期刊：
Journal of Chemical Information and Modeling,2004年44(6):2099-2105 ISSN：1549-9596
通讯作者：
Yang, GF
作者机构：
[Yang, GF] Cent China Normal Univ, Coll Chem, Key Lab Pesticide & Chem Biol, Minist Educ, Wuhan 430079, Peoples R China.;Univ Kentucky, Coll Pharm, Dept Pharmaceut Sci, Lexington, KY 40536 USA.
通讯机构：
[Yang, GF] C;Cent China Normal Univ, Coll Chem, Key Lab Pesticide & Chem Biol, Minist Educ, Wuhan 430079, Peoples R China.
摘要：
This study examined the applicability of various density functional theory (DFT)-based descriptors, such as energy gap (ΔE) between the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO), weighted nucleophilic atomic frontier electron density (WNAFED, F <inf>i</inf><sup>N</sup>), mean molecular polarizability (α), and net atomic charge (Q<inf>i</inf>), in quantitative structure-activity relationship (QSAR) studies on a class of important protoporphyrinogen oxidase (Protox) inhibitors including a series of cyclic imide derivatives with various heterocyclic rings and substituents. Our QSAR analysis using the quantum chemical descriptors calculated at the B3LYP/6-31G(d,p) level led to a useful explicit correlation relationship, i.e. pI<inf>50</inf> = -5.7414 + 0.1424α- 0.0003α<sup>2</sup> - 0.4546F<inf>C.</inf><sup>N</sup> + 0.2974Q<inf>N.</inf> (n=26, R<sup>2</sup>=0.87), showing that descriptors mean molecular polarizability, α, and WNAFED F<inf>C.</inf><sup>N</sup> of a critical carbon atom and net atomic charge (Q<inf>i</inf>) in the molecules are most likely responsible for the in vitro biological activity of cyclic imides. It has been shown that the use of the DFT-based quantum chemical descriptors indeed led to a better QSAR equation than that obtained from the use of the corresponding descriptors calculated at a semiempirical PM3 level. The present work demonstrates that the DFT-based quantum chemical descriptors are potentially useful in the future QSAR studies for quantitatively predicting biological activity, and, therefore, the DFT-based QSAR approach could be expected to help facilitate the design of additional substituted cyclic imide derivatives of Protox inhibitors with the potentially higher biological activity.
期刊：
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY,2004年126(32):10035-10043 ISSN：0002-7863
通讯作者：
Isaacs, L
作者机构：
[Isaacs, L] Univ Maryland, Dept Chem & Biochem, College Pk, MD 20742 USA.;Cent China Normal Univ, Coll Chem, Wuhan 430079, Peoples R China.
通讯机构：
[Isaacs, L] U;Univ Maryland, Dept Chem & Biochem, College Pk, MD 20742 USA.
摘要：
We report the synthesis and characterization of eight C-shaped methylene-bridged glycoluril dimers (1-8) bearing hydrogen-bonding amide groups on their aromatic rings. Compounds 1-6 undergo tight dimerization in CDCl <inf>3</inf> solution (K<inf>s</inf> >9 ×10<sup>5</sup> M <sup>-1</sup>);binary mixtures of 1-7 form mixtures of homodimers and heterodimers in moderately selective dimerization processes (0.23 &le K <inf>eq</inf> &le 768;0.253 &le χAB <0.933). The high affinity formation of 1·1-6·6 is due to the commensurate nature of the geometrical constraints imposed by the π-πinteractions and only two hydrogen bonds. The differential response of the strengths of the π-πinteractions and H-bonds of 2·2 to changes in solvent polarity-from C<inf>6</inf>D<inf>6</inf> to D<inf>2</inf>O-results in the formation of a solvent-independent isostructural aggregate that exhibits high affinity dimerization across the full range of solvents.
摘要：
The carbodiimides 4, obtained from aza-Wittig reactions of iminophosphorane 3 with aromatic isocyanates, reacted with secondary amines to give 2-dialkylamino-5,6,7,8-tetrahydro-benzothieno[2,3-d]pyrimidin-4(3H)-ones 6 in presence of catalytic EtO<sup>-</sup>Na<sup>+</sup>. Reactions of 4 with phenols or ROH in presence of catalytic K<inf>2</inf>CO<inf>3</inf> or RO <sup>-</sup>Na<sup>+</sup> gave 2-aryl(alkyl)oxy-5,6,7,8-tetrahydro- benzothieno[2,3-d]pyrimidin-4(3H)-ones 6 in satisfactory yields. The effects of the nucleophiles on cyclization have been investigated.
摘要：
The isothiocyanates 2, obtained from aza-Wittig reactions of vinyliminophosphoranes 1 with CS<inf>2</inf>, reacted with hydrazine to give 3-amino-2-thioxo-4-imidazolidinones 4. Reactions of 4 with triphenyphosphine, hexachloroethane and Et<inf>3</inf>N produced iminophosphoranes 5. A tandem aza-Wittig reaction of iminophosphoranes 5 with isocyanates generated imidazo[2,1-b]-1,3,4-thiadiazol-5(6H)-ones 7 in moderate yield.
作者机构：
[Xu, MF] Cent S Univ, Sch Met Sci & Engn, Changsha 410083, Peoples R China.;Cent China Normal Univ, Dept Chem, Wuhan 430079, Peoples R China.;Wuhan Univ, Sch Chem, Wuhan 430072, Peoples R China.
通讯机构：
[Xu, MF] C;Cent S Univ, Sch Met Sci & Engn, Changsha 410083, Peoples R China.
摘要：
The influence of four kinds of Schiff bases on a strain of Escherichia coli was studied by microcalorimetry. Differences in their capabilities of suppressing the metabolism of this bacterium were observed. The results show that the extent and duration of the inhibitory effect on the metabolism as judged from the multiplication rate constant, k, varies with different Schiff bases.The multiplication rate constant k, of Escherichia coli (in log phase) in the presence of Mo-salicylioaldehyde-thiadizole, Mo-piperonaldehyde-thiosemicarbazone and Mo-3-methoxy-salicylicaldehyde-thiadizole decreases with the increase of concentrations of compounds c, and the relationships between k and c, maximum heat production rate Pm and c, peak time of growth curves tp and c are of linearity. For Mo-6-nitro-pieronalde-thiosemicarbazone, the multiplication rate constant is constant irrespective of variation in concentration. The sequence of antibiotic activity of Schiff base is: Mo-salicylioaldehyde-thiadizole＞Mo-3-methoxy-salicylicaldehyde-thiadizole＞Mo-piperonaldehyde-thiosemicarbazone＞ 6-nitro-pieronalde-thiosemicarbazone.
期刊：
Transition Metal Chemistry,2003年28(5):563-567 ISSN：0340-4285
通讯作者：
Song, FH
作者机构：
[Song, FH; Zhu, XD; Li, HM; Hu, ZQ; Wang, CG] Cent China Normal Univ, Sch Chem, Wuhan 430079, Hubei, Peoples R China.
通讯机构：
[Song, FH] C;Cent China Normal Univ, Sch Chem, Wuhan 430079, Hubei, Peoples R China.
摘要：
N′-2-Hydroxy-3-methoxy-benzalmethylene-O,O′-diethylphosphorohydrazonothionate (HL) and its six complexes (ML2) with CuII, ZnII, NiII, FeII, CoII and MnII have been synthesized and characterized. The crystal structure of CuL2 shows that the metal ion is tetracoordinated, bound to 2N from imine and 2O from hydroxybenzene to form a parallelogram. The effects on Stenostigma remota cells of complexes CuL2, CoL2 and MnL2 have been determined by microcalorimetry, which indicates that the compounds inhibit the metabolism of the insect cells.
摘要：
A sensitive and selective method has been developed for the speciation of Cr(III) and Cr(VI) in natural water using a nanometer titanium dioxide micro-column (20 mm×3.0 mm i.d.) and inductively coupled plasma atomic emission spectrometry (ICP-AES). Under the optimized conditions (pH 6.0, flow rate 1.0 ml min−1), Cr(III) was retained on the column, then eluted with 2.0 mol l−1 HCl and determined by ICP-AES. Total chromium was determined after the reduction of Cr(VI) to Cr(III) by ascorbic acid as reducing reagent. The adsorption capacity of nanometer TiO2 for Cr(III) was found to be 7.6 mg g−1. The detection limit for Cr(III) was 0.32 μg l−1 and the relative standard deviation (R.S.D.) was 2.4% (n=11, C=100 μg l−1) with an enrichment factor of 50. The proposed method has been applied to the determination and speciation of chromium in natural water samples with satisfactory results.
期刊：
JOURNAL OF ORGANIC CHEMISTRY,2003年68(6):2490-2493 ISSN：0022-3263
通讯作者：
Yeung, CH
作者机构：
[Yeung, CH] Hong Kong Polytech Univ, Inst Mol Technol Drug Discovery & Synth, Open Lab Chirotechnol, Hong Kong, Hong Kong, Peoples R China.;Hong Kong Polytech Univ, Dept Appl Biol & Chem Technol, Hong Kong, Hong Kong, Peoples R China.;Cent China Normal Univ, Dept Chem, Wuhan 430070, Peoples R China.
通讯机构：
[Yeung, CH] H;Hong Kong Polytech Univ, Inst Mol Technol Drug Discovery & Synth, Open Lab Chirotechnol, Hong Kong, Hong Kong, Peoples R China.
摘要：
Highly enantioselective hydrogenation of beta-alkyl-substituted (E)-beta-(acylamino)-acrylates catalyzed by Ru((R)-Xyl-P-Phos)(C(6)H(6))Cl(2) complex (cat. 1c) was achieved in up to 99.7% ee. Moderate to good enantioselectivities in the hydrogenation of corresponding (Z)-isomers in the presence of [Rh((R)-Xyl-P-Phos)(COD)]BF(4) (cat. 2c) were also obtained. The results demonstrated that the electronic and steric properties of the dipyridylphosphine ligands as well as the different transition metal ions have significant influences on the catalytic properties in the hydrogenation of beta-(acylamino)acrylates.
期刊：
JOURNAL OF CHEMICAL PHYSICS,2003年119(12):5949-5954 ISSN：0021-9606
通讯作者：
Wan, J
作者机构：
York Univ, Dept Chem, Toronto, ON M3J 1P3, Canada.;Cent China Normal Univ, Dept Chem, Wuhan 430079, Peoples R China.;[Wan, J] York Univ, Dept Chem, 4700 Keele St, Toronto, ON M3J 1P3, Canada.
通讯机构：
[Wan, J] Y;York Univ, Dept Chem, 4700 Keele St, Toronto, ON M3J 1P3, Canada.
关键词：
time of flight mass spectra;density functional theory;molecular configurations
摘要：
Bimetallic anionic and neutral clusters which consist of group III elements are studied. Density functional theory was used. Optimized equilibrium geometries and total energies of neutral and anionic clusters were measured. Results showed that icosahedral structures do not always hold for the magic cluster anions.
作者机构：
[Yu, Y] Cent China Normal Univ, Coll Phys Sci & Technol, Wuhan 430079, Peoples R China.;Nankai Univ, Coll Environm Sci & Engn, Tianjin 300071, Peoples R China.;Cent China Normal Univ, Chem Coll, Wuhan 430079, Peoples R China.
通讯机构：
[Yu, Y] C;Cent China Normal Univ, Coll Phys Sci & Technol, Wuhan 430079, Peoples R China.
摘要：
A novel resin NKZ, which is a macroporous resin intermediate modified with nitroguanidine, was synthesized and identified. The adsorption behavior of five kinds of water-soluble dyes onto the resin NKZ was investigated thermodynamically in detail. The results showed that the adsorption rate for reactive brilliant blue KN-R is higher than those for the other dyes. The equilibrium data can be well-described by a three-parameter equation. The values of ΔG° demonstrate that the first layer adsorption of the dyes onto NKZ involves both physical adsorption and chemisorption but multilayer adsorption is a physical one. Both the values of ΔH° and ΔS° on the adsorption of reactive brilliant blue KN-R onto NKZ was positive, indicating that the adsorption is endothermic and can occur spontaneously. The apparent activated energy (Ea) of the adsorption process was 16.84 kJ/mol, which shows that there is a great potential barrier for adsorption.
作者机构：
[Cui, YF] Chinese Acad Sci, Wuhan Inst Phys & Math, State Key Lab Magnet Resonance & Atom & Mol Phys, Wuhan 430071, Peoples R China.;Hong Kong Univ Sci & Technol, Dept Biochem, Kowloon, Hong Kong, Peoples R China.;Cent China Normal Univ, Dept Chem, Wuhan 430079, Peoples R China.
通讯机构：
[Cui, YF] C;Chinese Acad Sci, Wuhan Inst Phys & Math, State Key Lab Magnet Resonance & Atom & Mol Phys, Wuhan 430071, Peoples R China.
摘要：
2-Alkylthio-5-phenylmethylidene-4H-imidazol-4-ones 4-were synthesized by S-alkylation of 2-thioxo-3-alkyl(aryl)-4-imidazolidinones 3, which were obtained via cyclization of isothiocyanates 2 with aliphatic (aromatic) primary amines. (C) 2003 Wiley, Periodicals, Inc.
作者机构：
Cent China Normal Univ, Dept Chem, Wuhan 430079, Peoples R China.;Hubei Jingzhou Teacher Coll, Dept Chem, Jinzhou 434100, Peoples R China.;[Lu, GH; Yao, X; Zhan, T; Long, DW] Department of Chemistry, Central China Normal University;[Zhou, XC] Department of Chemistry, Hubei Jingzhou Teacher College
通讯机构：
[Lu, G.-H.] D;Dept. of Chem., Central China Normal Univ., China
摘要：
A chitosan-modified glassy carbon electrode (CMGCE) was employed for the determination of thiocyanate. The measurement wad carried out by means of anodic stripping voltammetry. The effects of several experimental parameters, such as pH, the amount of modifier, deposition potential and deposition time were studied for analytical application, respectively. A liner response was obtained in the concentration range of 3.5×10-8-9.3×10-7 g/mL of SCN-. The detection limit was found to be 1.9×10-8 g/mL. The method was satisfactorily used to detect SCN- in saliva.
摘要：
The formation of urease monolayer at air-water interface,Pi-A isotherm and stability of this monolayer are studied as a function of urease concentration and pH of subphase. The optimal conditions for transfer of the Langmuir-Blodgett film (LB film) of urease onto the hydrophobic surface of octadecylsilane-modified SiO2/Si substrate are determined. The sensitivity of detection of urea of the enzyme/insulator/semiconductor (EnIS) system is found to be 22 mV/pUrea. (C) 2002 Published by Elsevier Science B.V. [References: 14]
期刊：
JOURNAL OF AOAC INTERNATIONAL,2002年85(2):456-459 ISSN：1060-3271
通讯作者：
Lu, GH
作者机构：
[Lu, GH] Cent China Normal Univ, Dept Chem, Wuhan 430079, Peoples R China.;Wuhan Inst Sci & Technol, Dept Chem & Environm Engn, Wuhan 430074, Peoples R China.;Wuhan Univ, Med Coll Basic Dept, Wuhan 430077, Peoples R China.
通讯机构：
[Lu, GH] C;Cent China Normal Univ, Dept Chem, Wuhan 430079, Peoples R China.
摘要：
In an acid medium, nitrite diazotized with p-rosaniline and then coupled with 8-hydroxyquinoline in a weak alkaline medium produces azo compounds. The azo compounds produce a very sensitive polarographic wave at -0.70 V (versus the saturated calomel electrode). The height of the peak is linear with the concentration of nitrite in the range of 5 x 10(-9) to 5 x 10(-7) g/mL. The detection limit is 3 x 10(-9) g/mL. The electrochemical characteristics of the polarographic wave are also discussed. The method was used to determine nitrite in sausage. The results agree well with those obtained by spectrophotometry.
作者机构：
[Yu, Y] Cent China Normal Univ, Dept Chem, Wuhan 430079, Peoples R China.;Nankai Univ, Coll Environm Sci & Engn, Tianjin 300071, Peoples R China.;Riyue Yongli Battery Ltd Co, Wuhan 430034, Peoples R China.
通讯机构：
[Yu, Y] C;Cent China Normal Univ, Dept Chem, Wuhan 430079, Peoples R China.
摘要：
On the basis of the experimental methods of flocculated decolorization and equilibrium dialysis, the effect of dye structure on the interaction between organic flocculant PAN-DCD and dye has been explored. It was found that, under acidic conditions, PAN-DCD is effective in the decolorization of dyes with sulfonic acid groups and carboxyl groups and that the number of these groups has something to do with decolorization effectiveness. The more acidic groups in the dye, the greater the interaction extent between the flocculant and the dye and the higher the decolorization efficiency (DE) of the dye. Meanwhile, the hydrophobic groups in dyes also affect the binding of the dyes by PAN-DCD. The more hydrophobic groups in the dye, the higher the DE of the dye. The bigger the hydrophobic group in the dye, the more intensive the interaction of the dye with the flocculant. Furthermore, amino and hydroxyl groups in dyes are related to the DE of the dyes as well, according to the formation of a hydrogen bond with the groups in the macromolecule. Therefore, the process of flocculated decolorization, resulting from the interaction between dye molecules and the flocculant, is controlled by both energetic and hydrophobic interactions.
