Electrocatalytic hydrogen evolution of conducting coordination polymers based on 1,1,2,2-ethenetetrathiolate

Electrocatalysis based on metal–organic coordination polymers (CPs) catalyst, especially metal-1,1,2,2-ethenetetrathiolate (ett), has received increasing attention due to their high-electrical conductivity, unique morphology and excellent redox activity. Here, amorphous powder of CPs is synthesized and firmly coated on the surfaces of carbon fiber cloth (CFC), then serves as active electrocatalyst for hydrogen evolution reaction (HER). The operating overpotentials of the poly[K_x(M-ett)] (Co, Ni or Cu) are 0.43, 0.36, 0.45 V, respectively, at a current density of 10 mA cm⁻² with pH = 0, along with the Tafel plot of 144, 153, 329 mV dec⁻¹. Moreover, they show remarkable electrolysis stability under harsh acid conditions. This study extends the HER application of poly[K_x(M-ett)] coating on CFC surfaces.     

导电聚合物基电致变色器件的研究进展

导电聚合物作为电致变色活性材料是目前最有应用前景的智能材料之一。本文概述了电致变色器件的基本结构和导电聚合物的电致变色机理,着重介绍了多种导电聚合物基电致变色器件的特点、组成及制备,并展望了未来电致变色器件的发展及应用趋势。     

Synthesis and properties in solution of ruthenium(II) coordination polymers

Synthetic strategies are presented for the preparation of readily soluble ruthenium(II) coordination polymers of high molecular weight. The constitutional homogeneity of the polymers is proved using high-resolution NMR spectroscopy, and their molar masses are estimated from ¹H NMR spectra, viscosity data and SAXS investigations. The polymers are shown to be conformationally rigid, and to form either densely packed coils or rods. It is mainly this difference in shape which causes the very specific properties of the respective polyelectrolytes in the solid state as well as in dilute solution. Finally, the UV-vis absorption spectra of some of these materials are presented.     

Highly soluble conducting poly(ethylene oxide) grafted at two sites of poly(o‐aminobenzyl alcohol)

Poly(o‐aminobenzyl alcohol) (POABA) was grafted with poly(ethylene oxide)s (PEOs) through the reaction of tosylated PEO with both the hydroxide and amine moieties of reduced POABA. Reduced POABA was prepared through the acid‐mediated polymerization of o‐aminobenzyl alcohol, followed by neutralization with an aqueous ammonium hydroxide solution and reduction with hydrazine. The grafted copolymers were very soluble in common polar solvents, such as chloroform, tetrahydrofuran, and dimethylformamide, and the copolymers with longer PEO side chains (number‐average molecular weight > 164) were even water‐soluble. The conductivities of the doped grafted copolymers decreased with increasing PEO side‐chain length because of the nonconducting PEO and its torsional effect on the POABA backbone. The conductivity of highly water‐soluble POABA‐g‐PEO‐350 was 0.689 × 10^?3 S/cm, that is, in the semiconducting range. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 4756–4764, 2004     

Proton‐conducting polymers based on benzimidazoles and sulfonated benzimidazoles

A sulfonated derivative of polybenzimidazole is reported, and its properties are analyzed in comparison with related polybenzimidazole proton‐conducting materials. Poly(2,5‐benzimidazole), poly(m‐phenylenebenzobisimidazole), and poly[m‐(5‐sulfo)‐phenylenebenzobisimidazole] were prepared by condensation of the corresponding monomers in polyphosphoric acid. Several adducts of these polymers with phosphoric acid were prepared. The resulting materials were characterized by chemical analysis, Fourier transform infrared spectroscopy, and thermogravimetric analysis; also, the dc conductivity of doped and undoped derivatives was measured. Similar to what has been observed for the commercial polybenzimidazole polymer (also examined here for comparison), the title polymers exhibit high thermal stability. Furthermore, their doping with phosphoric acid leads to a significant increase in conductivity from less than 10^?11 Scm^?1 for the undoped polymers to 10^?4 Scm^?1 (both at room temperature) for their acid‐loaded derivatives. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 3703–3710, 2002     

Synthesis,spectral and thermal studies on pyrazolatebridged palladium(II) coordination polymers

Synthesis, spectroscopic characterization and thermal behavior of pyrazolate-bridged palladium complexes [Pd(μ-Pz)₂]_n (1), [Pd(μ-mPz)₂]_n (2), [Pd(μ-dmPz)₂]_n (3), [Pd(μ-IPz)₂]_n (4) {pyrazolate (Pz^–), 4-methylpyrazolate (mPz^–), 3,5-dimethylpyrazolate (dmPz^–), 4-iodopyrazolate (IPz^–)} have been described in this work. The exobidentate coordination mode of pyrazolato ligands in 1–4 was inferred on basis of IR spectroscopic evidences. TG investigations indicated that the introduction of substituents at the 4 position in the pyrazolyl moiety into coordination polymers do not affect significantly their thermal stability, whereas at the 3 and 5 position reduced the stability of the main chain. Metal palladium was the final product of the thermal decompositions, which was identified by X-ray powder diffraction.     

Betaine-induced assembly of neutral infinite columns and chains of linked silver(I) polyhedra with embedded acetylenediide

Ten polymeric silver(I) double salts containing embedded acetylenediide: [(Ag2C2)2(AgCF3CO2)9(L1)3] (1), [(Ag2C2)2(AgCF3CO2)10(L2)3]H2O (2), [(Ag2C2)(AgCF3CO2)4(L3)(H2O)]0.75 H2O (3), [(Ag2C2)(1.5)(AgCF3CO2)7(L4)2] (4), [(Ag2C2)(AgCF3CO2)7(L5)2(H2O)] (5), [(Ag2C2) (AgC2F5CO2)7(L1)3(H2O)] (6), [(Ag2C2)(AgCF3CO2)7(L1)3(H2O)]2 H2O (7), [(Ag2C2)(AgC2F5CO2)6(L3)2] (8), [(Ag2C2)2(AgC2F5CO2)12(L4)2(H2O)4]H2O (9), and [(Ag2C2)(AgCF3CO2)6(L3)2(H2O)]H2O (10) have been isolated by varying the types of betaines, the perfluorocarboxylate ligands employed, and the reaction conditions. Single-crystal X-ray analysis has shown that 1-4 all have a columnar structure composed of fused silver(I) double cages, with C2(2-) species embedded in its stem and an exterior coat comprising anionic and zwitterionic carboxylates. For 5 and 6, single silver(I) cages are linked into a beaded chain through both types of carboxylate ligands. In 7, two different coordination modes of L1 connect the silver(I) polyhedra into a chain. For 8, the mu(2)-O,O' coordination mode of L3 connects the silver(I) double cages into a chain. Compound 9 exhibits a two-dimensional architecture generated from the cross-linkage of double cages by C2F5CO2-, L4, and [Ag2(C2F5CO2)2] units. Similar to 9, 10 is also a two-dimensional structure, which is formed by connecting the chains of linked double cages through [Ag2(CF3CO2)2] bridging.     

Synthesis,characterization and molecular weight studies of certain soluble poly(3-alkylthiophene) conducting polymers

Soluble conducting polymers of 3-hexylthiophene, 3-octylthiophene, 3-decylthiophene and 3-dodecylthiophene were synthesized by constant potential electrolysis. The resultant polymers were characterized by cyclic voltammetry, ultraviolet spectroscopy, thermogravimetric analysis and differential scanning calorimetry. Molecular weights were studied with gel permeation chromatography on solutions of the polymers in toluene. Surface properties were investigated by scanning electron microscopy. Substituent groups lengths have been found to strongly influence the electronic properties of the resultant polymers. Poly(3-hexylthiophene) has shown the highest conductivity, with the highest degree of polymerization. The conductivity and the degree of polymerization values decrease as the substituent chain length increases.H.B. Mark Jr.: deseased     

Studies on the conducting nanocomposite prepared by in situ polymerization of aniline monomers in a neat (aqueous) synthetic mica clay

The in situ polymerization of the anilinium‐intercalated synthetic mica clay can easily result in an intercalated polyaniline (PANI)/clay nanocomposite. The FT‐IR spectra demonstrated a significant shift for ν_{(C? N)} at 1292 cm^?1 of the templated polymerized and intercalated PANI molecules. A red shift of λ_max for PANI was found from UV–vis spectra. The intercalated PANI also expanded the clay basal spacing seen from WAXD patterns. The degradation rate and temperature of the nanocomposites were found to alleviate and increase compared to neat PANI, respectively. The microscopic examinations including TEM, SEM, and AFM pictures of the nanocomposite demonstrated an entirely different and more compatible morphology. Conductivity of nanocomposite gradually increased with PANI and apparent increase was found when intercalated PANI content reached 40.6 wt %, the possible percolation threshold. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 1800–1809, 2008     

Crystal structure and fluorescence/phosphorescence of two novel Cd(II) coordination polymers

Two novel Cd(II) coordination polymers [Cd₄(C₆H₄O₂N)₈(H₂O)₄]_n (1) and [Cd₂(C₁₀H₂O₈)(H₂O)₆]_n (2) have been synthesized under hydrothermal condition and structurally characterized. Crystal data: (1), orthorhombic, Pbca, a=11.4494(19) Å, b=12.0969(6) Å, c=17.4073(8) Å, V=2410.9(4) ų, Z=8, D _calc=2.064 g·cm⁻³; (2), triclinic, P , a=5.5962(7) Å, b=7.7758(6) Å, c=9.6975(10) Å, α=111.981(5)°, β=101.649(6)°, γ=98.240(5)°, V=371.95(7) ų, Z=2, D _calc=2.603 g·cm⁻³. Complex (1) possesses three-dimensional infinite structure, while complex (2) adopts two-dimensional layers and the layers are connected by the many types of hydrogen bonds, forming three-dimensional network. Study results of the photophysical properties show that both complexes can emit strong blue fluorescence and complex (1) also emits phosphorescence (λ ^pl _max=511 nm, τ=32 ms) in the solid state at room temperature.     

A new basic motif in cyanometallate coordination polymers: structure and magnetic behavior of M(mu-OH2)2[Au(CN)2]2 (M=Cu, Ni)

The structures of two cyanoaurate-based coordination polymers, M(mu-OH(2))(2)[Au(CN)(2)](2) (M=Cu, Ni), were determined by using a combination of powder and single-crystal X-ray diffraction techniques. The basic structural motif for both polymers contains rarely observed M(mu-OH(2))(2)M double aqua-bridges, which generate an infinite chain; two trans [Au(CN)(2)](-) units also dangle from each metal center. The chains form ribbons that interact three dimensionally through CNH hydrogen bonding. The magnetic properties of both compounds and of the dehydrated analogue Cu[Au(CN)(2)](2) were investigated by direct current (dc) and alternating current (ac) magnetometry; muon spin-relaxation data was also obtained to probe their magnetic properties in zero-field. In M(mu-OH(2))(2)[Au(CN)(2)](2), ferromagnetic chains of M(mu-OH(2))(2)M are present below 20 K. Interchain magnetic interactions mediated through hydrogen bonding, involving water and cyanoaurate units, yield a long-range magnetically ordered system in Cu(mu-OH(2))(2)[Au(CN)(2)](2) below 0.20 K, as indicated by precession in the muon spin polarization decay. Ni(mu-OH(2))(2)[Au(CN)(2)](2) undergoes a transition to a spin-glass state in zero-field at 3.6 K, as indicated by a combination of muon spin-relaxation and ac-susceptibility data. This transition is probably due to competing interactions that lead to spin frustration. A phase transition to a paramagnetic state is possible for Ni(mu-OH(2))(2)[Au(CN)(2)](2) upon application of an external field; the critical field was determined to be 700 Oe at 1.8 K. The dehydrated compound Cu[Au(CN)(2)](2) shows weak antiferromagnetic interactions at low temperatures.     

Cu(II) coordination polymers stabilized by pyridine-2,6-dicarboxylate anion and pyrazole derivatives through ligand hydrolysis

Abstract

2,6-Pyridinedicarbonyldichloride (PDD) was treated with pyrazole, 3-methylpyrazole, and 3,5-dimethylpyrazole in the presence of trimethylamine at room temperature. Reactions afforded 2,6-bis(pyrazolyl-1-carbonyl)pyridine (1), 2,6-bis(3-methylpyrazolyl-1-carbonyl)pyridine (2) and 2,6-bis(3,5-dimethylpyrazolyl-1-carbonyl)pyridine (3). 1-3 were treated with copper ion under ambient conditions in open air. Such coupling of 1 and 2 with copper led to coordination polymers 6 and 7, bearing 1D architectures, of general formulas [Cu(C₇H₃NO₄)(C₃H₄N₂)]_n and [Cu(C₇H₃NO₄)(C₄H₇N₂)]_n (C₇H₃NO₄?=?2,6-pyridinedicarboxylate ion, C₃H₄N₂?=?pyrazole and C₄H₇N₂?=?3-methylpyrazole), respectively. Under the same experimental conditions, 3 instead forms a mononuclear Cu(II) complex (8). Structures of 1-3 and 6-8 were determined with X-ray diffraction. The solid state structures reveal that short-range intermolecular interactions in the ligands afford 1D (1) and 2D (2 and 3) supramolecular chains, respectively. 6 and 7 both crystallize in the orthorhombic system, space group P2₁2₁2₁. 1–3 were also characterized with elemental analysis and NMR spectroscopy. The magnetic susceptibility measurements indicate that both complexes are paramagnetic with effective moments of 1.75 (6) and 1.90 (7) µ_B at 300 K. The voltammetric signatures of 6 and 8 show two steps reversible redox behavior as evidenced by the appearance of two cathodic waves with corresponding anodic peaks in the backward scan.     

Diversity of coordination modes in the polymers based on 3,3′,4,4′-biphenylcarboxylate ligand

Four new compounds [Ni₂(4,4′-bpy)(3,4-bptc)(H₂O)₄]_n (1), [Ni(4,4′-bpy)(3,4-H₂bptc)(H₂O)₃]_n (2), [Mn₂(2,2′-bpy)₄(3,4-H₂bptc)₂] (3) and {[Mn(1,10-phen)₂(3,4-H₂bptc)]·4H₂O}_n (4) (3,4-H₄bptc=3,3′,4,4′-biphenyltetracarboxylic acid, 4,4′-bpy=4,4′-bipyridine, 2,2′-bpy=2,2′-bipyridine, 1, 10-phen=1, 10-phenanthroline), have been prepared and structurally characterized. In all compounds, the derivative ligands of 3,4-H₄bptc (3,4-bptc⁴⁻ and 3,4-H₂bptc²⁻) exhibit different coordination modes and lead to the formation of various architectures. Compounds 1 and 2 display the three-dimensional (3D) framework: 1 shows a 3,4-connected topological network with (8³)(8⁵·10) topology symbol based on the coordination bonds while in 2, the hydrogen-bonding interactions are observed to connect the 1D linear chain generating a final 3D framework. 3 exhibits the 2D layer constructed from the hydrogen-bonding interactions between the dinuclear manganese units. Complex 4 shows the double layers motif through connecting the 1D zigzag chains with hydrogen-bonded rings. The thermal stability of 1-4 and magnetic property of 1 were also reported.