摘要:

AbstractIn this paper we present the three dimensional EHMO crystal orbital calculations for crystalline Li2CsC60, Na2CsC60, K2CsC60and Rb2CsC60. For all these four dopants with a fcc structure, our calculated band structures and density of state unequivocally suggest a metallic conducting phase with each a set of three half‐filled band across the Fermi level which is just located close to a peak of density of state. A monotonic relationship is found between our calculated Fermi‐level density of stateN E fand experimental transition temperatureTcwhich is in excellent agreement with some theoretical studies and experimental results. With our other calculation results, such as the overlap populations between A (where A represents an alkali‐metal) and C60molecules, net atomic and orbital charges, crystal orbital vectors and various projected DOS, we could probably shed some light on the mechanism of the superconductivity for this new marvelous kind of materials from a chemical poin

ISSN:1001-604X    

DOI:10.1002/cjoc.19960140102

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

年代:1996

数据来源: WILEY

摘要:

AbstractAb initiomolecular orbital theory was used to compute entropies, heat capacities and other thermochemical properties for a new organosilicon compound H2SiNaF in the temperature range 300–1500 K. There is currently no information of this kind available about this compound. On the basis of the calculated heat capacities, we have fitted the temperature‐dependent functions for heat capacities to the forms (a+bT+cT2) and (a'+b'T+c'T−2) in the range 300–1500 K. Furthermore, we calculated the equilibrium constants of conversions among the four configurations of this compound. Thus, a new way of determining thermodynamic data theoretically can be derived and is expected to be esta

ISSN:1001-604X    

DOI:10.1002/cjoc.19960140103

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

年代:1996

数据来源: WILEY

摘要:

AbstractThe structures of B32 and B32H2–32withIhsymmetry have been investigated by means ofab initiocalculations at STO‐3G level. The relationship between molecular orbitals of them has been analyzed and their bonding properties have been discussed. Then the possibility of their existence, as well as the similarity and difference between B32(B32H2–32) and C60(C60H60) have been inf

ISSN:1001-604X    

DOI:10.1002/cjoc.19960140104

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

年代:1996

数据来源: WILEY

摘要:

AbstractThe behaviour of porphyrins [mono‐meso‐(2‐hydroxyphenyl)octamethylporphyrin, mono‐meso‐(4‐hydroxyphenyl)octamethylporphyrin and mono‐meso‐(3,4‐dihydroxyphenyl)octamethylporphyrin] in basic solution is examined by UV‐Visible and1H NMR spectroscopy. The unusual nature of the spectra may be explained by the formation of porphomethene moieties in which the porphyrin chromophore is modified by interruption of theπ‐system. The porphyrins in bases are less susceptible to oxidation in contrast withmeso‐tetrakis‐(4

ISSN:1001-604X    

DOI:10.1002/cjoc.19960140105

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

年代:1996

数据来源: WILEY

摘要:

AbstractA new phosphate, KMgY(PO4)2, isostructural with xenotime, was firstly reported in detail. It crystallizes in tetragonal system with space groupI41/amd (No. 141). The cell parameters were obtained from X‐ray powder diffraction data witha=0.6886,c=0.6025 nm,Z=2. The proposed structure of KMgY(PO4)2was further confirmed by its vibrational spectra, IR and Raman spectra, which were also compared with those ofiso‐structural Y

ISSN:1001-604X    

DOI:10.1002/cjoc.19960140106

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

年代:1996

数据来源: WILEY

摘要:

Abstract[(C6H5CH2C5H4)2GdCl.THF]2(1) and (C6H5CH2C5H4)2ErCl.THF (2) were prepared by the reaction of LnCl3(LnGd, Er) with benzylcyclopentadienyl sodium in THF and characterized by elemental analysis, IR,1H NMR,13C NMR, MS and thermal gravimetry. The crystal structures of both compounds were determined. Complex 1 is dimeric and its structure belongs to the monoclinic, P21/c space group witha=1.1432(2),b=1.2978(2),c=1.7604(3) nm,β=108.75(2),V=2.4732(9) nm3,Z=2(four monomers),Dc“1.54 g.cm−3.R=0.0342 andRw“0.0362. Complex 2 is monomer and its structure belongs to the orthorhombic,P212121space group witha=0.8645(2),b=1.1394(3),c=2.5289(4) nm,V=2.4919(9) nm3,Z=4,Dc“1.56 g.cm−3.R=0.0514,Rw“0.0529. The determination of the crystal structure shows that in complex 1 the benzyl groups on the cyclopentadienyls coordinated to Gd3+are located in the opposite direction (139°); in complex 2 the benzyl groups on the cyclopentadienyls coordinated to Er3+are located in the same d

ISSN:1001-604X    

DOI:10.1002/cjoc.19960140107

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

年代:1996

数据来源: WILEY

摘要:

AbstractThree computer‐assisted statistical scanning methods, the monofactor optimization system (MOS), multicomponent solvent optimization system (MSOS), and difactor optimization system (DOS) for optimizing HPLC separations, have been integrated to produce the optimization system of HPLC (OS‐L). The method proposes the complementary use of these techniques, maximizing their strengths while compensating for their weaknesses. The result of OS‐L is a method development strategy which obtains simple solutions for simple separation problems and reserves the more complex solutions for difficult separa

ISSN:1001-604X    

DOI:10.1002/cjoc.19960140108

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

年代:1996

数据来源: WILEY

摘要:

AbstractThe copper‐catalyzed oxidation of hydrazine by iron(III) in acid solution follows the rate law ‐d[Fe(III)]/dt =kKh[Cu(II)]2/(Kh+ [H+]), whereKhis the hydrolysis constant of Cu2+,kwas found to be 8.8±0.8, 13.2±1.4 and 17.5±1.3 min−1at 35, 40, and 45°C respectively andμ=0.2 mol/L. The composition of the activated complex is Cu2+, CuOH+, N2H4, H+or others. Perhaps several hydrazine complexes of Cu(II) participate in the reaction and one of them isolated was Cu(N2H4)2(HSO4)2. Study on the oxidation of this complex is also in conformity with the abov

ISSN:1001-604X    

DOI:10.1002/cjoc.19960140109

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

年代:1996

数据来源: WILEY

摘要:

AbstractA new series ofn‐alkyl 4‐[4‐(4‐n‐octyloxybenzyloxy‐2,3,5,6‐tetrafluorophenyl)ethynyl)benzoates have been prepared. Polarizing microscopic textural observation shows that they are liquid crystals with

ISSN:1001-604X    

DOI:10.1002/cjoc.19960140110

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

年代:1996

数据来源: WILEY

摘要:

AbstractSynthesis of 20(R)‐and 20(S)‐trifluoromethyl substituted steroids as the key intermediates (1a, 1b) to 23,24‐dinor‐20‐trifluoromethyl‐25‐hydroxy‐cholesterol and VD3 analogs, using trifluoromethyltrimethylsilane (CF3SiMe3) as a trifluoromethylating agent

ISSN:1001-604X    

DOI:10.1002/cjoc.19960140111

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

年代:1996

数据来源: WILEY