摘要:

AbstractThe interaction between C60's in solid C60has been calculated by (exp‐6–1) potential, and the cause and the controlled factor of the high rapid rotations of C60's were discussed. In order to describe the disordered degree of C60rotation, an equivalentMis introduced. The phase transitions at the ∼260 K and at the ∼90 K are studied from the viewpoint of C60rotation. The potential barriers of the ordered rotation below the ∼260 K and the disordered rotation above the ∼260 K have been given, and the effect of the external pressure on the temperature of phase transition has also

ISSN:1001-604X    

DOI:10.1002/cjoc.19960140602

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

年代:1996

数据来源: WILEY

摘要:

AbstractStructures, energies and vibrational frequencies have been calculated for hollow cage clusters N28, B4N24, B12N16, and B16N12withTdsymmetry usingab initioquantum mechanical methods at the RHF/3–21G level. Each species is predicted to be both chemically and kinetically stable. Skeletal polyhedrons of all considered boron nitride hollow cage clusters are constructed from 5‐and 6‐membered

ISSN:1001-604X    

DOI:10.1002/cjoc.19960140603

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

年代:1996

数据来源: WILEY

摘要:

AbstractIn situinfrared spectra of dimethyl ether adsorbed on two H‐ZSM‐5 zeolites are reported which are different in both lattice and extraframework aluminium contents. A number of dissociatively adsorbed dimethyl ether species associated respectively with the Bronsted acid sites, the external silanol groups and extraframework aluminium species at different temperatures are identified. In particular, dimethyl ether reacts with non acidic hydroxyl species associated with extraframework aluminium to form the third methoxy species. The distributions of hydrocarbons desorbed from a single pulse of dimethyl ether (1.0 mL) onto these zeolite samples are presented. Propene is the major product, and the yield of hydrocarbons correlates with the concentration of Bronsted acid bound methoxy gro

ISSN:1001-604X    

DOI:10.1002/cjoc.19960140604

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

年代:1996

数据来源: WILEY

摘要:

AbstractThe crystal structure of [Gd2(μ‐L)3(H2O)2]1.5(NO3)1.5 (OH)5H2O (where L is union ofN, N‐Diisonicotinoyl‐2‐hydroxy‐5‐methyl‐isophthalaldehyde dihydrazone) has been determined by X‐ray diffraction method. The complex crystallizes in the monoclinic system, space groupP21/c witha=1.6654(3),b=1.6904(3),c=2.8039(6) nm, β=91.30(3), finalRfactor is 6.3%. The structure consists of [Gd2(μ‐L)3(H2O)2]3+cation, one and a half nitrate and 1.5 hydroxyl anions and five water molecules. Within dinuclear cation, Gd(III)—Gd(III) is bridged by oxygen and nitrogen atoms of the three ligands, resulting in GdGd distance of 0.36353(2) nm. Gd(III) exhibits a distorted 1333 stack coordination environment. Magnetic susceptibility measurements in the temperature range 300–4 K revealed the occurrence of weak antiferromagnetic exchange interaction between two Gd(III) ions with aJva

ISSN:1001-604X    

DOI:10.1002/cjoc.19960140605

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

年代:1996

数据来源: WILEY

摘要:

AbstractSuperconductor mixed oxides were often used as catalysts at higher temperature in gas phase oxidations, and considered not suitable for lower temperature reactions in the liquid‐solid phase; here the catalysis of YBa2Cu3O7±xand Y2BaCuO5±x, in the phenol hydroxylation at lower temperature with H2O2as oxygen donor was studied, and found that the superconductor YBa2Cu3O7±xhas no catalytic activity for phenol hydroxylation, but Y2BaCuO5±xdoes, even has better catalytic activity and stability than most previously reported ones. With the studies of catalysis of other simple metal oxides and perovskite‐like mixed oxides, a radical substitution mechanism is proposed and the experimental facts are explained clearly, and draw a conclusion that the perovskite‐like mixed oxides with (AO)(ABO3) and (AO)2(ABO3) structure have better catalytic activity than the simple perovskite oxides with (ABO3)3structure alone, and (AO) structure unit is the key for the mixed oxides to have the phenol hydroxylation activity. No pollution of this process is very important for its further industrial ap

ISSN:1001-604X    

DOI:10.1002/cjoc.19960140606

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

年代:1996

数据来源: WILEY

摘要:

AbstractA kinetic nonlinear regression model for multi‐component assay of esters was proposed based on their different alkaline‐catalysed hydrolysis rate. The reaction rate was determined by monitoring the conductance change in solution with a liquid‐purpose surface acoustic wave impedance sensor(SAW). The model was tested theoretically and experimentally with the mixture of methyl acetate andn‐propyl acetate. The experimental detection limit of methyl acetate andn‐propyl acetate (within 10 min) was 0.5 μmol/L and 1.0 μmol/L respectively and the recovery of the sensor system ranged from 93% to

ISSN:1001-604X    

DOI:10.1002/cjoc.19960140607

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

年代:1996

数据来源: WILEY

摘要:

Abstract3‐(4‐Phenyl) benzoyl propionic acid was used as the starting material for the synthesis of furanones (2), pyrrolinones (5), pyridazinones (7), benzoxazinones (8) and quinazolinones (9–11). The behaviour of the derivatives of furanones and benzoxazinones toward different nucleophiles is rep

ISSN:1001-604X    

DOI:10.1002/cjoc.19960140608

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

年代:1996

数据来源: WILEY

摘要:

AbstractThe photochemical reactions of azobenzene (AB) incorporated into different solvent‐swollen Nafion membranes were investigated. The location of azobenzene in water‐swollen Nafion membranes was different from that in methanol‐swollen Nafion membranes, which was responsible for the different photochemical reactions of AB. In methanol‐swollen Nafion membranes onlytrans↔cisisomerization took place, while in water‐swollen Nafion membranes photochemical cyclization of AB occurred after rapidtrans↔cisisomerization. The relation between the relative quantum yields and the light intensity showed that the cyclization was a two‐photo process. The numbers of AB molecules per cluster (nAB/cluster) in Nafion membranes with different AB concentrations and different water contents were calculated. Under the experimental condition two competitive photocyclization mechanisms were suggested bynAB/cluster in Nafion membranes, relative quantum yields of the cyclization, and the change of the ratio of benzidine to be

ISSN:1001-604X    

DOI:10.1002/cjoc.19960140609

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

年代:1996

数据来源: WILEY

摘要:

AbstractThe addition reaction of difluorodiiodomethane (1) with alkenes in the presence of PdCl2(PPh3)2or Pd(PPh3)4afforded the corresponding iododifluoromethylated compounds in excellent yield.

ISSN:1001-604X    

DOI:10.1002/cjoc.19960140610

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

年代:1996

数据来源: WILEY

摘要:

AbstractReaction of C60withDL‐valine and cyclohexanone in refluxing chlorobenzene under N2yields three [60]fulleropyrrolidine derivatives (mono‐, bis‐and triadduct) which are characterized on the basis of spectroscopies and cyclic voltammetry. It is found that the ratio of the three products greatly depends on the reaction condi

ISSN:1001-604X    

DOI:10.1002/cjoc.19960140611

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

年代:1996

数据来源: WILEY