TiO2-CdS-MCM-41复合纳米材料的合成和表征

利用γ-巯丙基三甲氧基硅烷及表面预吸附水解技术在MCM-41介孔分子筛孔道内部以化学键合的形式依次引入了CdS和TiO2纳米粒子.紫外-可见吸收光谱结果表明,借助于巯基的络合能力,MCM-41能有效地从反胶束中萃取CdS纳米粒子.利用小角XRD谱图成功地跟踪观察到了MCM-41介孔分子筛随纳米粒子的引入而产生的孔径变化.     

Biomimetic Asymmetric Reduction of Quinazolinones with Chiral and Regenerable NAD(P)H Models

A facile approach to chiral dihydroquinazolinone derivatives has been described via biomimetic asymmetric reduction of quinazolinones with chiral and regenerable NAD(P)H models. The utility of this method was demonstrated by a concise synthesis of the bromodomain protein divalent inhibitor.     

3－苯氧甲基－6－（2，4－二氟苯基）－7H-1,2,4-三唑并[3,4-b][1,3,4]噻二嗪的合成与晶体结构研究

由苯氧乙酸出发，经多步反应，制得3-苯氧甲基－4－氨基－5－巯基－1，2， 4－三唑，它与2-氯－2'，4'－二氟苯乙酮进行环化反应，生成3-苯氧甲基－6－（ 2,4-二氟苯基）－7H-1,2,4-三唑并[3,4-b][1,3,4]噻二嗪，通过元素分析、红外 光谱、核磁共振氢谱与碳谱、质谱进行表征，并利用单晶X射线衍射法测定其结构 。晶体属单斜晶系、P2_(1/c)空间群，a = 1.339(3) nm, b = 1.4683(4) nm, c = 0.8606(2) nm, β = 108.49(2)°, Z = 4, F(000) = 736, R_1 = 0.0509。还 对均三唑并噻二唑两类稠杂环的晶体结构作了比较。     

Studies of the g factors and zero-field splitting for the trigonal Ti(2+)(Ga)-S(p) defect center in GaP crystal

The EPR g factors g(parallel), g(perpendicular) and zero-field splitting D suggested to be caused by a donor-acceptor nearest-neighbour pair defect [Ti(Ga)(2+)-Sp] in GaP:Ti(2+) co-doped with sulphur are calculated from the high-order perturbation formulas based on a two spin-orbit coupling parameter model for the EPR parameters of 3d(2) ion in trigonal symmetry. The calculated results are close to the observed values. The suggestion of [Ti(Ga)(2+)-Sp] pair defect in GaP:Ti co-doped with sulphur is also confirmed from this calculation.     

多色蓝在核酸分子上的Langmuir聚集吸附

用微相吸附-光谱修正（MPASC）新技术研究核酸与多色蓝(PCB)探针分子间的相互作用，分析核酸分子内双静电膜的形成与Langmuir吸附的关联性.通过pH 7.24的介质核酸-PCB反应的光谱研究，测定了结合产物的物理化学参数：结合比1PCB:2DNA-PCB、1PCB:3RNA-PCB, 平衡常数KDNA-PCB=5.42×104， KRNA-PCB=2.82×104,摩尔吸收系数ε(DNA-PCB, 625 nm)=5.65×103（mo1－1•L ）•cm－1， ε(RNA-PCB, 625 nm)=3.85×103 （mol－1•L）•cm－1.结果表明， RNA分子仅形成约60％双螺旋结构链，核酸双螺旋每一周期的负静电沟最大聚集10个PCB分子.该吸附反应用于核酸样品测定，结果良好.     

杂原子HMS介孔分子筛的催化脱氢和加氢脱硫性能

ＭＣＭ４１［１］和ＨＭＳ［２］等介孔分子筛对大分子的扩散阻力较小且具有良好的热稳定性,特别是在合成中可以直接将各种杂原子引入骨架,从而调变其催化性能,因此目前介孔分子筛在催化中的应用引起了各国研究者的广泛兴趣．Ｔｉ,Ｚｒ,Ｖ,Ｃｒ,Ｍｎ,Ｃｕ和Ｆｅ...     

Capture by stabilized continuum: Classical and quantum aspects

We review here the results of our investigations concerning chaotic atomic scattering in the presence of a laser field. Particular emphasis is put on the existence of classical stable resonance structures, induced by the intense laser field, which are embedded in the field-free continuum. We show that phase space structures in the vicinity of a resonance island play an important role in the chaotic scattering behavior and form the basis for a mechanism to enhance the lifetimes of the collisional partners. Quantum calculations, based on a wave packet propagation method, show that quantum solutions are strongly influenced by the classical phase space structures. More specifically, a wave packet is found to spread differently in the regular and chaotic regions; in the latter case it spreads exponentially with time until saturation occurs, defining the saturation time. We also investigate the dependence of the spreading rates in both the regular and chaotic regimes. Calculations with an ensemble of classical trajectories are also presented to further illustrate the smoothing effects of varying.     

Star-shaped and linear nanosized molecules functionalized with hexa-peri-hexabenzocoronene: synthesis and optical properties

[structure: see text] A synthetic strategy promising the establishment of a new star-shaped and linear polycyclic aromatic hydrocarbons (PAHs) family with distinct molecular topologies has been developed. The Sonogashira reaction between the iodide derivatives 2a-e and phenylacetylene catalyzed with Pd(0) affords 3a-e in high yields. The Diels-Alder and decarbonylation reactions between 3a-e and tetraphenylcyclophentadiene following the oxidation by FeCl(3) produce the star-shaped and linear PAHs 5a-e containing a five-membered ring. The structural analysis and the optical properties of all new compounds are performed by a combination of MALDI-TOF mass spectrometry, UV-vis, and fluorescence spectrometry. The electronic and photophysical properties are studied by orthogonal comparisons of the absorption and fluorescence spectra in THF solutions, which not only give insight into the interactions among aromatic submoieties in each molecule and the effects of meta-conjugation and para-conjugation on electronic delocalization, but also indicate effective conjugation length variations from oligophenylacetylenes 3a-e to oligophenylene dendrimers 4a-e and PAHs 5a-e. The star-shaped 5c exhibits the highest aggregation in excited states compared with the other four hexa-peri-hexabenzocoronene (HBC) derivatives.     

稠杂环化合物的研究（XV）──6－取代－3－（1H－苯并三唑－1－亚甲基）－1，2，4－三唑并［3，4－b］－1，3，4－噻二唑的合成

研究了３－（１Ｈ－苯并三唑－１－亚甲基）－４－氨基－５－巯基－１，２，４－三唑与取代苯甲酸在三氯氧磷催化下的反应，制得１０种新的３－（１Ｈ－苯并三唑－１－亚甲基）－１，２，４．三唑并［３，４－ｂ］－１，３，４－噻二唑，通过元素分析、ＩＲ、￣１ＮＭＲ和ＭＳ确证了它们的结构并讨论了其波谱性质。     

A High－efficiency Preparation, Properties and Structure of （R, S ）－and （ S, S）－Pyrrolidine－2－carboxylic Acid 3,5－Dioxa－4－boracvclo.hepta [ 2,1－α; 3,4－α′] dinaphthalen－4－yl Esters

A highly-efficient preparative procedure for ( R, S )- and ( S, S)-pyrroHdine-2-carboxyHc acid 3,5-dioxa-4-boracyclohepta[2, 1-α ; 3,4-α′] dlnaphthalen-4-yl esters [ namely ( R, S )-BNBAP and (S, S )-BNBAP] is described and the crystal structure of (R, S )-BNBAP was obtained. The data indicate that ( R, S )-BNBAP is a spirocyclic inner borate salt with almost normal te-trahedral configuration. This structural form may be the basic reason for their high chemical, optical and thermodynamic sta-bility.