Physicochemical studies on square-planar Cu(II), Ni(II) and Co(II) chelate polymers

Chelate polymers of Cu(II), Ni(II) and Co(II) with bis-oxime of 5,5′-methylene bis(salicylaldehyde) have been prepared. The square-planar structure of the complexes was determined on the basis of infrared and electronic spectral measurements in conjunction with magnetic susceptibility measurements. The thermal stability of the chelates, obtained from the TG thermograms has the following order: Co(II) and Ni(II) chelates are found to increase their coordination number by interaction with pyridine at right angles to the plane of the parent molecule. The resulting complex is found to have octahedral structure. The ligand-field and nephelauxetic parameters have been determined from the spectra, using ligand-field theory of spin-allowed transitions which are found consistent with six-coordinate structure for these adducts.     

Functional metal-porphyrazine derivatives and their polymers, 10. Secondary fuel cells based on oxygen reduction on platinum electrode modified by polymers and metal-phthalocyanines

Secondary fuel cells based on oxygen reduction of platinum electrode modified by polymers and metal-phthalocyanine (Mt = Fe(III), Co(II), Ni(II), and Cu(II)) were studied. The discharge curves for the platinum electrode modified by poly(2-vinylpyridine) (or polystyrene) and Co-phthalocyanine in 30% KOH aqueous solution, for a 30 min charge at 500 μA, followed by a 100 μA discharge showed a stable plateau at about ?0.24 V SCE (Saturated Calomel Electrode). The open circuit voltage (vs. Zn) of the cell was 1.2 V, and the discharge capacity was of 46 A · h/kg. For this battery there was no significant decay in its characteristics after more than 30 charge-discharge cycles. In Mt-phthalocyanines, the values decreased in the order of Co(II) > Fe(III) > > Cu(II) > Ni(II). From a cyclic voltammogram for the electrode modified by the polymer and Co-Pc, the cathodic reactions were discussed.     

Synthesis of poly(acrylamide‐co‐4‐vinylpyridine) hydrogels and their application in heavy metal removal

A series of poly(acrylamide‐co‐4‐vinylpyridine) hydrogels having varied acrylamide/4‐vinylpyridine content and different crosslink ratios of N,N′‐methylene‐bisacrylamide was prepared by using solution polymerization. The prepared hydrogel polymers were characterized by their elemental analysis, infrared spectroscopy, and equilibrium water content. The polymers were investigated toward metal ion uptake of Mn(II), Co(II), Ni(II), Cu(II), and Zn(II). The polymers were more sensitive to Cu(II) and Ni(II) and the order of metal ion binding was Ni(II), Cu(II) > Zn(II) > Co(II) > Mn(II). Metal ion uptake by the polymers was reduced as the pH of the medium decreased. Recycling of the resins resulted in high recovery of the metal ions from their aqueous solutions. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 2522–2526, 2003     

Synthesis,characterization, and catalytic activity of 4 mol % N,N′‐methylene bisacrylamide crosslinked poly(acrylic acid)–metal complexes

The metal‐ion complexation behavior and catalytic activity of 4 mol % N,N′‐methylene bisacrylamide crosslinked poly(acrylic acid) were investigated. The polymeric ligand was prepared by solution polymerization. The metal‐ion complexation was studied with Cr(III), Mn(II), Fe(III), Co(II), Ni(II), Cu(II), and Zn(II) ions. The metal uptake followed the order: Cu(II) > Cr(III) > Mn(II) > Co(II) > Fe(III) > Zn(II) > Ni(II). The polymeric ligand and the metal complexes were characterized by various spectral methods. The catalytic activity of the metal complexes were investigated toward the hydrolysis of p‐nitrophenyl acetate (NPA). The Co(II) complexes exhibited high catalytic activity. The kinetics of catalysis was first order. The hydrolysis was controlled by pH, time, amount of catalyst, and temperature. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 272–279, 2004     

Relation between polymer surface tension and orientation of thermotropic liquid crystals

The orientation (tilt angle φ) of thermotropic liquid crystals (LC) on the interface to a polymer-coated surface is not only determined by the numerical value ${\rm \gamma }_{\rm S} {\rm }\left( {{\rm \gamma }_{\rm S} {\rm = \gamma }_{\rm S}^{\rm d} {\rm + \gamma }_{\rm S}^{\rm p} } \right)$ of the substrate surface tension. However, the ratio between the dispersive and the polar part of ${\rm \gamma }_{\rm S} {\rm }\left( {{\rm\gamma }_{\rm S}^{\rm d} {\rm : \gamma }_{\rm S}^{\rm p} } \right)$ also influences the LC orientation on the substrate surface. A polyimide and an amide-modified styrene/maleic anhydride copolymer were used as polymers.     

Characterization of polyvinyl chloride. Part III. An alternative GPC method for measuring the radii of gyration,and the degree of long-chain branching of polydispersed polymers

A method for measuring the unperturbed radius of gyration and the degree of long-chain branching in Gaussian-distribution polymers is proposed. Polyvinyl chloride (PVC) and polyvinyl acetate (PVAc) were selected to illustrate the method. It was observed that PVC samples prepared by homogeneous and heterogeneous polymerizations exhibit the same degree of long-chain branching. This conclusion is supported by viscometric data. The polydispersity ratios (M_w/M_n) indicate that both types of polymerizations would yield a very small amount of total branching (long chain and short chain.) The calculated unperturbed radius of gyration of linear PVC samples was found to be 0.185 \documentclass{article}\pagestyle{empty}\begin{document}$ \left( {\frac{{{\rm \dot A}^{\rm 2} {\rm mole}}}{{{\rm gm}}}} \right) $\end{document}, and that of PVAc was determined to be 0.107 \documentclass{article}\pagestyle{empty}\begin{document}$ \left( {\frac{{{\rm \dot A}^{\rm 2} {\rm mole}}}{{{\rm gm}}}} \right) $\end{document}. The value obtained for PVC is shown to be in agreement with the value determined from the viscometric method as described in our previous work.     

Coordination polymers, 2. Effect of iodine doping on electrical properties of coordination polymers derived from terephthalaldehyde bis(S-benzyldithiocarbazate)

The electrical properties of Mn(II), Fe(II), Co(II), Ni(II), Cu(II), and Zn(II) chelate polymers of terephthalaldehyde bis(S-benzyldithiocarbazate) (TBDTC) have been studied. Similarly, different concentrations of iodine were doped to these chelate polymers to increase their conductivity for producing a new class of electrical conductive material. The current interest in doping of iodine in chelate polymers is to a great extent due to their possible application in power sources and electrochemical devices. Electrical conductivity of chelate polymers and iodine doped chelate polymers have been studied over a wide range of temperature (～ 300?450 K). From the electrical conductivity of these polymers activation energies of electrical conduction have been evaluated. A comparison of electrical conductivity and activation energy of electrical conduction of simple and iodine doped polymers has been made and conclusions about the role of iodine in chelate polymers regarding the electrical conductivity have been drawn.     

Synthetic,spectroscopic, magnetic,thermal, and antimicrobial approach towards new biocidal coordination polymers

O‐aminophenol was reacted with glutraldehyde to obtain Schiff base, which was then reacted with formaldehyde in slight acidic medium to generate phenolic groups. Now the substituted Schiff base was reacted with the transition metal acetates of Mn(II), Co(II), Ni(II), Cu(II), and Zn(II) to get polymeric metal complexes. Their structures have been elucidated on the basis of elemental analyses, ¹H NMR spectra, ¹³C NMR spectra, magnetic measurements, thermogravimetric analyses, electronic spectra, and infrared spectra. The results are in accordance with an octahedral environment around the central metal ion. The polychelates of Mn(II), Co(II), Ni(II), and Cu(II) are paramagnetic while Zn(II) polychelate was found to be diamagnetic. The synthesized Schiff base acted as a uninegative bidentate ligand and bonding occurs through the hydroxyl oxygen and nitrogen atoms. The thermal behavior of these coordinating polymers was studied by TGA in nitrogen atmosphere up to the temperature range of 800°C. All the synthesized polychelates were also screened for their biocidal activity against Escherichia coli, Staphylococcus aureus, Bacillus subtilis (bacteria), Candida albicans, and Muller species (yeast) by using agar well diffusion method. All the metal polychelates show promising antimicrobial activities. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci 124:3971–3979, 2012     

Physicochemical properties of some new coordination polymers

Coordination polymers of Cu(II), Ni(II), CO(II), Mn(II), Zn(II), oxovanadium (IV), and dioxouranium(VI) with 2-hydroxy-4-methoxyacetophenone thiourea trioxane polymer were synthesized. Elemental analyses of the coordination polymers indicate a metal-to-ligand ratio of 1:2. The diffuse reflectance spectra and magnetic moments of coordination polymers show a distorted octahedral structure. Infrared spectral studies show that the metals are coordinated through the oxygens of carbonyl and phenolic groups and the nitrogen of thioamide group. Thermal stabilities of coordination polymers were determined by thermogravimetric analysis. Semiconducting behavior of the polymer and its coordination polymers was also studied by electrical conductivity measurements at different temperatures.     

Amorphous polyolefins: A relationship between molecular structure,submolecular motion,and mechanical behavior

The thermomechanical spectra of two series of amorphous polyolefins represented by $\rlap{--} [{\rm CH}_2 )_m {\rm - C}\left( {{\rm CH}_3 } \right)_2 \rlap{--} ]_n$ and $\rlap{--} [\left( {{\rm CH}_2 } \right)_m \bond {\rm C}\left( {{\rm CH}_3 } \right)\left( {{\rm C}_2 {\rm H}_5 } \right)\rlap{--} ]_n$, where m = 1, 2, and 3, are presented from ?180°C to above the glass transition temperatures. The polymers were obtained by cationic polymerization of α-olefins. The mechanical spectra show a maximum in glass transition temperature and secondary transition temperature for the second member of each series. This maximum is interpreted in terms of a proposed geometrical intermolecular interlocking which is considered to be at a maximum for the second member of the series and serves to restrict the submolecular motions associated with the transitions. The proposal is discussed in terms of its consequences upon free volume, density, cohesive energy density, and chain flexibility.     

Total concentration of main components in solutions for metal electroplating as a criterion for classifying and choosing resource-saving compositions of solutions

A comparative analysis is performed of the variations in the total concentration of the main components $\left( {\sum\limits_i {c_i } } \right)$ , in the solutions proposed and used in different years for electroplating individual metals (Cr, Cu, Ni, Zn, Sn, Cd, Pb, and Fe). A quantitative concentration criterion is determined for classifying solutions into resource-saving ( $\left( {\sum\limits_i {c_i \leqslant 2.32} } \right)$ mol-equiv/L) and resourceintensive ( $\left( {\sum\limits_i {c_i \geqslant 2.78} } \right)$ mol-equiv/L) compositions. In addition to scientific interest, this material can be useful for developing studies aimed at reducing the negative environmental impact of electroplating shops or sections.     

Polymeric coordination complexes of some bipositive metal ions with 5,5′-(benzidinebisazo)-8-hydroxyquinoline

Summary Coordination chain polymers of Mn(II), Fe(II), Co(II), Ni(II), Cu(II), zn(II), and Cd(II) with 5,5-(benzidinebisazo)-8-hydroxyquinoline were synthesized by refluxing a mixture of metal acetate hydrates and ligand (11) in DMSO. From analytical data an empirical formula of ML.2H₂O is indicated. Ir spectra reveal coordination through O and N of oxine units, thus forming the polymeric chain; presence of coordinated water is also indicated. Magnetic moments and electronic spectra suggest octahedral geometry around the central metal ion. Besides the presence of 2H₂O, TGA shows the order of thermal stability as : CdZn> Mn> CoNiCu>Fe.     

Plasma polymerization of organoisothiocyanates. II. Structure of polymer film

Methyl-, n-propyl-, allyl-, and phenyl isothiocyanates (MITC, PITC, AITC, and PHITC respectively) were polymerized in an RF (13.56 MHz) plasma electrodeless flow system. The plasma produced polymers were characterized using IR, GPC, GC/MS, and direct pyrolysis mass spectrometry (DPMS) techniques. The solubility tests and chromatographic examinations of the polymers revealed a small soluble fraction which contained a mixture of oligomers with a predominance of dimers and trimers. Molecular structure of the components of these fractions, identified by GC/MS, suggests fragmentation of the monomers to reactive fragments: $$ ^ \cdot {\rm RSCN},^ \cdot {\rm RCN},{\rm R}^ \cdot ,^ \cdot {\rm CN} $$ (in the case of MITC, PITC, AITC) and $ ^ \cdot {\rm ArNCS},{\rm PhS}^ \cdot ,{\rm Ph}^ \cdot ,^ \cdot {\rm CN} $ (in the case of PHITC). The DPMS data, being generally consistent with IR and GS/MS results, proved the presence in the polymers of sulfide, polysulfide, thiocarbonyl (–CS–S–and–S–CS–S–) groups, and molecular sulfur S₈. Elementary plasma reactions involved in the formation of the observed structural units are proposed.     

Magnetic cobalt-zinc ferrite/PVAc nanocomposite: synthesis and characterization

Metal oxide nanoparticles are the subject of current interest because of their unusual optical, electronic, and magnetic properties. In this work, cobalt zinc ferrite ( $ {\text{Co}}_{0.3} {\text{Zn}}_{0.7} {\text{Fe}}_{2} {\text{O}}_{4} $ ) nanoparticles have been synthesized successfully through redox chemical reaction in aqueous solution. The synthesized $ {\text{Co}}_{0.3} {\text{Zn}}_{0.7} {\text{Fe}}_{2} {\text{O}}_{4} $ nanoparticles have been used for the preparation of homogenous polyvinyl acetate-based nanocomposite ( $ {\text{Co}}_{0.3} {\text{Zn}}_{0.7} {\text{Fe}}_{2} {\text{O}}_{4} /{\text{PVAc}} $ ) via in situ emulsion polymerization method. Structural, morphological and magnetic properties of the products were determined and characterized in detail by X-ray powder diffractometry (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and vibrating sample magnetometer (VSM). The XRD patterns of the $ {\text{Co}}_{0.3} {\text{Zn}}_{0.7} {\text{Fe}}_{2} {\text{O}}_{4} $ confirmed that the formed nanoparticles are single crystalline. According to TEM micrographs, the synthesized $ {\text{Co}}_{0.3} {\text{Zn}}_{0.7} {\text{Fe}}_{2} {\text{O}}_{4} $ nanoparticles had nano-needle morphology with an average particle size of 20 nm. The calculated coefficient of variation (CV) of nanoparticles diameters obtained by TEM micrographs was 16.77. The $ {\text{Co}}_{0.3} {\text{Zn}}_{0.7} {\text{Fe}}_{2} {\text{O}}_{4} $ nanoparticles were dispersed almost uniformly in the polymer matrix as was proved by SEM technique. The magnetic parameters of the samples, such as saturation magnetization (M _s) and coercivity (H _c) were measured, as well. Magnetization measurements indicated that the saturation magnetization of synthesized $ {\text{Co}}_{0.3} {\text{Zn}}_{0.7} {\text{Fe}}_{2} {\text{O}}_{4} /{\text{PVAc}} $ nanocomposites was markedly less than that of $ {\text{Co}}_{0.3} {\text{Zn}}_{0.7} {\text{Fe}}_{2} {\text{O}}_{4} $ magnetic nanoparticles. However, the nanocompoites exhibited super-paramagnetic behavior at room temperature under an applied magnetic field.     

Recovery and Concentration of Metal Ions. II Multimembrane Hybrid System

Abstract

The multimembrane hybrid system (MHS) has been developed and used for the transportation and separation of divalent metal ions from multicomponent solutions. The system consists of three membranes in series

ion-exchange membrane | liquid membrane | ion-exchange membrane

The experiments were performed with liquid membranes composed of di(2-ethylhexyl)phosphoric acid in kerosene and Nafion-120 perfluorosulfonic acid polymer membranes. The fluxes and separation characteristics have been determined for MHS separating a solution of Zn(II), Mn(II), Cu(II), and Ni(II) sulfates as the feed phase, and the strip phase containing sulfuric acid. The results of competitive permeation experiments have shown the selectivity order Zn(II) > Mn(II) > Cu(II) ? Co(II), Ni(II). High separation coefficients were found for Zn(II), Cu(II), and Mn(II) compared to Ni(II) and Co(II).     

Synthetic and spectroscopic studies of chelate polymers involving azelaoyl bis‐N‐phenyl hydroxamic acid with transition metal ions

Chelate polymers of azelaoyl bis‐N‐phenyl hydroxamic acid with Mn(II), Co(II), Ni(II), and Zn(II) were synthesized for the first time in a dimethylformamide (DMF) medium. These newly synthesized chelate polymers were characterized on the basis of several analytical techniques, namely, elemental analyses, infrared and reflectance spectral studies, magnetic moment, and thermal analyses. On the basis of data obtained with these techniques, the composition of the polymeric units, the structure, and the geometry were ascertained. It was found that the Mn(II) and Zn(II) chelate polymers had a tetrahedral geometry, whereas the Co(II) and Ni(II) chelate polymers were octahedral. Thermal analytical data clearly indicated that the Ni(II) chelate polymer was highly thermally stable relative to the Mn(II), Co(II), and Zn(II) chelate polymers. Since these chelate polymers are highly insoluble in almost all the organic solvents, including alcohol, acetone, chloroform, carbon tetrachloride, DMF, and DMSO, and have high thermal stability, they may be used as surface‐coating materials and as thermally stable materials. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 273–278, 2006     

Synthesis and characterization of coordination polymers of polyesters with pendant amino groups

Oligomeric polyester, namely, poly(tetramethylene aspartate) (PTMA), was synthesized from D ,L -aspartic acid and 1,4-butanediol by a melt-condensation technique. Polyester–metal complexes were synthesized by the reaction of PTMA with hydrated acetates of Mn(II), Co(II), Ni(II), Cu(II), Zn(II), Cd(II), Hg(II), Mg(II), Ca(II), Pb(II), and Ce(IV) in DMSO. The polyester–metal complexes were characterized by elemental analysis, IR spectral studies, magnetic susceptibility measurements, and thermogravimetry. The metal ions were found to be six-coordinated with two water molecules as additional ligands besides oxygen and nitrogen atoms of polyester repeating units. Thermogravimetric analysis (TGA) showed that coordination polymers are thermally more stable than is polyester. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 69: 751–759, 1998     

Insights into the mode of action of the anti-Candida activity of 1,10-phenanthroline and its metal chelates

Metal complexes of malonie acid (metal = Mn(II), Co(II), Ni(II), Cu(II), Zn(II), Ag(I)) were prepared and only the Ag(I) complex inhibited the growth of Candida albicans. Malonate complexes incorporating the chelating 1,10-phenanthroline (1,10-phen) ligand showed a range of activities: good (Mn(II), Cu(II), Ag(I)); moderate (Zn(II)); poor (Co(II), Ni(II)). Metal-free 1,10-phen and Ag(CH(3)CO(2)) were also highly active. The metal-free non-chelating ligands 1,7- phenanthroline and 4,7-phenanthroline were inactive and the Cu(II), Mn(II) and Zn(II) complexs of 1,7-phen displayed only marginal activity. Whereas the Cu(II) malonate/1,10-phen complex induces significant cellular oxidative stress the Zn(II) analogue does not.     

Coordination polymers of 3,3′-benzidine dicarboxylic acid

Polymeric metal complexes of 3,3′-benzidine dicarboxylic acid with bivalent metal ions such as copper, nickel, cobalt, zinc and manganese have been synthesized and their properties, composition, IR-absorption spectra and magnetic susceptibilities were investigated. The coloured, powderly solids were obtained by refluxing the metal acetate and the ligand in the appropriate ratio for about half an hour and dried at 110°C. The compounds are stable and insoluble in common solvents. The analytical data indicate the general formula, [ML]_n for Cu(II), Mn(II) and [M₄L₅]_n for Ni(II), Co(II) and Zn(II). The mode of coordination of the ligand with metal ions has been elucidated by comparing IR spectra of the ligand and the complexes. A polymeric structure is proposed for the complexes.     

[CuL(H2O)2]{[CuL][Fe(CN)6]}2·2H2O (L=3,10-Bis(2-hydroxyethyl)-1,3,5,8,10,12-hexaazacyclotetradecane): A Novel Three-Dimensional Coordination Polymer via H-Bonded Linkages of One-Dimensional Zigzag Chain

A complex with the formula [CuL(H₂O)₂]{[CuL][Fe(CN)₆]}₂·2H₂O, where L=3,10-bis(2-hydroxyethyl)-1,3,5,8,10,12-hexaazacyclotetradecane, has been synthesized and crystallographically characterized. The structure is composed of a one-dimensional zigzag chain of $\left\{ {[{\text{CuL}}][{\text{Fe(CN)}}_{\text{6}} ]} \right\}_2^{2 - } $ units, and [CuL(H₂O)₂]²⁺ units. The one-dimensional zigzag chain extents through ${\text{Cu}}{\kern 1pt} - {\kern 1pt} {\text{CN}} - {\kern 1pt} {\text{Fe}}{\kern 1pt} - {\kern 1pt} {\text{CN}} - {\kern 1pt} {\text{Cu}}$ linkages. The adjacent two polymer chains are linked by the ${\text{O}}{\kern 1pt} - {\kern 1pt} {\text{H}}{\kern 1pt} \cdot \cdot \cdot {\kern 1pt} {\text{N}}{\kern 1pt} \equiv {\kern 1pt} {\text{C}}{\kern 1pt} - $ hydrogen bonding between [CuL(H₂O)₂]²⁺ and [Fe(CN)₆]^3?, forming a 3D supramolecular structure with inner hydrophilic channels. Magnetic susceptibility measurements show no exchange interaction between the Cu(II) and Fe(III) ions due to the longer ${\text{Cu}}{\kern 1pt} - {\kern 1pt} {\text{N}}$ (axial) bond length.