双(2,4-二甲基戊二烯基)氯化钆的合成及晶体结构

合成双(2,4-二甲基戊二烯基)氯化钆{[2,4-(CH₃)₂C₅H₅]₂GD_cl}₂,并测定了晶体结构.晶体为单斜晶系,P2₁/n空间群.晶胞参数a=0.89141(18)nm,b=1.4486(3)nm,c=1.15925(15)nm,β=92.996(18)°,V=1.4949(4)nm³,Z=3.     

Nickel(II) Complexes with Pentane-2,4-dione Bis(4-allylthiosemicarbazone)

Reaction of pentane-2,4-dione with N-(prop-2-en-1-yl)hydrazinecarbothioamide at a 1: 2 molar ratio in ethanol resulted in the formation of a pyrazole derivative. The latter reacted with nickel perchlorate at a 1: 1 molar ratio to form the nickel complex with pentane-2,4-dione bis(4-allylthiosemicarbazone). The same type of nickel complex was obtained as a result of N-(prop-2-en-1-yl)hydrazinecarbothioamide reaction with pentane-2,4-dione and nickel nitrate at a 2: 1: 1 molar ratio. Antimicrobial, antifungal, antioxidant, and anticancer activities of the obtained compounds were studied.     

双席夫碱双-(2,4-二羟基苯乙酮)缩肼的合成及其与铜的荧光猝灭反应

报道了一种新的双席夫碱荧光试剂——双—(2，4—二羟基苯乙酮)缩肼的合成；试剂在492.8nm处有一强荧光峰，当有铜离子存在时，可与试剂形成稳定的配合物而使试剂的荧光猝灭；利用此反应建立了一个荧光测定痕量铜的新方法，测定铜的线性范围为0．0～180．0μg／L，检出限0．02μg／L，方法可应用于矿泉水和水中痕量铜的测定。     

1,3‐Bis(2,4‐dibromophenyl)triazene

The crystal structure of the title compound, C₁₂H₇Br₄N₃, shows that the stereochemistry about the N=N double bond of the N=N—N(H) moiety is trans. The whole mol­ecule deviates slightly from planarity (r.m.s. deviation 0.164 Å). While one of the aryl substituents is almost coplanar with the triazene chain, weak intermolecular Br?C contacts cause the second aryl substituent to deviate by an angle of 9.1 (8)° from the plane defined by the N=N—N group. Weak intermolecular N—H?Br interactions between mol­ecules related by the diagonal glide plane give rise to chains, which are stacked along the [100] crystallographic direction. An unequal distribution of double‐bond character between the N atoms suggests a delocalization of π electrons over the diazo­amino group and the adjacent aryl groups.     

Highly Cis-Selective Horner-Wadsworth-Emmons (HWE) Reaction of Methyl Bis(2,4-Difluorophenyl) Phosphonoacetate

Of the previously reported Horner-Wadsworth-Emmons (HWE) reaction, the olefination of methyl bis(2,4-difluorophenyl)phosphonoacetate (la) with various aldehydes gave unsaturated esters in the highest cis-selectivity.     

“一锅法”简便合成1,4—双（2,4—二羟基苯基）—丁二酮—1,4

１，４－双（２，４－二羟基苯基）丁二酮－１，４－是Ｐｒａｋａｓｈ等从买麻藤属龈（ＧｅｎｅｈｕｍＵＬａ）中分离得到的一种微量组分。文中报道了以丁二腈和间苯二酚为原料，“一锅法”简便合成了此化合物。     

Kinetics and Mechanism of the Nucleophilic Substitution Reaction of Imidazole with Bis(2,4,6-trichlorophenyl) Oxalate and Bis(2,4-dinitrophenyl) Oxalate

The kinetics of the imidazole-catalyzed decomposition of bis(2,4,6-trichlorophenyl) oxalate (TCPO) and bis(2,4-dinitrophenyl) oxalate (DNPO) was investigated by the stopped-flow technique. Pseudo-first-order rate constants were determined as a function imidazole concentration in the temperature range 6-45 degrees C by fitting the temporal changes in absorbance throughout the 245 to 345 nm wavelength range for TCPO and at 420 nm for DNPO. The reaction proceeds by release of two molecules of substituted phenol and formation of 1,1'-oxalyldiimidazole (ODI) for both esters. The identity of ODI was confirmed in the reaction of imidazole with TCPO by its UV absorbance spectrum and (13)C-NMR spectrum. The reaction of imidazole with TCPO has a second-order dependence on imidazole concentration and an observed negative activation energy of -6.2 +/- 0.3 kJ/mol, whereas the DNPO reaction has a first-order dependence on imidazole concentration and an observed positive activation energy of 12.0 +/- 0.6 kJ/mol. The differences in the temperature dependence and order of the reaction with respect to imidazole for the two oxalate esters are explained by a shift in the rate-determining step from addition to the acyl group for DNPO to imidazole-catalyzed release of the phenol leaving group for TCPO. These kinetics results are useful in interpreting the initial reaction steps in peroxyoxalate chemiluminescence.     

2,4-二(2-烯炳基苯氧基)-6-N,N-二甲(乙)基胺基-1,3,5-三嗪的直接一步法合成

近年来,以三聚氯氰为原料合成含烯丙基和均三嗪环的反应性单体的研究时有报道［１～３］．这类单体易于合成、储存稳定性好,可作为双马来酰亚胺的增韧改性剂,并且由于这类化合物分子结构中活性反应点较多,它们有望在药物、生物材料等领域找到新的用途．我们曾以水为反应介质合成了２,４,６三（２烯丙基苯氧基）１,３,５三嗪（ＴＡＰＴ）［４,５］．为获得对双马来酰亚胺有显著改性效果的系列品种,我们在保留三嗪环上有一定数量的烯丙基和芳香结构,以确保单体有一定反应性又保证其与双马来酰亚胺的共聚物有较好的耐热性的…     

基于2,4-二丙稀酰胺嘧啶的氢键复合物的稳定性和光谱

氢键对含有以嘧啶为基的衍生物的生命体具有重要作用。用AM1 和 DFT 方法对2,4-二丙稀酰胺嘧啶(2,4-BAAP) 衍生物与1-取代的脲嘧啶形成的氢键复合物电子结构进行理论研究。用INDO/SCI 和 B3LYP/6-31G(d)方法分别计算了复合物的UV和NMR光谱。结果表明,由于结合能为负值,两单体能通过三重氢键形成复合物,取代基存在时结合能变小。这种削弱效应取决于电子效应和空间效应的协同作用。当2,4-BAAP上哌啶基存在时,由于异构复合物的形成,复合物的结合能变小。供电基存在时复合物的能隙变小。共轭体系的扩展使复合物易于注入电子和空穴。复合物电子光谱的第一吸收峰与母体相比发生红移由于其具有较小的LUMO-HOMO能隙。在13C NMR谱中,复合物C=O键上的C原子的化学位移向低场移动。     

[Bis(2,4-dimethyl-6-tert.butyl-phenyl)ketone]chromium tricarbonyl—Stable torsional isomers

Complexation of bis(2,4-dimethyl-6-tert.butyl)ketone with chromium hexacarbonyl yields a mixture of two diastereomeric mono complexes in a ratio of 5 : 1. They can be separated by chromatography on silica gel at room temperature thus representing stable torsional isomers (isolable residual diastereomers).Dedicated to Prof. Dr.A. Neckel with cordial wishes on the occasion of the 60th anniversary of his birthday.