摘要:

AbstractA chemoenzymatic approach was applied to the preparation of chiral 3‐hydroxy‐3‐arylpropionates and 3‐hydroxy‐4,4,4‐trifluorobutanoate that are potential precursors for certain chiral pharmaceuticals including chiral tomoxetines and

ISSN:1001-604X    

DOI:10.1002/cjoc.20040220802

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:2004

数据来源: WILEY

摘要:

AbstractA series of monomers of 5,15‐dithienyl porphyrin, 5,15‐di‐bithienyl porphyrin and their metal complexes were synthesized in high yields. 5,15‐Di‐bithienyl porphyrin and its metal complexes were polymerized by chemical oxidation using FeCl3as oxidant (>go%) for making organic conductor and the linear porphyrin‐thiophene copolymers were obtained. The structures of the copolymers were identified by elemental analysis and IR spectra. The conductivity of poly 5,15‐di‐bithienyl porphyrin was measured to reach over 10−6S/cm. 5,15‐Dithienyl porphyrins and its metal complexes could not be polymerized under the similar conditions, but could be polymerized by electrochemical oxidation on the g

ISSN:1001-604X    

DOI:10.1002/cjoc.20040220803

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:2004

数据来源: WILEY

摘要:

AbstractA novel environmentally benign process for the synthesis of methylN‐phenyl carbamate (Mpc) from methanol and phenylurea was studied. Effect of solvent and catalyst on the reaction behavior was investigated. The IR spectra of methanol and phenylurea dissolved in different solvents were also recorded. Compared with use of methanol as both a reactant and a solvent, phenylurea conversion and selectivity to Mpc increased by using toluene, benzene or anisole as a solvent, while phenylurea conversion decreased slightly by using n‐octane as a solvent. The phenylurea conversion declined nearly 50% when dimethyl sulfoxide (DMSO) was used as a reaction media, and MPC selectivity decreased as well. The catalytic reaction tests showed that a basic catalyst enhanced the selectivity to Mpc while an acidic catalyst promoted the formation of methyl carbamate and aniline. Moderate degree of basicity showed the best catalytic performance in the cases stud

ISSN:1001-604X    

DOI:10.1002/cjoc.20040220804

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:2004

数据来源: WILEY

摘要:

AbstractThe ternary solid complex has been synthesized with sodium diethyldithiocarbamate (NaEt2dtc·3H2O), 1,10‐phenanthroline (o‐phen·H2O) and hydrated neodymium chloride in absolute ethanol. The title complex was identified as the general formula of Nd(Et2dtc)3(phen) by chemical and elemental analyses. IR spectrum of the complex showed that the Nd3+coordinated with six sulfur atoms of three NaEt2dtc and two nitrogen atoms ofo‐phen. It was assumed that the coordination number of Nd3+is eight. The enthalpy change of liquid‐phase reaction of formation, ΔrH Θm(1), was determined as (‐12.274±0.050) kJ·mol−1at 298.15 K by a microcalorimeter, the enthalpy change of the solid‐phase reaction of formation, ΔrH Θm(s), was calculated as (149.069±0.314) kJ·mol−1on the basis of a thermochemical cycle. The thermodynamics of reaction of formation was studied by changing the temperature of liquid‐phase reaction. The constant‐volume combustion energy of the complex, ΔcU, was determined as (‐18674.22±8.33) kI·mol−1by a precise rotating‐bomb calorimeter at 298.15 K. Its standard enthalpy of combustion, ΔcH Θm, and standard enthalpy of formation, ΔfH Θm, were calculated as (‐18693.43 ± 8.3

ISSN:1001-604X    

DOI:10.1002/cjoc.20040220805

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:2004

数据来源: WILEY

摘要:

AbstractThe reaction of acetaldehyde with hydroxyl radical was studied by means of quantum chemical methods. The geometries for all the stationary points on the potential energy surfaces were optimized fully, respectively, at the G3MP2, G3. and MP2/6‐311++G(d,p) levels. Single‐point energies of all the species were calculated at the QCISD/6‐311++G(d,p) level. The mechanism of the reaction studied was confirmed. The predicted product is acetyl radical that is in agreement with the exper

ISSN:1001-604X    

DOI:10.1002/cjoc.20040220806

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:2004

数据来源: WILEY

摘要:

AbstractThe molecular noncovalent interaction often originates from the electrostatic attraction and accords with the Langmuir isothermal adsorption. The sodium dodecyl benzene sulfonate (SDBS)‐polychrome blue B (PCB>protein bovine serum albumin (BSA), ovalbumin (OVA) and myoglobin (MB)] ternary reaction has been investigated at pH 3.88. Protein to replace PCB from the PCB‐SDBS binding product was used to characterize the assembly of an invisible‐spectral compound, SDBS, on proteins by measuring the variation of FCB light‐absorption by tbe micro‐surface adsorption‐spectral correction (MSASC) technique. The effect of ionic strength and temperature on the aggregation was studied. Results showed that the aggregates SDBS92·BSA, SDBS58·VA and SDBS15·MB at 30 C and SDBS83·BSA. SDBS39·OVA and SDBS10·MB at

ISSN:1001-604X    

DOI:10.1002/cjoc.20040220807

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:2004

数据来源: WILEY

摘要:

AbstractThree novel 25,27‐dihydroxy‐26,28‐bis(3‐benzylselenopropoxy)‐5,11,17,23‐tetra‐tert‐butylcdix[4]‐arene (2), 25,27‐dihydroxy‐26,28‐bis[3‐(2‐hydroxyethylseleno)propoxy]‐5,11,17,23‐tetra‐tert‐butyl‐calix[4]arene (3) and 25,27‐dihydroxy‐26,28‐bis(3‐propylselenopropoxy)‐5,11,17,23‐tetra‐tert‐butyI‐calix[4]arene (4) were synthesized for the comparison of their ion‐selectivity in ion‐selective electrodes (ISE). X‐ray structure of the CH/π complex of 4·CH2Cl2was elucidated. ISEs based on 2‐4 as neutral ionophores were prepared, and their selectivity coefficients for Ag+ (logK potAg,M) were investigated against some main group metal ions and transition metal ones using the fixed interference method (FZM). These ISEs showed excellent Ag' selectivity over most of the interfering cations examined. It is evident that the stronger Hg2+interference may not be produce

ISSN:1001-604X    

DOI:10.1002/cjoc.20040220808

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:2004

数据来源: WILEY

摘要:

AbstractThe adsorption and diffusion of hydrogen atom on open rough Pd(311) and Ni(311) stepped surface were investigated in detail using 5‐parameter Morse Potential (5‐MP for short) method. The results on theoretical studies indicate that only threefold adsorption states exist at low coverage, and fourfold states are annihilated on the top layer which become the diffusion channels between threefold adsorption states due to strong competition and repulsion between hydrogen adat

ISSN:1001-604X    

DOI:10.1002/cjoc.20040220809

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:2004

数据来源: WILEY

摘要:

AbstractA novel coordination polymer, [Ag4ppdc)(H2bpdc)(Hbpdc)2] (bpdc = 2,2′‐bipyridyl‐3,3′‐dicarboxylate), was hydrothermally synthesized at 403 K and structurally characterized by single crystal X‐ray diffraction analysis. The compound crystalizes in the monoclinic space group C2/cwitha=1.9516(4) nm, b=1.9503(4) nm. c=1.2566(3) nm, and β=112.48(3)°. In the two‐dimensional crystal structure, AgIcenter is coordinated, in a scarce coordination environment, double‐capped tetrahedron, by one bpdc ligand to form N‐Ag‐N chelate bond via two pyridyl N atoms, and other two bpdc ligands to form two O‐Ag‐O chelate bonds, respectively, via two carboxyl O atoms. The bpdc ligands are present in one non‐protonated form, bpdc, and two protonated forms, Hbpdc and H2bpdc, which all act as μ3‐ligand in a hexadentate fashion (N, N′; O, O′; O, O′) to coordinate with three Ag centers, respectively, through the three chelate bonds. This coordinated fashion of bpdc ligand is first found in the title compound. W‐Us‐NIR reflectance spectroscopy study revealed insulator nature for the crys

ISSN:1001-604X    

DOI:10.1002/cjoc.20040220810

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:2004

数据来源: WILEY

摘要:

AbstractThe studies of the enthalpic interaction parameters,hxy, hxyyandhxyyof alkali metal halides with glycine, α‐alanine and a‐aminobutyric acid were published. Synthetic considering of the results of the studies, some interesting behaviors of the interaction between alkali metal halides and the a‐amino acids have been found. The values ofhxywill increase with the increase of the number of carbon atoms in alkyl side chain of amino acid molecules and decrease with the increase of the radius of the ions. The increasing of the salt's effect on the hydrophobic hydration structure as the radii of anion is more obvious than as that of cation. The value ofhxxywill regularly decrease with the increase of the number of carbon atoms in the alkyl chain of amino acids and linear increase with the increase of the radius. But the relation of hxxy with the radius of cations is not evident. The value ofhxyywill increase with the increase of the radii of the ions. As the increase of the number of carbon atom of amino acids,hxyyis decreas for the ions which have lager size and there is a maximum value at α‐aniline for the ions which have small she. The behaviors of the interaction mentioned above were further discussed in view of electrostatic and structural int

ISSN:1001-604X    

DOI:10.1002/cjoc.20040220811

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:2004

数据来源: WILEY