摘要：
Acetophenone reacted with a series of aromatic aldehydes with grinding under catalysis of a double-component solid base system consisting of NaOH and K2CO3 to furnish highly chemoselectively 1,2,3,4,5-pentasubstituted cyclohexanols in 80-95% yield, and their composition and structure are identified by spectral technologies and single crystal X-ray diffraction analysis, and a possible mechanism of the formation was suggested. (c) 2006 Elsevier Ltd. All rights reserved.
摘要：
In the crystal structure of the title compound, C15H12Cl2O2, the chloro-substituted benzene rings are not parallel; the other rings are nearly parallel and the molecules stack in layers parallel to these rings. There are two molecules in the asymmetric unit.
摘要：
The title compound, C40H36O5, was synthesized from p-anisaldehyde and acetophenone. The central six-membered ring adopts a chair conformation and most of the bulky side groups are located in equatorial positions. The hydroxyl group is involved in weak intra- and intermolecular hydrogen bonding.
作者机构：
[付时雨] State Key Laboratory of Pulp and Paper Engineering, South China University of Technology, Guangzhou 510640, China;[周攀登] Department of Chemistry and Environment Engineering, Hunan City University, Yiyang 413000, China
通讯机构：
[Fu, S.] S;State Key Laboratory of Pulp and Paper Engineering, , Guangzhou 510640, China
摘要：
A new strategy for constructing the capacitance immunosensor was developed based on gold nanoparticles, which were employed as the platform to immobilize immunospecies. Gold nanoparticles were fixed on the gold electrode, on which the oligomer layer of o-aminobenzenthiol was pre-formed via electrochemical polymerization. An interesting immunospecies was loaded on gold nanoparticles to complete the fabrication of capacitance immunosensor. The changes in morphology of the gold electrode during the experiments were revealed by atomic force microscopy (AFM). The properties of the gold electrode were investigated by cyclic voltammetry, in the presence of an electro-active species as indictor. Also, potentiostatic pulse technique was used in order to evidence the changes of electrode capacitance. The feasibility of the proposed capacitive immunosensor was evaluated for a non-competitive heterogeneous immunoassay of transferrin. The assay covers a relatively large dynamic range of 0.125–100 ng/ml transferrin with a detection limit of 80 pg/ml and a relative high signal-to-noise ratio.
作者机构：
[Liu, GD] New Mexico State Univ, Dept Chem & Biochem, Las Cruces, NM 88003 USA.;Hunan City Coll, Dept Environm Chem & Engn, Yiyang 413049, Peoples R China.
通讯机构：
[Liu, GD] N;New Mexico State Univ, Dept Chem & Biochem, Las Cruces, NM 88003 USA.
摘要：
An amperometric immunosensor was constructed by dispersing graphite, schistosoma-japonicum antigen (SjAg) and silica sol-gel at low temperature. The performance characteristics of the prepared immunosensor were examined in the buffered solution of o-aminophenol (o-AP) used as a substrate. It exhibited excellent physical and electrochemical stability with a renewable external surface. A competitive binding assay was employed to determine schistosoma-japonicum antibody (SjAb) with the aid of horseradish peroxidase labeled SjAb (HRP-SjAb). The experimental parameters for SjAb assay were optimized, including the amount of labeled SjAb in incubation solution, incubation time, temperature and the pH of solution. The use of o-AP substrate and amperometric detection at -250 mV (vs. SCE) results in a determination limit of 0.32 μg/ml and a linear range extending up to 0.18 μg/ml. The results of SjAb assay in serum samples demonstrate the feasibility of using the proposed immunosensor for clinical analysis.
摘要：
A highly selective and sensitive electrochemical sensor modified with carboxymethylated, beta-cyclodextrin (CM-beta-CDP) polymer film was fabricated for the determination of dopamine (DA) in the presence of ascorbic acid (AA). The electrochemical behavior of DA and AA at the chemically modified electrode was investigated by cyclic voltammetry (CV) and differential pulse voltammetry. The response mechanism of CM-beta-CDP film for DA was based on the combination of electrostatic and inclusion interaction of CM-beta-CDP for DA, which was distinguished from the response mechanism of the charged polymer film modified electrode that only relied upon the electrostatic interaction between charged polymer film and DA (or AA) to realize the separation of overlapping peak potential of DA and AA. The CM-beta-CDP film showed preferable analytical performance characteristics in catalytic oxidation of DA compared with the beta-CDP polymer film. Under optimized conditions, it was feasible for the electrode modified with the CM-beta-CDP film to selectively determine DA in the presence of a large excess of AA. A linear calibration plot was obtained over the range 0.8-60 muM with a sensitivity of 65 nA/muM and a detection limit (signal/noise (S/N) = 3) of 0.2 muM in the presence of 1.0mM AA. This electrochemical sensor showed excellent sensitivity, repeatability, stability, and recovery for the determination of DA. The interference of AA with the determination of DA could be efficiently eliminated.
摘要：
A new enzyme-based amperometric biosensor for hydrogen peroxide was developed relying on the efficient immobilization of horseradish peroxidase (HRP) to a nano-scaled particulate gold (nano-Au) film modified glassy carbon electrode (GC). The nano-Au film was obtained by a chitosan film which was first formed on the surface of GC. The high affinity of chitosan for nano-Au associated with its amino groups resulted in the formation of nano-Au film on the surface of GC. The film formed served as an intermediator to retain high efficient and stable immobilization of the enzyme. H2O2,was detected using hydroquinone as an electron mediator to transfer electrons between the electrode and HRP. The HRP immobilized on nano-Au film maintained excellent electrocatalytical activity to the reduction of H2O2. The experimental parameters such as the operating potential of the working electrode, mediator concentration and pH of background electrolyte were optimized for best analytical performance of amperometry. The linear range of detection for H2O2 is from 6.1 x 10(-6) to 1.8 x 10(-3) mol L-1 with a detection limit of 6.1 mumol L-1 based on signal/noise = 3. The proposed HRP enzyme sensor has the features of high sensitivity (0.25 Almol(-1)cm(-2)), fast response time (t(90%) less than or equal to 10 s) and a long-term stability (> 1 month). As an extension, glucose oxidase (GOD) was chemically bound to HRP-modified electrode. A GOD/HRP bienzyme-modified electrode formed in this way can be applied to the determination of glucose with satisfactory performance.
摘要：
Benzil is an important photosensitive initiator of organic synthesis intermediates,medicinal intermediates and ultraviolet solidified resin (UVresin),and is usually prepared by oxidizing benzoin, The oxidizers and methods reported are mainly;(PhCH_2Et_3N)~+Br~-/(PhCO)_2O_2/MeCN~[1],DMSO/(COCL)_2 CH_2CL_2~[2],CrO_3·CH_3NH_2·HCl/Al_2O_3~[3], the metallorganic compound~[4],microwave radiation~[5],etc.The reaction conditions of some methods are harsh, the toxicity is heavy, the reaction reagent is expensive, the preparation is difficult, the aftertreatment is tedious or the conversion ratio of materials is low.Cupric compound is a kind of weak oxidizer.Up till now there is only the report of oxidizing benzoin with cupric sulfate-pyridine~[6] with cupric acetate-acetic acid~[7].This paper studies the problem of oxidizing benzoin by using cupric nitrate, cupric chloride, cupric sulfate,cupric acetate and cupric subcarbonate as oxidizers.The experimental results indicate that these cupric compounds can all oxidize benzoin into benzil in acetic acid solutions, and cupric nitrate is the best one.Its product has these adventages of fine color and luster,high yield, available raw material and simple and easy operation and it has the prospects of being used widely.
