二氯苯3种同分异构体及其阳离子的红外光谱研究

用从头算理论,在B3LYP/6-31G（d）基组水平上对二氯苯3种同分异构体及其阳离子进行了优化计算,得到其稳定构型,从而得到它们的红外振动光谱;计算结果显示,二氯苯的3种同分异构体的电离是对二氯苯中氯原子的电离。通过对所得红外光谱的分析得到,二氯苯3种同分异构体及其阳离子的红外振动谱有很大的差别,氯的位置的不同对偶极矩变化的大小有很大的影响;而且,分子的电离对振动偶极矩的变化产生了较大的影响。     

Coupled-channel and distorted-wave Born approximation analyses for 25.1 MeV and 32.5 MeV energies of p- <Superscript>40</Superscript>Ar inelastic scattering

The radioactive decay of the isotopes ^254-256Lr and their daughter products was investigated by means of α , prompt α -γ and delayed conversion electron-γ coincidence spectroscopy. The isotopes were produced using the reaction ⁴⁸Ca + ²⁰⁹Bi .     

4,5-二氧-(2-硫)-1,3,2,4-二氮二磷杂环戊烷衍生物的合成

本文报道了22个新的4,5-二氧-(2-硫)-1,3,2,4-二氮二磷杂环戊烷化合物。对合成路线和条件作了初步探讨。产物的结构经IR、¹H和³¹PNMR及元素分析得到证实,测定了部分产物的MS。在³¹PNMR谱中产物的顺式和反式异构体均得到了指认。部分产物的生物活性初步测定结果表明,它们具有一定的除草和抑菌活性。     

Structure and stability of (CuNO) isomers

Quantum-mechanical calculations have been performed on various isomers of the (CuNO)⁺ system. A ²Π ground state is found for the linear CuNO⁺ and CuON⁺ isomers and a ²A′ state for the bent CuNO⁺ and CuON⁺ isomers. Energy calculations indicate that the linear CuNO⁺ structure is the most stable, the bent CuNO⁺ and CuON⁺ and the linear CuON⁺ structures are at 0.86 eV, 0.99 eV and 1.04 eV above this respectively. In the CuNO⁺ → CuON⁺ interconversion between the linear isomers, three transition states are involved, whereas the bent CuNO⁺ isomer is found to be an intermediate species. The isomerization barriers, dissociation energies, equilibrium geometries and vibration frequencies are given for all isomers in their ground and first excited states.     

EuMO3的XPS和Mossbauer谱研究

对ＥｕＭＯ３进行了ＸＲＤ、ＸＰＳ、ＩＲ和＾１５１Ｅｕ Ｍｏｓｓｂａｕｅｒ谱测量，研究了晶胞参数与离子半径、Ｅｕ４ｄ光电子峰的结合能、同质异能移位的关系。结果表明，Ｅｕ４ｄ结合能和同质异能移位均与Ｂ位离子Ｍ的变化有关，且结合能与同质异能移位成线性关系。     

合成抗孕酮新药RU-486中间体3,3-乙撑二氧-5α,10α及5β,10β-环氧-Δ9(11)-雌烯-17α(1-丙炔基)-17β-羟基的1H和13C NMR谱线全归属

用1D及2D NMR技术(COSY,TOCSY,HMQC及HMBC)归属了合成抗孕酮新药RU-486中间体3,3-乙撑二氧-5α,10α及5β,10β-环氧-Δ⁹⁽¹¹⁾,雌烯-17α(1-丙炔基)-17β-羟基的¹H和¹³C NMR谱线.     

Pyrazine bridged benzyl dicobaloximes: Competition between π-interaction and steric crowding in crystal structure

Pyrazine (Pz) bridged benzyl dicobaloximes [ArCH₂Co(dioxime)₂]₂-μ-Pz [dioxime = dmgH, dpgH] have been synthesized and characterized with ¹H and ¹³C NMR. The complexes have been synthesized by a simple procedure in one-pot directly from the corresponding benzyl aqua cobaloxime. In the crystal structure of [PhCH₂Co(dpgH)₂]₂-μ-Pz, two cobaloxime units are in eclipsed form whereas they were completely staggered in the reported [EtCo(dpgH)₂]₂-μ-Pz. This is due to the π-π interaction between the axial benzyl group and phenyl ring of the equatorial dpgH group. Both cis and trans isomer crystallized together in the crystal structure of [PhCH₂Co(dpgH)(dmgH)]₂-μ-Pz. The cyclic voltammetry study in [PhCH₂Co(dioxime)₂]₂-μ-Pz [dioxime = dmgH, dpgH] shows two cobalt center mixed together due to electron delocalization through pyrazine and behaves like a monocobaloxime and the reduction potentials are much higher than the monocobaloximes.     

Synthesis and characterization of an ultrathin polyion complex membrane containing β-cyclodextrin for separation of organic isomers

An ultrathin polyion complex (PIC) layer containing β-cyclodextrin (β-CD) was formed on the surface of a charged base membrane. Thus, a positively charged copolymer containing β-CD was synthesized by the radical copolymerization of β-CD monomer and allylamine, and was used to modify the surface of a Nafion membrane containing negatively charged fixed ions. Electron spectroscopy for chemical analysis (ESCA) confirmed the presence of the copolymer on the surface of the Nafion membrane due to the formation of a PIC layer. The ability of the membrane to separate organic isomer mixtures was tested by the pervaporation technique, using butanol isomer mixtures as the feed model. The membrane exhibited a good selectivity toward butanol isomers, indicating the effectiveness of β-CD as a selective fixed carrier for the isomers.     

Cyclodextrins Binding to Paeonol and Two of Its Isomers in Aqueous Solution. Isothermal Titration Calorimetry and 1H NMR Investigations of Molecular Recognition

Interactions between CDs with three substituted phenols, paeonol (Pae), acetovanillone (Ace) and 2-hydroxyl-5-methoxy-acetophone (Hma), which are isomers, have been determined by isothermal titration calorimetry (ITC) and ¹H NMR in aqueous solution at 298.2 K. Both the binding thermodynamics and ¹H NMR spectra show that the interaction between α-cyclodextrin (α-CD) molecule and each guest molecule is extremely weak. The thermodynamic parameters indicate that the binding processes of β-cyclodextrin (β-CD) with the isomers are mainly entropy driven and that β-CD binds with Pae or Ace in 1:1 stoichiometry, whereas with Hma binds in 1:1 and 2:1 stoichiometries. The thermodynamic parameters also suggest that γ-cyclodextrin (γ-CD) binds each isomer in the same 1:1 stoichiometry. The binding processes of Pae and Hma with γ-CD are enthalpy driven whereas Ace with γ-CD is predominantly driven by entropy. The ¹H NMR spectra reveal that the three isomers were trapped into the torus cavity of the β-CD molecule from the narrow side during the binding process. Pae penetrates into the γ-CD cavity from the primary rim of the macrocycle whereas Ace does so from the secondary rim, but Hma appears not interact with the internal cavity of γ-CD at all.     

Ab initio study of structures and energies of Al2H4 and Al2H 4 −

The low-lying isomers of Al₂H₄ and their anions are investigated with the hybrid density functional B3LYP, the coupled-cluster CCSD and CCSD(T) methods, and the electron propagator theory. The positive adiabatic electron affinities 5,798 and 10,112 cm⁻¹ are predicted for the neutral C_2v and D_2d symmetric isomers, respectively. The D_2h symmetric anion is more stable by 852 cm⁻¹ than the C_2v symmetric anion. The photodetachment spectra for Al₂H₄⁻ anions at the C_2v and D_2h symmetries are simulated on the basis of the Franck–Condon factor calculations, indicating a reasonable way to study the transition state of the intramolecular torsion process