三正辛基氧化膦萃取钯的研究

本文研究了用三正辛基氧化膦(TOPO)煤油溶液从盐酸介质中萃取钯及用硫脲反萃钯的条件。用等摩尔系列法、饱和法、化学分析法和斜率法确定了萃合物的组成。用紫外-可见光谱法探讨了TOPO萃取钯的机理。     

大位阻、富电子MOP型烷基膦配体在钯催化的1,3-二羰基化合物 α-芳基化反应中的应用

富电子、大位阻MOP型烷基膦配体2-二叔丁基膦-2’-异丙氧基-1,1’-联萘(L1)在钯催化的1,3-二羰基化合物的α-芳基化反应中显示了较好的催化活性. 在这类催化反应中, 碱的选择具有重要的影响: 以K3PO4为碱, Pd(OAc)2/L1催化体系在丙二酸二乙酯的α-芳基化中, 富电子溴代芳烃显示较好的活性; Pd(OAc)2/L1催化的乙酰乙酸乙酯α-芳基化时, 以 K2CO3为碱, 催化体系显示较好的活性, 这个催化体系可控制反应得到α-芳基乙酰乙酸乙酯, 而不是脱乙酰基的产物. 较为惰性的氯代芳烃在Pd(OAc)2/L1的催化下, 也能够跟1,3-二羰基化合物发生α-芳基化反应.     

钯催化甲基苯基膦氢的不对称烷基化反应合成含膦手性中心化合物

研究了Pincer-钯催化的甲基苯基膦氢对卤代烃的不对称取代反应.以高收率、中等的立体选择性得到含膦手性中心的膦化合物,同时对反应的催化循环和可能的立体化学过程进行了探讨.     

C60与硅烯环加成反应机理的理论研究

用半经验AM1法研究了C₆₀与单态硅烯环加成反应机理.经Berny梯度法优化得到反应的过渡态,并进行了振动分析确认.计算结果表明:硅烯在C₆₀的66键上的加成反应分两步,第一步反应物生成中间配合物,无势垒;第二步由中间配合物经过渡态变为产物.65键上的加成反应分三步,第一步由反应物生成中间配合物,第二步由中间配合物经过渡态I得到闭环结构的中间体,第三步由中间体经过渡态Ⅱ形成产物.66键加成反应的活化势垒较低,从反应机理和动力学角度解释了66键加成优于65键加成的原因.     

亚甲基硅烯与乙烯环加成反应机理的理论研究

The mechanism of a cycloaddition reaction between singlet methylidenesilene and ethylene has been investigated with MP2/6-31G^＊ and B3LYP/6-31G^＊ methods, including geometry optimization and vibrational analysis for the involved stationary points on the potential energy surface. Energies of the involved conformers were calculated by CCSD（T）//MP2/6-31G＊ and CCSD（T）//B3LYP/6-31 G＊ methods, respectively. The results show that the dominant reaction pathway of the cycloaddition reaction is that a complex intermediate is firstly formed between the two reactants through a barrier-free exothermic reaction of 13.3 kJ/mol, and the complex is then isomefized to a four-membered ring product P2,1 via a transition state TS2.1 with a barrier of 32.0 kJ/mol.     

二氟硅烯与甲醛环加成反应机理的理论研究

硅烯（R2Si：）是某些有机硅反应的重要活性中间体[1],硅烯反应（如插入反应,加成反应,聚合反应等）被认为是合成含硅新键和含硅杂环的有效方法,因而硅烯反应的研究一直是有机硅化学家十分感兴趣的一个前沿研究领域[2]．对于硅烯的环加成反应而言,由于它具有合成含硅张力小环的重要价值,因此受到了许多化学家的高度重视,并对此做了若干的研究工作[3-7]。然而到目前为止,关于硅烯环加成反应的机理还处于一种推测水平,尤其是对卤代硅烯环加成反应机理的研究,至今尚未见文献报导,考虑到卤代卡宾在合成张力小环方面的重要作用[8,9]…     

碱土金属与多卤代偶氮氯膦类试剂显色反应的研究

近年来合成的多卤代偶氮氯膦类试剂有希望成为一类有效的碱土金属显色剂。本文研究了此类试剂与钙、锶、钡所生成配合物的吸收光谱、显色酸度、选择性、灵敏度和配合物的组成,以及试剂结构与性能的关系等。说明了不同取代助色基对显色反应各方面的影响。通过研究筛选出了较好的碱土显色剂,这几种试剂的结构如下:     

二氟硅烯与甲醛环加成反应机理的理论研究

The mechanism of the cycloadditohn reaction of singlet difluorosilylene with formaldehyde have been studied by RHF/6-311G* gradient method. The electron correlation energy corrections of energies for all the structures were computed using second-order Moller-Plesset perturbation theory(MP2). The results show that this reaction proceeds via two steps:1)Difluorosilylene and formaldehyde form an intermediate complex, it is an exothermal reaction with no barrier.2) The intermediate complex isomerizes to form the product, after being corrected by zero-point energies, the barrier is 127.28 kJ•mol-1 (MP2/6-311G* 6-311G*).     

钯催化卤代芳烃Ullmann偶合反应

Ullmann偶合反应是有机合成中构建碳—碳键最重要的方法之一. 综述了钯催化卤代芳烃Ullmann偶合反应的研究进展, 其中包括钯催化还原Ullmann偶合反应和钯催化氧化Ullmann偶合反应等两部分.     

2,3-二氢-1,4-酞嗪二酮的微波合成

以邻苯二甲酸酐和肼类化合物为原料,用微波辐射合成了6种2,3-二氢-1,4-酞嗪二酮类化合物,其结构经^1H NMR和^13C NMR表征。     

新试剂5-(对-苯胺偶氮)-2,3-二氢-1,4-酞嗪二酮的电化学发光研究

应用自制的ECL-1型电致化学发光仪,对新试剂5-(对-苯胺偶氮)-2,3-二氢-1,4-酞嗪二酮(简称ADPD)在Na_2CO_3-NaHCO_3-H_3BO_3缓冲介质中的电化学发光行为作了研究。结果表明,当介质pH值为10.20时,在各种选定的实验条件下,施加+2.0V(vs.SCE)三角波脉冲电压,体系发光强度与ADPD浓度在2×10~(-9)～1×10~(-7)mol/L范围内呈线性关系。反应的检测限为5×10~(-10)mol/L。并且提出了ADPD电化学发光的可能机理。     

A Mechanistic Investigation of the Oxidative Addition of Alkyl Halides to Palladium Atoms

Palladium atoms (vapor) have been cocondensed at low temperature with a series of alkyl halides. Oxidative addition to form RMX occurs. Trapping experiments, free radical scavenging experiments, and decomposition product distributions suggest that the metal atom CX bond insertion occurs direclty $\text{via}$ a caged radical pair.     

Microwave-promoted Palladium Catalyzed Suzuki Cross-coupling Reaction in Water

Suzuki coupling is probably the most versatile approach among the cross-coupling reactions and the reaction has long been the subject of intensive work in the area of transition-metal chemistry1. In recent years, various modifications involving the catalyst, solvents, bases, reaction conditions and synthetic technique have been developed 2. The Suzuki cross-coupling reaction in water is more safe, economical. It is an environmentally friendly alternative in organic synthesis. The use of w…     

Syntheses and Crystal Structures of Methyl 2-（4,5-Dibromo- 1-methylpyrrole-2-carbonylamino）-3-phenyl propanoate and 4,5-Dibromo-1-methyl-2-trichloroacetylpyrrole

1 INTRODUCTION Pyrrole and its derivatives have attracted much attention due to their chemical properties as well as biological activities[1]. They have been widely used as the materials to produce pharmaceutical, essences, biochemicals, etc. It has been found that a great deal of pyrrole derivatives present bioactivities, such as antitumor and antiviral activities[2~5]. Thus, due to the interest in exploring the syntheses of potential bioactive materials which contain pyrrole ring andna…     

Nucleophilic Addition of Amines to N-Aryl-substituted Pyrrolin-2-ones

The nucleophilic addition of n-butyl- and benzylamines to 1-(4-nitrophenyl)-5H-pyrrolin-5-one and 1-(4-sulfamoylphenyl)-5H-pyrrolin-2-one at 50°C in an excess of the amines with the formation of N-substituted amides of 3-alkyl(benzyl)amino-4-(4-R-anilino)butyric acids was investigated. The N-substituted amides of 3-arylamino-4-hydroxybutyric and 4-hydroxy-2-butenoic acids were synthesized from 2(5H)-furanone and aromatic amines (1:3) at 180°C. 4-Alkylamino-1-(4-nitrophenyl)pyrrolid-2-ones were obtained in the reaction of 1-(4-nitrophenyl)-5-pyrrolin-2-one with ammonia or aliphatic, alicyclic, and aromatic amines (1:3, 90°C, in DMF).     

Microwave-assisted Palladium Catalyzed Cross-coupling Reaction of Sodium Tetraphenylborate with Carboxylic Anhydrides

A rapid and efficient method for synthesis of unsymmetrical ketones under microwave irradiation is reported.     

Reaction of 2,3-Dihydro-1,5-benzothiazepines and Phenylacetyl Chloride in the Presence of Triethylamine： A New Aspect on the Formation Mechanism of Dihydro-1,3-oxazin-4-one Derivatives

2a,4-Disubstituted 2,2a,3,4-tetrahydro-2-phenyl-1H-azeto[2,1-d][ 1,5]benzothiazepin-1-ones, as well as 2-substi-tuted 2,3-dihydro-3-phenylacetyl-2-styryl-benzothiazoles and 4a,6-disubstituted 3- .benzyl-4a,5-d/hydro-2-phenyl-1H,6H-[1,3]oxazino[2,3-d][1,5]benzothiazepin-1-ones, were obtained from the reaction of 2,4-disubstituted 2,3-dihydro-1,5-benzothiazepines with phenylacetyl chloride in the presence of triethylamine. The mechanism for the formation of 4a,5-dihydro-1H,6H-[1,3]oxazino[2,3-d][1,5]benzothiazepin-1-ones, 2,3-dihydro-1,3-oxazin-4-one derivatives, was suggested.     

聚苯胺对2,5-二巯基-1,3,4-噻二唑氧化还原反应的电化学催化作用的循环伏安研究

研究了聚苯胺(PAn)膜电极在2,5-二巯基-1,3,4-噻二唑(DMcT)溶液中电化学处理或浸泡后的循环伏安(CV)曲线的变化规律.实验结果表明,PAn膜电极在DMcT溶液中进行电化学处理或浸泡过程可使DMcT进入PAn膜内部与PAn形成复合物.PAn对DMcT的电化学催化作用可能和二者之间形成的电子给体-受体复合物有关.该复合物的电化学氧化还原特性不同于PAn和DMcT,其氧化还原反应速率和可逆性均优于DMcT.