结合三维静电势参数研究二取代苯的定量结构－疏水性关系

对含有常见取代基的92个二取代苯化合物进行了结构优化和静电势及其导出参数的计算,运用多元线性回归方法对化合物的疏水常数与分子的结构参数进行了关联.结果表明,分子表面负静电势的加和ΣV－S、分子空间内最负的静电势Vmin、表面最大静电势Vs,max以及分子体积V、极性表面积APS和分子的偶极密度μ/V这六个参数,可以很好地用于表达这些化合物疏水性与分子结构间的定量关系,而不用具体考虑分子中极性基团间的相互作用.用建立起来的QSPR(quantitative structure-property relationship)关系式对111个类似化合物的疏水性进行了预测,获得了满意的结果.     

Protein secondary structure and stability determined by combining exoproteolysis and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry

In the post-genomic era, several projects focused on the massive experimental resolution of the three-dimensional structures of all the proteins of different organisms have been initiated. Simultaneously, significant progress has been made in the ab initio prediction of protein three-dimensional structure. One of the keys to the success of such a prediction is the use of local information (i.e. secondary structure). Here we describe a new limited proteolysis methodology, based on the use of unspecific exoproteases coupled with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS), to map quickly secondary structure elements of a protein from both ends, the N- and C-termini. We show that the proteolytic patterns (mass spectra series) obtained can be interpreted in the light of the conformation and local stability of the analyzed proteins, a direct correlation being observed between the predicted and the experimentally derived protein secondary structure. Further, this methodology can be easily applied to check rapidly the folding state of a protein and characterize mutational effects on protein conformation and stability. Moreover, given global stability information, this methodology allows one to locate the protein regions of increased or decreased conformational stability. All of this can be done with a small fraction of the amount of protein required by most of the other methods for conformational analysis. Thus limited exoproteolysis, together with MALDI-TOF MS, can be a useful tool to achieve quickly the elucidation of protein structure and stability.     

Synthesis and Characterization of the Chiral Skeleton Cluster [NiRuMo(CO)_5(μ_3-S)(η~5-C_5H_5)(η~5-C_5H_4COCH_3)]

1 INTRODUCTION The chemistry of transition metal cluster has enjoyed an exceptional growth since the mid 1970s[1, 2], especially in recent years the structural and bonding aspects of mixed-metal tetrahedral skeleton clusters have been extensively studied[3]. One important reason is that such chiral cluster can induce an asymmetric catalysis potentially. In our research group, considerable efforts have been directed to the synthesis of chiral tetrahedral clusters containing four different…     

气相[（SiO2）nX]^—团簇产生机理

利用ＸｅＣｌ准分子激光烧蚀多种硅氧多孔结构材料，在负离子通道测得丰富的「（ＳｉＯ２）ｎＸ」＾－负离子团簇，并讨论了多孔网结构和表面活性基团的分布对激光能量的吸收，传输及团簇产生的重要作用。     

水相中金属铜表面生成亚铜—邻菲罗啉配合物的反应

本文研究了零价铜在邻菲罗啉水溶液中的反应。当溶液敞露于空气并存在有机阴离子Ｘ－时，例如苯甲酸盐（Ｂｚ）、对甲基苯磺酸盐（Ｔｓ）等，铜的表面生成了致密的反应产物的薄层，经ＩＲ、ＵＶ／ＶＩＳ、ＭＳ和元素分析证明了该薄层为相当纯的亚铜的邻菲罗啉配位化合物，结构为［Ｃｕ（ｐｈｅｎ）２］＋Ｘ－。在乙醇／甲苯混合溶剂中得到了表面反应产物的晶体［Ｃｕ（ｐｈｅｎ）２］（ＣＨ３Ｃ４Ｈ６ＳＯ３）Ｃ２Ｈ５ＯＨ，并用Ｘ－ｒａｙ测得了结构。本工作表明溶液中的ＣｕⅡ离子抑制Ｃｕ０氧化成ＣｕⅠ而影响反应层的形成，同时又促进ＣｕⅠ氧化成ＣｕⅡ的过程     

[1-芳基甲羰基-2-(1,2,4-三唑-1-基)]乙基-N,N-二烷基二硫代氨基甲酸酯衍生物的合成、结构表征及生物活性研究

以芳香基三唑类杀菌剂三唑酮为先导物设计并合成了5个含N,N-二烷基二硫代氨基甲酸酯的芳香三唑类化合物, 通过元素分析、红外光谱、核磁共振氢谱和质谱对其结构进行了表征. 用X射线单晶衍射测定了[α-(4-甲氧基苯甲酰基)-2-(1,2,4-三唑-1-基)]乙基-N,N-二甲基二硫代氨基甲酸酯的晶体结构, 晶体属于三斜晶系, 空间群, 晶胞参数为: a＝0.73482(15) nm, b＝1.1051(2) nm, c＝1.1209(2) nm, α＝90.32(3)°, β＝101.97(3)°, γ＝105.13(3)°, V＝0.8578(3) nm³, Z＝2, D_c＝1.357 g/cm³, F(000)＝368, µ＝0.324 mm^－1. 生物测试结果显示这5种有机化合物都具有杀菌性和植物生长调节活性     

Formation and Crystal Structure of Stable Five‐coordinate Diorgano Cobalt(III) Complexes

The mer‐octahedral complexes(2‐carbonyl)(4‐Me)(6‐tBu)phenolato[C,O]hydridotris(trimethylphosphine)cobalt(III) ( 1 ) or ‐(1‐carbonyl)(2‐oxo)(1,2‐diphenylethene)[C,O]hydridotris(trimethylphosphine)cobalt(III) ( 2 ) via formal insertion of propynoic acid ethyl ester into Co‐H functions afford pentacoordinate vinylcobalt(III) 3 and 4 , respectively, that are diamagnetic and attain a square pyramidal structure as exemplified by an X‐ray diffraction analysis of 3 .     

Synthesis and Crystal Structure of Pd（ptac—C,N）（acac—O,O）

1INTRODUCTIONTherehasbeenconsiderableattentionfocusedonthestudyofpalladiumcomplexinorganicsynthesis,catalyticprocesses,chemicalreactivity,spectroscopyandstructuralanalysisandfunctionalmaterials[1].Manypalladacycleshavebeenappliedinthepreparationofliquid-crystallinecomplexes[2],andsomeofthemshowantitumoractivity.Theincreasingimportanceofsuchcyclo-organometalliccomplexleadsustoinvestigatethecyclicPdcomplexeswithenhancedchemicalandthermalstability,fromwhichdetailedspectroscopicandstructuralc…     

Adsorption of water molecules in slit pores

We report molecular dynamics (MD) simulations on the adsorption of water in attractive and repulsive slit pores, where the slit and a bulk region are in contact with each other. Water structure, surface force and adsorption behavior are investigated as a function of the overall density in the bulk region. The gas–liquid transition in both types of pores occurs at similar densities of the bulk region.     

Quantum-Chemical Investigation of Intermediates in the Addition of Phenylsulfenium Cation to Substituted Acetylenes

The reaction paths for the transformations of substituted acetylenes (X—CC—Y; X, Y = H, Me, Ph, CN) in reaction with phenylsulfenium cation were studied by quantum-chemical methods. It was shown that the reactions take place with the formation of acyclic and cyclic cationic intermediates. The factor that determines the structure and characteristics of these cations is the induction and polarizing action of the substituents in the acetylenes and to a lesser degree their electron-donor characteristics. The resonance effect of the phenyl substituent has a predominantly levelling action on the distribution of charges.