摘要:

AbstractMolecular recognition mechanism was introduced into the monolayer formation of two barbituric derivatives, B1 and B2. on a series of melamine derivatives containing water subphase. The recognition pattern was found that each barbituric(or melamine) group forms 3‐fold H‐bonds on its two edges, respectively, with two of its neighboring melamine(barbituric) cores in the ratio of 1:1 on air‐water interface. The area per molecule in this pattern is about 60–65 Å2for both B1 and B2. Such recognition improves the monolayer formation of B1 by increasing the collapse pressure around 20 mN/M and modulates the intermolecular distance of B2 in monolayer These effects should be quite meaningful for both theoretical research and practical application of Langmuir‐Blodgett films,

ISSN:1001-604X    

DOI:10.1002/cjoc.19950130502

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

年代:1995

数据来源: WILEY

摘要:

AbstractThe microcanonical rate constants for the hydrogen‐transfer process of HCCF (reaction 7) and the fluoro‐transfer process of FCCF (reaction 8) are carried out with tunneling correction and curvature correction. The results show that the tunneling effects and curvature effects on the rate constant of reaction 7 is quite different from that of reaction 8. The rate constants for different rotational states are also studied for these reacti

ISSN:1001-604X    

DOI:10.1002/cjoc.19950130503

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

年代:1995

数据来源: WILEY

摘要:

AbstractThe faradaic current of interest can often be obscured by some extraneous current. A new method called staircase pulse voltammetry (SPV), with which involving a potential pulse is superimposed on a staircase, is used for removing the double‐layer charging current This paper presents the theoretical consideration and the experimental evidence of this method for a simple reversible system and a catalytic process. The parameters affecting currents are also discussed. Experimental verifications are in agreement with the theorie

ISSN:1001-604X    

DOI:10.1002/cjoc.19950130504

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

年代:1995

数据来源: WILEY

摘要:

AbstractThe classical trajectory method is employed to calculate the rate coefficientkrfor the reaction H++He+He→HHe++ He at the temperatures ranging 200–350 K, based on anab initiopotential energy surface. The results show thatkris strongly dependent on the temperature, which can be well fitted by the functionkr=ATDr‐3withA=4.192×10−31cm6/s and the reaction dimensionDr=2.706. The product molecules HHe+are found in high vibrationa

ISSN:1001-604X    

DOI:10.1002/cjoc.19950130505

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

年代:1995

数据来源: WILEY

摘要:

AbstractThe structure and properties of mixed monolayer or LB film of 5,10,15,20‐tetra‐4‐oxy(2‐stearic acid)phenyl porphyrin/C60were studied.π‐Aisotherms and small angle X‐ray diffraction (SAXD) results show that C60molecules were incorporated into the cavities of porphyrin molecules in mixed monolayer and LB film. UV‐vis spectra of mixed LB films show that the absorption intensity of porphyrin varied compared with pure porphyrin film, probably arising from the interactions between C60and porphyrin ring. C60molecules in mixed systems are well‐dispersed. The TPP(CO2H)/C60mixed LB film is a kind of two‐dimensional

ISSN:1001-604X    

DOI:10.1002/cjoc.19950130506

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

年代:1995

数据来源: WILEY

摘要:

AbstractSix compounds of the general formula [Ln(pfpr)3]2(NITPhOMe)·nH2O, where LnNd, Gd, Dy, Ho, Er, Y, pfpr=pentafluoropropionate, NITPhOMe=2‐(4'‐methoxyphenyl)‐4,4,5, 5‐tetra‐methylimidazoline‐1‐oxyl‐3‐oxide, andn=4 (for Nd, Dy, Er); 3 (for Gd); 6 (for Ho); 5 (for Y), have been synthesized. These complexes were characterized by elemental analyses, IR, electronic spectra and molar conductances. The variable temperature (4–300 K) magnetic susceptibility of the complex [Gd(pfpr)3]2(NITPhOMe)·3H2O was determined. The observed susceptibility data were fit to those from theoretical magnetic equation by least‐squares method. The exchange integral,J, was found to be equal to 2.14 cm−1. This indicates a weak ferromagnetic spin‐exchange interaction between the radica

ISSN:1001-604X    

DOI:10.1002/cjoc.19950130507

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

年代:1995

数据来源: WILEY

摘要:

AbstractTTHA complexes with diamagnetic rare earth ions (La3+, Y3+and Lu3+) were studied by1H and13C NMR spectroscopy. A symmetric structural model was suggested for La(TTHA) complex and an asymmetric model for Y(TTHA) and Lu(TTHA) complexes. The complex formation was dependent on the pH value of the solution. The interactions of La(TTHA) with the additional metal ions (La3+, Y3+and Ca2+) were relatively weak, but relatively strong for that of Lu(TTHA) with the additional Lu3+.

ISSN:1001-604X    

DOI:10.1002/cjoc.19950130508

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

年代:1995

数据来源: WILEY

摘要:

AbstractA series coupled fused‐silica open tubular columns of a chiral and an achiral stationary phase were used to achieve the enantiomeric separation of a‐phenylethylamine,o,m,p‐methyl‐ ando,m,p‐methoxy‐α‐phenylethylamine. A simplified equation describing the retention values of series coupled columns was derived, which relates the capacity factors of series coupled columns to the capacity factor of individual columns, their lengths, inlet and outlet pressure. Very good agreement was obtained both between calculated values by this equation and those by Krupcik's equation and between values measured experimentally and calculated theoretically. By means of this simplified equation a computer program was developed in locating the operating range of optimum αmin, enantiomeric separation of all α‐phenylethylamine and its derivatives were achiev

ISSN:1001-604X    

DOI:10.1002/cjoc.19950130509

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

年代:1995

数据来源: WILEY

摘要:

AbstractSix sterically hindered chloro meso‐tetra‐ortho‐alkylphenylporphinato irons (T(o‐R)PPFe(III)Cl, R = Me, Et, n‐Pr, i‐Pr, n‐Bu,t‐Bu) were synthesized and used to catalyze the monooxygenation of cyclohexane with PhIO. Both the yields of cyclohexanol and the relative rates of monooxygenation of cyclohexane catalyzed by T(o‐R)PPFe(III)Cl were higher than those of TPPFe(III)Cl respectively. The order of the yields(%) of cyclohexanol and the rate of cyclohexanol formation in the monooxygenation of cyclohexane catalyzed by T(o‐R)PPFe(III)Cl for the different substituents are: i‐Pr(58)>Et(57)>nPr(52)>Me(51)>n‐Bu(48)>t‐Bu(46)>H(35) andi‐Pr>Et>t‐Bu>n‐Pr ⩽ Me ⩽ n‐Bu ⩽ H respectively. The special steric effect on the catalytic character of these different alkyl substituents in T(o‐R )PPFe(III)C

ISSN:1001-604X    

DOI:10.1002/cjoc.19950130510

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

年代:1995

数据来源: WILEY

摘要:

AbstractIn this paper. 10 novel 6‐aryl‐3‐(5′‐phenyl‐2H‐tetrazole‐2′‐methylene)‐S‐triazolo[3,4‐b]‐l,3,4‐thiadiazoles have been synthesized by the condensation of 3‐(5′‐phenyl‐2H‐tetrazole‐2′‐methylene)‐4‐amino‐5‐mercapto‐1,2,4‐triazole with various aromatic carboxylic acids in the presence of phosphorus oxychloride. The structure of these compounds was determined by elemental analysis. UV, IR,1H

ISSN:1001-604X    

DOI:10.1002/cjoc.19950130511

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

年代:1995

数据来源: WILEY