Production of Dihydrogen Using Ammonia Borane as Reagent and Pyrazole as Catalyst

Theoretical chemistry (DLPNO-CCSD(T)/def2-TZVP//M06-2x/aug-cc-pVDZ) was used to design a system based on ammonia boranes catalyzed by pyrazoles with the aim of producing dihydrogen, nowadays of high interest as clean fuel. The reactivity of ammonia borane and cyclotriborazane were investigated, including catalytic activation through 1H-pyrazole, 4-methoxy-1H-pyrazole, and 4-nitro-1H-pyrazole. The results point toward a catalytic cycle by which, at the same time, ammonia borane can initially store and then, through catalysis, produce dihydrogen and amino borane. Subsequently, amino borane can trimerize to form cyclotriborazane that, in presence of the same catalyst, can also produce dihydrogen. This study proposes therefore a consistent progress in using environmentally sustainable (metal free) catalysts to efficiently extract dihydrogen from small B−N bonded molecules.     

Formation and Structure of an Anionic Ruthenaborane Compound:[Et4N][(PPh3)2ClRuB12H12]

在研究RuCl2(PPh3)3 和 closo-B10H102- 在乙醇中的反应时,意外分离得到一个阴离子型的钌硼烷化合物[Et4N][(PPh3)2ClRuB12H12], 并且经过红外光谱和单晶X射线衍射分析确证. 在其结构中,闭式B12H122-配体与Ru(II)中心通过三个B-H-Ru三中心-二电子键结合. 分析原因应是在通过文献方法制备闭式B10H102-时的少量副产物闭式B12H122-在反应体系中与RuCl2(PPh3)3反应而生成了标题化合物. 根据硼烷簇合物的电子计数规则, 标题化合物也可以看成是含有2n (n为簇顶点数)个骨架电子的pileo型簇合物, 具有加帽(capped)的闭式多面体骨架构型. 这是第一个阴离子型的含有闭式B12H122- 的钌化合物.     

鼻咽癌细胞分泌物的拉曼光谱研究

Plasminogen Activator Inhibitor 1(纤溶酶原激活物抑制物1, 简称PAI-1)在鼻咽癌(Nasopharyngeal Carcinoma, 简称NPC)分泌物中大量存在。本文绘制了Plasminogen Activator Inhibitor 1的分子结构, 根据局部能量最低原理对其做了结构优化, 给出了空间结构参数, 然后利用DFT B3LYP/3-21G基组计算了其拉曼光谱, 并对102 cm-1至4559 cm-1区间的谱线进行指认。理论计算Plasminogen Activator Inhibitor 1的拉曼光谱将有助于鼻咽癌的临床检测技术的提高。     

Two-Dimensional Chromatographic Analysis of Polystyrene-block-poly(methyl methacrylate) Copolymers Synthesized by Selective Oxidation of Polystrene-9-borabicyclo[3.3.1]nonane

Summary: The preparation of polystyrene block methyl methacrylate copolymers (PS-b-PMMA) is described. The polystyrene segment was prepared by anionic polymerization and the methylmethacrylate segment was prepared via free radical autoxidation of a borane agent attached to the styrene chain. 1 The chemistry involves a transformation of the anionic polymerization process to borane chemistry by firstly producing polystyrene with chain end unsaturated alkyl functional groups prepared using a n-butyllithium initiator and termination with allylchlorodimethylsilane. Secondly, the unsaturated macroinitiator end was hydroborated by 9-borabicyclo[3.3.1]nonane (9-BBN) to produce a borane terminated PS. Thirdly, the borane group at the chain end was selectively oxidized and converted to polymeric radicals in the presence of methyl methacrylate which then initiated radical polymerization to produce block copolymers. The polymer obtained was characterized using several chromatographic techniques including LC-CC (liquid chromatography under critical conditions) for the polystyrene segments and two-dimensional chromatography with LC-CC in the first dimension and SEC in the second. The results show that block formation was successful although significant homopolymerization of methyl methacrylate is also obtained.     

Optical characteristics of alkali-halide crystals doped with nickel ions

Scientific-Research Institute of Mechanics and Physics at the Saratov State University, 112-A, Bolshaya Kozach'ya Str., Saratov, 410071, Russia. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 62, No. 3, pp. 235–238, May–June, 1995.     

B_nX_n~（0，2－）（X＝H，Cl；n＝4，6，8，9，10，12）稳定性的从头计算研究

用双ζ型收缩高斯基对全卤代硼烷Ｂ_ｎＸ_ｎ~（０，２－）及相应硼烷Ｂ_ｎＸ_ｎ~（０，２－）（ｎ＝４，６，８，９，１０，１２）进行了从头计算。讨论中性卤代硼烷稳定存在的原因及Ｂ_ｎＣｌ_ｎ与Ｂ_ｎＸ_ｎ~（０，２－）稳定性随ｎ变化的不同趋势，并通过对Ｂ_４Ｘ_ｎ~（０，２－）结构规则的计算与分析，提出骨架成键轨道未填满电子是Ｂ_４Ｘ_ｎ~（０，２－）不稳定及迄今尚未发现中性Ｂ_ｎＨ_ｎ存在的重要原因。     

基质辅助激光解吸附电离飞行时间质谱分析化学合成酵母转录活化因子

基质辅助激光解吸附电离飞行时间质谱是近年来发展很快的一种新颖的质谱分析仪，尤其适用于生物大分子的分子量测定，本文介绍它在确证化学合成酵母转录活化因子Ａｃ（Ｑ＾２３６，Ｑ＾２４２），ＧＣＮ４（２２６－２５２）－ＧＧＣ－ＮＨ２的一级结构中的重要作用。