The chiral Zn(II)–Na(I) coordination polymer: Synthesis, crystal structure, thermal and optical properties

The chiral Zn(II)–Na(I) coordination polymer with formula [NaZn(acac)₂(AcO)(EtOH)] (1) has been synthesized, and characterized by ¹H NMR and FT-IR spectra, elemental, X-ray, and thermogravimetric analysis (TGA). X-ray crystallographic study revealed that 1 crystallizes in the non-centrosymmetric space groups P2₁2₁2₁ and exhibits a one-dimensional polymer chain. Linear optical properties were investigated by UV/Vis spectrophotometer techniques. Kurtz–Perry powder second-harmonic-generation (SHG) test confirms the non-linear optical (NLO) property of the grown crystal.     

Crosslinking of poly(vinyl chloride)—I. Grafting of vinyltri(alkoxy)silanes using UV irradiation

In a nitrogen atmosphere the UV irradiation of thin PVC films (ca. 0.1 mm thick) containing vinyltri(isopropoxy)silane results in a grafting reaction. By appropriate choice of conditions, dehydrochlorination can be kept to a minimum while up to 60% gel content is realized. Reaction of the pendent alkoxy groups, either with HCl byproduct or subsequent hydrolysis by exposure to water, results in the formation of Si—O—Si bonds that serve as chemical crosslinks. Although the addition of photosensitizers favors the grafting reactions at short exposure times, the ultimate level of crosslinking is greatly diminished by their presence. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 69: 1901–1906, 1998     

An unexpected sulfinate–sulfonate mixed coordination polymer of copper(II)

By reaction of copper nitrate trihydrate and 2,2′-dipyridyldisulfide in both aerobic and anaerobic conditions, the mixed [{Cu(2-pySO₂)₂}_n]–[{Cu(2-pySO₃)₂}_n] coordination polymer of copper(II) (1) has been synthesized. The X-ray diffraction analysis indicates that complex 1 exhibits an infinite one-dimensional polymeric chain consisting of [Cu(C₅H₄N)₂] building units connected by SO₂/SO₃ groups. The atom which has been labelled O3 is only present in 60% of the molecules. Complex 1 exhibits a very weak ferrogmagnetic spin coupling (zJ = +0.40 cm⁻¹).     

Hydrothermal synthesis and crystal structure of a novel cyanide-bridged double helical copper(I) coordination polymer [Cu3(CN)3(phen)]n

Hydrothermal reaction of CuCN, K₃[Fe(CN)₆] and 1,10-phenanthroline affords a novel cyanide-bridged copper(I) coordination polymer [Cu₃(CN)₃(phen)]_n (1). The complex displays an interesting one-dimensional neutral double helical framework with (phen)Cu–CN– side-arms as interchain bridges. The double helical chains are close packed in a parallel fashion, and the phen ligands stack in an interpenetrating mode, which leads to π–π interactions between parallel phen planes. The thermal stability and fluorescent property have also been investigated.     

A new three-dimensional Cu(II) coordination polymer with triaminoguanidin building blocks

The reaction between the tris(2-hydroxybenzylidene)triaminoguanidin hydrochloride (H₆L)Cl and copper(II) chloride in the presence of triethylamine leads to a three-dimensional coordination polymer with two interpenetrating (10,3)-a networks of opposite chirality. Magnetic studies revealed strong antiferromagnetic coupling between copper ions of the spin frustrated trinuclear building unit.     

2-取代苯并咪唑与铜（II）配合物的微波合成与表征

采用2-取代基苯并咪唑化合物、氯化铜为原料、丙酮或2-丁酮为溶剂,在微波辐射下合成了2-苄基苯并咪唑(BIm_a)和1-(对甲氧基苄基)-2-(对甲氧基苯基)苯并咪唑(BIm_b)的铜配合物,收率分别为80%和75%.测得BIm_a和BIm_b铜配合物熔点分别为144.7～145.8 ℃和224.5～226.0℃.应用摩尔电导率、XRD、紫外光谱、SEM和热分析测试对目标配合物进行表征,摩尔电导率、紫外和红外光谱解析表明,2-取代苯并咪唑配体与Cu(Ⅱ) 发生了配合反应;XRD和SEM表征证明晶型为单斜晶系;热分析得出BIm_a、BIm_b和氯化铜的配位数分别为1和1/2.     

Synthesis of benzylpyridine using copper zeolite and irradiation – a modified method

The rearrangement of benzylpyridinium chloride to 2‐ and 4‐benzylpyridines (Ladenberg rearrangement) using copper(II)‐exchanged zeolite‐A as a catalyst has been investigated under combined thermal and irradiation conditions. The reaction occurs at a lower temperature (∼160 °C) than the usual temperature of 220 °C. A good yield of a mixture of 2‐ and 4‐benzylpyridines was obtained. Moreover, this catalyst could be recycled. The effects of various parameters have been studied and it is concluded that this modified method holds promise for commercialisation. © 1999 Society of Chemical Industry     

Syntheses and crystal structures of novel silver(I) coordination polymers based on linear or tetrahedral coordination environments

Two coordination polymers containing Ag(I) atoms, {[Ag(3-pia)](PF₆)}_n (1) and {[Ag(3-pia)₂](PF₆)}_n (2) (3-pia = N-pyridin-3-yl-isonicotinamide), have been synthesized using different solvents, and characterized by single X-ray analyses. In compound 1, Ag(I) atoms are linearly coordinated by two 3-pia ligands, resulting in one-dimensional chains. On the other hand, in compound 2, Ag(I) atoms are tetrahedrally coordinated by four 3-pia ligands, resulting in two-dimensional sheets.     

Synthesis and characterization of a novel 3D copper(I) coordination polymer with a ligand generated in situ

Hydrothermal reaction of CuCl₂ · 2H₂O, NaN₃ with 1,4-dicyanobenzene in water/ethanol yielded a novel Cu(I)-tetrazolate, {Cu(cptz)}_n, (1) (Hcptz is 5-(4-cyanophenyl)-tetrazole). The cptz ligand in the complex was generated in situ through the [2 + 3] cycloaddition reaction involving one of the two cyano-groups of the precursor 1,4-dicyanobenzene. The structure characterization shows that 1 possesses a 3D 4-connected SrAl₂ topological network. Additionally, complex 1 exhibits strong yellow fluorescence at room temperature in the solid state.     

One‐pot synthesis of photosensitive dendrimer‐like polystyrenes from simultaneous copper(I)‐catalyzed azide–alkyne cycloaddition and atom transfer radical polymerization

Dendrimer‐like polystyrenes (PSs) containing azobenzene moieties/core were prepared by one‐pot copper(I)‐catalyzed azide–alkyne cycloaddition (CuAAC) and atom transfer radical polymerization (ATRP) in the presence of PS with terminal azide groups, styrene monomers, 2,4‐dibromoisobutyrate‐4′‐propynyloxyazobenzene, copper(I) bromide and ligand. The successful preparation of the dendrimer‐like PSs was confirmed using gel permeation chromatography and ¹H NMR and Fourier transform infrared spectroscopy. The dendrimer‐like PSs prepared from one‐pot CuAAC and ATRP exhibit a well‐defined and controlled molecular structure in both whole macromolecules and the branches, which is attributed to the controlled character of ATRP and the quantitative yield of click chemistry. The dendrimer‐like PSs prepared also exhibit good photo‐isomerization properties due to the incorporation of azobenzene units within the dendrimers. Copyright © 2012 Society of Chemical Industry     

Aerobic oxidative polymerization of 2,6‐dimethylphenol in water with a highly efficient copper(II)– poly(N‐vinylimidazole) complex catalyst

A Cu(II)–poly(N‐vinylimidazole) (PVI) complex was prepared and used to catalyze the oxidative polymerization of 2,6‐dimethylphenol (DMP) to form poly(2,6‐dimethyl‐1,4‐phenylene oxide) (PPO) in water. The stoichiometric ratio between imidazole groups in PVI and copper ions was found to be 4 when continuous variation analysis was applied. Compared with a conventional Cu(II)–low‐molecular‐weight ligand complex, a high catalytic efficiency was observed in the polymerization of DMP catalyzed by the Cu(II)–PVI complex. The influence of the Cu(II)–PVI complex concentration and imidazole/Cu(II) molar ratio on the oxidative polymerization of DMP was studied. Both the yield and molecular weight of PPO increased significantly with the catalyst concentration and decreased with the imidazole/Cu(II) molar ratio. The molecular weight of PVI also played an important role in the improvement of the catalytic efficiency. The high catalytic efficiency of the Cu(II)–PVI complex may have been due to the concentration effect of the catalyst and substrate. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Preparation of melting‐free poly(lactic acid) by amorphous and crystal crosslinking under UV irradiation

The poly(lactic acid) (PLA) with 3.6% mol of benzophenone (BP) per repeat unit of PLA can be crosslinked to a gel fraction of 98.5% at UV energy of 160 J/cm². From NMR analysis, the photocrosslinking of PLA was attributed to the recombination of primary and tertiary carbon radicals in the repeating units which were generated by the hydrogen abstraction of BP. With increasing crosslinking, melting peak disappeared and glass transition temperature elevated with loss of crystallinity, indicating that the crosslinking occurred in the crystalline region as well as in the amorphous region. The thermal stability of the crosslinked PLA also improved as shown by higher onset temperature as much as 56°C and higher maximum decomposition temperature compared with the pristine PLA. The higher toughness of the crosslinked PLA film was obtained together with the improvement in tensile strength and modulus with increasing crosslinking density. In addition to photocrosslinking of amorphous region, the crosslinking of crystalline region can have significant influence in the improvement of thermal and mechanical properties. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Structure and magnetic properties of a copper malonate/dipyridylamine layered coordination polymer with both syn–anti and anti–anti copper carboxylate chains

The novel 2-D copper metal–organic layered coordination polymer {[Cu₂(malonate)₂(dpa)(H₂O)₂] · H₂O} (1, dpa = 4,4′-dipyridylamine) has been prepared and characterized by single-crystal X-ray diffraction, IR and thermogravimetric analysis. The structure of compound 1 consists of alternating syn–anti and anti–anti copper malonate 1-D chains linked into a (6,3) herringbone layer motif through tethering dpa ligands. Variable temperature magnetic studies indicate weak ferromagnetic coupling through the 1-D copper malonate chains with J = 0.64(1) cm⁻¹ and g = 2.033(4).     

Mn and Cu–Na coordination compounds containing the tetrazole-5-acetato anion (tza) ligands

Two novel coordination compounds [Mn(tza) · (H₂O)₂]_n (1) and [CuNa₂(tza)₂ · (H₂O)₄]_n (2) (tza = tetrazole-5-acetato) were synthesized by reaction of tetrazole-5-ethyl acetate with Mn(ClO₄)₂ · 6H₂O and CuCl₂ · 2H₂O in sodium hydroxide solution, respectively. Compound 1 has a one-dimensional (1D) polymeric chain that are bridged by tza linker, while compound 2 has two crystallographically independent metal centers (Cu and Na), that are bridged by tza into a 2D layer structure. The magnetic susceptibility study of 1 demonstrates the presence of antiferromagnetic interaction between two adjacent Mn(II) ions.     

Separation of gold(III) ions from copper(II) and zinc(II) ions using thiourea–formaldehyde or urea–formaldehyde chelating resins

Thiourea–formaldehyde (TF) and urea–formaldehyde (UF) chelating resins were synthesized and these resins were used in the separation of gold(III) ions from copper(II) and zinc(II) base metal ions. In the experimental studies, the effect of acidity on gold(III) uptake and gold(III) adsorption capacities by batch method, and loading and elution profiles of gold(III) ions, gold(III), copper(II), and zinc(II), dynamic adsorption capacities and the stability tests of TF and UF resins by column method were examined. By batch method, the optimum acidities were found as pH 2 and 0.5M HCl, and gold(III) adsorption capacities in the solutions including copper(II) and zinc(II) ions were obtained as 0.088 and 0.151 meq Au(III)/g for UF and TF resins, respectively. On the other hand, by column method, the dynamic adsorption capacities were calculated as 0.109 meq Au(III)/g with TF, 0.023 meq Au(III)/g with UF, 0.015 meq Cu(II)/g with TF, 0.0057 meq Cu(II)/g with UF, and under 6.1 × 10^?5 meq Zn(II)/g with TF or UF. TF resin was more effective in the separation and the concentration of gold(III) ions from copper(II) and zinc(II) ions than UF resin. It was seen that sulfur atoms contributed the gold(III) adsorption comparing with oxygen atoms. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

A novel stair-like lithium coordination polymer constructed from 4,4′-bipyridine

A novel stair-like lithium coordination polymer Li₂(4,4′-bpy)₂(NO₃)₂, 1, has been synthesized by using standard Schlenk techniques. X-ray diffraction shows the 2D stair-like framework contains an approximately perpendicular 1D “Z” type Li-4,4′-bpy chain and an unprecedented Li–NO₃ chain.     

Synthesis and properties of styrene–EPDM–vinyl acetate graft polymer

The styrene–EPDM–vinylacetate (SEV) graft polymer, which linked respectively the styrene (St) unit and vinylacetate the (VAc) unit to the ethylene–propylene–diene terpolymer (EPDM) backbone was synthesized by two‐step graft polymerizations: First the graft polymerization of VAc onto EPDM was carried out, and then St was added successively in the prepolymerized solution and further polymerized for a given period to obtain SEV. The effects of concentration of EPDM and an initiator, mole ratio of VAc to St, polymerization time, temperature, and solvent were examined on the graft polymerizations. The synthesized graft polymers (SEVs) that have different contents of St or VAc were identified by Fourier transform IR spectrum. The highest graft ratio has been obtained by 10 wt % of EPDM, 1.0 mole ratio of VAc to St, and 1.0 wt % of BPO in toluene for 48 h at 70°C. The glass transition temperature of SEV is lower than that of poly(vinyl acetate) (PVAc) and polystyrene (PS). The thermal stability of SEV is higher than that of PVAc, PS, and the acrylonitrile–butadiene–styrene (ABS) resin. The tensile strength of SEV was improved as compared with that of EPDM. The light resistance and weatherability of SEV were better than those of ABS. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 2296–2304, 2000     

Application of FTIR spectroscopy for structural characterization of ternary poly(acrylic acid)–metal–poly(vinyl pyrrolidone) complexes

The FTIR spectroscopic technique was used in the study of ternary polymer–metal complexes containing two polyelectrolytes of opposite charge and metal ions. The structure of the ternary (PAA‐Fe³⁺‐PVP) complexes was examined by following the changes in their infrared spectra. It was found that the shapes of the absorption bands of the resultant compounds are influenced by the presence of Fe³⁺. According to this result it was suggested that two types of structure which differ in the composition are formed, one of which results from the coordination of Fe³⁺ with PAA‐PVP complex and the other is due to the formation of Fe³⁺ polycarboxylate. Comparison between the spectrum of PAA‐PVP complex and those of the compounds resulted from the reaction between the two opposite charged electrolytes, PAA and PVP and each of the divalent metal chlorides NiCl₂, CoCl₂, CuCl₂, and ZnCl₂) led to the conclusion that a reaction took place between the divalent transition metal chlorides and the extent of reaction depends on the nature of metal ions and PAA‐PVP complex. The FTIR spectra of the precipitate resulted from the mixtures of PAA‐PVP and Ni(NO₃)₂ or Sr(NO₃)₂ were investigated. It was noted that the addition of Ni(NO₃)₂ or Sr(NO₃)₂ to the mixture of the electrolytes of PAA and PVP provoked appreciable changes in the characteristic spectral features of the complex resulting from the interaction of the metal ions with the polymer–polymer complex. The FTIR spectra of the precipitate resulted from the reaction between CeCl₃, ErCl₃, and LaCl₃ were also investigated. It was concluded that a reaction took place between the rare earth metals and the PPC. This means that ternary polymer–metal–polymer complexes were formed. The extent of changes in the spectral features differs from metal to metal according to the nature of metal ions. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci, 2007     

Liquid–liquid extraction of copper(II)–EDTA chelated anions with microporous hollow fibers

The rates of extraction of Cu(II)–EDTA (ethylenediaminetetraacetic acid) chelated anions from aqueous solutions across microporous hollow fibers to kerosene solutions of Aliquat 336 (a quaternary amine) were measured. Experiments were performed as a function of aqueous pH, the chelated anion concentration, the organic amine concentration, and temperature. From experiments performed on the temperature dependence of extraction rate, it was shown that the resistance of interfacial chemical reaction was negligible. It was shown that the extraction rate increased with increasing concentrations of both the chelated anions and the amine. However, the aqueous pH had little effect on extraction rate under the ranges studied. The mass transfer mechanism of this extraction process was also discussed. © 2000 Society of Chemical Industry