KeFei Wang

New Ionic Liquid Crystal of N,N'-Dialkylbenzimidazolium Salt Comprising Cobalt (II) Thiocyanate

A new metal-containing ionic liquid crystal of N,N ′- dialkylbenzimidazolium of [(C12H25)2-bim]2[Co(SCN)4] (bim = benzimidazole) was synthesized by reaction of the ligand [(C12H25)2-bim]Br and cobalt (II) thiocyanate. Its structure was characterized by X-ray crystallography, IR spectroscopy, and elemental analysis. The cation of the title complex adopts a U-shaped conformation and is packed in a highly interdigitated bilayer fashion. The distorted tetrahedron [Co(SCN)4]2– is located between the cationic bilayers individually. The liquid crystalline behavior of the title complex was studied by differential scanning calorimetry and polarized optical microscopy. The results of the ionic conductivity measurement displayed that the ionic conductivity of the title complex was significantly higher than that of the ligand. The conductivity of the title complex had very large difference in the different organic solvents, while that had a maximum value in N,N ′-dimethylformamide solution.

An electrochemical sensing platform based on a new copper complex for the determination of hydrogen peroxide and nitrite

Abstract A new copper(II) complex [Cu(C12H23N3)4Br2·2H2O] was synthesized and its structure was characterized by x-ray crystallography and elemental analysis. The copper atom had a distorted octahedron coordination involving two bromide anions and four nitrogen atoms from the 1-decyl-1H-[1,2,4]triazole ligands. Moreover, the electrochemical behavior and electrocatalysis of the carbon paste electrode (Cu-CPE) bulk-modified by the complex have been studied in detail. The Cu-CPE showed excellent electrocatalytic activities toward the reduction of hydrogen peroxide and nitrite, and the detection limit was much lower than that mentioned in earlier reports. This bulk-modified CPE has good reproducibility, long-term stability and surface renewability, which appear promising for constructing chemical sensors.

Two new manganese(II) complexes bulk-modified carbon paste electrodes: Preparation and electrocatalytic activities

Two new manganese complexes of [(2-py)CNOH]2Cl2 (1) and [(2-py)CNOH] 2(OAc) 2 (2) were synthesized and their structures were characterized by X-ray crystallography, IR spectroscopy and elemental analysis. Two complexes were used as bulk modifier to fabricate two carbon paste electrodes (Mn-CPE: 1-CPE and 2-CPE). The electrochemical behaviors of two modified electrodes were characterized by cyclic voltammetry. They have similar electrochemical behaviors and good electrocatalytic activities toward the reduction of hydrogen peroxide and nitrite. The results are reproducible with a lower detection limit than earlier reports. There exist a good linear relationship between peak current with the concentration in the range of 0.10–1.20 μM and a detection limit of 0.08 μM for hydrogen peroxide, and in the range of 0.02–0.10 μM and a detection limit of 0.01 μM for nitrite. Also Mn-CPE exhibits remarkable long term stability, simple preparation and inexpensive material, which is important for practical application on electrochemistry sensors.

(6E)-N-[(4Z)-2,5-Dimethyl-4-(p-tolyl­imino)cyclo­hexa-2,5-dienyl­idene]-4-methyl­aniline

The title compound, C22H22N2, was prepared by the reaction of 4-aminotoluene with sodium carbonate, sodium hydroxide and potassium permanganate. The molecule is disposed about a crystallographic inversion centre with one half-molecule comprising the asymmetric unit. The dihedral angle between the terminal and central benzene rings is 88.05 (1)°. The crystal packing is stabilized by van der Waals forces.

THREE NEW IONIC LIQUIDS OF U-SHAPE N,N-DIALKYLBENZIMIDAZOLIUM SALTS: PREPARATION AND CHARACTERIZATION

The present work reports on the synthesis, crystal structures, thermal behaviors and conductivities of three new ionic liquids of [(C12H25)2-bim]NO3 (1a), [(C8H17)2-bim]HSO4 (1b) and [(C10H21)2-bim]ClO4 (1c) (bim=benzimidazole). Their structures were characterized by X-ray crystallography, IR spectroscopy and elemental analysis. The cations of three compounds adopt U-shaped conformations and are packed in a highly interdigitated bilayer fashion. Thermal behaviors were studied by differential scanning calorimetry (DSC). The conductivity of 1b was lower than 1a and 1c. The difference of the conductivity may be attributed to the difference of anion.

Synthesis, characterization, and electrocatalysis of a dinuclear cobalt(III) thioxanthate complex

This study reports on the synthesis, characterization, and performance of a new dinuclear cobalt(III) thioxanthate complex of [Co2(μ-SC2H4OH)2(HOC2H4SCS2)4] as an electrocatalyst for trichloroacetic acid (TCA) and bromate reduction. Its structure was characterized by X-ray crystallography and elemental analysis. The structure contains two different anions of 2-sulfanylethanol thioxanthate and 2-sulfanylethanol. The electrochemical behavior and the electrocatalysis of the cobalt complex bulk-modified carbon paste electrode have been studied by cyclic voltammetry. It shows good electrocatalytic activities toward the reduction of TCA and bromate. The values for the detection limit and the sensitivity are 0.06 µmol L−1 and 19.40 µA µmol L−1 for TCA detection and 0.01 µmol L−1 and 177.6 µA µmol L−1 for bromate detection, respectively. This modified electrode exhibits good reproducibility, high stability, low detection limit and technical simplicity, and allows a possibility for rapid preparation, which is important for practical applications.

A new zinc complex of 1-propyl-1H-benzo[d] imidazole: synthesis, characterization and electrocatalysis

AbstractThe present work reports the synthesis, characterization and performance of a new zinc(II) complex of [Zn(C3H7-bim)2Br2] (bim = benzimidazole) as electrocatalyst for trichloroacetic acid and bromate reduction. Its structure was characterized by X-ray crystallography, IR spectroscopy and elemental analysis. The zinc atom adopts a distorted tetrahedral geometry by coordinating to two bromine atoms and two nitrogen atoms from two 1-propyl-1H-benzo[d]imidazole ligands. The electrochemical behavior and electrocatalysis of the zinc complex bulk-modified carbon paste electrode (Zn-CPE) have been studied by cyclic voltammetry. The Zn-CPE shows good electrocatalytic activities toward the reduction of trichloroacetic acid and bromate. The detection limit and the sensitivity are 0.05 μM, 67.43 μA μM−1 for trichloroacetic acid detection, and 0.02 μM, 69.94 μA μM−1 for bromate detection, respectively. This modified electrode shows good reproducibility, high stability, low detection limit, technical simplicity and possibility of rapid preparation, which is important for practical applications.

1,2-Di-2-furylethane-1,2-dione

The title compound, C10H6O4, lies across a twofold rotation axis through the midpoint of the C—C bond between the two carbonyl groups. The furan ring plane and the plane through all atoms are inclined at 23.88 (1)°. In the crystal structure, weak C—H⋯O hydrogen bonds form sheets in the bc plane and columns down the c axis.

2,3-Bis(4-bromo­phen­yl)quinoxaline

The title compound, C20H12Br2N2, was prepared by the reaction of 1-(3-bromophenyl)-2-(4-bromophenyl)ethane-1,2-dione with o-phenylenediamine in refluxing ethanol. In the molecule, all bond lengths and angles are within normal ranges. The dihedral angle between the two benzene rings is 34.89 (1)°. The dihedral angles between the benzene rings and the quinoxaline system are 57.23 (1) and 36.75 (1)°. The crystal packing is stabilized by van der Waals forces.