An ab initio molecular orbital study of the grignard reagents CH3MgCl and [CH3MgCl]2: The Schlenk equilibrium

Ab initio molecular orbital calculations are used to study the modified Schlenk equilibrium: 2RMgCl (RMgCl)² MgR₂ + MgCl₂ Mg(Cl₂)MgR₂ with R=H and CH₃. In the absence of any solvents, calculations indicate that the formation of the various possible bridged dimers (RMgCl)₂ is substantially exothermic. However, using dimethylether as a model solvent, we show that the formation of the dimer (Me₂O)(CH₃)Mg(Cl₂)Mg(CH₃)(OMe₂) is exothermic only when entropic effects are included.     

Electrochemical behaviour of a series of Fe(III) complexes with tetradentate Schiff base ligands

Summary The electrochemical reduction of the Fe(III) complexes with a series of substituted N,N-Ethylenebisacetonimines was investigated by cyclic voltammetry in acetonitrile solution at a platinum electrode. The substituent does not significantly influence the redox properties of the studied complexes. The symmetry of the redox orbital is responsible for the observed behaviour of the complexes.

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Elektrochemisches Verhalten einer Reihe von Fe(III)-Komplexen mit vierzähnigen Schiffschen Basen als Liganden

Zusammenfassung Die elektrochemische Reduktion der Fe(III)-Komplexe einer Reihe von substituierten N,N-Ethylenbisacetoniminen wurde mittels cyclischer Voltammetrie in Acetonitril an einer Platinelektrode untersucht. Der Substituent beeinflußt die Redoxeigenschaften der untersuchten Komplexe nicht signifikant. Das beobachtete Verhalten der Komplexe wird von der Symmetrie des Redoxorbitals bestimmt.

     

原位氧化还原沉淀水热合成法制备LixMn2O4尖晶石

Li xMn2O4尖晶石是新一代的锂离子二次电池正极材料 [1], 其合成方法对材料的电化学性质影响很大[2].常规合成大多采用高温固相反应法, 此法具有反应温度高, 反应时间长, 容易产生缺陷和产物不纯净等缺点, 导致所合成的锂离子二次电池正极材料的性能较差. 目前用水热合成法制备电池正极材料Li xMn2O4尖晶石尚未见文献报道. 本文在常规水热合成法的基础上采用原位氧化还原沉淀水热合成法 [3]制备前驱物, 该法合成条件更温和, 而且使材料的综合性能得到了改善和提高.      

Regioselective synthesis of polysubstituted benzenes from Baylis-Hillman adducts via [4+2] annulation protocol

A new and regioselective [4+2] benzannulation protocol toward polysubstituted benzenes was developed. A nitroalkane derivative, which was prepared from Baylis-Hillman adduct, served as the four-carbon unit and a Michael acceptor as a two-carbon unit. Vinyltriphenylphosphonium salt could also be used as a Michael acceptor efficiently.     

Transformation of thioacetals to cyclopropanes

Cyclopropanes were obtained by the titanocene(II)-promoted reaction of thioacetals with vinyl pivalate. It was also found that vinycyclopropanes were produced by a similar treatment of thioacetals with the titanocene(II) species in the presence of 1,3-dienes.     

金属有机化合物的分析（Ⅷ）：氢硼酸金属有机络合物的反相色谱机理

本文研究了具有特殊结构的氢硼酸金属有机络合物的反相色谱及机理。在MicropakC_(18)柱上,加入含离子试剂的甲醇-水作为流动相,通过用电导法测定流动相电性能,Break-through法测定离子试剂在固定相上的吸附量及制备色谱法研究各流分组成,认为此类化合物的保留机理为动态离子交换过程。     

十八元环多钒硼酸盐的水热合成及其氧化还原性质研究

在水热条件下合成了[Ni(en)2]6[(VO)12O6B18O39(OH)3].6H2O多钒硼酸盐,X射线衍射分析表明,该晶体属三方晶系,R-3空间群.测试了晶体的IR光谱和TG曲线,用循环伏安法详细研究了合成化合物的氧化还原性质及电子转移机理,结果表明该化合物具有两对氧化还原峰,其电子转移数分别为单电子和三电子.     

钯（0）／离子交换树脂对有机锡试剂和有机卤化物偶联反应的催化性能和结构表征

制备了强碱性阴离子交换树脂（）负载钯（０）催化剂，发现它对有机锡试剂和有机卤化物的偶联反应有很高的催化活性，分离容易，可重复使用．起催化作用的是金属态把．ＸＰＳ等实验结果表明，在催化剂中钯作为桥将功能基－Ｎ（ＣＨ３）３与ＯＨ－联结起来．催化剂中的把可以看作是两配位的和配位不饱和的，经过氧化加成、金属交换、还原消除过程完成催化反应．     

Potential response in the uncatalyzed bromate oscillatory system

The potential response of the platinum indicator electrode in the uncatalyzed bromate oscillator (UBO) with three different substrates, namely gallic acid (GA), pyrogallol (PG) and veratraldehyde (VA) has been analyzed. The large amplitude oscillations obtained with a Pt electrode are due to the sequential response of the indicator electrode to the varying concentration ratios of the redox couples present in the reaction mixture.     

One-pot synthesis of N-acyl-substituted sulfamides from chlorosulfonyl isocyanate via the Burgess-type intermediates

The title N-alkoxycarbonyl- or N-aryloxycarbonyl-substituted sulfamides were synthesised in one-pot in efficient yields from chlorosulfonyl isocyanate (CSI), alcohols and aqueous (or dry) amines via the corresponding water-resistant intermediates, carboxysulfamoylammonium salts (Burgess-type reagents), which were generated in situ by the deactivation of the corresponding water-sensitive N-(chlorosulfonyl)carbamates with tertiary amines.