硝酸甲酯与不同亲核试剂的SN2反应的理论研究

用从头计算和半经验分子轨道ＡＭ１方法分别对系列亲核试剂和硝酸甲酯的电子结构以及它们之间的气相ＳＮ２反应进行了理论研究，揭示了反应过程中体系的结构，能量和电荷的递变规律，由反应活化能得了这些亲核试剂的亲核性次序为：ＯＨ＾－〉Ｆ＾－〉Ｉ＾－〉ＮＯ＾－３〉ＣＮ＾－〉Ｂｒ＾－〉Ｃｌ＾－〉Ｎ＾－３。     

溶胶—凝胶合成（Mg,Ca）O—SiO2：Eu^3＋,Bi^3＋发光体及其发光行为

以Ｍｇ（ＮＯ３）２，Ｃａ（ＮＯ３）２，Ｅｕ（ＮＯ３）３，Ｂｉ（ＮＯ３）３和Ｓｉ（ＯＣ２Ｈ５）４为反应物，采用溶胶－凝胶法，在比较低的温度，首次合成０．７０１ｍｏｌＭｇＯ－０．１７５ｍｏｌＣａＯ－１．２５ｍｏｌＳｉＯ２：０．０６ｍｏｌＥｕ＾３＋，０．００２ｍｏｌＢｉ＾３＋（加入Ｌｉ＾＋作为电荷补偿剂）发光体，得到了最佳合成条件，研究了由溶胶向凝胶转变和凝胶向发光晶体的转变过程，探讨了发光体在不同激光     

Synthesis and Characterization of Lead Sulfide Nanoparticles in Zirconia-Silica-Urethane Thin Films Prepared by the Sol-Gel Process

PbS nanocrystals (NCs) ranging between 4–8 nm were incorporated into Zirconium-Silica-Urethane (ZSUR) matrix obtained by the sol-gel method. The sizes of the particles were controlled by temperature treatment and by concentration of PbS in ZSUR matrix. The sizes of PbS NCs were determined by TEM measurements. The quantum size effect could also be extracted from optical absorption and photoluminescence spectra. The new matrix allows incorporation of up to 40% PbS forming a characteristic structure of dendrite by reacting lead acetate with ammonium thiocyanate in sol-gel matrix. The sol precursors of the matrix for Zirconium-Silica-Urethane contained zirconium oxide (ZrO₂) matrix solution, tetramethoxysilane (TMOS), 3-glycid oxypropyl trimethoxysilane (GLYMO) and polyethylene urethane silane (PEUS) synthesized separately. The ZrO₂ matrix solution was obtained from zirconium n-tetrapropoxide in propanol and acetic acid was used as a chelating agent to stabilize the zirconium oxide precursor.     

Use of chemometrics and mid infrared spectroscopy for the selection of extraction alternatives to reference analytical methods for total fat isolation

Chemometric techniques have been used to compare two methods for fat extraction, namely focused microwave-assisted Soxhlet extraction (FMASE) and dynamic ultrasound-assisted extraction (DUAE), with the conventional Folch method, frequently used as reference. The data generated by a mid infrared spectrometer, after appropriate treatment, provide a simple and effective way for the detection of potential alterations of the fat obtained with the assistance of auxiliary energies, in this case, microwaves and ultrasounds. The results thus obtained are as compared with those from the Folch method, a mild extraction method with a view to finding faster alternatives for routine analysis. Moreover, classification of the samples between cookies and snacks based on extraction kinetics studies was possible, thus demonstrating the importance of these studies for the development of analytical methods. Principal Component Analysis (PCA) and Hierarchical Cluster Analysis (HCA) were used for both purposes, namely detection of alterations and classification of the samples as a function of their extraction kinetics, while K Nearest Neighbours (KNN) and Soft Independent Modelling of Class Analogy (SIMCA), based on PCA, models were generated in order both to predict the extraction kinetics of unknown samples, thus adjusting the extraction time as a function of the matrix, and find out explanation to the different extraction kinetics.     

Synthesis and Second‐Order Nonlinearities of Chiral Prolinol‐Substituted Chromophores

A new series of thiophene‐ and furan‐containing chromophores with a chiral prolinol donor and a sulfone acceptor has been synthesized. The UV‐vis absorptions, second‐order nonlinear optical properties, and X‐ray crystal structures are described.     

环境内分泌干扰素分析方法进展

本文详细介绍了国内外环境内分泌干扰素的分析研究进展。着重介绍了环境样品的预处理方法，并进行了比较和评价，对不同环境样品中内分泌干扰素的分析检测方法进行了介绍。     

钯催化全氟及多氟碘化物与三乙胺的反应

Pullin等人曾对全氟碘代烷与三级胺的相互作用进行了研究,发现R_(?)I与NR_3能形成电荷转移络合物,即:R_(?)…I…NR_3。但此后却未见到有关反应的报道。我们发现在钯催化剂存在下,全氟碘化物与三乙胺能发生反应,反应条件较为温和,产物为氟代烷基烯基二乙基胺1。反应可能是在三乙胺中先产生一个双键,然后β碳原子接上一个全氟烷基。1的IR和NMR与Blanc报道的一致。化合物1经水解可得胺基烯酮2。在酸溶液中水解时,速度明显加快,而在碱溶液中,不仅不能加快水解速度,而且还有副反应发生。我们对化合物2进     

Morphology Control over the Organic Nanoparticles of 1,3-Diphenyl-5-（9-anthryl）-2-pyrazoline

The organic nanoparticles of a blue-light-emitting molecule, 1,3-diphenyl-5-(9-anthryl)-2-pyrazuline, were prepared by reprecipitation method using acetonitrile as the solvent for the molecular precursor. Three morphologies, spherical, doughnut-shaped and cubic, could be observed on the silicon substrate forthe nanoparfides by the volume-controlled addition of acetonitrile. The evolution of particle morphology as a function of acetonitrile addition was attributed to the variation of the growth habits of the particles in the different environment. The nanoparticles exhibit the novel photoluminescence spectra as compared to those of monomer and the bulk crystals.     

Nanostructure evolution studies of bulk polymer materials with synchrotron radiation: progress in method development

The prospects of a modern analysis of nanostructure evolution during the processing of polymer materials by means of scattering from synchrotron radiation are demonstrated in examples. The beam sources have gained stability, shortages are located in beamline setups and in method development for the quantitative analysis of voluminous data sets.By using the proposed multidimensional chord distribution function (CDF) analysis method, nanostructure information from small-angle X-ray scattering (SAXS) data are extracted and visualised. The method can be automated if the beamline setup is able to deliver a full data set with simple constraints. In this case even a simultaneous data evaluation is possible (while one pattern is accumulated, the previous one is analysed). The advantages of the method are demonstrated in a study of the straining of a thermoplastic elastomer. The possibilities of an automated analysis are demonstrated in an investigation of the crystallisation behaviour of high-pressure injection-moulded polyethylene (HPIM-PE). The achievable results of nanostructure analysis of polymer materials are discussed. It is shown that the time-resolved SAXS of polymer materials studied during a transformation and analysed by the CDF method is not just a powerful tool to investigate the relationship between structure and properties of materials; the information that can be gained concerning the processes that control nanostructure evolution is equally important. In the future the enlightenment of such relationships may help to tailor polymer materials with respect to their properties and, beyond that, to improve assessments concerning their aging.     

Tautomerism and Acidic Properties of N‐Unsubstituted Benzohydroxamic Acids: Semiempirical Quantum Chemical Estimation

Tautomerism of Nunsubstituted benzohydroxamic acids and their anions in the gas phase was investigated by the semiempirical AM1 method. The possibility of estimating pK _a in aqueous solutions using calculated characteristics of molecules is demonstrated.