Gholamhossein Grivani

Four new bis-chelate ML2 complexes (M = Cu2+, Ni2+, Zn2+, VO2+ and L = 1-[Furan-2-ylmethylimino)methyl]naphthalene-2-olate) with bidentate NO Schiff base ligand were synthesized and characterized by spectral and analytical techniques. The crystal structures of CuL2, NiL2, and VOL2 were determined by single crystal X-ray analysis. These complexes crystalized in the monoclinic system with the space groups of P21/n, P21/n, and C2/c, respectively. The Schiff base ligand acts as bidentate ligand and coordinates to the metal center via N and O atoms. The NiL2 and CuL2 complexes exhibit a distorted square planar coordination geometry while in the case of VOL2 the geometry is distorted square-pyramidal. In all cases, two Schiff base ligands bind to the metal centers in the trans O–M–N manner. Thermal analysis and thermal decomposition of the titled complexes were investigated. The data of TGA, XRD and SEM analyses revealed that they were converted to corresponding metal oxides in a form of nanoparticles (NiO, CuO, ZnO and V2O5). © 2018 Elsevier Ltd

By reaction of 5-(chloromethyl)salicylaldehyde with triphenylphosphine and N-methylimidazole in two separate reactions, salicylaldehydetriphenylphosphonium chloride (S2) and salicylaldehydemethylimidazolinium chloride (S3) were prepared. Reaction of 2-(aminomethyl)pyridine with these aldehydes resulted in the task-specific ionic liquid Schiff base ligands L1 and L2, respectively. Then six-coordinated vanadium(IV) Schiff base complexes of VO(acac)L1–4 were synthesized by reactions of these tridentate Schiff base ligands and VO(acac)2 in 1:1 stoichiometry. The aldehydes, ligands and VO(acac)L1–4 complexes were characterized using infrared, 1H NMR, 13C NMR, 31P NMR, UV–visible and mass spectroscopies, as well as elemental analysis. Paramagnetic property of the complexes was also studied using magnetic susceptibility measurements. The complexes were used as catalysts in epoxidation of cyclooctene and oxidation of methylphenyl sulfide and the reaction parameters were optimized. The effect of the ionic nature of the complexes was investigated in these oxidation reactions. The catalytic activity of the complexes could be varied by changing the ionic (cationic or anionic) character of VO(acac)L1–4 catalysts in which counter anion variation showed a greater effect than cationic moiety variation. Copyright © 2017 John Wiley & Sons, Ltd.

For years, Cu(iii)NHCs have been proposed as active intermediates in Cu(i)NHC catalyzed reactions, yielding the desired products by reductive elimination, but until today, no one has ever reported the characterisation of such a compound. When working on the synthesis of biomimetic transition metal (NHC) complexes and their application in homogeneous catalysis, we recently found a highly unusual reactivity for Cu(ii) acetate in the presence of a particular cyclic tetra(NHC) ligand. Therein, the formation of the first stable CuNHC compound, displaying Cu in the formal oxidation state +III, by simple disproportionation of Cu(ii) acetate in dimethyl sulfoxide (DMSO) was observed. At elevated temperatures selective mono-oxidation of the NHC ligand occurs, even under anaerobic conditions. Acetate was identified as the origin of the oxygen atom by 18O-labelling experiments. The remarkably high stability of the title compound was furthermore proven electrochemically by cyclic voltammetry. An in-depth investigation of its reactivity revealed the involvement of four additional compounds. Three of them could be isolated and characterised by 1H/13C-NMR, single crystal XRD, mass spectrometry and elemental analysis. The fourth, a Cu(i)NHC intermediate, formed by formal reductive elimination from the Cu(NHC)3+ compound, was characterised in situ by 1H/13C-NMR and computational methods. © 2018 The Royal Society of Chemistry.

This study was designed to investigate the interaction of three oxovanadium (IV) Schiff base complexes with bovine serum albumin (BSA) by means of various spectroscopic and electrochemical methods along with molecular docking study and molecular dynamics simulations. Binding constants were estimated by fluorescence and UV-Vis spectroscopy. The results indicated a good affinity of the complexes for BSA in which furyl derivative had more activity. Molecular docking study showed that these complexes have the similar binding modes and located within subdomain IB in site III of BSA. The supporting of molecular docking and molecular dynamics results by experimental data, confirms the validity of the interactions data obtained by these methods. Biological activity against cancer cell showed that furyl derivative has higher activity than other complexes. Pharmaceutical analysis also showed that, these complexes potentially can be used as anticancer agents. © 2017 Informa UK Limited, trading as Taylor & Francis Group

New centrosymmetric trinuclear zinc(II) complex {[Zn(μ-ONN)(μ2-O)(μ-OO)]2Zn} has been synthesized by the reaction of a potentially ONN tridentate Schiff base ligand, and N,N-dimethylethylendiamin, with Zn(OAc)2·2H2O in methanol, in the refluxed conditions and characterized by elemental analysis, FT-IR and UV–Vis spectroscopy. Single crystal X-ray structure analysis reveals a trinuclear complex {[Zn(μ-ONN)(μ2-O)(μ-OO)]2Zn} with zinc(II) ions connected by three different bridges, (μ-ONN) of the Schiff base ligand, μ2-O and μ-OO of the acetate. The complex is centrosymmetric, with one of the Zn atoms located at the inversion center. While the central Zn(II) ion is six-coordinated, the coordination number of the other Zn(II) ions is five. Finally, the {[Zn(μ-ONN)(μ2-O)(μ-OO)]2Zn} complex was thermally decomposed in air at 700 °C resulted in ZnO nano crystalites with the average size of 42 nm. The antibacterial activity of ligand and its zinc(II) complex were tested against gram-positive and gram-negative bacteria. The ligand showed higher activity than its zinc(II) complex. © 2017, Springer Science+Business Media, LLC.

New ionic Schiff-base ligands have been synthesized by condensation of (3-formyl-4-hydroxybenzyl)triphenylphosphonium and 3-(3-formyl-4-hydroxybenzyl)-1-methyl-1H-imidazol-3-ium chloride and hexafluorophosphate salts with N,N-dimethylethylenediamine. Treatment of the dimeric derivative [{RuCl(μ-Cl)(η6-p-cymene)}2] with two equivalents of these ligands allowed the preparation of novel mononuclear water-soluble Ru(II) complexes, which proved to be catalytically active in the transfer hydrogenation of ketones and aldehydes under aqueous conditions. © 2016 Elsevier B.V.

This paper reports preparation and characterization of Ni/NiO nanocomposite using solid-state thermal decomposition method at 400, 500 and 600 °C from bis(N-(2-hydroxyphenyl)cinnamaldimine)nickel(II). Thermogravimetric analysis of the complex revealed its thermal stability and decomposition pattern. The as-prepared Ni/NiO nanocomposites were characterized by FT-IR, XRD, SEM and XRF. The XRD results confirmed that the composites were a mixture of Ni and NiO and also show upon increasing the temperature from 400 to 600 °C in air atmosphere; the amount of metallic Ni was found to decrease due to transformation to NiO. The SEM images confirmed that the Ni/NiO nanocomposites were almost similar morphology. XRF results show that the mass ratio between Ni and NiO prepared at 400, 500 and 600 °C is decreasing in order of 10:90, 8:92 and 4:96 %, respectively. © 2016, Akadémiai Kiadó, Budapest, Hungary.

The five coordinated vanadium(IV) Schiff base complexes of VOL1 (1) and VOL2 (2), HL1 = 2-{(E)-[2-bromoethyl)imino]methyl}-2- naphthol, HL2 = 2-{(E)-[2-chloroethyl)imino]methyl}-2- naphthol, have been synthesized and they were characterized by using single-crystal X-ray crystallography, elemental analysis (CHN) and FT-IR spectroscopy. Crystal structure determination of these complexes shows that the Schiff base ligands (L1 and L2) act as bidentate ligands with two phenolato oxygen atoms and two imine nitrogen atoms in the trans geometry. The coordination geometry around the vanadium(IV) is distorted square pyramidal in which vanadium(IV) is coordinated by two nitrogen and two oxygen atoms of two independent ligands in the basal plane and by one oxygen atom in the apical position. The catalytic activity of the Schiff base complexes of 1 and 2 in the epoxidation of alkenes were investigated using different reaction parameters such as solvent effect, oxidant, alkene/oxidant ratio and the catalyst amount. The results showed that in the presence of TBHP as oxidant in 1: 4 and 1:3 ratio of the cyclooctene/oxidant ratio, high epoxide yield was obtained for 1 (76%) and 2 (80%) with TON(= mole of substrate/mole of catalyst) of 27 and 28.5, respectively, in epoxidation of cyclooctene. © 2016 Elsevier B.V.

The copper (II) Schiff base complex of [CuL2] (1), HL = 2-{(E)-[2-chloroethyl) imino]methyl}phenol, has been synthesized and characterized by elemental (CHN) analysis, UV-Vis and FT-IR spectroscopy. The molecular structure of 1 was determined by single crystal X-ray diffraction technique. The conformational analysis and molecular structures of CuL2 were investigated by means of density functional theory (DFT) calculations at B3LYP/6-311G∗level. An excellent agreement was observed between theoretical and experimental results. The Schiff base ligand of HL acts as a chelating ligand and coordinates via one nitrogen atom and one oxygen atom to the metal center. The copper (II) center is coordinated by two nitrogen atoms and two oxygen atoms from two Schiff base ligands in an approximately square planar trans-[MN2O2] coordination geometry. Thermogravimetric analysis of CuL2 showed that it was decomposed in five stages. In addition, the CuL2 complex thermally decomposed in air at 660 °C and the XRD pattern of the obtained solid showed the formation of CuO nanoparticles with an average size of 34 nm. © 2016 Elsevier B.V. All rights reserved.

The experimental and theoretical studies on asymmetrical Schiff base, salicylideneimino-ethylimino-pentan-2-one (SEIPO) were studied. The tautomerism of SEIPO was also studied by calculations using density functional theory (DFT). Two of the four tautomers were shown to coexist. Tautomerism and the effect of solvent on the tautomeric equilibria in the gas phase and in different solvents were studied. According to calculated results, L3, L4 tautomers are more stable than the L1, L2 tautomers. The 1H NMR spectra give the additional evidence for the coexistence of the tautomers keto-amine and enol-imine for SEIPO. UV-vis spectra of SEIPO were recorded in various organic solvents to check the dependence of tautomerism on solvent types. The theoretical calculations and spectroscopic results indicate that the intramolecular hydrogen bonding (IHB) strength of SEIPO is stronger than that in 4-amino-3-penten-2-one)APO(. In addition, natural atomic charges, global reactivity parameters, and HOMO-LUMO gaps have also been discussed. © 2016 Elsevier B.V. All rights reserved.

A new (μ-acetato)-bridged dinuclear copper(II) complex [Cu2(L)2(μ-OAc)2] (I) has been synthesized by the reaction of a tridentate N2O Schiff base ligand (HL) with Cu(OAC)2 in methanol at refluxed conditions and characterized by elemental analysis (CHN) and FT-IR spectroscopy. The crystal structure of I was investigated by single-crystal X-ray diffraction (CIF file CCDC no. 1013907). X-ray results showed that two OAC groups bridge the copper(II) ions in a Cu2O2 core of a binuclear complex. Each copper(II) ion adopts a distorted square-pyramidal geometry with one imine nitrogen, one amine nitrogen and one phenolato oxygen from the tridentate Schiff base ligand, completed by two acetate oxygen atoms. Finally, the complex was thermally decomposed in order to obtain CuO nano-particles. The particles were characterized by powder X-ray diffraction, which confirmed the formation of the CuO nano-particles with the average size of 24 nm. © 2015 Pleiades Publishing, Ltd.

(Graph Presented) A new copper (II) Schiff base complex, CuL1, was prepared from the reaction of asymmetrical Schiff base ligand of L1 and Cu(OAC)2 (L1 = salicylidene imino-ethylimino-pentan-2-one). The Schiff base ligand, L1, and its copper (II) complex, CuL1, have been characterized by elemental analysis (CHN) and FT-IR and UV-vis spectroscopy. In addition, 1H NMR was employed for characterization of the ligand. Thermogrametric analysis of the CuL1 reveals its thermal stability and its decomposition pattern shows that it is finally decomposed to the copper oxide (CuO). The crystal structure of CuL1 was determined by the single crystal X-ray analysis. The CuL1 complex crystallizes in the monoclinic system, with space group P21/n and distorted square planar coordination around the metal ion. The Schiff base ligand of L1 acts as a chelating ligand and coordinates via two nitrogen and two oxygen atoms to the copper (II) ion with C1 symmetry. The structure of the CuL1 complex was also studied theoretically at different levels of DFT and basis sets. According to calculated results the C-O bond length of the salicylate fragment is slightly higher than that in the acetylacetonate fragment of ligand, which could be interpreted by resonance increasing between phenyl and chelated rings in ligand in relative to the acetylacetonate fragment. © 2014 Elsevier B.V. All rights reserved.

Abstract After synthesis of an asymmetric tetradentate ONN′O′ Schiff base ligand (H2L) followed by reaction of the synthesized H2L with an equimolar mixture of methanolic solutions of the VO(acac)2, a new oxidovanadium(IV) Schiff base complex (VOL) was synthesized. The Schiff base ligand and its complex were characterized by FT-IR and UV-vis spectra and C, H, N analysis. The crystal structure of VOL was also determined by single crystal X-ray analysis. The VOL complex crystallizes in monoclinic space group Cc. The Schiff base ligand acts as a tetradentate ligand through its two iminic nitrogens and two phenolic and acetylacetonate oxygens. Thermogravimetric analysis of the VOL showed that it decomposes in two steps and converts to mixed vanadium oxides at 477 C. In addition, thermal decomposition of the VOL complex in air at 660 C leads to formation of V2O5 nanoparticles with the average size estimated from XRD 49 nm. The catalytic activity of the VOL complex was investigated in the epoxidation reaction and different reaction parameters were optimized. The results showed that the cyclic alkenes were efficiently converted to the corresponding epoxides, whereas the VOL did not appreciably convert the linear alkenes. © 2015 Gholamhossein Grivani.

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) Å, V = 1246.52(7) Å3, 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. © 2013 Springer Science+Business Media Dordrecht.

A new oxidovanadium(IV) Schiff base complex, VOL2 (1), HL = 2-{(E)-[2-(bromoethyl)imino]methyl}-6-methoxy phenol, containing ethyl bromide pendant group was synthesized by direct reaction of HL and VO(acac)2 in the ratio of 2: 1 in methanol at reflux. The Schiff base ligand and its vanadyl complex were characterized by FT-IR spectra and CHN analysis. Additionally, the Schiff base ligand has been characterized by 1H NMR spectroscopy. The crystal structure of 1 was also determined by single-crystal X-ray analysis, showing the distorted square-pyramidal N2O3 coordination around vanadium(IV). The catalytic activity of 1 was studied in the oxidative bromination of 2-nitrophenol as a model substrate, and different reaction parameters were investigated. The oxidative bromination of some organic compounds in the presence of 1 in optimal conditions showed that it was an effective and selective catalyst in those optimal conditions. Thermogravimetric analysis of 1 showed that it decomposed in two stages. 1 was thermally decomposed in air at 660 °C, and the XRD pattern of the obtained solid showed the formation of the V2O5 nanoparticles with average size of 34 nm. © 2014 Taylor & Francis.

A new bidentate ON Schiff base ligand of HL (HL = 5-nitro-2-hydroxybenzyl-2-furylmethyl) imine), was synthesized by simple condensation reaction of 5-nitro-2-hydroxybenzaldehyde and 2-furfurylamine. Then by reaction of a methanolic solutions of the HL and VO(acac)2in the ratio of 2:1, a new oxidovanadium(IV) Schiff base complex of VOL2was synthesized. The Schiff base ligand and its vanadyl Schiff base complex were characterized by FT-IR, UV-vis spectra and CHN analysis. Single crystals suitable for X-ray analysis were obtained in DMSO as a VOL2(DMSO) complex. The crystal structure of the VOL2(DMSO) was determined by the single-crystal X-ray analysis. The coordination geometry around the vanadium center can be described as a distorted octahedron formed by two phenolato oxygen and two imine nitrogen atoms of the two Schiff base ligands in the equatorial position, the oxygen atom of DMSO and the oxido ion coordinated in the axial position. Thermogravimetric analysis of the VOL2showed that the formation of mixed vanadium oxides at 450 °C. In addition, decomposition of the vanadyl Schiff base complex (VOL2) in air at 660 °C resulted in the formation of the V2O5nano particles with the average size of 52 nm. The catalytic activity of the VOL2complex was evaluated in the epoxidation of cyclooctene (90% conversion and 100% epoxide) and oxidation of methyl phenyl sulfide (100% conversion and 100% sulfoxide). © 2014 Elsevier B.V. All rights reserved.

The Nickel (II) Schiff base complex of NiL2, (L = 2-{(E)-[2-chloroethyl) imino]methylphenolate) have been synthesized and characterized by elemental (CHN) analysis, UV-vis and FT-IR spectroscopy. The molecular structure of [NiL2] was determined by single crystal X-ray diffraction technique. The Schiff base ligand HL acts as a chelating ligand and coordinates via one nitrogen atom and one oxygen atom to the metal center. The nickel (II) center is coordinated by two nitrogen and two oxygen atoms from two Schiff base ligands in an approximately square planar trans-[MN 2O2] coordination geometry. Thermogravimetric analysis of NiL2 showed that it decomposed in three stages. In addition, complex NiL2 thermally decomposed in air at 660 °C and the XRD pattern of the obtained solid showed the formation of NiO nanoparticles with an average size of 43 nm. In addition, the conformational analysis and molecular structures of NiL2 were investigated by means of density functional theory (DFT) calculations at B3LYP/6-311G* level and the calculated geometrical parameters were compared with the experimental results. © 2014 Elsevier B.V. All rights reserved.

By reaction of aldehydic polystyrene and ethylene diamine, polystyrene-imine-amine reagent was produced. Reaction of this reagent with benzaldehyde and 4-nitrobenzaldehyde resulted in polystyrene-diimines (3a and 3b). These reagents were used for the immobilization of molybdenum hexacarbonyl. The functionalized polystyrene and supported-diimine molybdenum carbonyl catalysts were characterized by FT-IR spectrum and CHN analysis. The molybdenum content of catalysts was determined by neutron activation analysis. Supported-diimine molybdenum carbonyl pre-catalysts (3aM and 3bM) were used in epoxidation of cyclooctene, and the reaction parameters such as solvent and oxidant were optimized and the epoxidation of different alkenes was investigated in optimizing these conditions. The obtained results in the presence of polymer-supported diimine molybdenum carbonyl pre-catalysts (3aM and 3bM) showed that they were very active and selective in the epoxidation of a wide range of alkenes. The reusability of the supported pre-catalysts was also studied. The results showed that they were highly reusable in epoxidation of alkenes. © 2013 Iranian Chemical Society.

A new oxidovanadium(IV) schiff base complex (1) containing an ethyl bromide pendant group was synthesized by the reaction of the related bidentate O, N-Schiff base ligand and VO(acac)2 in a 2:1 ratio in methanol, under reflux conditions. The Schiff base ligand and its vanadyl Schiff base complex were characterized by 1H NMR and FT-IR spectra, and CHN analysis. The crystal structure of 1 was also determined by single crystal X-ray analysis. The vanadium center in this structure has a distorted tetragonal pyramidal N2O3 coordination sphere. The Schiff base ligand HL acts as a bidentate ligand by coordinating via the nitrogen atom of the imine group and the oxygen atom of the phenolic group, thereby forming a six-membered chelating ring. There are some non-classical inter- and intra-molecular hydrogen bonds of the type C-Hâ̄O and C-Hâ̄Br in 1. The catalytic activity of 1 was studied for the oxidative bromination of 2-nitrophenol as a model substrate. Different reaction parameters were studied in this reaction and the oxidative bromination of some organic compounds by a catalytic amount of 1 showed that it was an effective and selective catalyst under optimal conditions. Thermogravimeric analysis of 1 showed that it decomposed in two stages. In addition, complex 1 thermally decomposed in air at 660 C and the XRD pattern of the obtained solid showed the formation of V2O5 nanoparticles with an average size of 57 nm. © 2013 Elsevier Ltd. All rights reserved.

A new oxidovanadium(IV) Schiff base complex, VOL2 (1), containing furfuryl pendant group was synthesized by the reaction of the related bidentate O, N-type Schiff base ligand and VO(acac)2 in the ratio of 2:1 in methanol in the reflux conditions. The Schiff base ligand and its vanadyl complex were characterized by 1H-NMR and FT-IR spectra and elemental analysis. The crystal structure of 1 was also determined the single-crystal X-ray analysis. It showed that the metal center located in a distorted tetragonal pyramidal (N2O3) geometry in which the two bidentate Schiff base ligands were coordinated to the vanadium(IV) ion in four equatorial positions, and one oxygen atom in its axial position. The catalytic activity of the vanadyl Schiff base complex was elucidated in the epoxidation of cyclooctene as a model substrate. Different reaction parameters were investigated in this reaction and the results showed that it was an effective and selective catalyst in these optimal conditions. Thermogravimetric analysis of 1 showed that it was decomposed in two stages by losing two methoxy groups and other organic residuals, respectively, in the temperature range of 253-532 °C. In addition, the vanadyl Schiff base complex (1) was thermally decomposed in air at 660°C and the XRD pattern of the obtained solid showed the formation of the V2O5 nano-particles with the average size of 52 nm. © 2013 Iranian Chemical Society.

Two new Schiff base compounds 2-{(E)-[2-(bromoethyl)imino]methyl}-4- bromophenol (1) and 2-{(E)-[2-(chloroethyl)imino]methyl}-4-bromophenol (2) have been synthesized and characterized by FT-IR and 1H NMR spectroscopy, elemental analysis, thermal studies and single-crystal X-ray diffraction. They crystallize in the triclinic system, space group P-1. Both Schiff base compounds 1 and 2 display a trans configuration with respect to the CN double bond. Quantum theory of atoms in molecules (QTAIM) has been also used to find intramolecular interactions and investigate their chemical nature. The results show that in both of the compounds 1 and 2, there is a hydrogen bonding between nitrogen of imine and oxygen of phenol which is considerably stronger than normal hydrogen bonds. In addition, it has been shown that these hydrogen bonds are partially covalent and partially electrostatic in nature, in contrast to normal hydrogen bonds, which are usually considered as electrostatic interactions. © 2013 Elsevier B.V. All rights reserved.

In this study four coordinated complexes of zinc(II) halides with a new symmetrical bidentate Schiff base ligand (2,5-MeO-ba)2En are synthesized and characterized. The metal to ligand ratio of the complexes is found to be 1:1 with the formula of Zn((2,5-MeO-ba)2En)X2 (X = Cl (1), Br (2), I (3)). The crystal structure of the Schiff base ligand (2,5-MeO-ba)2En is determined by X-ray crystallography from single crystal data. Also, the optimized geometries of the Schiff base ligand (2,5-MeO-ba)2En and its zinc(II) complexes are calculated using the density functional theory method (B3LYP/6-31G). The obtained structural parameters of (2,5-MeO-ba)2En are in agreement with the experimental data. © 2013 Pleiades Publishing, Ltd.

The synthesis and characterization of three zinc(II) complexes [Zn(34-MBTSC)2Cl2] (1), [Zn(34-MBTSC)2Br 2] (2), and [Zn(34-MBTSC)2I2] (3) of 3,4-dimethoxybenzaldehyde thiosemicarbazone (34-MBTSC) are reported. Elemental analysis (CHN) and spectral (FT-IR and 1H-NMR) measurements have been used to characterize the complexes. In addition, the structure of the complex 1 has been determined by X-ray diffraction methods. In these complexes, the zinc(II) ion is bonded to two thioketonic sulfur donors in η1-S bonding mode and to two halide ions in tetrahedral geometry. Supplementary materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfer, and Silicon and the Related Elements for the following free supplemental files: Additional figures. © 2013 Copyright Taylor and Francis Group, LLC.

The vanadium(IV) Schiff base complex VOL2, L = 2-{(E)-[2-chloroethyl)imino]methyl}-6-methoxy phenol, has been synthesized by the reaction of a methanolic solution of VO(acac)2 with a methanolic solution of the Schiff base ligand, and it has been characterized using single-crystal X-ray crystallography, elemental analysis (CHN) and FT-IR spectroscopy. The crystal structure determination of this complex shows a deformed tetragonal pyramidal N2O3 coordination sphere of the vanadium center. The Schiff base ligand acts as a bidentate ligand with the two phenolato oxygen atoms and the two imine nitrogen atoms in trans positions. Non-classical inter- and intra-molecular hydrogen bonds of the type CH⋯O have been found in the structure, the latter connecting the monomeric VOL 2 units. The catalytic activity of the VOL2 Schiff base complex in the epoxidation of cyclooctene was investigated using different reaction parameters, such as solvent effect, oxidant, alkene/oxidant ratio and the catalyst amount. The results showed that with a catalytic amount of the VOL2 Schiff base complex and a 1:3 ratio of the cyclooctene/TBHP, the cyclooctene was effectively and selectively converted into the corresponding epoxide with CHCl3 as the solvent. © 2012 Published by Elsevier Ltd.

Polymer-supported bis (2- hydroxylanyl) acetylacetone Schiff base ligand was prepared by reaction of bis (2- hydroxylanyl) acetylacetone with chloromethylated polystyrene in DMF. In the subsequent reaction of this polymer-supported Schiff base ligand with MoO2(acac)2 the polymer-supported bis (2- hydroxylanyl) acetylacetonato MoO2 Schiff base complex was prepared. This polymer-supported molybdenum Schiff base catalyst was highly active and selective in epoxidation of various alkenes in the presence of tert-buthyl hydroperoxide (TBHP) in CCl4. It can be recovered and reused for 8 times without any loss in its activity. © 2012 Elsevier B.V.

The zinc(II) and mercury(II) complexes [Zn((2,6-Cl-ba)2en)I 2] (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. © 2012 Elsevier Ltd. All rights reserved.

Polynuclear oxovanadium(IV) Schiff base complex [VOL2] n of bidentate NO Schiff base ligand (L = 5-bromo-2-hydroxybenzyl-2- furyl(methyl)imine) was synthesized and characterized by elemental analysis and FT-IR spectroscopy. The crystal structure of [VOL2]n has been determined by single crystal X-ray diffraction. The complex has two symmetry independent vanadium centers located on a two-fold axis. Both centers have a distorted octahedral N2O4 coordination sphere. Two Schiff base ligands act as chelating ligands and coordinate to the vanadium center each via one nitrogen and one oxygen atom. The remaining two apices of the octahedron are occupied by oxygen shared by the neighboring vanadium atoms, giving rise to 1D coordination polymer [VOL2]n with the interatomic V···V distance 3.7670(6) Å. This complex is used as a catalyst for the epoxidation of the cyclooctene. Different reaction parameters were optimized and the results showed that it can be active and selective in the optimized conditions. After thermal decomposition of the complex, the XRD pattern of the obtained solid shows the formation of the V 2O5 nano particles with the average size of 41 nm. © 2012 Elsevier B.V. All rights reserved.

In the title compound, [ZnBr2(C17H 14Cl4N2)], the ZnII ion is bonded to two bromide ions and two N atoms of the diimine ligand and displays a moderately distorted tetrahedral coordination geometry. The Schiff base ligand acts as a chelating ligand and coordinates to the ZnII atom via two N atoms. © 2012 International Union of Crystallography.

Chloromethylated polystyrene was oxidized to aldehydic polystyrene and by reaction of this aldehydic polystyrene resin with furfuryl amine and 2-(amino methyl) pyridine, imine-bounded polystyrene resins 1a and 1b were obtained. Amine-bounded polystyrene resins 1c-1f were also prepared by direct reaction of chloromethylated polystyrene and amines. These functionalized polystyrene resins were used to immobilize MoO 2Cl 2 on polystyrene. These functionalized polystyrene resins were characterized with elemental analysis (CHN) and FT-IR spectrum. Polymersupported catalysts were characterized with FT-IR and neutron activation analysis (NAA). These catalysts were used in oxidation of methyl phenyl sulfide in the presence of H 2O 2 as oxidant and the results showed that these catalysts were highly active and selective. The reusability of these heterogeneous catalysts was also investigated and the results showed that the supported MoO 2Cl 2 catalyst on polystyrene via imidazole liker was highly reusable as it was used 15 times in oxidation of methyl phenyl sulfide in the presence of environmental benign oxidant (H 2O 2) and solvent (H 2O) without any decrease in its activity. Then the catalytic activity of these supported catalysts was investigated in oxidation of some aliphatic and aromatic sulfides. Almost all of these supported molybdenum-based catalysts were highly active and selective in the conversion of these sulfides to their corresponding sulfoxides. © 2012 Iranian Chemical Society.

A new oxovanadium(IV) Schiff base complex, V IVOL 2 (1), was prepared by the reaction of a bidentate Schiff base ligand L and VO(acac) 2 (L = N-salicylidin-2-chloroethylimine). The Schiff base ligand, L, and its oxovanadium(IV) complex, 1, were characterized by the elemental analysis (CHN) and FT-IR spectroscopy. In addition, 1H-NMR was employed for characterization of the ligand. The crystal structure of 1 was determined by the single crystal X-ray analysis. The Schiff base ligand L acts as a chelating ligand and coordinates via one nitrogen and one oxygen atom to the vanadium center. The complex 1 crystallizes in the monoclinic system, with space group P2 1/n, having one symmetry-independent V 4 + ion coordinating in an approximately square pyramidal N 2O 3 geometry by two imine nitrogen, two phenolato oxygen atoms from two Schiff base ligands in a square plane and one oxygen atom in an apical position. The catalytic activity of the complex 1 was tested in the epoxidation of cyclooctene. The results showed that the complex 1 was highly active and selective catalyst in optimized conditions in the epoxidation of cyclooctene. © 2012 Elsevier B.V. All rights reserved.

The Schiff base ligand N-salicylidin-2-bromoethylimine (L) and its vanadium(IV) complex, VOL2 (1), were synthesized and characterized by using X-ray, CHN, 1H NMR and FT-IR methods. X-ray analysis shows the Schiff base ligand L acts as a bidentate (O, N) chelating ligand and coordinates via imine nitrogen and phenolato oxygen atoms to the V(IV) center. The coordination geometry around the V(IV) center in 1 is approximately square pyramidal, as indicated by the unequal metal-ligand bond distances and angles, with the basal plane formed by the N2O2 donors of the two bidentate Schiff base ligands, the two phenolato O atoms and the two imine N atoms are in the trans position. The coordination sphere of the V(IV) is completed by one oxygen atom in apical position. In the Schiff base ligand, L, there are some classical intramolecular O1-H1⋯N1 and non-classical intermolecular C9-H9b⋯O1 hydrogen bonds, while in 1, there are two non-classical intermolecular C7-H7⋯O3 and C8-H8b⋯O3 hydrogen bonds. The catalytic activity of 1 in epoxidation of cyclooctene was investigated in different conditions to obtain optimum conditions. The effects of solvent, oxidant, catalyst concentration and alkene/oxidant ratio were studied and the results showed that in CCl4 in the presence of tert-butylhydroperoxide in 1:3 alkene/oxidant ratio, high epoxide yield was obtained. The epoxidation of alkenes was also carried out in optimized conditions that high catalytic activity and selectivity were obtained. © 2011 Elsevier Ltd. All rights reserved.

Two zinc(II) complexes [ZnI 2((2,3-MeO-ba) 2en)] (1) and [ZnCl 2((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 [ZnI 2((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. Graphical Abstract: 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.[Figure not available: see fulltext.] © 2011 Springer Science+Business Media, LLC.

Three mercury(II) complexes, [Hg((23-MeO-ba)2en)X2] (X = I (1), Br (2) and Cl(3)), and the ligand (23-MeO-ba)2en ((23-MeO-ba)2en = N,N′-bis(2,3-dimethoxybenzylidene)-1,2- diaminoethane) have been synthesized and characterized by elemental analyses, FT-IR and 1H NMR spectroscopy. The crystal and molecular structures of 1 and 2 were determined by X-ray crystallography from single-crystal data. The metal-to-ligand ratio was found to be 1:1. The mercury(II) center in 1 and 2 has a distorted tetrahedral geometry with HgN2I2 and HgN2Br2 chromophores, respectively. The Schiff base ligand (23-MeO-ba)2en acts as a chelating ligand, coordinating via the two nitrogen atoms to the mercury(II) center, and it adopts an E,E conformation. The coordination sphere of the mercury(II) center in 1 and 2 is completed by the two I and Br atoms, respectively. In complex 1 an inter-molecular non-classical hydrogen bond of the type C-H⋯O was found, while in complex 2 inter- and intra-molecular non-classical hydrogen bonds of the type C-H⋯X (X = O and Br) were found. The 1H NMR spectra of the complexes exhibit downfield as well as upfield shifts of the free ligand resonances, reflecting changes in the ligand's geometry during its coordination. © 2011 Elsevier Ltd. All rights reserved.

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. © 2011 Pleiades Publishing, Ltd.

Schiff-base compound (E)-4-dimethamino[(1-phenylethyl)iminomethyl]benzyne was synthesized and characterized by elemental analyses (CHN), FT-IR and 1H-NMR spectroscopic techniques and thermogravimetric analyses (TG). Crystal structure of the title compound was obtained by single crystal X-ray diffraction. The title compound crystallizes in the monoclinic space group P21 with unit cell parameters: a = 8.5283(2), b = 6.0699(2), c = 13.6997(4) Å, β = 91.471(2)°, V = 708.94(4) Å3 and Z = 2. © 2011 Springer Science+Business Media, LLC.

Cobalt(III) complex [CoL3], where L=(5-bromo-2-hydroxybenzyl-2- furylmethyl)imine, has been synthesized by reacting cobalt(II) nitrate with L. The complex has been characterized by elemental analysis and FT-IR spectroscopy. The crystal structure of [CoL3] was determined by X-ray crystallography from single crystal data. It crystallizes in the triclinic space group P1̄ with unit cell parameters:a=9.6644(10) Å,b=11.5657(11) Å,c=16.5809(17) Å,α=102.833(4)°,β=102.999(3)°, γ=105.480(3)°,V=1659.9(3) Å3andZ=2. Thermal decomposition of [CoL3] was studied by thermogravimetry in order to evaluate its thermal stability and thermal decomposition pathways. © 2011 SIOC, CAS, Shanghai & WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

New dinuclear copper(II)-azido complex [Cu2((3,4-MeO-Ba) 2En)2(μ1,1-N3)2(N 3)2] (I) ((3,4-MeO-Ba)2En = N,N′-bis(3,4-dimethoxybenzylidene)-1,2-diaminoethane) has been synthesized and characterized by elemental analyses, FT-IR spectroscopy, and X-ray single-crystal diffraction. Complex I consists of a dinuclear unit that represents a new example of a copper(II)-azido compound and the Cu2+ ions are bridged by two azido ions in a double end-on fashion, consisting of two terminally bonded azido ligands. The Schiff base ligand (3,4-MeO-Ba) 2En is chelated by two imino nitrogen atoms. © 2011 Pleiades Publishing, Ltd.

New asymmetric bidentate Schiff-base ligand (5-bromo-2-hydroxybenzyl-2- furylmethyl)imine, (HL), and its nickel(II) and copper(II) complexes with the general composition ML2 [M = Ni (1) and Cu (2)], were prepared. The ligand and the metal complexes were characterized by elemental analysis, FT-IR, and UV-Vis spectroscopy. In addition, 1H-NMR and X-ray powder diffraction (XRD) were employed for characterization of ligand and metal complexes, respectively. Thermogravimetric analysis (TGA) of the ligand and metal complexes revealed the thermal stability and decomposition pattern of the species. © 2010 Akadémiai Kiadó, Budapest, Hungary.

Two thiosemicarbazones, (E)-2-(2,4-dimethoxybenzylidene)thiosemicarbazone (24-MBTSC (1)) and (E)-2-(2,5-dimethoxybenzylidene)thiosemicarbazone (25-MBTSC (2)), derived from 2,4-dimethoxybenzaldehyde and 2,5-dimethoxybenzaldehyde, respectively, with thiosemicarbazide have been synthesized and their structures were characterized by elemental analyses, FT-IR, 1H NMR spectroscopy, and X-ray single-crystal diffraction analysis. Molecular orbital calculations have been carried out for 1 and 2 by using an ab initio method (HF) and also density functional method (B3LYP) at 6-31G basis set. Compound 1 crystallizes in the monoclinic system, space group P21/c, with a = 8.1342(5) Å, b = 18.1406(10) Å, c = 8.2847(6) Å, β = 109.7258(17)°, V = 1150.75(12) Å3, and Z = 4, whereas compound 2 crystallizes in the orthorhombic system, space group Pbca, with a = 11.0868(6) Å, b = 13.1332(6) Å, c = 15.9006(8) Å, V = 2315.2(2) Å3, and Z = 8. The compounds 1 and 2 displays a trans-configuration about the C=N double bond. © 2010 Springer Science+Business Media, LLC.

In this study two zinc(II) halide complexes with the Schiff-base ligand (3,4-MeO-ba)2en [N,N′-bis(3,4-dimethoxybenzylidene)ethane-1,2- diamine] have been synthesized and characterized by elemental analyses (CHN), single-crystal X-ray diffraction, Fourier-transform infrared (FT-IR), and 1H nuclear magnetic resonance (NMR) spectroscopy. The metal-to-ligand ratio was found to be 1:1 within the formula ZnX2((3,4-MeO-ba) 2en) (X = Br, I). Crystal structure analysis reveals that the coordination geometry around the zinc(II) ions in the two isotypic complexes is distorted tetrahedral. The Schiff-base ligand (3,4-MeO-ba)2en acts as a chelating ligand and coordinates via two N atoms to the metal center and adopts an (E,E) conformation. The coordination spheres of the metal atoms are completed by the two halide atoms, which are also involved in weak non-classical hydrogen-bonding interactions of the type C-H•••X-Zn. Graphical abstract: [Figure not available: see fulltext.] © 2010 Springer-Verlag.

Polymer-bound Schiff base ligand 2 was prepared by oxidation of chloromethylated polystyrene to aldehydic polystyrene 1 and then reaction with ethylene diamine. The functionalized polystyrene 2 was used to immobilize Mo(CO)6 and polymer-bound molybdenum carbonyl Schiff base catalyst 3 was produced. This supported catalyst shows high activity in epoxidation of various alkenes in the presence of tert-butylhydroperoxide (TBHP). The supported molybdenum catalyst can be recovered and reused for eight times without loss in its activity. © 2007.