Synthesis and Crystal Structure of Dichlorobis-(1-methylimidazoline-2(3H)-thione-S) Cobalt(II)

The reaction of anhydrous cobalt(II) dichloride with 1-methylimidazoline-2(3H)- thione in dichloromethane solution gave the title complex, [Co(C4H6N2S)2Cl2]. X-ray single-crystal analysis revealed that the complex crystallizes in a monoclinic system, space group P21/c, a = 13.9707(10), b = 10.0435(7), c = 10.3910(6) ?, β = 91.181(3)o, V = 1457.70(17) ?3, Z = 4, C8H12Cl2N4S2Co, Mr = 358.17, Dc = 1.632 g/cm3, μ = 1.813 mm–1, F(000) = 724, the final R = 0.0710 and wR = 0.1224 for 1549 observed reflections with I > 2σ(I). The Co atom is coordinated by two S atoms from two 1-methylimidazoline-2(3H)-thione ligands and two chloride ions in a slightly distorted tetrahedral geometry. The intramolecular classical hydrogen-bonding interactions involving chloride ions and N–H groups of the heterocyclic thione ligands are observed. The offset π-π stacking interactions between the imidazole rings of adjacent molecules with a face-to-face dis- tance of 3.604 ? are found in the packing diagram.

Spectroscopic and molecular structure characterization of the bis(2-aminophenol)(5, 10, 15, 20-tetraphenylporphyrinato) cobalt(II) complex

The reaction of the cobalt(II) meso-tetraphenylporphyrin (TPP) starting material with an excess of 2-aminophenol (Hon) in organic solvents, yields the cobalt(II) porphyrin species [CoII(TPP)(Hon)2] (1). This compound has been characterized by UV-vis., IR, MSI MS and 1H NMR spectroscopy. The UV-vis data and especially the proton NMR results, for the isolated product, indicated that complex 1 is a Co(II) mesoporphyrin derivative.The X-ray molecular structure of the title compound bis(2-aminophenol) (tetraphenylporphyrinato) cobalt(II) has been determined. This structure is the first one reported of a metalloporphyrin with a 2-aminophenol axial ligand species. The central metal is hexacoordinated by the four nitrogen atoms of the pyrrole rings and the nitrogen atoms of the two Hon trans axial ligands.

Highly Efficient Cobalt (II) Catalyzed O-Acylation of Alcohols and Phenols under Solvent-Free Conditions

Solvent free, highly efficient method has been developed using ecofriendly, heterogeneous reusable cobalt chloride catalyst at ambient reaction conditions for the O-acylation of various alcohols and phenols with acetyl chloride in excellent yield in a short reaction time. The catalyst is recycled several times without loss of catalytic activity.

A Novel Mixed Ligand Dinuclear Complex of Cobalt (II): Synthesis, Characterization and Magnetic Studies

A novel dinuclear complex [Co2(atr)3(mal)2(H2O)2]·4H2O(1) (atr = 4-amino-1,2,4-triazole and mal = malonic acid) containing mixed N and O-donor atoms has been prepared and structurally characterized. The structure is made up of the symmetrically 1, 2, 4-triazole bridged [Co2(atr)3(mal)2(H2O)2] moiety and four lattice water molecules. The single crystal X-ray analysis reveals that the complex has a distorted octahedral structure. Magnetic susceptibility measurements reveals that antiferromagnetic interactions exists between the high spin Co(II) ions within the dinuclear unit.

Synthesis, Characterization and Crystal Structure of Cobalt(II) Complex of a Schiff Base Derived from Isoniazid and Pyridine-4-Carboxaldehyde

A new hydrogen bonded Cobalt(II) Schiff base complex,?N’-(pyridine-4-carboxaldehyde) isonicotinoylhydrazone Cobalt(II), has been synthesized from isoniazid and pyridine-4-carboxaldehyde and characterized by IR spectroscopy, 1H-NMR, elemental analysis, TGA and single crystal X-ray structure determination. X-ray crystal structure analysis shows an octahedral complex with a metal centre coordinated to two ligand molecules through the pyridine nitrogen atoms and four water molecules and containing two nitrate groups as counter ions. The complex crystallizes in the monoclinic crystal system and P2(1)/n space group. The unit cell dimensions are: a = 7.2108(4) Å, b = 16.6020(9) Å, c = 13.0389(6) Å,α = 90°, β = 103.972(4)°, γ = 90°. The molecule is symmetrical about the cobalt centre as observed from the 1H-NMR and 13C-NMR and confirmed by the single crystal X-ray structure of the complex. Thermogravimetric analysis shows two steps decomposition of the complex to leave a metal oxide residue. The title compound is expected to be biologically active as one of the precursors (isoniazid) is a therapeutic agent with well-established clinical applications.

Highly Efficient and Selective Removal of Pb（II） ions by Sulfur-Containing Calcium Phosphate Nanoparticles

A facile one-step co-precipitation method was demonstrated to fabricate amorphous sulfurcontaining calcium phosphate （SCP） nanoparticles, in which the sulfur group was in-situ introduced into calcium phosphate. The resulting SCP exhibited a noticeable enhanced performance for Pb（II） removal in comparison with hydroxyapatite （HAP）, being capable of easily reducing 20 ppm of Pb（II） to below the acceptable standard for drinking water within less than 10 min. Remarkably, the saturated removal capacities of Pb（II） on SCP were as high as 1720.57 mg/g calculated by the Langmuir isotherm model, exceeding largely that of the previously reported absorbents. Significantly, SCP displayed highly selective removal ability toward Pb（II） ions in the presence of the competing metal ions （Ni（II）, Co（II）, Zn（II）, and Cd（II））. Further investigations indicated that such ultra-high removal efficiency and preferable affinity of Pb（II） ions on SCP may be reasonably ascribed to the formation of rodlike hydroxypyromorphite crystals on the surface of SCP via dissolution-precipitation and ion exchange reactions, accompanied by the presence of lead sulfide precipitates. High removal efficiency, fast removal kinetics and excellent selectivity toward Pb（II） made the obtained SCP material an ideal candidate for Pb（II） ions decontamination in practical application.

Dioxygen Affinity and Catalytic Performance of Bis-(furaldehyde) Schiff Bases Co(II) Complexes in Cyclohexene Oxidation

Oxygenation constants and thermodynamic parameters DeltaH degrees and DeltaS degrees of cobalt (II) complexes with bis-(furaldehyde) Schiff bases (1, 2, 3, 4)were obtained by mearsuring saturated dioxygen uptake of these complexes in pyridine at different temperature. These complexes could activate molecular oxygen and were used as catalysts in cyclohexene oxidation. The influence of ligand structure on the dioxygen affinity and catalytic activity of the complexes were discussed.

Dioxygen Affinities and Catalytic Oxidation Performance of Cobalt (Ⅱ)Complexes with N—Aryl Hydroxamic Acid

The oxygenation of cobalt (II) hydroxamates (CoL2) and its catalytic performance in oxidation of p-xylene to p-toluic acid (PTA) were examined. The effects of X and Y bonded to hydroxamate group on dioxygen affinities and catalytic oxidation performance were also investigated.

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

The self-assembly of a flexible bipyridyl ligand 2,2?-bis(4-pyridylmethyle- neoxy)-1,1?-biphenylene (4,4?-bpp) with cobalt(II) center gave rise to a one-dimensional chain complex [Co(μ-4,4?-bpp)2(SCN)2?H2O]n 1 which has been characterized by single-crystal X-ray diffraction. The polymer crystallizes in monoclinic, space group C2/c with unit cell parameters: a = 13.1888(13), b = 24.230(2), c = 15.4218(17) ?, β = 93.291(6)o, V = 4920.1(8) ?3, Z = 4, C50H42CoN6O5S2, Mr = 929.95, Dc = 1.255 g/cm3, F(000) = 1932 and μ(MoKα) = 0.484 mm-1. The final R and wR are 0.0691 and 0.1670 for 3746 observed reflections with I > 2σ(I). 1 possesses an infinite 1-D polymeric chain structure consisting of the repeated basic square units Co2(μ-4,4?-bpp)2, where the Co(II) center acts as the joint of the square ring. The Co(II) center is coordinated in a slightly distorted octahedral geometry with four nitrogen atoms from four different 4,4?-bpp ligands in the equatorial plane and two trans thiocyanate ligands occupying the axial positions, preventing the formation of an extended framework.

Synthesis and Crystal Structure of a Dinuclear Cobalt(II) Complex [Co_2(1H-benzimidazole)_4(1,4-bdoa)_2]

A novel dinuclear complex with an empirical formula [Co2(1H-benzimidazole)4(1, 4-bdoa)2] (1,4-bdoa2– = benzene-1,4-dioxyacetate dianion) has been synthesized and characterized by elemental analysis, IR and single-crystal X-ray diffraction. It crystallizes in monoclinic system, space group P21/c with a = 11.000(2), b = 19.385(4), c = 11.417(2) ?, β = 95.49(3)o, V = 2423.3(8) ?3, Z = 2, Mr = 1074.77, Dc = 1.473 g/cm3, μ = 0.760 mm–1, F(000) = 1108, the final R = 0.0645 and wR = 0.0714 for 3273 observed reflections (I > 2σ(I)). Two octahedrally coordinated Co(II) atoms are bridged by two 1,4-bdoa2– groups, generating a macrocyclic ring complex. The Co…Co separa- tion is 7.677(3) ?. An extended 3-D supramolecular network is formed through hydrogen bonds and weak π-π stacking interactions.

Bioadsorption of Cd (II) from Contaminated Water on Treated Sawdust: Adsorption Mechanism and Optimization

Sawdust (SD) a very low cost material has been utilized as adsorbent material for the removal of Cd (II) from aqueous solutions after treatment with mono methylol urea (MMU) in the presence of zinc chloride as a catalyst to form MMU-SD. The reaction of MMU-SD was carried out under different conditions including MMU/SD molar ratio, catalyst concentration, and reaction time and temperature. Adsorption studies have been carried out to determine the effect of agitation time, pH, adsorbent and adsorbate concentrations on the adsorption capacity of Cd (II) ions onto MMU-SD. Langmuir, Freundlich and Redlich-Peterson isotherm models were applied in the adsorption studies. The experimental data were analyzed using various sorption kinetic models. The removal processes of Cd (II) onto MMU-SD particles could be well described by the pseudo-second order model. The maximum adsorption capacity of Cd(II) onto MMU-SD was 909 mg/g. Similarly, the Freundlich constant 1/n value was 0.45.

Deep removal of copper from cobalt sulfate electrolyte by ion-exchange

SP-C was applied for the removal of Cu^2＋ from simulated cobalt sulfate electrolyte containing Co2＋ 50 g/L and Cu2＋ 0.5-2.0 g/L. Experimental conditions included pH of 2-4, temperature of 20-60℃ and contact time of 10-40 min. The investigation demonstrated that SP-C had recommendable efficiency in adsorbing Cu2＋ from the electrolyte with 25- to 100-fold of Co2＋ The optimal adsorption conditions of SP-C were pH of 4, contact time of 30 min and ambient temperature. The study also showed that the loaded resin could be effectively eluted with 2.0 mol/L H2SO4 solution at a contact time of 40 min; the peak concentration of Cu2＋ in the eluate was about 35 g/L. The sorption characteristics of Cu2＋ by SP-C could be described by Langrnuir isotherm and the pseudo second-order kinetic equation. Infrared spectra showed that nitrogen atoms in the functional group coordinated with Cu2＋ to form coordination bands.

Sesame Husk as Adsorbent for Copper(II) Ions Removal from Aqueous Solution

In this study, the adsorption behavior of copper(II) ions from aqueous solutions onto sesame husk (SH) was investigated. The effect of different parameters such as pH, contact time, adsorbent dosage, adsorbate concentration, temperature and agitation speed was studied. Thermodynamic parameters, equilibrium isotherms and kinetic data have been evaluated. The functional groups and surface morphology of SH adsorbent were characterized by FTIR and SEM. Adsorption equilibrium isotherms were expressed by Langmuir, Freundlich and Dubinin-Radushkevich (D-R) adsorption models and it was found that Langmuir adsorption model fits the experimental data better than Freundlich and D-R models. The adsorption can be best described by the pseudo second-order kinetic model.

Cobalt Sulfide Confined in N-Doped Porous Branched Carbon Nanotubes for Lithium-Ion Batteries

Lithium-ion batteries(LIBs) are considered new generation of large-scale energy-storage devices.However,LIBs suffer from a lack of desirable anode materials with excellent specific capacity and cycling stability.In this work,we design a novel hierarchical structure constructed by encapsulating cobalt sulfide nanowires within nitrogen-doped porous branched carbon nanotubes(NBNTs)for LIBs.The unique hierarchical Co9S8@NBNT electrode displayed a reversible specific capacity of 1310 mAhg-1 at a current density of 0.1 Ag-1,and was able to maintain a stable reversible discharge capacity of 1109 mAhg-1 at a current density of 0.5 Ag-1 with coulombic efficiency reaching almost 100% for 200 cycles.The excellent rate and cycling capabilities can be ascribed to the hierarchical porosity of the one-dimensional Co9S8@NBNT internetworks,the incorporation of nitrogen doping,and the carbon nanotube confinement of the active cobalt sulfide nanowires offering a proximate electron pathway for the isolated nanoparticles and shielding of the cobalt sulfide nanowires from pulverization over long cycling periods.

离子印迹磁性碳纳米球基电化学传感器用于铜(II)的选择性检测

本文报道一种基于Cu(II)离子印迹聚合物为识别元件的电化学传感器。通过耦合表面离子印迹和电化学沉积的制备方法,制备了由磁性碳纳米球组成的离子印迹聚合物电极。所组装的传感器表现出对Cu(II)检测的特异识别性和高灵敏特性。通过场发射扫描电子显微镜和透射电子显微镜对印迹聚合物的微观形貌进行表征,采用傅里叶变换红外光谱对其官能团和化学结构进行表征。传感器电化学性能表明,与非印迹电极和裸电极相比,印迹电极对Cu(II)具有更强的选择性和更高的灵敏度。传感器对浓度为10^(-6)至10^(-10) mol L^(-1)的Cu(II)表现出良好的线性相应电流,其检测限提升至5.138×10^(-16) mol L^(-1)(S/N=3)。此外,该传感器具有良好的抗干扰性、重现性和稳定性,为金属离子的检测提供了新的策略。

Atomic Absorption and Vibrational Spectral Magnetic Studies on the Removal of Cu(II) and Co(II) Ions Using Synthetic Nano Adsorbent Fe₃O₄

Adsorption of Cu(II) and Co(II) from aqueous solutions on synthetic nano Fe3O4 has been studied. The effect of experimental parameters such as initial concentration of the metal ions, adsorbent dosage, contact time and pH has been investigated. Optimum removal efficiency of Cu(II) ion was found to be 97.8% with the dose rate of 1.07 g/L in 60 minutes at pH = 5.5 and for Co(II) ion, it was found to be 99.2% with the dose rate of2.57 g/L in 10 minutes at pH = 5.4. The removal of Co(II) ions require only 10 minutes with the efficient removal of 99.2%, whereas Cu(II) ions require 60 minutes with the maximum removal of 97.8%. In order to understand the effective removal of Cu(II) and Co(II) ions on Fe3O4, room temperature magnetic measurement was carried out using Vibrational Spectrum Magnetometer (VSM), before and after adsorption with a maximum applied magnetic field of 20,000 G.

Electrochemical properties of some cobalt antimonides as anode materi-als for lithium- ion batteries

Some cobalt antimonides have been prepared and studied as the candidate anodematerials for lithium ion batteries. Reversible capacities of 424,423 and 546 mA.h.g^(-1) weremeasured at the first cycle for as-solidified CoSb_2, CoSb_3 and annealed CoSb_3 respectively. A lowlithium ions diffusion coefficient in the order of 10^(16) m^2.s^(-1) was estimated from thecoulometric titration measurements in the annealed CoSb_3 electrode. It was found that theelectrochemical properties of fine powders are significantly better than coarse powders. However theSEM picture shows that the nano-sized CoSb_3 powders gathered to larger granules, which worsenssomewhat the capacity retention of the nano-sized materials, although the volume capacities of theannealed and ball milled CoSb_3 remain near twice of that of graphite after 50 cycles.

Stabilising Cobalt Sulphide Nanocapsules with Nitrogen-Doped Carbon for High-Performance Sodium-Ion Storage

Conversion-type anode materials with a high charge storage capability generally su er from large volume expansion, poor electron conductivity, and sluggish metal ion transport kinetics. The electrode material described in this paper, namely cobalt sulphide nanoparticles encapsulated in carbon cages(Co9S8@NC), can circumvent these problems. This electrode material exhibited a reversible sodium-ion storage capacity of 705 mAh g^-1 at 100 mA g^-1 with an extraordinary rate capability and good cycling stability. Mechanistic study using the in situ transmission electron microscope technique revealed that the volumetric expansion of the Co9S8 nanoparticles is bu ered by the carbon cages, enabling a stable electrode–electrolyte interface. In addition, the carbon shell with high-content doped nitrogen significantly enhances the electron conductivity of the Co9S8@NC electrode material and provides doping-induced active sites to accommodate sodium ions. By integrating the Co9S8@NC as negative electrode with a cellulose-derived porous hard carbon/graphene oxide composite as positive electrode and 1 M NaPF6 in diglyme as the electrolyte, the sodium-ion capacitor full cell can achieve energy densities of 101.4 and 45.8 Wh kg^-1 at power densities of 200 and 10,000 W kg^-1, respectively.

Synthesis and Characterization of a Cobalt Complex with Maleate and Pyridine

A new polymeric cobalt complex [Co(-male)(py)(H2O)]n (male = maleate; py = pyridine) 1 was prepared by cobalt chloride hexahydrate with disodium maleate and pyridine in an alcohol-aqueous solution. Single-crystal X-ray analysis has revealed that 1 crystallizes in the orthor- hombic system, space group Pnma with a = 18.001(1), b = 7.6001(6), c = 7.4731(6) ? V = 1022.4(1) 3, Z = 4, C9H9CoNO5, Mr = 270.10, Dc = 1.755 g/cm3, F(000) = 548, m(MoK? = 1.683 mm-1, S = 1.002, the final R = 0.0280 and wR = 0.0746 for 883 observed reflections with I > 2s(I). The structure analysis shows an approximate octahedral coordination environment of metal center. The Co(II) ions are bridged by maleic anions in a rare tetradentate coordination fashion with a syn-anti coplanar con- formation of the carboxyl group, forming a two-dimensional corrugated 2-D structure which is further attached into a three-dimensional framework via non-classical CH…O interactions between adjacent layers.

A Fluorescent Cobalt(Ⅱ) Complex for the Recognition of Cations and Small Molecules: Synthesis, Structure and Characterization

A fluorescent cobalt（II） complex, 1 [Co（H2bibim）2（5-nipa）], for the recognition of cations and small molecules constructed with 5-nitroisophthalic acid （5-H2nipa） and 2,2＂-biben- zimidazole （H2bibim） has been synthesized by hydrothermal methods and structurally characterized by elemental analysis, IR spectroscopy, PL and single-crystal X-ray diffraction. The cobalt units are six-coordinated by two H2bibim ligands and one 5-nitroisophthalic acid group, which are further connected into a three-dimensional （3D） network by intermolecular hydrogen bonds. Complex 1 exhibits fluorescence and thus has detection capabilities for different cations and small solvent molecules in the solution state at room temperature.