Cage Compounds of Phosphorus and the Heavier Group 14 Elements

The Sn/P cage compounds [Sn₁₀(tBuP)₄] ( 1 ) and [Sn₁₀(tBuP)₇Cl₄] ( 2 ) were obtained by the reaction of LitBuPH with SnBr₂ and SnCl₂, respectively. Theoretical calculations confirm that the tin atoms in 2 feature different formal oxidation states. The reaction of PbCl₂ with LitBuPH and LiPHSiiPr₃ yields the Pb/P cage compounds [Pb₇(tBuP)₇] ( 3 ) and [Pb₆(PSiiPr₃)₆] ( 4 ), respectively, that represent new derivatives of known polyhedrons of this class of compounds. The new products were characterized by X‐ray diffraction, elemental analysis and partially by MS and MAS‐NMR spectroscopy.     

稀土－钴－茜素氨羧络合剂异核络合物极谱吸附波的研究

稀土－钴－茜素氨羧络合剂异核络合物极谱吸附波的研究崔毅,李南强（北京大学化学系,北京,１００８７１）关键词稀土异核络合物,络合吸附波,单扫极谱Ｌｅｏｎａｒｄ［１］曾用光度法初步确定了Ｌａ（Ⅲ）或Ｃｅ（Ⅲ）、Ｎｉ（Ⅱ）或Ｃｏ（Ⅱ）与茜素氨羧络合剂（ＡＬ...     

正反相模式下键合纤维素手性固定相对手性化合物的拆分

在自行合成的键合型纤维素-(3,5-二甲基苯基氨基甲酸酯)(CDMPC-CSP)手性固定相上,在正相模式下对苯偶姻和甲霜灵外消旋体进行了拆分,考察了流动相中醇以及温度在手性识别中对手性分离的影响。同时考察了反相模式下外消旋体的拆分。     

高效液相色谱二氮杂冠醚键合相的合成及性能研究

本文报道在硅胶表面进行固－液相反应，合成硅胶键合二氮杂冠醚高效液相色谱固定相。采用有机元素分析、热分析、红外光谱、金属离子的络合容量测定等对键合材料进行鉴定和表征，并对其色谱性能进行了研究。     

钼、钨四重键化合物电子光谱的含时密度泛函理论研究

运用含时密度泛函理论(TD-DFT),对具有代表性的钼、钨四重键化合物M2Cl4-8,M2Cl4(PMe3)4,M2(O2CCH3)4和M2(PhNCHNPh)4(M=Mo,W)的低占据电子激发能进行了计算,系统地考察了局域(LDA)、离域(GGA)和杂化(Hybrid)泛函对金属四重键化合物中d-d跃迁和电荷转移跃迁...     

Permethylated Disila[2]metallocenophanes of Group 14 and 15 Elements

Permethylated disila[2]metallocenophanes of silicon, germanium, tin, lead, 2 a – d , (tetrelocenophanes) and antimony, 3 a , b , (pnictogenocenophanes) are described. In the case of antimony, a chloro-substituted stibonocenophane, 3 a , as well as cationic stibonocenophanium tetrachloroaluminate and tetraphenylborate salts, 3 b [X] (X=[AlCl₄], [BPh₄]), were synthesized. These represent the first examples of metallocenophanes of any Group 15 element. All compounds were studied in solution and in the solid state. Without exception the ansa-bridge exerts a strong influence on the bending angle of the two Cp-ligands. For disila[2]plumbocenophane, 2 d , its reactivity towards Group 15 halides was probed. Treatment of disila[2]plumbocenophane, 2 d , with two equivalents of phosphorus(III) chloride or arsenic(III) chloride, results in a ring-opening reaction and gives the bis(dihalopnictogenyl)-substituted products, 4 a , b .     

Structure and Bonding in Organometallic Anions of Heavy Group 14 and 15 Elements

Alkali metal organometallic complexes (containing C–metal bonds) and the frequently structrually related alkali metal amides and alkoxides have been investigated extensively both in the solid state and in solution in the past two decades. However, until recently, the related complexes containing the heavier metallic and semi-metallic p block elements and the alkali and alkaline earth metals had rarely been studied in their own right. Recent solid-state structural studies have illustrated the immense structural diversity and bonding modes to be found within these species. One of the principal focuses of recent studies has been complexes containing organometallic anions of p block metals (e.g., triorganostannates, containing R₃Sn^?) in which metal–metal bonds occur between the heavy p block metal and the alkali or alkaline earth metal and the investigation of the nature of this bonding. The development of new synthetic routes has also allowed the preparation of a variety of anionic ligands with p block metal centers which promise new opportunities in coordination chemistry. In addition, the synthesis of a family of homologous anionic π complexes has given a fresh direction in the chemistry of p block metal metallocene complexes.     

含吡啶环系和中心功能基氮杂冠醚的合成研究

合成了氮杂大环化合物Ⅰ－Ⅳ，并通过＾１Ｈ ＮＭＲ、ＭＳ和元素分析表征了它的结构，对其中间体（７）的合成方法进行了改进，使收率得到了大幅度提高，探讨了在不同温度下的成环反应，结果表明，室温有利于成环和提高反应收率。     

ChemInform Abstract: Formation and Stability of Gaseous Ternary Oxides of Group 14-16 Elements and Related Oxides of Group 15 Elements: Mass Spectrometric and Quantum Chemical Study.

The formation of the new compounds PbTeO₃, PbTe₂O₅, Pb₂TeO₄, and Pb₂Te₂O₆ is observed in the gas phase by heating a mixture of solid PbO and TeO₂ at 1063 K using a mass-spectrometric Knudsen-cell method.     

Steric effects on controlling of photoinduced electron transfer action of anthracene modified benzo-15-crown-5 by complexation with Mg and Ca

Benzo-crown ether based chemosensors linked by an amide bond at the 1-, 2- or 9-positions of anthracene rings were synthesized. Their complexation behavior with alkaline earth metal ions in acetonitrile was investigated using fluorescence, UV, and ¹H NMR spectroscopy. In the absence of a metal ion, all compounds showed only very slight fluorescence emissions (fluorescence ‘off’ state) because of intramolecular charge/electron transfer process. After the complex formation with Mg²⁺ and Ca²⁺, however, only the 2-position analogue gave a fluorescence ‘on’ response by inhibiting the photoinduced electron transfer. Because 2-positioned anthracene was free from steric hindrance of the crown ether ring, a strongly bent complex structure was formed with Mg²⁺ and Ca²⁺, which induced a breakdown of π-conjugation between the amide moiety and the benzene ring.     

含氮氧功能基新型键合固定相色谱性能及应用研究

用新合成的３－（二乙醇）氨丙基硅氧烷（ＤＥＡＰ）、３－（氮杂１８－冠－６）丙基硅氧烷（ＢＣＰ）作固定相，对二取代苯异构物进行液相色谱分离，研究流动相组成，ｐＨ值及其Ｋ￣＋离子浓度对色谱行为的影响．探讨溶质保留机理，并比较ＤＥＡＰ、ＢＣＰ与ＯＤＳ的色谱性能．     

笼状双环磷酸酯类化合物的合成与生物活性研究

近年来,科学家们相继合成出高度对称结构的双环磷酸酯笼状化合物,并研究了它们的生物活性,这类化合物具有良好的杀虫抗菌活性,且有独特的活性机理,在医药、农药、纤维、树脂及石油工业中已得到了广泛应用,本文采用季戊四醇和苯乙腈为起始原料,以下列反应步骤设计合成了8个新型笼状双环磷酸酯衍生物I,[1′-硫(氧)代-2′,6′,7′-三三氧杂-1′-磷杂双环(2,2,2)辛烷基-4′-甲基]-4-烷基-4-苯基-4-氰基丁酸酯:     

NMR and DFT Studies with a Doubly Labelled 15N/6Li S-Trifluoromethyl Sulfoximine Reveal Why a Directed ortho-Lithiation Requires an Excess of n-BuLi

This work shows why it is imperious to use an excess of butyllithium for a directed ortho-lithiation of a trifluoromethyl sulfoximine. The analysis of mixtures of n-BuLi and sulfoximine 1 in THF-d₈ using {¹H, ⁶Li, ¹³C, ¹⁵N, ¹⁹F} NMR experiments at low temperatures reveal that a first deprotonation occurs that leads to dimeric and tetrameric N-lithiated sulfoximine (93 : 7). Using an excess n-BuLi (5 equivalents), the second deprotonation on the ortho-position of the aromatic occurs. Six species were observed and characterized on the way. It includes three aggregates involving a sulfoximine: i) a [dilithiated sulfoximine/(n-BuLi)] dimer solvated by four molecules of THF ( Agg2 , 39 %); ii) a [dilithiated sulfoximine/(n-BuLi)₃] tetramer solvated by six molecules of THF ( Agg3 , 39 %); iii) a [dilithiated sulfoximine/(n-BuOLi)₃] tetramer solvated by four molecules of THF ( Agg1 , 22 %). A DFT study afforded optimized solvated structures for all these aggregates, fully consistent with the NMR data.     

微量元素与人类健康的研究进展

综述了微量元素的生理作用以及微量元素与健康关系的近年研究概况。     

微量元素与肿瘤关系的研究进展

本文根据近年国内外的文献报道,概述了微量元素的生理作用及与肿瘤的关系。作者认为肿瘤的发展程度与微量元素含量变化有关,铜／锌比值对恶性肿瘤的疗效和预后估计有一定的参考价值。     

不同产地的黄芪微量元素的测定与研究

应用电感耦合等离子体发射光谱仪，对五种不同产地的黄芪进行了３２种元素的测定，并对微量元素的含量进行了比较。     

微量元素与中药功效关系的探讨

中药中含有丰富的微量元素，其种类和含量与中药功效有着密切的关系。从微量元素与中药的滋补作用，解热作用．抗菌消炎作用和止血作用等四方面，论述了微量元素与中药功效的关系。