Electrochemical characterization of Co(II) and Pd(II) phthalocyanines carrying diethoxymalonyl and carboxymethyl substituents

In this study, electrochemical behaviors of Co(II) and Pd(II) phthalocyanines carrying tetrakisdiethoxymalonyl and Pd(II) phthalocyanine carrying tetrakiscarboxymethyl substituents at the peripheral positions are investigated by cyclic voltammetry and applied potential chronocoulometry techniques. Cyclic voltammetric studies show that, while Pd(II) phthalocyanines carrying diethoxymalonyl and carboxymethyl substituents give up to three common phthalocyanine ring reductions, Co(II) phthalocyanine carrying diethoxymalonyl substituents gives a metal-centered oxidation and a metal-centered reduction and three ligand-centered reduction and a ligand-centered oxidation processes. First reduction processes of both the PdPc complexes have shoulders. This different voltammetric behaviors of Pd(II) phthalocyanines carrying carboxymethyl and diethoxymalonyl substituents results from interaction of this distinctive substituents with the phthalocyanine ring π electron system and interaction with the different solvent systems. Observation of the splitting of the first reduction process of Pd(II) phthalocyanines carrying diethoxymalonyl and carboxymethyl substituents suggests the aggregation of the complex. Very small diffusion coefficient of the complexes with respect to Co(II) phthalocyanine also confirms the existence of the aggregation of the complex during the electrochemical studies. Effects of the substituents and the solvent media are clearly observed from the differences of the voltammograms of Pd(II) phthalocyanines carrying diethoxymalonyl and carboxymethyl substituents in DMSO and THF solvent media, respectively. Published in Russian in Elektrokhimiya, 2006, Vol. 42, No. 1, pp. 36–43. The text was submitted by the authors in English.     

Synthesis and Crystal Structure of a Co（II） Coordination Polymer Derived from a Flexible Bipyridyl Derivative Ligand

1 INTRODUCTION The infinite networks constructed from transition metal complexes have attracted considerable current interest in recent years. The motivation behind this activity has been stimulated by their potential appli- cations in selective inclusion of ions, molecular re- cognition, host-guest chemistry, ion exchange, cata- lysis, electrical conductivity, magnetism, optics and so on[1～4]. It is well known that the diversity in structures and topologies of supramolecules is attri- b…     

Electrochemistry and Spin-Crossover Behavior of Fluorinated Terpyridine-Based Co(II) and Fe(II) Complexes

Due to their ability to form stable molecular complexes that have tailor-made properties, terpyridine ligands are of great interest in chemistry and material science. In this regard, we prepared two terpyridine ligands with two different fluorinated phenyl rings on the backbone. The corresponding Co^II and Fe^II complexes were synthesized and characterized by single-crystal X-ray structural analysis, electrochemistry and temperature-dependent SQUID magnetometry. Single crystal X-ray diffraction analyses at 100 K of these complexes revealed Co−N and Fe−N bond lengths that are typical of low spin Co^II and Fe^II centers. The metal centers are coordinated in an octahedral fashion and the fluorinated phenyl rings on the backbone are twisted out of the plane of the terpyridine unit. The complexes were investigated with cyclic voltammetry and UV/Vis-NIR spectroelectrochemistry. All complexes show a reversible oxidation and several reduction processes. Temperature dependent SQUID magnetometry revealed a gradual thermal SCO behavior in two of the complexes, while EPR spectroscopy provided further insights on the electronic structure of the metal complexes, as well as site of reduction.     

Synthesis, Crystal Structure and Electrochemical Properties of One-dimensional Chain Coordination Polymer [Co(II)(C_6H_5CH=CHCOOH)_2(4,4′-bipy)(H_2O)_5]_n

A one-dimensional chain coordination polymer [Co(II)(C6H5CH=CHCOOH)2(4,4′- bipy)(H2O)5]n has been synthesized with cinnamylic acid, 4,4′-bipy and cobaltous chloride as raw materials. Crystal data for this complex: monoclinic, space group P21/c, a = 1.1481(3), b = 1.1230(2), c = 1.1759(3) nm, β = 97.054(4)o, V = 1.5046(6) nm3, Mr= 617.50, Dc = 1.363 g/cm3, Z = 2, μ(MoKα) = 0.627 mm-1, F(000) = 646, S = 1.062, R 0.0443 and wR = 0.1178. The crystal structure shows that two neighboring cobalt(II) ions are linked together by one 4,4′-bipy, and the whole complex molecule adopts a one-dimensional chain structure. Each cobalt(II) ion is coordinated with two nitrogen atoms from two 4,4′-bipy molecules and four oxygen atoms from four water molecules, giving a distorted octahedral coordination geometry. The electrochemical properties were analyzed by combining with the crystal structure.     

电化学方法对两性接枝星形聚合物LB膜屏蔽效应的研究

本文将自制Y式玻碳电极拉上两性接枝星形聚合物(GPSMA)的LB膜,用循环伏安法研究谈膜的屏蔽效应,讨论了接枝量、成膜条件等对膜缺陷的影响,并提出了减少缺陷的办法。     

The Solvent Effect on Composition and Dimensionality of Mercury(II) Complexes with Picolinic Acid

Three new mercury(II) coordination compounds, {[HgCl(pic)]}_n (1), [HgCl(pic)(picH)] (2), and [HgBr(pic)(picH)] (3) (picH = pyridine-2-carboxylic acid, picolinic acid) were prepared by reactions of the corresponding mercury(II) halides and picolinic acid in an aqueous (1) or alcohol–methanol or ethanol (2 and 3) solutions. Two different types of coordination compounds were obtained depending on the solvent used. The crystal structures were determined by the single-crystal X-ray structural analysis. Compound 1 is a one-dimensional (1-D) coordination polymer with mercury(II) ions bridged by chelating and bridging N,O,O′-picolinate ions. Each mercury(II) ion is four-coordinated with a bidentate picolinate ion, a carboxylate O atom from the symmetry-related picolinate ion and with a chloride ion; the resulting coordination environment can be described as a highly distorted tetrahedron. Compounds 2 and 3 are isostructural mononuclear coordination compounds, each mercury(II) ion being coordinated with the respective halide ion, N,O-bidentate picolinate ion, and N,O-bidentate picolinic acid in a highly distorted square-pyramidal coordination environment. Compounds 1–3 were characterized by IR spectroscopy, PXRD, and thermal methods (TGA/DSC) in the solid state and by ¹H and ¹³C NMR spectroscopy in the DMSO solution.     

Effect of Lithia and Substrate on the Electrochemical Performance of a Lithia/Cobalt Oxide Composite Thin‐Film Anode

Highly porous reticular Li₂O/CoO composite thin films fabricated by electrostatic spray deposition were investigated by using X-ray diffraction, scanning electron microscopy, galvanostatic cell-cycling measurements, and AC impedance spectroscopy measurements. The results of the electrochemical tests indicate that the initial coulombic efficiency and capacity retention are dependent on Li₂O content and the specific surface area of the deposited layer. Irrespective of the type of substrate, the electrode gave the best electrochemical performance when the molar ratio of Li to Co was controlled at 1:1. At the optimal composition, at 0.2 C the initial coulombic efficiency was as high as 81.9 % and 83.6 % for the film on Cu foil and on porous Ni, respectively. The Li₂O/CoO (Li/Co=1:1) films on Ni foam and Cu foil had sustained capacities of up to 790 and 715 mAh g⁻¹, respectively, at a rate of 1 C over 100 cycles at 25 °C. Similar cycling experiments carried out at 70 °C showed that the capacity is temperature-sensitive, and it exhibited reversible capacities as high as 1018 (Cu foil) and 1269 mAh g⁻¹ (Ni foam) for up to 100 cycles. The thin-film electrodes on Ni foam always performed better than those on Cu foil. Cycling at elevated temperature (70 °C) also resulted in a significant increase in capacity.     

Anthracene Substituted Co (II) and Cu (II) phthalocyanines; Preparations,Investigation of Catalytical and Electrochemical Behaviors

An approach to investigation of catalytical behaviors of Co (II) and Cu (II) phthalocyanines is reported that is based on changing any parameter to effect these behaviors. Towards this end, new anthracene substituted Co (II) and Cu (II) phthalocyanines were prepared and characterized spectroscopic methods. New cobalt (II) and copper (II) phthalocyanines were used as catalyst for oxidation of different phenolic compounds (such as 2,3‐dichlorophenol, 4‐methoxyphenol, 4‐nitrophenol, 2,3,6‐trimethylphenol) with different oxidants. Then, electrochemical characterization of cobalt (II) and copper (II) phthallocyanines were determined by using cyclic voltammetry (CV) and square wave voltammetry (SWV) techniques. Although copper (II) phthalocyanine showed similar Pc based electron transfer processes, cobalt (II) phthalocyanine showed metal and ligand based reduction reactions as expected.     

混合溶剂诱导PS膜的去润湿过程

采用光学显微镜及原子力显微镜等实验手段研究了聚苯乙烯(PS)膜在水和丙酮混合溶剂诱导下的去润湿过程.实验发现,在亲水基底上,随着丙酮含量的减少,在整个去润湿过程中孔半径与时间呈e指数关系[R～exp(t/τ)],然后呈线性关系(R～t),最后为R～t0.76,并且孔增长机理从成核增长机理转变为取代机理.在疏水基底上,随...     

Synthesis and Structural Characterization of Co(Ⅱ) Coordination Polymer [Co(-phth)(imi_)2]_n

1 INTRODUCTION The polymeric metal complexes with extended structures are of great interest because of their useful chemical or physical properties[1]. Due to the noticeable fact that the aromatic polycarboxylate can provide versatile coordination mode and the non-coplanar structure of the carboxylate groups and the benzene rings, a lot of efforts in this field have been particularly directed to the preparation of aromatic polycarboxylate (such as phthalate, tere- phthalate and isophthal…     

增塑剂对PVA碱性聚合物电解质电化学性能的影响

通过溶解―铸膜法制备聚乙烯醇(PVA)-KOH-H2O碱性聚合物电解质膜。向聚合物中添加增塑剂丙三醇(GROL)和碳酸丙烯酯(PC)来提高离子电导率。X射线晶体衍射分析(XRD)结果表明,添加增塑剂未改变聚合物的物相结构,薄膜仍主要为不定形态。差示扫描热分析(DSC)结果显示,添加增塑剂后聚合物电解质膜的玻璃化转变温度降低,促进了电解质膜向不定形态转变。电解质膜室温离子电导率随增塑剂添加而增大,增塑剂超过一定量后离子电导率开始下降。PC对提高离子电导率的作用优于GROL。循环伏安测试结果显示,电解质膜的电化学稳定性窗口随增塑剂的添加而有所变窄,但仍显示了较好的电化学稳定性。     

Electrochemical Properties of Poly (ethyl acrylate-co-lithium methacrylate) Latex Film Solid Electrolyte

Muchattentionhasbeenpaidtothedevelopmentofnewpolymerelectrolytewithspecialmorphology,soastoimprovetheirelectrochemicalpropertiestomeettheneedsoflithium(ion)battery.Inthiswork,PEMlatexwassynthesizedbyemulsion-fi-eepolymerization.ThemicrophotoofPEMlate...     

Solvent extraction studies of cobalt(II) by capric acid from sodium sulfate solution

The extraction of cobalt(II) from sulfate medium of ionic strength 0.33?mol dm^?3 by capric acid dissolved in chloroform has been carried out at 25°C. By using the slope analysis method, the stoichiometry of the organometallic complex extracted was determined. Cobalt(II) complex exists as a mononuclear species CoL₂.2HL in the lower concentration region of capric acid and a binuclear ones (CoL₂.2HL)₂ in the higher concentration region. Extraction constants for each species were given. UV–visible and FTIR spectroscopy have also been used for the investigation of the extractant and their complexes. Electronic spectrum of cobalt(II) caprate species indicates the octahedral structure.     

Electrochemical Properties of a Conducting Film Derived from Iron(II) Tris(diaminopolypyridyl) Complex in the S(IV) Oxoanions Reduction

A new conducting film derived from the complex [Fe (diaphen)₃]²⁺, (diaphen=5,6‐diamino‐1,10‐phenanthroline) was electropolymerized by cyclic voltammetry onto a glassy carbon electrode. Poly‐[Fe^II (diaphen)₃] was studied by cyclic voltammetry, SEM, UV‐vis and micro‐Raman spectroscopy. Poly‐[Fe^II (diaphen)₃] shows electrocatalytic activity in HSO₃^? reduction in an ethanol/water solution. Electrocatalysis is centered at the π ring of phenanthroline. Rotating disk electrode studies showed a 0.117 V/dec Tafel slope, suggesting an EC process where the electrochemical process is the determining step. The chemical step was studied by UV‐vis spectroelectrochemistry. Amperometric behavior showed a linear range between 47.5 µM to 417 µM and the LOD was 19.5 µM.     

Br^—对（TPP）Co电化学氧化还原行为影响研究

用微电极和薄层循环伏安（ＣＶ）技术研究了Ｂｒ＾－对四苯基钴卟啉（ＴＰＰ）Ｃｏ）在１，２－二氯乙烷（ＤＣＥ）中电化学行为的影响，发现在较高电位下，两个Ｂｒ＾－轴向配位的（ＴＰＰ）Ｃｏ（Ⅲ）（Ｂｒ＾－）２其一个Ｂｒ＾－发生脱落表现出（ＴＰＰ）Ｃｏ（Ⅲ）（Ｂｒ＾－）的行为特征，这被证明是Ｂｒ＾－的氧化所致证明了（ＴＰＰ）Ｃｏ（Ⅲ）Ｂｒ＾－在约０．１２Ｖ（ＳＣＥ）处还原，而（ＴＰＰ）Ｃｏ（Ⅲ）（Ｂｒ＾－）     

自生长镍基MOF材料的结构调控及其电化学性能

以六水合氯化镍(NiCl2·6H2O)为金属盐,对苯二甲酸(PTA)为有机配体,通过改变溶剂的类型,采用一步溶剂热法在泡沫镍表面自生长高负载量的镍基MOF材料(Ni-MOF/NF)。溶剂对PTA的溶解性越好或pH值越高,PTA在溶液中的去质子速率越快,材料的形核速率越快。自生长镍基MOF材料在不同溶剂体系下表现出球簇、片状和块体状三类形貌,同时负载量也随之改变。当采用三元混合溶剂(N,N-二甲基甲酰胺、水和乙醇的体积比为1∶1∶1)时,Ni-MOF/NF材料在泡沫镍表面的负载量达到10 mg·cm-2,在3 mol·L-1 KOH电解液中1 mA·cm-2的电流密度下的面积容量达到8780 mF·cm-2。在5 mA·cm-2电流密度下,面积容量仍达到5544 mF·cm-2,容量保持率为63%,表现出优良的倍率性能。经过1000次充放电循环后容量保持率为56%,具有良好的循环稳定性能。     

Hierarchical Hollow Co9S8 Microspheres: Solvothermal Synthesis,Magnetic, Electrochemical,and Electrocatalytic Properties

A simple solvothermal route in a binary solution of triethylenetetramine (TETA) and deionized water (DIW) has been used to synthesize hierarchical hollow Co₉S₈ microspheres with high surface area (80.38 m² g^?1). An appropriate volume ratio of TETA:DIW has been found to be essential for the formation of hollow Co₉S₈ microspheres. The magnetic study indicated that the Co₉S₈ hollow microspheres are paramagnetic at high temperature and antiferromagnetic at low temperature. The oxygen reduction reaction experiments demonstrated that the onset potential of the Co₉S₈ sample is 0.88 V, which is comparable to the value predicted for Co₉S₈ (0.74 V) from the theoretical simulation. The discharge capability of Co₉S₈ hollow microspheres as cathode materials for lithium ion batteries and their electrocatalytic activity for the oxygen reduction reaction (ORR) have been studied.     

聚苯乙烯-嵌段-聚丁二烯有序多孔膜在可收缩膜上的形变研究和光学性质

利用溶剂散逸自组装法在潮湿的条件下,制备了聚苯乙烯-聚丁二烯嵌段聚合物（PS-b-PB）有序多孔膜。 利用聚乙烯可收缩膜将PS-b-PB多孔膜进行两次收缩,形成小孔径的有序多孔膜。 通过收缩,膜上的孔由圆形变为长方形或者梭形,孔的尺寸从微米级收缩至亚微米级。 利用扫描电子显微镜对膜收缩过程中2种形状产生的机理进行了研究。 结果表明,PS-b-PB结合了聚苯乙烯（PS）和聚丁二烯（PB）两个均聚物的优点,收缩后仍然保持膜结构的平整性,从而将不可见的热场变化转变为可见的光学变化。     

Solvent extraction and bulk liquid membrane transport of Co(II) and Ni(II) ammine cations by proton-ionizable crown ethers

Separation efficiencies and selectivities in solvent extraction of Co(II) and Ni(H) ammine cations from aqueous solutions into chloroform and toluene and in transport through bulk toluene membranes by proton-ionizable crown ethers have been determined. Six proton-ionizable crown ethers with differing lipophilicities, polyether cavity sizes and ionizable groups (carboxylic and sulfonic acid functions) were examined. Higher selectivity and efficiency for Co(II) ammine cation extraction was observed for the more lipophilic, proton-ionizable crown ethers. Highly lipophilic crown carboxylic acids provided effective and selective transport of Co(II) ammine cations through bulk toluene membranes.Presented in part at the 6th International Symposium on High Purity Materials in Science and Technology: Preparation, Characterization and Application of Well-Defined Materials, Dresden, GDR, May 1985, Poster D91, Poster Abstracts, pp. 144, 145.All extraction and transport experiments were conducted at this location.