Polymeric Metal Complexes Research Articles

Synthesis and applications of 3,6-carbazole-based conjugated side-chain copolymers containing complexes of 1,10-phenanthroline with Zn(II), Cd(II) and Ni(II) for dye-sensitized solar cells

Three novel donor-acceptor polymeric metal complexes based on polycarbazole containing complexes of 1,10-phenanthroline with Zn(II), Cd(II) and Ni(II) have been synthesized by the Ullmann reaction and characterized by gel permeation chromatography, FT-IR, UV–visible absorption and photoluminescence spectroscopy, cyclic voltammetry and elemental analysis. The application of these organometallic polymers in fabricated dye-sensitized solar cells has been studied. The solar cells exhibited good device performance with a power conversion efficiency of up to 0.44%, under simulated air mass 1.5 G solar irradiation.

Adsorption properties of thermally stable and biologically active polyurea: its synthesis and spectral aspects

Novel polymer metal complexes were prepared by the condensation polymerization of a polymeric ligand with transition metal ions of Mn(II), Co(II), Ni(II), Cu(II) and Zn(II). The polymeric ligand was prepared by the addition polymerization of urea with toluene 2,4‐diisocyanate in 1:1 molar ratio. The polymeric ligand and its polymer metal complexes were characterized by elemental analysis, Fourier transform infrared spectroscopy, 13C‐NMR, and1H‐NMR (nuclear magnetic resonance). The geometry was determined by electronic spectra and magnetic moment measurement. Thermogravimetric analysis (TGA) was utilized to find out the degradation process of the polyurea ligand and the polymer metal complexes. The TGA data revealed that all the metal‐containing polyureas are much more thermally stable than the corresponding polyurea ligand. The surface morphology of the polyurea ligand and cobalt(II)‐containing polyureas was determined by scanning electron micrographs. The antibacterial and antifungal activities of all the synthesized polymers were investigated against Staphylococcus aureus, Escherichia coli, and Bacillus subtilis (bacteria) and Aspergillus niger, Candida albicans, and Aspergillus flavus (fungi). These compounds show remarkably good biocidal activities, which were enhanced after complexation with the metal. Batch adsorption studies of the ligand were carried out for malachite green dye, and the polyurea ligand was found to be a good adsorbent for this dye. Copyright © 2011 John Wiley & Sons, Ltd.

Sodium-phosphorylated chitosan/zinc oxide complexes and evaluation of their cytocompatibility: An approach for periodontal dressing

The aim of this study was to evaluate the possibility of metal complex formation between sodium-phosphorylated chitosan (PCTS) and ZnO. The polymer-metal complex formation was investigated in terms of thermal degradation. The structure deduction of the PCTS/ZnO complex was investigated by means of Fourier transform infrared spectroscopy and X-ray diffraction (XRD). The PCTS/ZnO complexes were formed by the sharing of lone pairs of electrons from the N atoms in the amine groups and O atoms in the phosphate and hydroxyl groups of PCTS to the protonated hydroxyl species on the ZnO surface. Because complex formation occurred at the surface of ZnO particles, it did not change the ZnO crystalline structure. Cytotoxicity, evaluated by a direct contact test with primary human gingival fibroblast cells, revealed that PCTS was biocompatible and reduced the cytotoxicity of ZnO by complexation, making PCTS/ZnO complexes potentially biocompatible. Within the limits of these data, it appears that PCTS could be used as a reaction rate-modifying agent in periodontal dressings.

New antimicrobial agents: The synthesis of Schiff base polymers containing transition metals and their characterization and applications

AbstractA new polymeric Schiff base containing formaldehyde and 2‐thiobarbituric acid moieties was synthesized by the condensation of a monomeric Schiff base derived from 2‐hydroxyacetophenone and hydrazine. Polymer–metal complexes were also synthesized by the reaction of the polymeric Schiff base with Mn(II), Co(II), Ni(II), Cu(II), and Zn(II) acetate. The polymeric Schiff base and its polymer–metal complexes were characterized with magnetic moment measurements, elemental analyses, and spectral techniques (infrared, 1H‐NMR, and ultraviolet–visible). The thermal behaviors of these coordination polymers were studied by thermogravimetric analysis in a nitrogen atmosphere up to 800°C. The thermal data revealed that all of the polymer–metal complexes showed higher thermal stabilities than the polymeric Schiff base and also ascribed that the Cu(II) polymer–metal complex showed better heat resistant properties than the other polymer–metal complexes. The antimicrobial activity was screened with the agar well diffusion method against various selected microorganisms, and all of the polymer–metal complexes showed good antimicrobial activity. Among all of the complexes, the antimicrobial activity of the Cu(II) polymer–metal complex showed the highest zone of inhibition because of its higher stability constant and may be used in biomedical applications. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

Preparation, spectral and biological investigation of formaldehyde-based ligand containing piperazine moiety and its various polymer metal complexes

A novel tetradentate salicylic acid–formaldehyde ligand containing piperazine moiety (SFP) was synthesized by condensation of salicylic acid, formaldehyde and piperazine in presence of base catalyst, which was subjected for the preparation of coordination polymers with metal ions like manganese(II), cobalt(II), copper(II), nickel(II) and zinc(II). All the synthesized polymeric compounds were characterized by elemental analysis, IR, 1H NMR and electronic spectral studies. The thermal stability was determined by thermogravimetric analysis and thermal data revealed that all the polymer metal complexes show good thermal stability than their parent ligand. Electronic spectral data and magnetic moment values revealed that polymer metal complexes of Mn(II), Co(II) and Ni(II) show an octahedral geometry while Cu(II) and Zn(II) show distorted octahedral and tetrahedral geometry respectively. The antimicrobial screening of the ligand and coordination polymers was done by using Agar well diffusion method against various bacteria and fungi. It was evident from the data that antibacterial and antifungal activity increased on chelation and all the polymer metal complexes show excellent antimicrobial activity than their parent ligand.

Synthesis, Spectral Characterization and Biocidal Activity of Thermally Stable Polymeric Schiff Base and Its Polymer Metal Complexes

The polymer metal complexes of transition metal ions Mn(II), Co(II), Ni(II), Cu(II) and Zn(II) with a new polymeric Schiff base containing formaldehyde and piperazine moieties have been synthesized by the condensation and characterized by elemental analyses, infrared spectra, electronic spectra, magnetic susceptibility measurements and thermogravimetric analyses (TGA). The results of the electronic spectra and magnetic moments indicate that the polymer–metal complexes of Mn(II), Co(II) and Ni(II) have octahedral geometry, while the complexes of Cu(II) and Zn(II) show square planar and tetrahedral geometry, respectively. The analyses of the thermal curves of all the polymer metal complexes show better thermal stability than the polymeric Schiff base. All compounds show excellent antibacterial as well as antifungal activity against three types of bacteria and two types of fungi. The antimicrobial activities were determined by using the agar well diffusion method with 100 μg/mL concentrations of polymer metal complex.

Polymer complexes: LIX. Supramolecular structural, spectral and thermal analysis of N‐[2‐(6‐aminopyridino)] acrylamide polymer complexes

AbstractNovel ligand N‐[2‐(6‐aminopyridino)] acrylamide (APA) is prepared via amidation of 2,6‐diaminopyridine with acryloyl chloride in dry benzene as solvent. The ligand is characterized on the basis of elemental analysis, infra‐red (IR) analysis and 1H nuclear magnetic resonance. Metal–polymer complexes are reported and characterized based on elemental analysis, molar conductance, magnetic susceptibility measurements, IR, 1H nuclear magnetic resonance, electronic spectra and thermal analysis. The molar conductance of the polymer complexes in dimethylformamide corresponds to a 1:1/1:2 electrolyte, which is non‐electrolytic. IR spectra show that polyAPA is coordinated to the metal ions in a uni‐negatively bidentate manner with N, O donor sites of azomethine N and deprotonated enolic‐O. All the polymer complexes are of high spin type. On the basis of spectral studies an octahedral geometry may be assigned for Co(II) and Ni(II) polymer complexes. The thermal stabilities of the polymer complexes were studied and the activation energies of the degradation were calculated. Copyright © 2011 Society of Chemical Industry

Switchable pH-Responsive Polymeric Membranes Prepared via Block Copolymer Micelle Assembly

A process is described to manufacture monodisperse asymmetric pH-responsive nanochannels with very high densities (pore density >2 × 10(14) pores per m(2)), reproducible in m(2) scale. Cylindric pores with diameters in the sub-10 nm range and lengths in the 400 nm range were formed by self-assembly of metal-block copolymer complexes and nonsolvent-induced phase separation. The film morphology was tailored by taking into account the stability constants for a series of metal-polymer complexes and confirmed by AFM. The distribution of metal-copolymer micelles was imaged by transmission electron microscopy tomography. The pH response of the polymer nanochannels is the strongest reported with synthetic pores in the nm range (reversible flux increase of more than 2 orders of magnitude when switching the pH from 2 to 8) and could be demonstrated by cryo-field emission scanning electron microscopy, SAXS, and ultra/nanofiltration experiments.

Metal-containing polyurethanes from tetradentate Schiff bases: synthesis, characterization, and biocidal activities

N,N′-bis(salicylidene)thiosemicarbazide Schiff base has been synthesized by the reaction of thiosemicarbazide with salicylaldehyde and then reacted with formaldehyde to generate phenolic groups, resulting in the formation of Schiff-base monomeric ligand. It was further incorporated with transition metals, Mn+2, Co+2, Ni+2, Cu+2, and Zn+2, to form Schiff-base metal complex, which was then polymerized with toluene 2,4-diisocyanate to form metal-chelated polyurethanes. Monomeric ligand, its metal complexes, and its metal polychelates were characterized and compared by elemental analysis, FT-IR, 1H NMR, thermal, and biocidal activities to evaluate the enhancement in physical and chemical properties on coordination with metal and on polymerization. SEM images of ligand and polymer metal complexes showed changes in surface morphology, while electronic spectra of polymer metal complexes were used to predict the geometry. Antimicrobial activities were determined by using agar-diffusion method with Staphylococcus aureus, Escherichia coli, Bacillus subtilis (bacteria), Aspergillus niger, Candida albicans, and Aspergillus flavus (yeast). The polymeric ligand had varied antibacterial and antifungal activities, enhanced after chelation and polymerization. Comparative results show that coordination of metal to the ligand enhances its physical and chemical properties which were meliorated on polymerization.

Anti-tumor efficacy of polymer–platinum(II) complex micelles fabricated from folate conjugated PEG-graft-α,β-poly [(N-amino acidyl)-aspartamide] and cis-dichlorodiammine platinum(II) in tumor-bearing mice

To develop a tumor-targeting nano-sized delivery system of cis-dichlorodiammine platinum(II) (CDDP), polymer-metal complex micelles were fabricated from folate-conjugated PEG-graft-α,β-poly [(N-amino acidyl)-aspartamide] (FA-PEG-g-PAAsp) and CDDP. The formation of polymer-metal complex micelles was confirmed by the measurements of critical aggregation concentration (CAC) and particle size, and the morphological observation. It was found that all the micelles showed spherical shapes with clear core-shell structures in narrow size distributions. The typical particle size measured by dynamic laser scattering (DLS) was ca. 105 nm, suggesting their passive targeting to tumor tissue and endocytosis potential. FA-PEG-g-PAAsp-CDDP micelles showed sustained drug release profiles over 40 h, and their accumulative drug release was ranked in the order of FA-PEG-g-PAsp-Ami-CDDP<FA-PEG-g-PAsp-Glu-CDDP<FA-PEG-g-PAsp-Asp-CDDP, depending on the category of used amino acid (Ami: potassium aminomalonate; Glu: glutamic acid; and Asp: aspartic acid). Cellular uptake of FA-PEG-g-PAsp-Ami-CDDP micelles was found to be higher than that of mPEG-g-PAsp-Ami-CDDP micelles because of folate receptor (FR)-mediated endocytosis, which is revealed by the cellular uptake image of Nile red-loaded micelles, and thereby provided higher cytotoxicity against FR-positive KB cells. Although the anti-tumor activity against KB cell-derived tumors was ordered at CDDP>FA-PEG-g-PAAsp-CDDP>mPEG-g-PAAsp-CDDP, the severe toxicity of CDDP in vivo limited its use as ideal anti-tumor drug. Furthermore, FA-PEG-g-PAAsp-CDDP and mPEG-g-PAAsp-CDDP showed rather low toxicity against mice, just similar to that of PBS. It indicated the great potential utilization of the FA-PEG-g-PAAsp-CDDP micelles as the tumor-targeted drug carriers of CDDP with improved anti-tumor efficacy.

New macromolecular ligands carrying side pyridylquinoline groups and their metal-polymer complexes with iridium

Copolymers of N-vinylcarbazole and methyl methacrylate carrying side pyridylquinoline groups are synthesized on the basis of the methacrylol derivative of 2-pyridylquinoline-4-carboxylic acid hydrazide. It is shown that the copolymers form stable metal-polymer complexes with Ir(ppy)2Cl (ppy = 2-phenylpyridine). The spectral and photoluminescent properties of the metal-polymer complexes are studied.

A novel main chain polymeric metal complex based on Zn(II) with thiophene and 2-(2′-pyridyl)benzimidazole ligand: Synthesis, characterization, photovoltaic property and application in DSSCs

Dye-sensitized solar cells (DSSCs) have extensive interests in recent years because of their unique advantages: low cost, simple preparation technologies and high efficiency. A novel main chain polymeric metal complex of [2-(2′-pyridyl)benzimidazolyl]-3-methylthiophene (Bmtp) with Zn (II) was designed and investigated as dye sensitizers for dye-sensitized solar cells (DSSCs). This polymer was found to be good stabilities with thermal decomposition temperatures at 292 °C and high glass transition temperature (152 °C), which indicates this polymer could be applied as photovoltaic material for DSSCs. The obtained polymer exhibited good photovoltaic property. The DSSCs based on Bmtp-Zn exhibited a maximum power conversion efficiency (PCE) up to 1.88% ( J sc = 4.09 mA/cm 2, V oc = 0.65 mV, and FF = 0.71) under simulated AM 1.5 G solar irradiation (90–95 mW/cm 2).

Cisplatin-loaded gelatin-poly(acrylic acid) nanoparticles: Synthesis, antitumor efficiency in vivo and penetration in tumors

Cisplatin (CDDP)-loaded gelatin-poly(acrylic acid) (GEL-PAA) nanoparticles were successfully prepared by polymerizing acrylic acid in the presence of gelatin in aqueous solution followed by incorporating CDDP into the formed GEL-PAA nanoparticles through polymer–metal complex formation of CDDP with carboxylic groups in the nanoparticles. The obtained nanoparticles had a spherical shape, with a mean size of about 100 nm, and high drug payload as well as stability. It is found that CDDP can be released from the nanoparticles in a sustained manner with a small initial burst release. In vitro cytotoxicity revealed that CDDP-loaded nanoparticles had similar cytotoxicity to free CDDP after 48 h co-incubation with human colorectal cancer cell line LoVo. In vivo antitumor activity indicated that the nanoparticle formulation was superior in anticancer effect to free CDDP on murine hepatic H22 tumor-bearing mice model through intraperitoneal (i.p.) administration and displayed a dose-dependent antitumor efficacy. Further, the penetration examination of the nanoparticles through tumor tissue revealed that the CDDP-loaded GEL-PAA nanoparticles could only affect the cells near the tumor vasculature after they entered into the tumor tissue.

Two novel branched chain polymeric metal complexes based on Cd(II), Zn(II) with fluorene, thiophene, 8-hydroxyquinoline, and 1,10-phenathroline ligand: synthesis, characterization, photovoltaic properties, and their application in DSSCs

Two novel side chain polymeric metal complexes (PFT-Cd and PFT-Zn) have been designed, synthesized, and characterized. These polymers were found to be good thermally stable and high glass transitions temperature, which indicate that these polymers could be applied as photovoltaic materials for dye-sensitized solar cells (DSSCs). The obtained polymers exhibited good photovoltaic property. The DSSCs based on the PFT-Cd and PFT-Zn exhibited a maximum solar-to-electricity conversion efficiency (η) up to 3.37% (Jsc = 7.27 mA/cm2, Voc = 0.67 V, and FF = 0.69) and 3.01% (Voc = 0.72 V, Jsc = 6.10 mA/cm2, FF = 0.69) under simulated AM 1.5 G solar irradiation (90–95 mW/cm2). The result shows that these novel materials are suitable for the dye-sensitized solar cells. Copyright © 2011 John Wiley & Sons, Ltd.

Structures and physical properties of oligomeric and polymeric metal complexes based on bis(pyridyl)-substituted TTF ligands and an inorganic analogue

The bis(pyridyl)-substituted TTF derivative, 2,6(7)-bis(4-pyridyl)-1,4,5,8-tetrathiafulvalene (TTF(py)(2)), and an inorganic analogue, [Ni(4-pedt)(2)] (4-pedt = 1-(pyridin-4-yl)ethylene-1,2-dithiolate), were used as bridging ligands to construct two multinuclear complexes {Co(II)(2)(Tp(Ph2))(2)(OAc)(2)[TTF(py)(2)]} (1, Tp(Ph2) = hydridotri(3,5-diphenylpyrazol-1-yl)borate) and {Co(II)(2)(Tp(Ph2))(2)(OAc)(2)[Ni(4-pedt)(2)]} (2), and two 1D zigzag chain complexes, {[M(II)(tta)(2)][TTF(py)(2)]}(n) (M = Cu for 3, and Mn for 4; tta = thenoyltrifluoroacetonate). X-Ray structural studies indicate that complexes 1 and 2 are very similar as a result of the isolobal analogy between TTF(py)(2) and [Ni(4-pedt)(2)], whereas complexes 3 and 4 are isostructural. The absorption spectra, electrochemical and magnetic properties for these new complexes have been studied. The results show that the interactions between the paramagnetic ions are weak owing to the large separation of the bridging ligands of TTFs and the inorganic analogue.

Polymer catenanes via a supramolecularly templated ATRP initiator

Synthesis of polymer catenanes via a living radical polymerization and supramolecular template approach are demonstrated. The ring closure was performed via atom transfer radical cross coupling (ATRC) to obtain polymer catenanes from the linear polymer metal complex precursor.

Phase Dependent Heterogeneous Dynamics of Li+ Ion in LiPO3 Based Systems

A normal lithium ion conductor, lithium metaphosphate has been taken up for transport studies, as it has enabled for investigation of the Li+ ion transport in (i) crystalline form as LiPO3, (ii) crystalline LiPO3 heterogeneously doped with inert oxide inclusion and homogeneously doped with aliovalent cations, (iii) glassy form as mol% 50Li2O:50P2O5, synthesized by melt-quenching process and (iv) newly identified polymer-metal salt complex (PEO)6:LiPO3. All the above materials have been characterized through XRD, DSC, SEM, Raman spectroscopy and impedance spectroscopy techniques.

Polymer–metal complex as gel electrolyte for quasi-solid-state dye-sensitized solar cells

A kind of polymer–metal complex gel electrolyte is successfully prepared and is used in dye-sensitized solar cells. Raman and X-ray photoelectron spectroscopy confirm the structure of this complex and is found that the metal ion reacts with nitrogen in the polymer. This novel electrolyte shows apparent diffusion coefficient of iodide of 8.37 × 10 −7 cm 2 s −1 and the energy conversion efficiency of 6.10% when the amount of ZnI 2 is 0.04 M. By studying the dissociation active energy of the inorganic salt in electrolytes, we find that the metal salts can dissociate more easily after reacting with polymer and as a result can provide extra free iodide ion. The cell maintains ca. 93% of its initial efficiency after 20 d without further sealing, which shows good long-time stability.

Antimicrobial agents: synthesis, spectral, thermal, and biological aspects of a polymeric Schiff base and its polymer metal(II) complexes

Some new coordination polymers of Mn(II), Co(II), Ni(II), Cu(II), and Zn(II) obtained by the interaction of metal acetates with polymeric Schiff base containing formaldehyde and piperazine have been investigated. Structural and spectroscopic properties have been studied by elemental, spectral (FT-IR, 1H-NMR, and UV-Vis), and thermogravimetric analysis. UV-Vis spectra and magnetic moments indicate that Mn(II), Co(II), and Ni(II) polymer metal complexes are octahedral, while Cu(II) and Zn(II) polymer metal complexes are square planar and tetrahedral, respectively. All compounds were screened for their antimicrobial activities against Escherichia coli, Bacillus subtillis, Staphylococcus aureus, Pseudomonas aeruginosa, Salmonella typhi, Candida albicans, Agelastes niger, and Microsporum canis using the Agar well diffusion method with 100 µg mL−1 of each compound.

Polymer-metal complexes based on gellan

By dropwise adding solutions of gellan (Gil) or gellan + poly(vinyl alcohol) (PVAL) mixture into different metal salt solutions - FeCl3 · 6 H2O, FeCl2 · 4 H2O, CoCl2 · 6 H2O, CuCl2 · 2 H2O - at 30 °C under constant stirring, preparation of spherical microparticles based on polymer-metal complexes has been performed. FT-IR spectroscopy, TGA analysis and swelling measurements of these microparticles in water showed the influence of the metal type ions on their structure, thermal stability and water swelling capacity. The FT-IR spectroscopy allows to explain the mechanism of polymer-metal complexes formation and the optical microscopy showed that the microparticles obtained had good sphericity with average diameter ranging from 719 μm to 830 μm. The thermal stability of the polymer-metal complexes was found to be higher than that of the gellan.