摘要:

AbstractThe matrix elements of the correlation function between symmetric potential harmonics am simplified into the analytical summations of the grand angular momenta by dy using the recurrence and coupling relations of the potential harmonics. 'The correlation‐function potential‐harmonic and generalized‐Laguerre‐function method (CFPHGLF), recently developed by us, is applied to the S states of the helium‐like systems forZ = 2to 9. The results exhibit good convergence with the bases in tern of both the angular and radial directions. The final eigen‐energies agree excellently with the best s‐limits of the variational configuration interaction (CI) method for the involved low‐lying S states. The accuracy of the potential harmonic (PH) expansion scheme is discussed relative to the exact Hylleraas CI results (HCI), and Hartree‐Fock results. Moreover, suggestion is given for the future improvement

ISSN:1001-604X    

DOI:10.1002/cjoc.19990170602

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

年代:1999

数据来源: WILEY

摘要:

AbstractPerturbation theory on optical ac stark effect is applied to study the NMR spectroscopy in paramagnetic systems. Application of the circularly or linearly polarized optical field would lead to shifts in the NMR line, which is proportional to the laser intensity and the induced polarizability tensors by hyperfine interaction.The induced shift for193Ir NMR spectrum of [ IrBr6]2–is expected to be of the order of 1–10 Hz as resonance is approached with light intensity 10 W*emn‐1. For the supersonic molecular beam samples193IrC, the laser‐induced NMR shift is estimated to be as large as 1–10 MHz near

ISSN:1001-604X    

DOI:10.1002/cjoc.19990170603

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

年代:1999

数据来源: WILEY

摘要:

AbstractThe structures, energies, atomic charges and IR spectra of complexes (CH2)2O…XY (X, Y = H, F, Cl, Br, and I) have been examined by means ofab initiomolecular orbital theory at the second‐order level of Møller‐Plesset perturbation correction. It is found that the hydrogen bond O…H‐X is non‐linear. The attraction between X and the H atoms in oxirane ring causes O…H‐X bond bending. The hydrogen bond slightly weakens the bond strength of C‐O, and leads the bending and stretching mode of IR to shift to the red. The calculation results show that there is no evidence of a significant extent of proton transfer to give (CH2)2OH+… X−in

ISSN:1001-604X    

DOI:10.1002/cjoc.19990170604

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

年代:1999

数据来源: WILEY

摘要:

AbstractSphere‐like compound C8H17Si(OPhC12H25)3N (1) forms mesophases. In order to investigate the relationship between molecular structure and liquid crystal properties, structural studies are carried out on the model molecules of compound 1 and its substituted derivatives usingab initiocalculations. The results show that the cyano or chloro substituted tribenzosilatrane compounds R Si(OPhR2)3N (R1,R2= CN or Cl) have much bigger dipole moments or anisotropy of polarizability and more like sphere than the corresponding alkyl substituted compounds. Cyano or chloro substituted tribenzosilatranes would be better candidates for sphere‐like mesog

ISSN:1001-604X    

DOI:10.1002/cjoc.19990170605

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

年代:1999

数据来源: WILEY

摘要:

AbstractThe interactions of oxidative radicals (Br2−‐, HO−etc.) with N‐phosphoryl dipeptide derivatives (NDM‐TrpOMe and NDT‐MetOMe) have been investigated by using pulse radiolysis at different pH values. It has been found that Br2−‐ and HO−radicals oxidize the Met‐site and Trp‐site in the dipeptide derivativesviaformation of the three‐electron‐bonded intermediate and indolyl radical simultaneously. Then the intramolecular electron transfer along the peptide backbone occurs. The rate constants of electron transfer,k, have been determined and the reaction m

ISSN:1001-604X    

DOI:10.1002/cjoc.19990170606

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

年代:1999

数据来源: WILEY

摘要:

AbstractTwo series of mixed oxides, GIAlM and MgAlM (M= G, Mn, Fe, Co, Ni, Cu), were prepared by calcining their corresponding hydrotalcite‐like compounds (HTLc). The ratio of Mg: Al: M (or Co: Al: M) was 3:1:1. The catalytic activity of all samples for the reaction of NO + CO was investigated. The results showed that the activity of CoAlM was much higher than that of MgAlM. The structure and the property of redox were characterized by XRD and H2‐TPR. The results indicated that only MgO phase was observed after calcining MgAlM hydrotalcites, and the transition metals became more stable. The spinel‐like phase appeared in all of CoAlM samples after the calcination, and the transition metals were changed to be more active, and easily reduced. The activities of three series of mixed oxides CoAlCu obtained from different preparation methods, Different ratio of Co: Al: Cu and at different calcination temperatures. were studied in detail for proposing the mechanism of reaction. The ability of adsorption of NO and CO were investigated respectively for supporting the mech

ISSN:1001-604X    

DOI:10.1002/cjoc.19990170607

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

年代:1999

数据来源: WILEY

摘要:

AbstractSeven new μ‐isophthalato dinuclear lanthanide(III) complexes, namely [Ln2(IPHTA)(Me2‐phen)4‐(ClO4)2](ClO4)2(Ln=La, Nd, Sm, Eu, Gd, Ho, Er), where Me2‐phen denotes 2,9‐dimethyl‐1,10‐phenanthroline (Me2‐phen), IPHTA represents isophthalate dianion, have been synthesized and characterized by elemental analyses, molar conductance measurements, IR, ESR and electronic spectra. The variable‐temperature magnetic susceptibilities of [ Gd2(IPHTA) (Me2‐phen)4( ClO4)2] ((ClO4)2complex were measured in the temperature range of 4–300 K and the observed data were successfully simulated by the equation based on the spin Hamiltonian operator, H = ‐2JS1. J2. giving the exchange parameterJ= ‐0.19 cm−1. This result is commensurate with a weak antiferromagnetic spin‐exchange interaction between Gd(III)

ISSN:1001-604X    

DOI:10.1002/cjoc.19990170608

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

年代:1999

数据来源: WILEY

摘要:

AbstractA novel Schiff base (TAMET) was synthesized by the condensation of tetraglycol aldehyde with methionine and a mild oxidant CrO3. (C5H5N)2was selected for the reaction. Seven new rare earth complexes with this Schiff base have been synthesized and characterized by elemental analysis, TG‐DTA, molar Conductivity, magnetic susceptibility and IR, especially1H NMR spectra. Information was obtained from reflectance spectra and the coordination of sulfur atom to rare earths was discussed. The experimental results show that these compounds have some biological activity and could dispose of O2

ISSN:1001-604X    

DOI:10.1002/cjoc.19990170609

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

年代:1999

数据来源: WILEY

摘要:

AbstractHydrolysis of DNA is an important enzymatic reaction, but it is exceedingly difficult to mimic in the laboratory because of the stability of hydrolysis of DNA. In this paper, the cleavage activity of complexes formed between Cu(II) and four different amino acid or amino acid methyl ester on DNA is studied by gel electrophoresis. It is found that DNA could be cleaved by Cu(II)‐L‐His and Cu(II)‐L‐His methyl ester complexes and the efficiency of cleavage is largely dependent on the metal ion‐to‐ligand ratio. Further experiments show that the cleavage of DNA mediated by Cu(II)‐L‐His complexes occursviaa hydrolytic mechanism and the active chemical species that affects DNA cleavage is proposed to be MI

ISSN:1001-604X    

DOI:10.1002/cjoc.19990170610

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

年代:1999

数据来源: WILEY

摘要:

AbstractThe title complex Eu(III)(TTA)3(phen) (where TTA = thenoyltrifluoroacetone monoanion; phen = 1,10‐phenanthroline) has been synthesized in mixed solvents of acetone and ethanol (1:1 volume ratio) and its crystal structure has been determined by X‐ray diffraction. The complex crystals are triclinic, space groupP1 (# 2) with cell dimensions ofa= 1.32.41 (2) nm,b =1.5278(4) nm,c= 0.9755(3) nm,α =92.49 (2)°,β= 102.57(2)°, γ = 91.62(2)°,V= 1.9268(8) nm3,Z= 2, μ (MoKa)= 18.77 cm−1,Dx=1.720 g/cm3. The coordination geometry of Eu atom is a distorted square antiprism, and the encapsulated structure that can meet the structural requirement of the typical europium luminescent sensor. The fluorescence spectrum suggests that the complex is a strong photoluminesc

ISSN:1001-604X    

DOI:10.1002/cjoc.19990170611

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

年代:1999

数据来源: WILEY