Tweezer分子的合成和对有机阴离子的配位效应

本文报道新的Ｔｗｅｅｚｅｒ（１）的合成，用＾１ＨＮＭＲ研究了新的Ｔｗｅｅｚｅｒ分子和对硝基苯甲酸盐的配位效应，结果表明它兴通过氢键，静电引力和芳环夹心堆叠作用而自动缔合。     

儿茶素活性成分分子印迹聚合物的固相萃取研究

以表没食子儿茶素没食子酸酯(Epigallocatechin-gallate,EGCG)为模板分子,α-甲基丙烯酸为功能单体,乙二醇二甲基丙烯酸酯为交联剂,在光冷引发条件下合成EGCG分子印迹聚合物,利用该聚合物制成分子印迹固相萃取柱,用于固相萃取茶叶提取物茶多酚,对萃取柱中的清洗液、洗脱剂、上载量等进行了选择.结果表明,在萃取柱上载样品之后,先用V(甲醇):V(水)＝1:9溶液进行清洗,再用V(甲醇):V(乙酸)＝9:1混合液进行目标分子的洗脱,可以得到比较纯的目标物质EGCG(色谱峰相对峰面积达92.4%),萃取柱在上载样品并进行清洗、洗脱之后,EGCG的回收率达69.3%.分子印迹柱具有较好的稳定性和耐用性能,使用20次后其选择性识别能力仍未降低,但空白印迹柱却没有这样的选择性识别能力.     

Repeatability and pattern recognition of bacterial fatty acid profiles generated by direct mass spectrometric analysis of in situ thermal hydrolysis/methylation of whole cells

Direct CI mass spectrometry profiling of fatty acid methyl esters (FAMEs) from in situ thermal hydrolysis/methylation (THM) of whole bacterial cells with tetramethylammonium hydroxide (TMAH) has been demonstrated as a potential method for real time and fieldable detection/identification of microorganisms. Bacillus anthracis (Ames), Yersinia pestis (Nair. Kenya), Vibrio cholerae (E1 Tor), Brucella melitensis (Abortus wild) and Francisella tularensis (LVS vaccine) were profiled by this method during a 10-month period. Repeatability of the in situ FAME data was calculated using one-way analysis of variance (ANOVA) and a t-test. Artificial neural network (ANN) and multivariate statistics of the FAME profiles were also compared for bacterial identification/classification. Equivalent results were obtained with a multivariate rule building expert system (MuRES) and the ANN. However, the ANN analysis required much less computer time and was deemed the best choice for this application. In situ THM FAME profiles of the bacterial samples provided comparable results with those obtained from the Microbial Identification System (MIDI) (Newark, DE) wet chemistry-gas chromatographic based system.     

Molecular Recognition of Nucleic Acid Bases in Water by Hydrogen Bonding of Poly(vinyldiaminotriazine)

Poly(2-vinyl-4,6-diamino-1,3,5-triazine) efficiently binds nucleic acid bases and nucleosides in water by using complementary hydrogen bonding. The binding activity decreases in the order: U, T > A C, G. The corresponding monomer shows virtually no activity, indicating a predominant role of polymer effect for the molecular recognition in water.     

Preparation of a novel molecularly imprinted polymer using a water-soluble crosslinking agent

A molecularly imprinted polymer was prepared using a water-soluble crosslinking agent. An ionic complex was utilized as the assembly for the template molecule and the functional monomer, and water as porogenic solvent during preparation of the imprinted polymer. The results of chromatographic evaluations for the prepared polymer suggested that the polymer had much lower hydrophobicity compared with usual octadecyl group bonded silica or the usual molecular imprinted polymer prepared from ethyleneglycol dimethacrylate, and the selective recognition ability for template molecule in the completely aqueous condition.     

Towards supramolecular fixation of NOX gases: encapsulated reagents for nitrosation

The use of simple calix[4]arenes for chemical conversion of NO2/N2O4 gases is demonstrated in solution and in the solid state. Upon reacting with these gases, calixarenes 1 encapsulate nitrosonium (NO+) cations within their cavities with the formation of stable calixarene-NO+ complexes 2. These complexes act as encapsulated nitrosating reagents; cavity effects control their reactivity and selectivity. Complexes 2 were effectively used for nitrosation of secondary amides 5, including chiral derivatives. Unique size-shape selectivity was observed, allowing for exclusive nitrosation of less crowded N-Me amides 5 a-e (up to 95 % yields). Bulkier N-Alk (Alk>Me) substrates 5 did not react due to the hindered approach to the encapsulated NO+ reagents. Robust, silica gel based calixarene material 3 was prepared, which reversibly traps NO2/N2O4 with the formation of NO+-storing silica gel 4. With material 4, similar size-shape selectivity was observed for nitrosation. The N-Me-N-nitroso derivatives 6 d,e were obtained with approximately 30 % yields, while bulkier amides were nitrosated with much lower yields (<8 %). Enantiomerically pure encapsulating reagent 2 d was tested for nitrosation of racemic amide 5 t, showing modest but reproducible stereoselectivity and approximately 15 % ee. Given high affinity to NO+ species, which can be generated by a number of NOX gases, these supramolecular reagents and materials may be useful for NOX entrapment and separation in the environment and biomedical areas.     

葫芦脲：分子识别与组装

综述了葫芦脲这一类合成受体的最新研究进展，包括葫芦脲的分子设计与合成 ，离子和分子识别，键合的热力学性质，分子组装及其功能的最新研究概况。     

Dynamic molecular recognition in the generation of a new crystal-engineering motif: a unique case study of a dicarboxylic acid with a ditopic receptor favouring a polymeric over a dimeric hydrogen-bonded supramolecular complex

A new crystal-engineering motif has been developed where a ditopic receptor 1 shows a novel syn-syn hydrogen-bonded polymeric supramolecular complex (Fig. 4b) (instead of a 1:1 dimeric syn-syn or polymeric syn-anti complex) giving rise to a hydrogen-bonded stair-like polymeric ribbon structure between the binding groups of the receptor pyridine amide and the carboxyl groups of the guest substrate.     

Combinatorial Synthesis and Multidimensional NMR Spectroscopy: An Approach to Understanding Protein–Ligand Interactions

Combinatorial chemistry is a laboratory emulation of natural recombination and selection processes. Strategies in this developing discipline involve the generation of diverse, molecular libraries through combinatorial synthesis and the selection of compounds that possess a desired property. Such approaches can facilitate the identification of ligands that bind to biological receptors, promoting our chemical understanding of cellular processes. This article illustrates that the coupling of combinatorial synthesis, multidimensional NMR spectroscopy, and biochemical methods has enhanced our understanding of a protein receptor used commonly in signal transduction, the Src Homology 3 (SH3) domain. This novel approach to studying molecular recognition has revealed a set of rules that govern SH3–ligand interactions, allowing models of receptor–ligand complexes to be constructed with only a knowledge of the polypeptide sequences. Combining combinatorial synthesis with structural methods provides a powerful new approach to understanding how proteins bind their ligands in general.