Characterized By Elemental Analysis Research Articles

A New Copper(I) Coordination Polymer with N2-Donor Schiff Base and Its Use as Precursor for CuO Nanoparticle: Spectroscopic, Thermal and Structural Studies

A new copper(I) coordination polymer, [Cu((3,4-MeO-ba)2bn)I]n (1), using a bridging Schiff base ligand, N,N′-bis(3,4-dimethoxybenzylidene)butane-1,4-diamine, (3,4-MeO-ba)2bn, containing a flexible spacer (=N–CH2–CH2–CH2–CH2–N=) has been synthesized and characterized by elemental analyses (CHN) and FTIR spectroscopy, thermal analysis and powder X-ray structure analysis. In 1, Cu(I) ions are bridged by Schiff base ligands and iodine atoms forming 1D-chain. The thermal stability of 1 was studied by thermal gravimetric and differential thermal analyses. 1 is used to prepare CuO nanoparticles via solid state thermal decomposition in air and nanoparticles thus formed are characterized by scanning electron microscopy, transmission electron microscopy and powder X-ray diffraction techniques.

A study on Structural Aspects and Biological Activity of (E)-N'- [2-Hydroxybenzylidene]benzohydrazide and its Metal Complexes

The spectroanalytical studies of VO(II), Mn(II),Co(II),Ni(II) and Cu(II) complexes with the title compound (E)-N'-(2-Hydroxybenzylidene)benzohydrazide, as wellas antifungal and antibacterial activity of Cu(II)-HBBH complex were carried out. The complexes were characterizedby elemental analysis, IR,NMR,mass,ESR and TGA & DTA. The mode of bonding in these complexes has been suggested on the basis of analytical and spectroscopic data. The ligand coordinates to the central metal ion through oxygen of enolic form of carboxy hydrazone, phenolic oxygen and azomethine nitrogen atoms in VO(II), Mn(II), and Cu(II) complexes through the dissociation of two protons. While in Co(II) and Ni(II) complexes the dissociation of only phenolic proton is observed and hence the donor sites are oxygen of phenolic group, amide carbonyl oxygen and imine nitrogen . The Cu(II) complex exhibits lethal effect on gram negative bacteria Escherichia coli and fungal strain Candida albicans. It has also been observed that concentration of compounds play a vital role in the degree of inhibition.

One-dimensional mercury(II) coordination polymers with a flexible bidentate Schiff base ligand (Me2N-Ba)2Bn: Synthesis, characterization, and crystal structures

Three one-dimensional mercury(II) complexes, [Hg2(μN,N-((Me2N-Ba)2Bn)(μ-X)2X2]n, where X = Cl (I), Br (II), and I (III), (Me2N-Ba)2Bn = N,N′-bis(dimethylaminobenzylidene)butane-1,4-diamine, involving a bidentate Schiff base with a flexible spacer (=N-C-C-C-C-N=) were prepared under mild condition and characterized by elemental analyses (CHN), FT-IR, 1H & 13C-NMR spectroscopy. The crystal structure of II has been determined by X-ray single-crystal diffraction. Each Hg(II) center adopts a distorted [HgNBr3] tetrahedron environment arising from two crystallographically equivalent (Me2N-Ba)2Bn Schiff base ligands. Each of ligands acts as N2-bis-chelating ligand with the nitrogen atoms of two imine functions in anti-form leading to the dinuclear [Hg2(μN,N-(Me2N-Ba)2Bn)Br2] groups. Such dinuclear [Hg2(μN,N-((Me2Nvg-Ba)2Bn)Br2] groups are bridged two iodine anions (μ-Br)2 to form a neutral 1D-chain mercury (II) coordination polymer.

Synthesis and Characterization of Two New Oxo-centered Trinuclear Complexes of Manganese and Iron

Two new oxo-centered trinuclear complexes, one of them a mixed-valence complex (Mn2MnO(CCl3CO2)6(Py)3) (1) and the other, mixed-metal complex of (Fe2MnO(CCl3CO2)6(H2O)3).NO3 (2) were synthesized by the direct reaction between metal nitrates and trichloroacetic acid. These complexes were characterized by elemental analyses (CHN), atomic absorption spectroscopy and spectral (IR, electronic) studies. These are new types of oxo-bridged mixed-metal complexes in which the carboxylate ligand is trichloroacetic acid. The UV spectra of the complexes exhibited strong bands in the region 213 and 257 nm which are related to the (π → π*) and (n → π*) transitions of the pyridine and H2O ligands, respectively. The IR spectra of these compounds showed two strong stretching vibrations bands, indicating a bridging coordination mode of the carboxylic group of the ligand in the complexes.

Synthesis, characterization, crystal structure and theoretical studies of new chiral Schiff base (E)-4-hydroxy[(1-phenylethyl)iminomethyl]benzyne

New chiral Schiff-base (E)-4-hydroxy[(1-phenylethyl)iminomethyl]benzyne (1) was synthesized through the condensation of 4-hydroxybenzaldehyde and 1-phenylethylamine in methanol at ambient temperature and characterized by elemental analyses (CHN), FT-IR, and 1H NMR spectroscopy. The crystal structure of the title compound was determined from single-crystal X-ray diffraction study. The title compound crystallizes in the orthorhombic space group P212121 with unit cell parameters: a = 5.9332(2), b = 10.0198(3), c = 20.9678(6) Ǻ, V = 1246.52(7) Ǻ3, and Z = 4. The molecular geometry of the title compound has been calculated using the density functional method (B3LYP) with 6-31G basis set and compared with the experimental data. Calculated results show that density functional theory can well reproduce the structure of the title compound. In the gas phase, the two conformers (cis and trans) for the title compound were found, with the trans isomer being the most stable one.

Co(III), Ni(II), and Cu(II) complexes of bidentate N,O-donor Schiff base ligand derived from 4-methoxy-2-nitroaniline and salicylaldehyde

Asymmetric bidentate Schiff base ligand (HL) and its cobalt(III), nickel(II), and copper(II) complexes have been synthesized (where L = 2-[(4-methoxy-2-nitrophenyl)iminomethyl]phenol). The ligand and its metal complexes have been characterized by elemental analyses (CHN) and FTIR spectroscopy. Thermogravimetric analyses of the compounds reveal their thermal stabilities along with their thermal decomposition pattern. In addition, the complexes have been used for the preparation of corresponding metal oxide nanoparticles by controlled aerobic thermal decomposed at 500 °C. The FTIR pattern of the obtained solids receals the formation of the metal oxides nanoparticles.

Characterization, and crystal structure of thiophenyl-2-methylidene-2-aminophenol

The Schiff base thiophenyl-2-methylidene-2-aminophenol (ImineOH) is obtained from a stoichiometric mixture of 2-thiophenecarboxaldehyde and 2-aminophenol in ethanol under reflux at 90°C. Its crystal structure is determined by single crystal X-ray diffraction. ImineOH packs in an orthorhombic unit cell in the Pbca space group with the unit cell parameters a = 16.942(4) A, b = 13.4395(11) A, and c = 17.5857(12) A, V = 4004.1(10) A3, Z = 16. Strong hydrogen bonds are present in the ImineOH structure. Apart from the X-ray study, ImineOH was characterized by elemental analysis (CHN-S) and FT-IR (4000 cm−1 to 400 cm−1), UV-Vis and 13C, 1H, and 15N NMR spectroscopic measurements.

Energy Transfer Processes in Tb(III)-Dibenzoylmethanate Complexes with Phosphine Oxide Ligands

The Tb3+-β-diketonate complexes [Tb(DBM)3L], [Tb(DBM)2(NO3)L2] and [Tb(DBM)(NO3)2(HMPA)2] (DBM = dibenzoylmethanate; L: TPPO = triphenylphosphine oxide or HMPA = hexamethylphosphine oxide) were prepared and characterized by elemental analysis (CHN), complexometric titration with EDTA and Fourier transform infrared (FTIR) spectroscopy, and the photoluminescence properties evaluated. The triplet state energies of the coordinated DBM ligands were determined using time-resolved phosphorescence spectra of analogous Gd3+ complexes. The results show that the energies increase along with the number of coordinated nitrate anions replacing the DBM ligand in the complexes. The luminescence spectra and emission lifetime measurements revealed that the ligand-to-metal energy transfer efficiency follows the same tendency. Unlike the tris-DBM complexes, bis- and mono-DBM presented high luminescence, and may act as promising candidates for preparation of the emitting layer of light converting molecular devices (LCMDs).

DNA Interaction Studies of a Cobalt(II) Mixed-Ligand Complex Containing Two Intercalating Ligands: 4,7-Dimethyl-1, 10-Phenanthroline and Dipyrido[3,2-a:2′,3′-c]phenazine

A new cobalt(II) complex [Co(dppz)2(4,7-dmp)]2+ (4,7-dmp = 4,7-dimethyl-1,10-phenanthrolline) and dppz = dipyrido[3,2-a:2′-3′-c]phenazine has been synthesized and characterized by elemental analysis (CHN), FT-IR, and UV-visible (UV-Vis) spectroscopic techniques. The DNA-binding property of the complex has been investigated employing absorption spectroscopy, fluorescence spectroscopy, circular dichroism, and viscosity measurements. The experimental results show that the complex can bind to DNA in an intercalation mode. In comparison with previous study, the DNA-binding affinity of [Co(dppz)2(4,7-dmp)]2+ (Kb=1.1·106 M−1) is smaller than that of complex [Co(dppz)2(2,9-dmp)]2+ (Kb=2.5·106 M−1).

Synthesis, spectral characterization, and crystal structure of mononuclear mercury(II) complex [Hg((3,4-MeO-Bza)2En)I2

Mercury(II) complex, [Hg((3,4-MeO-Bza)2En)I2] (I), where (3,4-MeO-Bza)2En = N,N′-bis(3,4-dimethoxybenzaldehyde)ethylenediimine, has been synthesized from the reaction of HgI2 with (3,4-MeO-Bza)2En in methanol as solvent at 50°C. It was characterized by elemental analysis (CHN), 1H-NMR spectroscopy and confirmed by single-crystal X-ray diffraction analysis. The complex I crystallizes in the monoclinic system, with space group P21/c, having one symmetry-independent Hg2+ ion coordinated in a distorted tetrahedral geometry by two N atoms of the Schiff base ligand and by two I atoms. The Schiff base ligand (3,4-MeO-Bza)2En acts as a chelating ligand and coordinates via two N atoms to the mercury center. It adopts an (E, E) conformation.

Rice Husk: Raw Material in the Catalyst Preparation for Advanced Oxidative Processes Applied in the Industrial Effluent Treatment and from Acid Drainage of a Mine

Application of an agricultural residue (rice husk, RH) as a raw material for catalyst support for advanced oxidative processes (AOPs) was evaluated. The supported catalyst was produced by the calcination of TiCl4 impregnated in RH, thereby providing a composite TiO2/Si-C, which was characterized by elemental analysis (CHN), scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM–EDX), X-ray photoelectron spectroscopy (XPS), UV/VIS diffuse reflectance spectroscopic (DRS), diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), atomic force microscopy (AFM), SEM, and nitrogen adsorption–desorption isotherms (BET and BJH). Catalytic photodecomposition of methylene blue (MB), naphthalene, phenol, and abamectin and acid drainage of a mine by a titania-based catalyst composite were investigated. For comparative purposes, a commercial photocatalyst (TiO2) was also employed. Photocatalytic degradation of MB, phenol, naphthalene, abamectin, and from coal mining effluent ranged from 8 to 93 % of the initial concentration. Performances of both catalysts were comparable. Additionally, in these evaluated systems, the toxicity of the effluent decreased after photocatalysis, either for Daphnia magna or for Scenedesmus subspicatus (employed as bioindicators).

Polyfluorinated–zinc(II)phthalocyanine complex immobilized on silica: A novel, highly selective and recyclable inorganic–organic hybrid catalyst for the synthesis of biologically important 1,5-benzodiazepines

A novel, efficient and recyclable catalyst was prepared by covalent grafting of polyfluorinated–zinc(II)phthalocyanine complex onto functionalized silica gel. The activity of the catalyst was investigated for the solvent-free synthesis of 1,5-benzodiazepines at room temperature. The immobilized catalyst was characterized by elemental analysis (CHN), diffuse reflectance UV–Vis spectroscopy, solid-state 13C CPMAS and 29Si CPMAS NMR spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), BET surface area analysis, energy dispersive X-ray fluorescence (ED-XRF), Fourier transform Infrared (FT-IR) and atomic absorption spectroscopy (AAS) techniques. Short reaction time, mild reaction conditions, high turnover numbers, and easy recovery and reusability of the catalyst make this method a novel, economic and waste-free chemical process for the synthesis of biologically important 1,5-benzodiazepines.

SYNTHESIS AND CHARACTERIZATION OF NANO COMPOSITES HAVING A CATALYTIC ACTIVITIES USING MICROWAVE TECHNIQUES

A new cobalt(II) 4-hydroxobenzoates, [Co 2 (C 7 H 5 O 3 ) 2 (NO 3 ) 2 (H 2 O) 4 ]2H 2 O was synthesized as binuclear complex and characterized by elemental analyses (CHN), spectroscopic (infrared, electronic, x-ray powder diffraction, scanning electron microscopy SEM,) studies and magnetic susceptibility measurements as well as thermal analysis. This complex is a new type of 4-hydroxybenzoate bridged metal complex in which the carboxylate ligand is p -hydroxobenzoic acid. Bridging coordination modes for the carboxylates were indicated by the presence of (ν asym – ν sym ) vibrations in the infrared spectra nearly the same as observed for ionic compounds. The magnetic moment value of cobalt(II) 4–hydroxybenzoate determined in at 300 K is 4.45 BM which refer to octahedral geometry. Thermo gravimetric analysis of the hydrated water molecules shows that the first degradation step is associated with the release of water molecules followed by the decomposition of the 4-hydroxobenzoate, nitrato, and coordinated water molecules. According to Horowitz-Metzger (HM) and Coats-Redfern methods, the kinetic parameters for the non-isothermal degradation of this complex were calculated using thermogravimetric data.

Zinc(II) and mercury(II) complexes [Zn((2,6-Cl-ba)2en)I2] and [Hg((2,6-Cl-ba)2en)Br2] with the bidentate Schiff base ligand (2,6-Cl-ba)2en: Synthesis, characterization and crystal structures

The zinc(II) and mercury(II) complexes [Zn((2,6-Cl-ba)2en)I2] (1) and [Hg((2,6-Cl-ba)2en)Br2] (2) were prepared from the reaction of zinc(II) iodide and mercury(II) bromide with the bidentate Schiff base ligand (2,6-Cl-ba)2en, having the systematic name [N,N′-bis(2,6-dichlorobenzylidene)ethane-1,2-diamine]. The two complexes were characterized by elemental analysis (CHN), FT-IR spectroscopy and X-ray single-crystal diffraction. The crystal structure analysis revealed that the coordination geometry around the metal ions in the two complexes is distorted tetrahedral. The Schiff base ligand (2,6-Cl-ba)2en acts as a chelating ligand and coordinates via two nitrogen atoms to the metal centers.

Silica-supported molybdenum complex: A novel, selective and reusable organic–inorganic hybrid catalyst for eco-friendly oxidation of sulfides and olefins

A novel, highly efficient and reusable molybdenum based catalyst has been synthesized by covalent grafting of 2,6-diacetylpyridine-monosalicyloylhydrazone onto functionalized silica followed by complexation with MoO2(acac)2, and the resulting organic–inorganic hybrid material was found to be highly effective catalyst for oxidation of various sulfides and olefins to their corresponding sulfoxides/sulfones and epoxides, respectively. The catalyst was characterized by elemental analysis (CHN), diffuse reflectance UV–Vis, 13C CPMAS NMR spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM) and BET surface area analysis, energy dispersive X-ray fluorescence (ED-XRF), Fourier-transform infrared (FT-IR) and atomic absorption spectroscopy (AAS). Mild reaction conditions, high turnover frequency, high selectivity, easy recovery and reusability of the catalyst render the present protocol very useful to address the industrial needs and environmental concerns.

Manganese phthalocyanine immobilized on silica gel: Efficient and recyclable catalyst for single-step oxidative esterification of aldehydes with alcohols

The functionalization of silica gel was carried out using 3-aminopropyltriethoxysilane as a reactive surface modifier followed by covalent grafting of novel tetrakis-(2-methoxy-4-formylphenoxy)phthalocyaninato manganese(III) acetate complex. The resulting inorganic–organic hybrid material was found to be a highly selective and recyclable catalyst for the single-step synthesis of esters. The catalyst was characterized by elemental analysis (CHN), diffuse reflectance UV–visible, 13C CPMAS and 29Si CPMAS NMR spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), BET surface area analysis, energy dispersive X-ray fluorescence (ED-XRF), Fourier-transform infrared (FT-IR) and atomic absorption spectroscopy (AAS) techniques, which demonstrates the covalent grafting of the complex onto functionalized silica gel. The catalytic performance of the novel inorganic–organic hybrid catalyst was evaluated in the direct oxidative esterification of aldehydes with alcohols, at ambient temperature, using hydrogen peroxide as an environment friendly oxidant. The hybrid catalyst presented up to 100% of substrate conversion with high turn-over numbers (TONs), up to 100% of selectivity toward the ester product, and can be recovered and reused for multiple cycles without appreciable loss in its catalytic activity.

Synthesis, characterization and interaction studies of copper based drug with Human Serum Albumin (HSA): Spectroscopic and molecular docking investigations

A new water soluble copper(II) complex, [Cu(glygly)(ssz)(H2O)]⋅6H2O, 1 derived from dipeptide (glycyl glycine anion) and sulfasalazine was synthesized and characterized by elemental analysis (CHN), molar conductance measurements and spectroscopic methods (IR, UV–vis, ESI-MS). The complex 1 is non-ionic in nature and possess octahedral geometry around Cu(II) metal ion. The interaction of complex 1 with Human Serum Albumin (HSA) was investigated under physiological condition in Tris–HCl buffer solution at pH 7.4 by means of various spectroscopic methods (fluorescence, CD and FTIR) and molecular docking technique. The results of fluorescence titration revealed that the complex 1 strongly quench the intrinsic fluorescence of HSA through a static quenching procedure. Binding constants (Kb) and the number of binding sites (n≈1) were calculated using modified Stern–Volmer equations. The thermodynamic parameters ΔG at different temperatures were calculated subsequently the value of ΔH and ΔS was also calculated which revealed that the hydrophobic and hydrogen bonding interactions play a major role in HSA–complex 1 association. The distance r between donor (HSA) and acceptor (complex 1) was obtained according to fluorescence resonance energy transfer and the alterations of HSA secondary structure induced by complex 1 were confirmed by FT-IR and CD measurements.

Synthesis, spectroscopic characterization and antibacterial activities of three Schiff bases derived from dehydroacetic acid with various substituted anilines

Objective: Aim and rationale of this study was to synthesize and characterize Schiff bases derived from dehydroacetic acid with various substituted anilines due to their potential antibacterial activities. Methods: Schiff bases like C15H15NO4 (HL1), C14H11NO3Cl2 (HL2) and C16H17NO3 (HL3) were synthesized in good yields by the reaction with dehydroacetic acid (DHA) with a number of substituted anilines using the standard methods used in organic synthesis. Their antibacterial activities were investigated against four bacteria, two G (+) i.e. Staphylococcus aureus, Bacillus subtilis and two G (-) bacterial strains i.e. Escherichia coli and Pseudomonas aureginosa by the agar well diffusion method. Synthesized products were characterized by elemental analysis (CHNS), FTIR, 1 H NMR and 13 C NMR spectroscopy. Results: The 1H NMR data revealed a strong intramolecular H-bonding between the azomethinic nitrogen and the alcoholic proton of pyran ring. Schiff base (HL2) showed better antibacterial activity when compared with other Schiff bases (HL1 and HL3) against the studied microbes. Conclusion: These newly reported Schiff bases have potential antibacterial activities against four strains of bacteria like Staphylococcus aureus, Bacillus subtilis, Escherichia coli and Pseudomonas aureginosa.

Synthesis, Spectroscopic and Thermal Studies of Zinc(II) Complexes with the Symmetrical Bidentate Schiff-Base Ligand (2,3-MeO-ba)2en: Crystal Structure of Zn((2,3-MeO-ba)2en)I2

Two zinc(II) complexes [ZnI2((2,3-MeO-ba)2en)] (1) and [ZnCl2((2,3-MeO-ba)2en)] (2), with the symmetrical bidentate Schiff-base ligand (2,3-MeO-ba)2en [N,N′-bis(2,3-dimethoxybenzylidene)-1,2-diaminoethane] have been synthesized and characterized by elemental analyses (CHN), FT-IR and 1H-NMR spectroscopy. The thermal behaviors of these complexes were studied using thermogravimetry in order to evaluate their thermal stability and thermal decomposition pathways. The crystal structure of [ZnI2((2,3-MeO-ba)2en)] (1) was determined from single-crystal X-ray diffraction. The coordination polyhedron about the zinc(II) center in the complex 1 is best described as a distorted tetrahedron. Zinc(II) complexes [ZnX2((2,3-MeO-ba)2en)] (X = I (1) and Cl (2)) have been synthesized and characterized by elemental analyses (CHN), FT-IR and 1H-NMR spectroscopy. The crystal structure of 1 was determined from single-crystal X-ray diffraction. The coordination polyhedron about the zinc(II) center in the complex 1 is best described as a distorted tetrahedron.

Synthesis, spectral and thermal studies of zinc(II) and mercury(II) complexes with bidentate Schiff-base ligand (234-MeO-Ba)2En: the crystal structure of Zn(234-MeO-Ba)2En)I2

New Symmetric bidentate Schiff-base ligands N,N′-bis(2,3,4-trimethoxybenzylidene)-1,2-di-aminoethane, (234-MeO-Ba)2En, and its corresponding zinc(II) and mercury(II) complexes, Zn((234-MeO-Ba)2En)I2 (I), Hg((234-MeO-Ba)2En)Cl2 (II) have been synthesized and characterized by elemental analyses (CHN), FT-IR and 1H NMR spectroscopy. The thermal behaviors of complexes were study using thermogravimetry in order to evaluate their thermal stability and thermal decomposition pathways. The crystal structure of I was determined from single-crystal X-ray diffraction. The coordination polyhedron about the zinc(II) center in complex I is best described as a distorted tetrahedron.