Thermal degradation of partly complexed poly(vinylpyridines) with transition metal chloride

The thermal degradation of poly(vinylpyridines), partly complexed with transition metal chlorides containing Co(II), Ni(II), Cu(II) and Zn(II) ions, was investigated using thermogravimetry, infrared spectrometry and gc/mass spectrometry. When poly(2-vinylpyridine) and poly(4-vinylpyridine) were partly complexed with transition metal ions, thermal degradation was initiated at low temperature. The complexes were decomposed even near the threshold temperature for weight loss. Degradations were modified by the complexation, particularly for poly(2-vinylpyridine). Yields of dimers, ethylpyridine, etc., increased linearly with degree of complexation, but that of monomer decreased linearly. The increase of the yield of dimer could be explained from the concept that polymer radicals reacted with metal chlorides, then dehydrochlorinated and underwent β-scission.     

Synthesis of new polyamidoximes and their crosslinking by transition metal ions

Three new polyamidoximes (PAO) having appropriate functionalities to bind transition metal ions were prepared. The polymers were obtained by the reaction of dichlorooximino ethane with the corresponding diamine. Characterization and crosslinking of PAOs via coordination with transition metal ions such as Ni(II), Co(II), Cu(II), and UO₂(II) are presented. The crosslinked polymer complexes exhibit good thermal stability. It was also found that both square planar and tetrahedral coordination structures are present in the crosslinked polymers.     

(4-Vinylpyridine-Styrene) Copolymer as Host Polymer for Chromophoric Complexes with Potential Second Order Nonlinear Optical Properties

A series of new metal containing polymers for second order nonlinear optics have been prepared by grafting Cu (II) and Pd (II) chromophoric complexes on a preformed (4-vinylpyridine-styrene) copolymeric backbone. The metallated polymers have been chemically and physically characterized. They show high glass transition temperatures, high thermal stability and good solubility. Their properties have been compared with analogous metallated poly(4-vinylpyridine) samples: variations in the polymeric backbone, as well as in ligands, metal, and metallation ratio, allow to tune their properties.     

Polymer/metal segmental Janus nanoparticles

Polymer/metal composite segmental Janus nanoparticles(NPs) are synthesized by sequential growth againstpoly(4-vinylpyridine)(P4VP) crosslinked cP4VP-PS Janus NPs. A Janus cluster of poly(4-vinylpyridine)-block-polystyrene(P4VPb-PS) diblock copolymer is self-organized after absorption onto a silica patchy sphere via hydrogen bonding. Selective crosslinking of P4VP leads to the formation of robust cP4VP-PS Janus NPs. Within the cP4VP domain, functional species such as metals are preferentially grown by in situ reduction. Other thiol-capped polymers, for example, thiol-cappedpoly(Nisopropylacrylamide)(PNIPAM-SH), can be conjugated onto the opposite side to form polymer/metal triple segmental Janus NPs. The hyperthermia effect of Au NP of PNIPAM-Au@cP4VP-PS by near infrared(NIR) irradiation can trigger a fast transition from amphiphilic to hydrophobic of the Janus NPs at low surrounding temperature. De-stabilization ofthe emulsion is NIR triggered although the system temperature is below LCST(~32 °C).     

Role of polymer ligands in the oxygenation of metal chlorophyllins

In order to obtain information about the characteristics of polymer-(metal chlorophyllins), their redox and oxygenation reactions were studied. Complexes composed of metal chlorophyllins (MChn) and partially quaternized poly(4-vinylpyridine) (QPVP) exhibited an increased stability due to electrostatic interaction between polymer cation and carboxylate anions of side groups in the MChn. The reduction of these polymer complexes by S₂O₄^2- occurred easily with an decrease in their apparent reduction potentials. The resulting low-valence complexes had an ability to absorb molecular oxygen. The oxygenation of these polymer complexes was not completely reversible; however the rate of the irreversible reoxidation was less by a factor of 10¹⁰ for the polymeric complex than that for the monomeric MChn-pyridine complex. The stability of these oxygen complexes is discussed in relation to the hydrophobicity of QPVPs.     

Coenzyme models. 15. A polymeric model system for the NADH-dependent dehydrogenase enzymes

Copolymers of 4-vinylpyridine (4-VP) and N-(p-vinylbenzyl)-1,4-dihydronicotinamide (VNicH) were synthesized, and a carbonyl substrate (benzil) was reduced to alcohol in an aqueous ethanol solution in the absence and presence of metal ions (Zn²⁺ and Ni²⁺) as part of a model study of NADH-dependent enzymes. The reduction rates by VNicH in polymers were four to seven times greater than that of the corresponding monomeric analog (N-benzyl-1,4-dihydronicotinamide). Added metal ions catalyzed the reduction by VNicH-29 (VNicH content, 29 mole%) but inhibited the reduction by VNicH-9 (VNicH content, 9 mole%). It was suggested that metal catalysis occurs only when metal ions are bound closely near the dihydronicotinamide moiety.     

Nucleation and growth of gold nanoparticles on adsorption layers and in ultrathin films of poly(2-vinylpyridine)

Peculiarities of the nucleation and growth of gold nanoparticles on adsorption layers and in ultrathin films of poly(2-vinylpyridine) (PVP) in the chemical reduction of sorbed Au(III) ions and the consequent thermal treatment of systems are studied by X-ray photoelectron spectroscopy and optical spectroscopy. It is shown that nitrogens of PVP pyridine groups coordinate gold atoms. It is revealed that, even at relatively short contact between PVP film saturated with chloroauric acid and the solution of strong reductant NaBH₄, Au(III) ions are reduced to metal. As a result, quasi-metal gold particles are formed. At the same time, when exposing a PVP-Au system to the solution of weak reductant NH₂OH, the process of reduction proceeds in several stages. First, Au(III) ions are reduced to Au(I) followed by the reduction to Au(0) as a result of disproportionation reaction. It is demonstrated for the first time that, upon using NH₂OH, the rate of reduction, as well as the structure of prepared PVP-Au nanocomposite films depends to substantial extent on solution pH. Prolonged annealing of ultrathin nanocomposites at 150 °C, i.e., above the glass transition temperature of polymer matrix, leads to an increase in the sizes of metal particles and the formation of systems characterized by intense absorption within the 500–600-nm range due to the localized plasmon resonance of gold nanoparticles.     

Influence of binary/ternary complex of imprint ion on the preconcentration of uranium(VI) using ion imprinted polymer materials

Ion imprinted polymer (IIP) materials were prepared for uranyl ion (imprint ion) by forming binary (5,7-dichloroquinoline-8-ol (DCQ) or 4-vinylpyridine (VP)) or ternary (5,7-dichloroquinoline-8-ol and 4-vinylpyridine) complexes in 2-methoxy ethanol (porogen) and copolymerizing in the presence of styrene and divinyl benzene as functional and crosslinking monomers, respectively and 2,2′-azobisisobutyronitrile as initiator. IIP particles were obtained by leaching the imprint ion in these polymer materials with 50% (v/v) hydrochloric acid, filtering, drying in an oven at 50 °C and grinding. Control polymer particles were also prepared under identical conditions. The above synthesized polymer particles were characterized by IR, CHN, X-ray diffraction, and pore size analyses. These leached polymer particles can now pick up uranyl ions from dilute aqueous solutions. The IIP particles obtained with ternary complex of uranyl ion alone gave quantitative enrichment of traces of uranyl ions from dilute aqueous solutions. The optimal pH for quantitative enrichment is 4.5-7.5 and eluted completely with 10 ml of 1.0 M HCl. The retention capacity of uranyl IIP particles was found to be 34.05 mg of uranyl ion per gram of polymer. Further, the percent extraction, distribution ratio, and selectivity coefficients of uranium and other selected inorganic ions were also evaluated. Five replicate determinations of 25 μg of uranium present in 1.0 l of aqueous solution gave a mean absorbance of 0.036 with a relative standard deviation of 2.50%. The detection limit corresponding to three times the standard deviation of the blank was found to be 5 μg l⁻¹.     

Polymer aggregates formed by polystyrene-block-poly(4-vinyl-pyridine) functionalized with rhenium(I) 2,2′-bipyridyl complexes

Some metal containing block copolymers derived from polystyrene-block-poly(4-vinylpyridine) were synthesized. The complexation was achieved by reacting the poly(4-vinylpyridine) block with 2,2′-bipyridyl(tricarbonyl)rhenium(I) chloride in the presence of silver perchlorate. The resulting polymer metal complexes are able to form micelles in different solvent systems. The morphologies were studied by transmission electron microscopy, and the structure of the micelles was found to be solvent dependent.     

离子印迹传感器选择性检测甲基汞离子

以甲基汞离子为模板,8-巯基喹啉为荧光单体,4-乙烯基吡啶为功能单体,乙二醇二甲基丙烯酸酯为交联剂,偶氮二异丁腈为引发剂,在二甲基亚砜溶剂中,以聚偏氟乙烯(PVDF)膜为支撑介质,65℃热引发聚合得到甲基汞离子荧光印迹膜。该荧光印迹膜对甲基汞离子表现出良好的选择性,最佳吸附pH值为7.0,检出限为3.5×10-7mol/L。将其作为吸附材料,应用于河水中甲基汞离子的分离和富集,结果表明,该传感器对甲基汞离子具有良好的选择性和特异性吸附,回收率达93%～104%。     

In vitro antibacterial and antifungal assay of poly‐(ethylene oxamide‐N,N′‐diacetate) and its polymer–metal complexes

A new polyester, poly‐(ethylene oxamide‐N,N′‐diacetate) (PEODA), containing glycine moiety was synthesized by the reaction of oxamide‐N,N′‐diacetic acid and ethylene glycol and its polymer–metal complexes were synthesized with transition metal ions. The monomer oxamide‐N,N′‐diacetic acid was prepared by the reaction of glycine and diethyl oxalate. The polymer and its metal complexes were characterized by elemental analysis and other spectroscopic techniques. The in vitro antibacterial activities of all the synthesized polymers were investigated against some bacteria and fungi. The analytical data revealed that the coordination polymers of Mn(II), Co(II) and Ni(II) are coordinated with two water molecules, which are further supported by FTIR spectra and TGA data. The polymer–metal complexes showed excellent antibacterial activities against both types of microorganisms; the polymeric ligand was also found to be effective but less so than the polymer–metal complexes. On the basis of the antimicrobial behavior, these polymers may be used as antifungal and antifouling coating materials in fields like life‐saving medical devices and the bottoms of ships. Copyright © 2007 John Wiley & Sons, Ltd.     

Studies on polymers containing functional groups. III. Charge-transfer interaction between quinone and aza polymers

Absorption maxima and equilibrium constants for charge-transfer complexes between quinone and aza polymers, such as poly-2-vinylpyridine, poly-4-vinylpyridine, poly-2-methyl-5-vinylpyridine, and poly-N-dimethylaminomethylacrylamide, were determined spectrophotometrically. For comparison, those for charge-transfer complexes between quinone and aza compounds, such as pyridine, methyl-substituted pyridines, quinoline, triethylamine, and dimethylaniline were also presented. It was found that the equilibrium constants for polymer complexes are always larger than those for the corresponding monomer complexes, while the time required for attaining the equilibrium was longer for polymer complexes than for monomer complexes. In the interaction between quinone and poly-N-dimethylaminomethylacrylamide, two absorption maxima which gradually shifted towards each other were observed. The same phenomenon was found in the interaction between quinone and the corresponding monomer, triethylamine.     

Metal nanoparticle formation on layer silicate lamellae

Nanoparticles (Ag, Pd) were prepared by heterogeneous nucleation on the interlayer space of layered montmorillonite and kaolinite minerals in aquatic dispersion. Interlamellar incorporation of nanoparticles was monitored by X-ray diffraction and verified by transmission electron microscopy (TEM). After the reduction of adsorbed metal ions, a new Bragg reflection appeared, proving the formation of nanoparticles in the interlamellar space of clay mineral. Lamellar structure of layered silicates is partly destroyed by the particle formation. TEM images showed that larger nanoparticles were formed by UV irradiation and hydrazine hydrate than in the case of reduction by NaBH₄. Aqueous solutions of polyvinyl pyrrolidone and clay minerals were used for the stabilization of Pd° nanoparticles. The size of particles generated on the surface of clay minerals by heterogeneous nucleation increased with increasing metal concentration. When polymer is added to this system, particle size can be decreased by increasing polymer concentration. In this case, the particles are stabilized by the concerted action of the support and the macromolecule. The polymers promoted intercalation of nanoparticles into the clay mineral. In the absence of nanoparticles, the intercalation of polymers was significantly less extensive.     

Polymer supported catalysts for oxidation of phenol and cyclohexene using hydrogen peroxide as oxidant

Polymer supported transition metal complexes of N,N′-bis (o-hydroxy acetophenone) hydrazine (HPHZ) Schiff base were prepared by anchoring its amino derivative Schiff base (AHPHZ) on cross-linked (6 wt%) polymer beads and then loading iron(III), copper(II) and zinc(II) ions in methanol. The loading of HPHZ Schiff base on polymer beads was 3.436 mmol g⁻¹ and efficiency of complexation of polymer anchored HPHZ Schiff base for iron(III), copper(II) and zinc(II) ions was 83.21, 83.40 and 83.17%, respectively. The efficiency of complexation of unsupported HPHZ Schiff base for these metal ions was lower than polymer supported HPHZ Schiff base. The structural information obtained by spectral, magnetic and elemental analysis has suggested octahedral and square planar geometry for iron(III) and copper(II) ions complexes, respectively, with paramagnetic behavior, but zinc(II) ions complexes were tetrahedral in shape with diamagnetic behavior. The complexation with metal ions has increased thermal stability of polymer anchored HPHZ Schiff base. The catalytic activity of unsupported and polymer supported HPHZ Schiff base complexes of metal ions was evaluated by studying the oxidation of phenol (Ph) and epoxidation of cyclohexene (CH). The polymer supported metal complexes showed better catalytic activity than unsupported metal complexes. The catalytic activity of metal complexes was optimum at a molar ratio of 1:1:1 of substrate to oxidant and catalyst. The selectivity for catechol (CTL) and epoxy cyclohexane (ECH) in oxidation of phenol and epoxidation of cyclohexene was better with polymer supported metal complexes in comparison to unsupported metal complexes. The energy of activation for oxidation of phenol (22.8 kJ mol⁻¹) and epoxidation of cyclohexene (8.9 kJ mol⁻¹) was lowest with polymer supported complexes of iron(III) ions than polymer supported Schiff base complexes of copper(II) and zinc(II) ions.     

Playing LEGO with macromolecules: Design,synthesis, and self‐organization with metal complexes

Several synthetic strategies for the incorporation of supramolecular binding units into polymers are described. Specifically, terpyridine ligands have been introduced into polymers in such a way that they are distributed either randomly throughout the polymer backbone or at the chain end(s). Two terpyridine ligands form octahedral complexes with a variety of transition‐metal ions, each having different properties. Some general statements regarding metal complex stability are presented as well as a special case representing the selective construction of heteroleptic terpyridine complexes. This leads to a kind of LEGO system for connecting and disconnecting the polymer blocks via metal complexes. Metallo‐supramolecular block copolymers, graft copolymers, and chain‐extended polymers can be designed and prepared with the principles described. Once the design parameters have been derived, thorough control over the final material and its properties can be gained. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 1413–1427, 2003     

Investigation of complex formation between poly(N-vinyl imidazole) and various metal ions using the molar ratio method

The complex formation of poly(N-vinyl imidazole) (PVIm) with various metal ions was studied. UV-vis spectroscopy was employed to study the interaction of PVIm and metal ions in aqueous solution. Formation constants of PVIm-metal complexes were calculated by applying a “mole ratio” method. The stoichiometric ratios between polymer and metal ions were found to be␣4. The stability constants for the complexes of PVIm with bivalent transition metal ions were in agreement with the Irving-William series. The biggest formation constant was found for the PVIm-Cu²⁺ complex system. Received: 4 January 1999 Accepted in revised form: 1 February 1999     

Luminescence Method for Studying the Formation and Stability of Macromolecular Complexes of Transition Metals with Carboxyl-Containing Polymers in Organic Solvents

Quenching of the luminescence of carboxyl-containing polymer molecules containing a luminescent marker by transition metal ions (Cu²⁺, Ni²⁺) is observed not only in aqueous and aqueous-salt solutions, but also in polar organic solvents (methanol, ethanol, dimethylformamide). In dilute solutions, quenching refl ects binding of metal ions with the polymer and changes in the degree of filling of the polymer carboxyl groups with transition metal ions quenching the luminescence. The equilibrium stability constant of the formed macromolecular metal complex in organic media can be quantitatively estimated from the quenching effect using the relationships that follow from the law of mass action. The formation and stability of Cu²⁺ and Ni²⁺ complexes with polymethacrylic acid in protic (methanol, ethanol) and aprotic (dimethylformamide) solvents at low polymer concentrations (0.4–0.02 mg mL^–1) were studied using the quenching effect. In methanol, in contrast to ethanol and dimethylformamide, two mechanisms of binding of transition metal ions with different equilibrium stability constants of the complexes (\({K_{{1^{st}}}}\) > 3 × 10⁹ and \({K_{{2^{st}}}}\) ≈ 10⁶–10⁴) were revealed. The infl uence exerted on the stability of the complexes and on the complexation mechanism by the nature and acidity of the organic solvent, polymer concentration, kind of the transition metal ion quenching the luminescence, and NaOH and HCl additions was studied. The results obtained demonstrate the efficiency of the luminescence method used and prospects for its further use for studying polymer systems containing transition metal ions in organic solvents.     

Roles of rhenium diimine complexes as metal‐ion probes and photosensitizers in functional polyurethanes

Polyurethanes incorporated with rhenium diimine complexes were synthesized. The polymers exhibited interesting morphologies and solution properties. Results from gel permeation chromatography suggested the formation of polymer aggregates in solutions. The polymers could act as probes for metal ions. The addition of metal ions to polymer solutions led to significant changes in the electronic absorption properties of the polymer solutions. This was attributed to the interactions between the polyether moieties and metal ions. The metal complexes could also act as efficient photosensitizers. After doping with charge‐transport viologens, the photoconductivity of the polymers was greatly enhanced. The experimental quantum efficiency was simulated with Onsager's theory. The thermalization distances and the primary yields were typically 12–14 Å and 10^?3, respectively. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 1708–1715, 2003     

N-2-(2-pyridyl)ethyl chitosan: Synthesis in gel and sorption properties

A procedure was developed for preparing a new heterocyclically substituted chelating aminopolymer, N-2-(2-pyridyl)ethyl chitosan, by direct addition of 2-vinylpyridine to chitosan under the conditions of synthesis in gel. The resulting polymer has the degree of substitution of up to 1. The ability of the samples obtained to sorb transition and noble metal ions was evaluated.     

Synthesis and characterization of metal-incorporated aniline formaldehyde resin modified by amino acid for antimicrobial applications

Advances in metal incorporated resins are now an active field of research. To develop resin having better antimicrobial and thermal activity, a series of metal-chelated resins have been synthesized by the condensation of (4-aminobenzene-1,3-diyl)dimethanol with 2,6-diaminohexanoic acid in alkaline medium and then this polymeric ligand further reacts with transition metal ions forming various coordination polymers. (4-Aminobenzene-1,3-diyl)dimethanol was initially prepared by the reaction of aniline and formaldehyde in 1?:?2 molar ratio in alkaline medium. The analytical data reveal that the polymer metal complexes of Mn(II), Co(II), and Ni(II) are coordinated with two water molecules, which are further supported by FTIR spectra and TGA data. Comparative analyses of the polymer metal complexes in thermal curves show better thermal stability than the polymeric ligand. Since these resins are relatively stable at high temperatures, they can be used for medical and biomaterial applications requiring thermal sterilization, solvent-resist coating materials because of their insoluble nature, and antifouling coating materials owing to antimicrobial activity in ?elds such as life-saving medical devices and the bottoms of ships.