Synthesis and characterization of a new vic-dioxime derivative of chitosan and its transition metal complexes

In this study, a new chitosan derivative including vic-dioxime was synthesized by adding anti-monochloroglyoxime to chitosan (CS) at heterogeneous medium. The vic-dioxime-chitosan (v-DOCS) was characterized by elemental analysis (C, H, N), FT-IR and 13C CP-MAS NMR spectroscopy. The degree of substitution (DS) of v-DOCS was evaluated by 13C CP-MAS NMR spectroscopy and found to be 13.57%. As a result of the solubility test, unlike chitosan, v-DOCS were not dissolved in the aqueous solution of acetic acid. Metal complexes of v-DOCS with Co (II) and Cu (II) were synthesized and characterized by FT-IR and atomic absorption spectroscopy (AAS). Surface characterizations of CS, v-DOCS and v-DOCS-Copper (II) were performed by scanning electron microscope (SEM). Thermal behaviors of the synthesized compounds were investigated by TG-DTA analysis. © 2007 Elsevier Ltd. All rights reserved.Çukurova ÜniversitesiThe authors thank the Çukurova University for financial support (Project No. FEF2006D-14). Also thanks the METU-Central Laboratory. CP–MAS 13 C NMR. Grateful for SEM images by M. Kemal SANGÜN (Mustafa Kemal University)

Synthesis, characterization and thermal poroperties of oligo-N,N'-bis (2,4-dihydroxybenzylidene) ethylenediamine and its cobalt (II) and manganese (II) complexes

In this study, the new oligomer Schiff base oligo-N,N'-bis (2,4-dihydroxybenzylidene) ethylenediamine (O-DHBEDA), with a double azomethine group, was synthesized by oxidative polycondensation (OP) of N,N'-bis (2,4-dihydroxybenzylidene) ethylenediamine (DHBEDA) with NaOCl as an oxidant in an aqueous alkaline medium at 90°C. About 69.3% DHBEDA was converted to O-DHBEDA. The structures of the products were studied by UV-Vis, FT-IR, 1H-NMR, 13C-NMR and elemental analysis. According to gel-permeation chromatography (GPC) analysis of O-DHBEDA, the number-average molecular weight (M n), weight-average molecular weight (M w) and PDI values were found to be 5255 g/mol, 9116 g/mol and 1.73, respectively. During the polycondensation reaction, a part of the azomethine (-CH=N-) groups oxidized to aldehyde (CHO) groups (approx. 4%). Oligomer-metal complexes of oligo-N,N'-bis (2,4-dihydroxybenzylidene) ethylenediamine (O-DHBEDA) with Co (II) and Mn (II) were synthesized and characterized by FT-IR, UV-Vis, TG-DTA and atomic absorption spectroscopy (AAS). TG/DTA analyses were shown to be stable of O-DHBEDA against thermo-oxidative decomposition. The residue values of DHBEDA, O-DHBEDA, O-DHBEDA-Co and O-DHBEDA-Mn were found to be 0%, 7.1%, 14% and 13.4%, respectively, at 1000°C. © 2008 Koninklijke Brill NV.106 T 365The authors thank The Scientific and Technological Research Council (Tübitak) for financial support (Project Number 106 T 365). Also thanks the METU-Central Lab. for 1H and 13C-NMR and TG/DTA analyses

Synthesis and thermal properties of a novel schiff base oligomer with a double azomethine group and its Co(II) and Mn(II) complexes

Schiff base oligomer of N,N'-bis (2,4-dihydroxybenzylidene) 1,2-phenylenediamine (DHBPDA), with a double azomethine group, was synthesized from the oxidative polycondensation (OP) reaction with NaOCl as an oxidant in an aqueous alkaline medium at 90C. About 75% DHBPDA was converted to O-DHBPDA. The structures of the products were studied by UV-Vis, FT-IR, 1H-NMR, 13C-NMR and elemental analysis. According to Gel Permeation Chromatography (GPC) analysis of O-DHBPDA, the number average molecular weight (Mn), weight average molecular weight (Mw) and PDI values were found to be 4328g mol-1, 6228g mol-1 and 1.43, respectively. TG/DTA analyses were shown to be stable of O-DHBPDA against thermo-oxidative decomposition. During the polycondensation reaction, a part of the azomethine (-CH=N-) groups oxidized to aldehyde (CHO) group (10-12%). Oligomer-metal complexes of oligo-N,N'-bis (2,4-dihydroxybenzylidene) 1,2-phenylenediamine (O-DHBPDA) with Co(II) and Mn(II) were synthesized and characterized by FT-IR, UV-Vis, TG-DTA and Atomic Absorption Spectroscopy (AAS). The residue of DHBPDA, O-DHBPDA, O-DHBPDA-Co and O-DHBPDA-Mn were found to be 0%, 3.65%, 11.67%, and 9.20%, respectively at 1000C.National Council for Scientific Research: 106 T 365The authors thank the Scientific and Technological Research Council (Tübitak) for financial support (Project Number 106 T 365). Also thanks are due the METU-Central Lab. for 13C-NMR and TG/DTA analyses

Synthesis, characterization, and biological properties of Ni(II), Co(II), and Cu(II) complexes of Schiff bases derived from 4-aminobenzylamine

New Schiff bases, N,N'-bis(salicylidene)-4-aminobenzylamine (H2L1), N,N'-bis(3-methoxysali- cylidene)-4-aminobenzylamine (H2L2), and N,N'-bis(4-hydroxysalicylidene)-4-aminobenzylamine (H2L3), with their nickel(II), cobalt(II), and copper(II) complexes have been synthesized and characterized by elemental analyses, electronic absorption, FT-IR, magnetic susceptibility, and conductance measurements. For the ligands, 1H and 13C NMR and mass spectra were obtained. The tetradentate ligands coordinate to the metal ions through the phenolic oxygen and azomethine nitrogens. The keto-enol tautomeric forms of the Schiff bases H2L1, H2L2, and H2L3 have been investigated in polar and apolar solvents. All compounds were non-electrolytes in DMSO (~10-3 M) according to the conductance measurements. Antimicrobial activities of the Schiff bases and their complexes have been tested against Acinobacter baumannii, Pseudomonas aeruginosa, Micrococcus luteus, Bacillus megaterium, Corynebacterium xerosis, Staphylococcus aureus, Escherichia coli, Candida albicans, Rhodotorula rubra, and Kluyveromyces marxianus by the disc diffusion method; biological activity increases on complexation. © 2009 Taylor & Francis.Institute for Research in Fundamental Sciences: FEF2006BAP-15The authors are grateful to the Science Research Fund of the C¸ ukurova University in Turkey for supporting this work (Project number: FEF2006BAP-15) and to the Department of Chemistry for allowing using the laboratory facilities

Electropolymerization of CuII-(N,N'-bis(3- methoxysalicylidene)-2-aminobenzylamine) on platinum electrode: Application to the electrocatalytic reduction of hydrogen peroxide

The complex of copper (II) with N,N'-bis(3-methoxysalicylidene)-2- aminobenzylamine (H2L) was synthesized and characterized by elemental analysis, magnetic susceptibility, UV-vis. and FT-IR spectroscopy. The results showed that the tetradentate ligand coordinated to the Cu(II) ion through the azomethine nitrogen and phenolic oxygen atoms. The prepared complex [CuL] was electropolymerized on platinum electrode surface in a 0.1 mol dm-3 solution of lithium perchlorate in acetonitrile by cyclic voltammetry between 0 and 1.6 V vs. Ag/Ag+. Cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), conductance measurements, FT-IR and SEM were used to characterize polymer film of Cu(II) complex. The reduction of hydrogen peroxide on poly[CuL] has been investigated mainly in phosphate buffer medium (pH 7.2), between 0 and -0.8 V versus Ag/Ag+ at a scan rate 0.1 V s-1. © 2011 Elsevier B.V. All rights reserved

Schiff base polymers obtained by oxidative polycondensation and their Co(II), Mn(II) and Ru(III) Complexes: Synthesis, characterization and catalytic activity in epoxidation of styrene

In this paper, Schiff base monomers having double azomethine groups, N,N'-bis(4-hydroxybenzylidene)1,4-phenylenediamine (M 1) and N,N'-bis(4-hydroxysalicylidene)1,4-phenylenediamine (M 2), were prepared by a common condensation reaction between 4-hydroxybenzaldehyde and 4-hydroxysalicylaldehyde with 1,4-phenylenediamine, respectively. The new Schiff base polymers, poly(N,N'-bis(4-hydroxybenzylidene)1,4-phenylenediamine) (P 1) and poly(N,N'-bis(4-hydroxysalicylidene)1,4- phenylenediamine) (P 2) were synthesized from the oxidative polycondensation of monomers with NaOCl in an aqueous alkaline medium. The characterization of synthesized monomers and polymers was carried out by FT-IR, UV-Vis, 1H-NM, 13C-NMR and elemental analysis. The new polymer-metal complexes were prepared by using polymers and Co(II), Mn(II) and Ru(III) metal salts. Thermal properties of the compounds were studied by TG-DTA techniques. In addition, the catalytic properties of the polymers and their metal complexes were investigated in epoxidation reactions of styrene. The results of the catalysis studies were monitored by GC-MS. © 2012 Koninklijke Brill NV, Leiden.106 T 365The authors thank The Scientific and Technological Research Council (Tübitak) for financial support (Project No. 106 T 365)

Crystal structure of an unsymmetrical Schiff base, immobilization of its cobalt and manganese complexes on a silica support, and catalytic studies

An unsymmetrical tetradentate Schiff base (H2L) was synthesized by the reaction of 3-methoxysalicylaldehyde, o-phenylenediamine, and salicylaldehyde in EtOH. H2L was characterized by single-crystallographic X-ray analysis. Its Co(II) and Mn(III) complexes ([CoL] and [MnLCl]) were prepared and immobilized on 3-aminopropyltriethoxysilane functionalized silica gel. The immobilized materials were found to be efficient catalysts for epoxidation of styrene in the presence of tert-BuOOH in acetonitrile at 40 C. The catalysts can be reused several times without significant loss of performance. © 2012 Springer Science+Business Media Dordrecht.109T416 National Council for Scientific ResearchAcknowledgments The authors thank the Scientific and Technological Research Council (TÜBİTAK) for financial support (Project Number 109T416). Also, the authors are grateful to Anadolu University and the Medicinal Plants and Medicine research Centre of Anadolu University, Eskis¸ehir, Turkey, for the use of X-ray Diffractometer

Synthesis and characterization of a Schiff base derived from 2-aminobenzylamine and its Cu(II) complex: Electropolymerization of the complex on a platinum electrode

A precursor (H3A) was synthesized by the mono condensation of 2-aminobenzylamine with salicylaldehyde and then a tetradentade Schiff-base ligand (H2L) prepared by using H3A and 3-methoxysalicylaldehyde. The copper(II) complex of this new ligand was prepared and characterized by elemental analysis, electronic absorption, Fourier transform infrared (FT-IR), and magnetic susceptibility. For the ligand, 1H- and 13C-NMR and liquid chromatography mass spectrometry (LC-MS) spectra were obtained. The tetradentate ligand is coordinated to Cu(II) through the phenolic oxygen and azomethine nitrogen. The use of this metal complex in the preparation of a modified electrode is also described. CuL was electropolymerized on a platinum electrode surface in a 0.1 mol dm-3 solution of lithium perchlorate in acetonitrile by cyclic voltammetry between 0 and 1.6 V versus Ag/Ag+. Electrochemical properties of the electroactive polymeric film have been investigated and a surface confined polymerization mechanism was proposed. © 2010 Taylor & Francis.Institute for Research in Fundamental SciencesThe authors are grateful to the Science Research Fund of the C¸ ukurova University in Turkey for supporting this study (project no. FEF2009YL-3) and to the Department of Chemistry of Mustafa Kemal University for allowing the use of its laboratory facilities