摘要:

AbstractThe parameters of ligand field of laser crystal Na3+: KY(WO4)2and Nd3+: KGd(WO4)2are obtained by a scheme which involved intermediate coupling and ligand field interaction. The calculated Stark‐levels are in good agreement with the experimental value

ISSN:1001-604X    

DOI:10.1002/cjoc.19920100401

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

年代:1992

数据来源: WILEY

摘要:

AbstractChemical or electrochemical oxidation ofN‐benzylaniline in perchloric acid solution yields a highly colored polymer—poly‐N‐benzylaniline (PBAn). The polymer has good solubility in a number of organic solvents in either acid or base form. At room temperature, conductivity measurements on pressed pellets of the acid form PBAn give a conductivity of 9.3 × 10−6S·cm−1. The soluble polymer was analyzed using a variety of common experimental techniques including UV‐vis, IR, NMR, ESR spectroscopy, elemental analysis and electrochemical analysis. All experimental results showed that PBAn has a structure similar to polyaniline with the elimination of som

ISSN:1001-604X    

DOI:10.1002/cjoc.19920100402

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

年代:1992

数据来源: WILEY

摘要:

AbstractESR measurements have been carried out for some copper(II) complexes of bis(4′‐benzo‐15‐crown‐5) at 77 K. The results of ESR spectrometric titration indicated that the binuclear complexes were prepared in the present system. The binuclear complexes revealed characteristic ESRg‐anisotropies (gZ

ISSN:1001-604X    

DOI:10.1002/cjoc.19920100403

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

年代:1992

数据来源: WILEY

摘要:

AbstractThe synthesis and spectroscopic characterization of cobalt(II) 5‐(4‐pyridyl)‐10, 15, 20‐triphenylporphyrin, cobalt(II) 5‐(4‐N‐hexadecylpyridiniumyl)‐10, 15, 20‐triphenylporphyrin bromide and cobalt(II) 5‐(2‐aminophenyl)‐10, 15, 20‐triphenyl‐porphyrin are reported. The corresponding copper and vanadyl derivatives ((TriP)Cu, [(hTriP)Cu]+Br−and [(hTriP)VO]+Br−) were also studied. Each metalloporphyrin was characterized by UV‐visible, ESR and1H NMR spectroscopy. These metalloporphyrins can be firmly adsorbed on the glassy carbon (GC) surface. The catalytic reduction of dioxygen at GC electrodes modified by these catalysts was studied by cyclic voltammetry (CV). The kinetic process of dioxygen reduction at the cobalt porphyrin‐modified electrodes was studied

ISSN:1001-604X    

DOI:10.1002/cjoc.19920100404

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

年代:1992

数据来源: WILEY

摘要:

AbstractHighly dispersed α‐Fe2O3/NaY, NiO/NaY, and CuO/NaY catalyst systems were prepared by impregnation method. Dispersion thresholds of the transition metal oxides on NaY zeolite were determined by XRD phase analysis. The dispersion capacities of the transition metal oxides on NaY zeolite are much lower than that estimated on the basis of a closed packed monolayer in the micro pores. The catalytic activity and selectivity of the highly dispersed oxide catalyst systems for ethylbenzene and cyclohexane dehydrogenation reactions were report

ISSN:1001-604X    

DOI:10.1002/cjoc.19920100405

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

年代:1992

数据来源: WILEY

摘要:

AbstractThe adsorption isotherms of phenylalanine from aqueous solution on active carbon and silica gel at varying pH, and the influence of inorganic salt upon the adsorption have been studied (at 25°C). The adsorption amount of phenylalanine on the silica gel is very low due to the strong adsorption of water by silica gel. The results on the active carbon show: (1) The adsorption is found to be pH‐dependent, within pH 4.1—5.1 it increases with pH, within pH 5.1—11.8 it decreases with pH, at pH 5.1 the adsorption reaches its maximum; (2) The phenylalanine is adsorbed mainly in the form of zwitterion; (3) A certain amount of cations and anions of phenylalanine are also adsorbed with van der Waals interaction; (4) After adding NaCl, the adsorption of phenylalanine increases ma

ISSN:1001-604X    

DOI:10.1002/cjoc.19920100406

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

年代:1992

数据来源: WILEY

摘要:

AbstractThis paper reports two lanthanide complexes of formula (C9,H7)Ln(C8H8) · (THF)2where Ln is Pr or Nd, C9H7is indenyl, and C8H8is cyclooctatetraene (COT). The complexes were prepared by the reaction of LnCl2with K(C9H7) and K2(C2H2) in THF. (C9H7)Pr(C8H8) · (THF)2crystallizes in THF at −15°C in the monoclinic space groupP212with unit cell dimensionsa= 8.446 (0),b= 10.083(2),c= 13.407 (3)Å, β = 105.48 (1)°,V= 1100.43 (35)Å2,Dc= 1.52 g / cm3andZ= 2. The finalRvalue is 0.033,Rwvalue is 0.030, respectively. In (C9H7)Pr(C8H8) · (THF)2a five‐membered ring centroid of C 9 H7, the C8H8ring centroid and the two oxygen atoms from the two THF molecules form a distorted tetrahedral geometry a

ISSN:1001-604X    

DOI:10.1002/cjoc.19920100407

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

年代:1992

数据来源: WILEY

摘要:

AbstractThe negative ion fast atom bombardment (NIFAB) mass spectra of mono‐, di‐saccharides and glycosides using phenylboronic acid (PBA) as reagent have been studied. In the ion source, PBA reacts stereospecifically with the molecules containingcis‐vicinal glycols to form characteristic ions, from which the stereo‐isomers of saccharides can be definitely distinguished. Disaccharides and glycosides with β‐glycosidic linkage seem to be unfavorabale to react with PBA, therefore, by comparison of the abundances of the characteristic ions, the configuration of the glycosidic linkage in these compounds may b

ISSN:1001-604X    

DOI:10.1002/cjoc.19920100408

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

年代:1992

数据来源: WILEY

摘要:

AbstractArylaldoxime dehydrodimers 3a—1 have been prepared from the corresponding oximes 1a—1 by using (HCrO4)2(Py)4Co as oxidant. Their structures were assigned to be bisnitrone by XPS studies. ESR studies of 3a—1 in hot chloroform show that iminoxy radicals 2a—1 are formed. Therefore the dehydrodimers can provide a convenient source of these r

ISSN:1001-604X    

DOI:10.1002/cjoc.19920100409

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

年代:1992

数据来源: WILEY

摘要:

AbstractDifluorocarbene generated from the decomposition of fluorosulfonyldifluoroacetic acid (2) reacted with various sodium salts ofN‐heterocyclic compounds(1) giving the corresponding difluoromethylated products in acetonitrile at 10–40°C. Benzotriazole(1a), benzimidazole(1b) and imidazole (1c) were converted into 1‐(difluoromethyl)benzotriazole(3a), 1‐(difluoromethyl)benzimidazole(3b) and 1‐(difluoromethyl)imidazole(3c) respectively. Indole(1d) reacted with 2 to giveN‐(fluorosulfonyldifluoroacetate)indole(2d) rather than the expected difluoromethylated

ISSN:1001-604X    

DOI:10.1002/cjoc.19920100410

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

年代:1992

数据来源: WILEY