic spectra of the complexes and their magnetic moments suggesttetrahedral geometry for the isolated complexes. The complexes are nonelectrolytes and insoluble in water and common organic solvents but soluble in DMSO.
PubDate: Tue, 30 Apr 2013 09:15:15 +000
- Synthesis, Characterization, and Antibacterial Activity of Co(II), Ni(II),
Cu(II), Zn(II), Cd(II), and Hg(II) Complexes of Schiff's Base Type Ligands
Containing Benzofuran Moiety
Abstract: Six new complexes of Co(II), Ni(II), Cu(II), Zn(II), Cd(II), and Hg(II) with substituted benzofuran derivatives have been synthesized and characterized by elemental analysis, magnetic moments, conductance measurements, spectral characterization, and so forth. Elemental data coincide with the general formula , where L = (E)-7-Methoxy-N1-(2,4,5-trimethoxy benzylidene) benzofuran-2-carbohydrazide (L1) or (E)-N1-(2,6-dichloro benzylidene)-7-methoxy benzofuran-2-carbohydrazide (L2), of the complexes. The ligands coordinate to the metal ions through the oxygen of the carbonyl group and the nitrogen of the hydrazine group. Electronic spectral data of the complexes suggests the probable geometry is octahedral in nature. All the complexes and ligands were screened for their antibacterial activity. Among them, Co, Ni, and Cu complexes of L2 showed good activity against all microbes.
PubDate: Wed, 24 Apr 2013 08:11:15 +000