Polymeric Metal Complexes Research Articles

Equilibrium and Molecular Mechanism of Anionic Dyes Adsorption onto Copper(II) Complex of Dithiocarbamate-Modified Starch

The assembly of dyes molecules on metal-polymer complexes is of interest due to their potential applications in photovoltaic cell, separation, and wastewater treatment. In the present work, the interaction of anionic dyes (acid orange 7, acid orange 10, acid green 25, and acid red 18) with the copper(II) complex of dithiocarbamate-modified starch (DTCSCu) was investigated. The sorption studies showed that the interaction mechanism was based on chelating adsorption. The equilibrium data fitted well with Langmuir-Freundlich isotherm, and the capacities followed the order AO7 > AG25 > AR18 > AO10. It was affected by the structure of the dye. The sulfonate groups located on benzene rings favored efficient adsorption. Despite the difference in capacity, the molar n(dye):n(Cu) ratios for acid orange 10, acid red 18, and acid green 25 were approximately 1:2 when the maximum capacities for the dyes were achieved at the optimal pH of 4. It suggested that one dye molecule bound to one dinuclear copper center on DTCSCu. The molar n(dye):n(Cu) ratio for the smallest dye, acid orange 7 (AO7), approached 1:1, demonstrating two AO7 molecules binding to two copper ions of the dinuclear core. The dyes adsorption related to the dinuclear copper core available on the polymer was further verified by electron spin resonance studies. Such interaction resulted in the formation of a ternary dye-metal-polymer complex. The ternary complexes were more stable than DTCSCu, which favored the adsorptions.

Synthesis, characterization, and biocide properties of semicarbazide–formaldehyde resin and its polymer metal complexes

Semicarbazide–formaldehyde resin (SFRs) was prepared by the condensation of semicarbazide with formaldehyde in an acidic medium and its polymer metal complexes were prepared with transition metal ions. All the synthesized polymers were characterized by elemental analysis, FTIR, 1H NMR, 13C NMR, electronic spectroscopy, magnetic moment measurement and thermogravimetric analyses. The percentage of metal in all the polymer metal complexes was found to be consistent with 2:1 (resin: metal) stoichiometry. The magnetic susceptibility measurement and electronic spectra of all the polymer metal complexes confirmed the geometry of the complexes. All the synthesized polymeric compounds have been screened in vitro against Bacillus subtilis, Staphylococcus aureus (Gram-positive) and Escherichia coli, Salmonella typhi (Gram-negative) using shaking flask method. The entire polymer metal complexes showed excellent anti-bacterial activity and low toxicity when compared with their parental polymeric resin. The anti-bacterial activity and toxicity of the entire synthesized compound is significant and they can be used as antimicrobial as well as anticancer agents for mammals in future.

Microwave assisted rapid synthesis of Bi 2O 3 short nanorods

In this research, a highly efficient and rapid approach of synthesizing Bi 2O 3 short nanorods is reported in aqueous solutions using microwave irradiation of bismuth (III) nitrate in the presence of Polyvinylpyrrolidone (PVP), as a stabilizing polymer. Transmission electron and field-emission scanning electron microscope images clearly indicate the formation of short nanorods in 6 min under microwave irradiation. Conventional heat treatment route yields only Bi 2O 3 powder and it is also comparatively complicated and needs high manufacturing cost. Formation of such short Bi 2O 3 nanorods may be due to the formation of a polymer–metal complex with the stabilizing polymer (PVP).

Cadmium removal from aqueous solutions by polyelectrolyte enhanced ultrafiltration

Enhanced ultrafiltration by the addition of poly(ammonium acrylate), with two average molecular weight 8000 Da and 15 000 Da, for the removal of Cd(II) from aqueous solutions has been studied. The solution is processed by ultrafiltration using a membrane with pore sizes (10 kDa) small enough to block the passage of the polymer and adsorbed metal ions. Suitable experimental conditions (e.g. pH, polymer and metal concentration, and polymer molecular weight) for cadmium recovery and permeate flux have been optimised. Cadmium rejection coefficient increases with monomer concentration and reaches 99% values at twofold cadmium concentrations. As a consequence, two monomers units (C2H3COO–) are necessary to coordinate 1 ion mol of cadmium. Based on this experimental result, a simple mathematical model that allows calculating the apparent polymer–metal complex (PMC) formation constant has been established. The influence of pH has been studied to fix the pH for metal retention and polymer regeneration experiments.

Design for an ultrafast water distributed sensor employing polyvinylamine cross-linked with Cu(II)

In this work, we developed a new sensor based on a specially designed polymer–metal complex which has the following characteristics: (i) resistance to dissolution in water, (ii) mechanical toughness, (iii) rapid reaction to humidity changes and (iv) precise pinpointing of a water leakage through simple technology. A hydrogel of polyvinylamine cross-linking with Cu(II) salts is employed as sensing material which has an ultrafast electrical response when it is exposed to water. Employing this composite it is possible to extrude in length continuous cables, which permits the production of actual distributed sensors of several kilometers long, which may survey water leakages or filtrations in a number of civil constructions as; pipelines, buildings, electric power stations, libraries, etc. Three PVAm formulations with different contents of Cu(II) salts were prepared and evaluated. Their cross-linking density was evaluated by viscosimetry and swelling tests, and its effect over morphological, thermal, rheological and electrical properties was evaluated by: SEM, TGA, rotatory rheometry and four probe resistivity measurements. A distributed water sensor prototype was prepared with PVAm–Cu(II) and its capability to detect and pinpoint water leakages was assessed. Experimental results showed that this sensor has an excellent performance on monitoring long water pipelines.

Functional water‐soluble polymers: polymer–metal ion removal and biocide properties

AbstractWater‐soluble polymers have attracted much interest due to their potential applications in environmental protection engineering to remove harmful pollutants and in biomedicine in the areas of tissue engineering, within‐body implants or other medical devices, artificial organ prostheses, ophthalmology, dentistry, bone repair, and so on. In this review, particular emphasis is given to the ability of water‐soluble polymers with amine, amide, carboxylic acid, hydroxyl and sulfonic acid functional groups to remove metal ions by means of the liquid‐phase polymer‐based retention (LPR) technique that combines the use of water‐soluble polymers and ultrafiltration membranes. The second part is dedicated to showing the potential application of functional water‐soluble polymers and their polymer–metal complexes as biocides for various bacteria. These polymers and polymer–metal complexes show an efficient bactericide activity, especially to Gram‐negative bacteria, Staphylococcus aureus reaching concentrations lower than 4 µg mL−1. This activity depends on polymer size, type of metal ion, contact time and concentration of polymer and metal ion. The discussion reveals that in the case of the LPR process the efficiency of metal ion removal depends strongly on the type of polymer functional group and the feed pH value. In general, two mechanisms of ion entrapment are suggested: complex formation and electrostatic interaction. In the case of the medical use of water‐soluble polymers and their complexes with metal ions, the review documents the unique bactericide properties of the investigated species. The polymer‐metal ion complexes show a reduced genotoxic activity compared with free metal ions. Copyright © 2009 Society of Chemical Industry

Polynuclear and polymeric metal complexes based upon 1,2,4-triazolyl functionalized adamantanes

A series of coordination compounds [Cd 2( trad) 7Br 2][Cd( trad)Br 3] 2 ( 1), [Cd 3( trad) 6{N(CN) 2} 4(H 2O) 2](N(CN) 2) 2 ( 2), [{Cd 2( trad) 5}{Cd(N(CN) 2) 6}]·3CH 3OH ( 3), [{Cd 3( trad) 6(SeCN) 2}{Cd(SeCN) 4} 2] ( 4), [Cd 2( trad) 3(NCS) 4] ( 5), [Cd 3( tr 2ad ) 3(μ-NCS) 3](NCS) 3 ( 6), [Cd 3( tr 2ad ) 6](NO 3) 6·22H 2O ( 7), [Cu 3( tr 2ad ) 4(SO 4)(H 2O) 3](SO 4) 2·34H 2O ( 8) and [Cu 2(OH)( tr 2ad ) 2](NO 3) 3·4H 2O ( 9) ( trad = 4-(adamantan-1-yl)-1,2,4-triazole; tr 2ad = 1,3-bis(1,2,4-triazol-4-yl)-adamantane) revealed the potential of 1,2,4-triazolyl functionalized adamantanes for design of metal–organic polymers incorporating polynuclear coordination units as multiconnected nodes. Structures 1– 5 are based upon characteristic di- and trinuclear clusters involving triple triazole bridges [M(μ 2- trad) 3M] (M = Cd), while doubling of the ligand functionality ( tr 2ad ) allows integration of the clusters into 3D polymeric frameworks 6– 9 (M = Cd, Cu).

Thermal and catalytic aspects of Ln(III) polymer–metal complexes

AbstractBACKGROUND: In this era, polymer‐supported catalysts are gaining more attention, as they are effective in reduction of pollution, production cost and give good yield. Due to the versatility of lanthanide catalysts in organic synthesis, we envisioned that lanthanides(III) supported polymers would afford a novel type of solid phase Lewis acids.RESULTS: The polymer–metal complexes are found to be efficient and effective catalysts in the Biginelli three‐component, one‐pot synthesis of 3,4‐dihydropyrimidin‐2(1H)‐ones. The synthesized polymer is thermally more stable and porous in nature than polychelates.CONCLUSION: The polymer–metal complexes can be used as economical and eco‐friendly catalysts for synthesis of substituted 3,4‐dihydropyrimidin‐2(1H)‐ones with different aromatic aldehydes and β‐ketoesters. Thermal stability of the polymer is higher than that of polychelates due to the presence of intramolecular hydrogen bonding. Copyright © 2009 Society of Chemical Industry

Block copolymers containing pyridine moieties: Precise synthesis and applications

This review highlights the precise synthesis and application of various well-defined rod–coil and coil–coil block copolymers composed of poly(2-(or 4-)vinylpyridine) (P2VP or P4VP) block(s) with pyridine moieties. These polymers were synthesized by means of living anionic polymerization. Poly(hexyl isocyanate) (PHIC) was used as the rod-like segment, because hexyl isocyanate undergoes living anionic polymerization under carefully selected conditions. This review describes the syntheses of the block copolymers, polystyrene- b-P2VP, polystyrene- b-P4VP, polyisoprene- b-P2VP, P2VP- b-poly(methyl methacrylate), P2VP- b-poly(ethylene oxide), P2VP- b-poly(2-( N-carbazolyl)ethyl methacrylate), P2VP- b-PHIC, P2VP- b-PHIC- b-P2VP, and PHIC- b-P2VP- b-PHIC. The formation of self-organized nanostructured materials and molecular assemblies by such block copolymers and their possible applications are also described. These assemblies include monolayers, microphase-separated periodic-ordered nanostructures, micelles, polymer–metal complexes, nanoparticles, inorganic and metal layers, and nanoporous films with nanoparticles.

Novel Polymeric Metal Complexes of 2,7-Bis[2-(2′-Pyridyl) Benzimidazole]- 9,9′-Dioctylfluorene with Cu(II)and Zn(II): Synthesis and Luminescence Properties

A novel ligand, 2,7-bis[2-(2′-Pyridyl)benzimidazole]- 9,9′-dioctylfluorene (BPDOF) and its polymeric complexes with copper(II) and zinc(II) were successfully synthesized and characterized by 1H NMR, FT-IR, elemental analysis, UV-vis, conductivity measurements and gel permeation chromatography. The UV–vis absorption, fluorescence spectra, and thermal properties of these complexes were investigated at room temperature. The experimental results show that polymeric metal complexes BPDOF-Cu(II) and BPDOF-Zn(II) emit purple/green luminescence at 430 and 509 nm in DMF solution and emit green luminescence at 495 and 527 nm in the solid state. Thermal properties measurement and analysis show that they have good thermal stabilities. Synthesis route: 2,7-bis[2-(2′-Pyridyl) benzimidazole]- 9,9′-dioctylfluorene (BPDOF) was synthesized using 2-(2′-Pyridyl)benzimidazole and 2,7-dibromo-9,9′-dioctylfluorene by Ullmann condensation. Polymeric metal complexes of the corresponding were synthesized with CuCl2 · 2H2O, ZnCl2.

Synthesis and green luminescent properties of Cu(II), Zn(II) polymeric complexes containing triphenylamine as hole-transporting unit and 1,10-phenanthroline derivative as electron-transporting unit

New polymeric metal complexes containing triphenylamine as hole-transporting unit and 1,10-phenanthroline derivative as electron-transporting unit, 4,4′-bis([1,10]phenanthroline-[5,6-d]imidazol-N-octyl-2-yl) triphenylamine with copper (II) and zinc (II), were prepared and characterized by FT-IR, elemental Analysis, conductivity measurement and gel permeation chromatography and UV–Vis. Gel permeation chromatography showed the number average molecular weights ( M n) of 6500 and the degree of polymerization ( n) of 7 for the polymeric complexes. Fluorescence spectra revealed that the polymeric complexes emit pure green luminescence at 548 nm and 547 nm in solid state and blue/green luminescence at 489 nm and 477 nm in DMSO solution, and the maximum wavelengths of the polymeric complexes are red shifted, compared with the ligand.

Polymer-metal complexes of phenolic resin with Ln (III): thermal, catalytic and antimicrobial aspects

The polycondensation of 2-hydroxy-4-ethoxybenzophenone with 1, 3 butane diol was carried out in presence of polyphosphoric acid as a catalyst at 155 °C for 10 h to synthesize desired resin. The resin was used to synthesize polymer-metal complexes with 4f-block elements. The resin and its polymer-metal complexes were characterized on the basis of elemental analyses, electronic spectra, magnetic susceptibilities, FTIR, NMR and Thermogravimetric analyses. Morphology of resin and its polymer-metal complexes was studied by SEM. Catalytic activity of selected polymer-metal complexes in organic synthesis was examined. Antimicrobial activity of polymer-metal complexes against Escherichia coli, Bacillus subtilis, Staphylococcus aureus (bacteria) and Saccharomyces cerevisiae (yeast) were measured. It is observed that polymer-metal complexes are efficient and effective catalysts and antimicrobial agents.

Metal Complexes of π-Conjugated Polymers

π-Conjugated chelating polymers such as poly(2,2′-bipyridine-5,5′-diyl), poly(1,10-phenanthroline-3,8-diyl), and salophen polymers have been prepared by organometallic polycondensations. The obtained polymers form metal complexes with various metal species such as [Ru(bpy)2]2+ and CuCl2. Metal complexes of π-conjugated ligands are also polymerized by dehalogenative organometallic polycondensations. Some of the metal complexes of π-conjugated polymers exhibit electrical conducting nature and show catalytic activity for redox reactions.

Polymer–metal complex micelles for the combination of sustained drug releasing and photodynamic therapy

Polymer–metal complex micelles (PMCMs) containing cisplatin (cis-dichlorodiammineplatinum(II), CDDP), an anticancer drug, were prepared by a coordination bond of CDDP to dendrimer phthalocyanine (DPc) and poly(ethylene glycol)-block-poly(L-aspartic acid) (PEG-PLAn; molecular weight of PEG segment = 12 000 g mol−1; polymerization degrees of aspartic acid segment n = 68, 96). Transmission electron microscopy (TEM) and laser light scattering (LLS) exhibited formation of unimodal PMCM68 and PMCM96 with average sizes of 108 and 135 nm, respectively. PMCMs were very stable in 10 mM phosphate buffer solution (PBS) without NaCl to maintain their shape and size over a month. However, PMCMs slowly released CDDP when they were incubated in physiological saline PBS solution at 37 °C. Upon laser light irradiation, generation of singlet oxygen was detected by photo-luminescence observation. The PMCMs would be effective nano-devices for anticancer drug carriers with sustained drug release and photodynamic therapy (PDT).

CHITOSAN METAL COMPLEXES AND CHITOSAN- Cu ESR STUDIES

Properties of the polymer metal complexes can be explained up to certain extent by the molecular structure of the complexes, but this area has not been well studied in the case of the chitosan metal complexes. In this work, we are proposing that chitosan is bonded through the 4 nitrogen to copper by means of square planar geometry. The polymer requires some structural modifications in order to be arranged in that geometry. Two sites in the chitin were detected, one similar to chitosan and the other in a square planar tetrahedrically distorted arrangement, with three atoms of nitrogen and one of oxygen or two atoms of nitrogen and two of oxygen. ESR studies of the copper complexes by means of chlorine and nitrate as ion counter were carried out. Nitrate exhibits one type of retention site and, on the other hand, chlorine presents two types of retention sites.

Fabrication of polymer–platinum(II) complex nanomicelle from mPEG–g-α,β-poly [( N-amino acidyl)- dl-aspartamide] and cis-dichlorodiammine platinum(II) and its cytotoxicity

The aim of research is to develop and optimize delivery system for cis-dichlorodiammine platinum(II) (CDDP) based on polymer–metal complex nanomicelles with controllable particle size in order to achieve the passive tumor targeting. In particular, graft copolymers, mPEG–g-α,β-poly [( N-amino acidyl)- dl-aspartamide] (mPEG–g-PAAsp) were synthesized by the ring-opening reaction of polysuccinimide with mPEG-NH 2 ( M w: 2000 and 5000 Da), and then with l-aspartic acid and l-glutamic acid, respectively. mPEG–g-PAAsp–CDDP complex nanomicelles were fabricated from mPEG–g-PAAsp and CDDP. The formation of mPEG–g-PAAsp–CDDP nanomicelles was confirmed by fluorescence spectrophotoscopy, electrical conductivity and particle size measurements. It was found that all the nanomicelles showed spherical shapes with clear core-shell structures and narrow size distributions. Their sizes ranged from 80 to 160 nm, suggesting of their passive targeting potential to tumor tissue. With the increase of the molecular weight of mPEG, the sizes of mPEG–g-PAAsp–CDDP micelles showed a tendency to increase. mPEG–g-PAAsp–CDDP nanomicelles showed linear gradual drug release profiles in 40 h, suggestion of their sustained drug release behaviors. Compared with CDDP, mPEG–g-PAAsp–CDDP micelles showed essential decreased cytotoxicity to Bel-7402 cell line.

Isomer‐dependent properties of poly(vinyl pyridine)‐based films grown on copper surfaces

AbstractThe effect of poly(2‐vinyl pyridine) (P2VP) and poly(4‐vinyl pyridine) (P4VP) isomers on the growth of surface films on copper substrates was studied by electrochemical, spectroscopic, thermogravimentric, and microscopic methods. In acid environment (3% v/v acetic acid) and in the presence of KSCN, electrochemically generated copper cations reacted rapidly with SCN− and P2VP or P4VP, yielding coordination compounds, which deposited onto copper surfaces as films. The characteristics of such polymer–metal complexes (films) were markedly isomer‐dependent. Cu(I)/P2VP/SCN− complexes with monovalent cations and sulfur‐coordinated thiocyanate were obtained in the presence of P2VP, whereas the formation of Cu(II)/P4VP/SCN− complexes with divalent cations and nitrogen‐coordinated thiocyanate was observed in the presence of P4VP. Interestingly, similar physical–chemical properties (electronic structure, stoichiometry, and thermal behavior) were observed for materials synthesized by electrochemical and chemical methods. These results suggest, therefore, that control over the surface properties of copper substrates can be achieved using electrosynthesized films based on different PVP isomers. Besides acting as effective protective barriers against aggressive media and thus reducing the metal dissolution (corrosion) kinetics, these materials are potentially attractive for other applications in which surface properties are paramount, such as in catalysis. © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 215–225, 2009

Synthesis and characterization of new water‐soluble metal–polymer complex and its application for arsenite retention

AbstractNew water‐soluble metal–polymers of poly(acrylic acid)s (AA) with different amounts of tin (3, 5, 10, and 20 wt %) were synthesized and characterized. The materials were characterized by 1H NMR and FTIR spectroscopy, X‐ray diffraction (XRD), specific area by isotherm of CO2, and thermogravimetry‐differential scanning calorimetry (TG‐DSC). The synthesized material is crystalline and shows an average crystal size 90–130 nm and has a high thermal stability (>200°C). Texturally, they are complexes of small specific area, which decreases when the crystal size increases with the tin content. Presumably, the Sn(II) ions coordinate through 2‐4 carboxylate groups by a conventionally bidentate structure; however, they are not symmetric. Studies have been dedicated to support of tin in polymers to increase its efficiency in eliminating pollutants. The tin‐metal salt is added to the poly(AA) matrix to increase its ability to remove As(III) from an aqueous solution. The liquid‐phase polymer‐based retention technique is applied to retain and separate contaminants from water. The analysis of As(III) and As(V) species was made by combining liquid high‐resolution chromatographic coupled to hydride generation absorption atomic spectrophotometer (HPLC‐HG‐AAS). All indicated that As(III) was the predominant species bound to the polymer complex for the pH range 4–8. The polymers containing 10 and 20 wt % Sn presented the highest retention of 70 and 90% As(III), respectively. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

Stability constants of polymer-metal complexes

Conditional stability constants of metal complexes with synthesized copolymers are studied by potentiometric titration. Linear copolymers are found to form more stable complexes than cross-linked sorbents with analogous functional groups. The stability of these complexes decreases in the order Th(IV) > Fe(III) ≈ La(III) > Cu(II).

On the synthesis and rebinding properties of [Co(C 2H 3O 2) 2(z-Histidine)] imprinted polymers prepared by precipitation polymerization

In the present study, the synthesis via free-radical precipitation polymerization of metal-complexing polymer microparticles capable of specific binding to [Co(C 2H 3O 2) 2(z-Histidine)] complex is reported. Initially, the functional monomer (i.e., 4-vinylpyridine, a vinyl monomer with metal chelate properties) is complexed together with the template [Co(C 2H 3O 2) 2(z-Histidine)] molecule via the mediation of cobalt ions. Evidence of the polymerizable complex formation is obtained through the compleximetric titration of the z-Histidine in the prepolymerization reaction mixture. Subsequent polymerization of the polymerizable complex with a bi-functional or tri-functional cross-linker results in the formation of imprinted polymer microparticles in the size range of 1–5 µm. The effects of agitation, cross-linker type, degree of cross-linking and molar ratio of the template to the functional monomer on the rebinding properties of the imprinted polymers are experimentally assessed. The synthesized imprinted polymers can potentially find application in the purification of his-tagged recombinant proteins.