Erratum to: Electrochemical Reduction of Trichlorobiphenyls: Mechanism and Regioselectivity

Russian Journal of General Chemistry - Affilation of M. V. Sangaranarayanan should read as follows: Department of Chemistry, Indian Institute of Technology, Madras Chennai, 600036 India.     

硝基三唑化合物的电化学还原机理

1　引　　言硝基三唑类化合物 (ＮＴＲ)是一种新型的放射增敏剂 ,在体内外均能特异的增强乏氧细胞对射线的敏感。此类化合物的增敏作用与硝基的氧化还原有关。因此 ,研究这类化合物的氧化还原机理有助于阐明其体内过程。本文应用直流极谱、循环伏安和库仑分析等方法研究了 4种具有放射增敏效果的ＮＴＲ1 、ＮＴＲ2 、ＮＴＲ3、ＮＴＲ4 (Ｘ、Ｙ分别为Ｈ ,ＣＨ2 ＣＯＯＣＨ2 ＣＨ3;ＣＨ3,ＣＨ2 ＣＯＯＣＨ2 ＣＨ3;Ｈ ,ＣＨ2 ＣＯＮＣＨ2 (ＣＨ2 ) 3ＣＨ2 ;ＣＨ3,ＣＨ2 ＣＯＮＣＨ2 (ＣＨ2 ) 3ＣＨ2 )的电化学还原机理 ,并观察到质子化的硝基自…     

肉桂腈电化学还原反应机理

采用循环伏安法研究了肉桂腈在乙腈溶液中的电还原行为,其在-1.46和-2.0V处各存在一个还原峰.第一个峰处恒电位电解得到了线性、环化氢化二聚产物以及苯基戊二腈;第二个峰处电解得到了饱和二氢还原产物苯丙腈.结合循环伏安模拟判定了整个电还原的具体反应机理是肉桂腈通过电化学-电化学-化学-化学(EECC)反应机理生成苯丙腈,同时经历自由基-自由基(RR)过程得到线性和环化二聚产物,肉桂腈还可以与乙腈的共轭碱反应得到苯基戊二腈.最终通过循环伏安模拟求得相应反应的动力学常数,自由基-自由基耦合反应速率常数为104L·mol-.1s-1,第二个电子转移反应速率常数为0.3cm.s-1,其后质子化反应的速率常数为105s-1.     

Efficient Reduction of Thiopyrylium Salts to Corresponding 2H- and 4H-Thiopyrans Under Solvent-Free Condition: Regioselectivity and Mechanism

Abstract

A solvent-free reduction of 2,4,6-triarylthiopyrylium with NaBH₄/alumina is described. The regioselectivity of these reductions were compared with those obtained in solution experiments.     

离子液体在CO_2电还原反应过程中的催化作用与机理研究

在1-丁基3-甲基咪唑三氟甲基磺酸盐([Bnlim][CF_3SO_3])/碳酸丙烯酯(PC)溶液中,采用循环伏安曲线、交流阻抗谱及阻抗模拟方法,研究了CO_2在Au上发生电还原反应的速率控制步骤与离子液体的催化作用.结果表明,在CO_2电还原反应过程中,吸附态CO_2经单电子还原生成CO_2~-自由基是速率控制步骤.由于离子液体的催化作用,CO_2在[Bmim][CF_3SO_3]/PC溶液中电还原的过电位比在四丁基三氟甲基磺酸铵([Bu_4N][CF_3SO_3])/PC溶液中降低了239 mV.交流阻抗测试结果表明,离子液体中的阳离子[Bmim]~+吸附在Au电极表面,形成离子液体吸附层,吸附态的CO_2分子经单电子还原后生成CO_2~·-)自由基,与周围离子液体发生相互作用,形成中间体[Bmim-CO_2]_(ad),降低了CO_2~(·-)的能量状态,使得CO_2电还原反应的过电位大幅度降低.     

和厚朴酚电化学还原机理的研究

用量子化学AM1、PM3方法研究了和厚朴酚分子的电化学还原反应机理.结果表明,和厚朴酚分子电还原的基团为两个烯丙基的双键,其中邻位烯丙基优先被还原,对位次之,整个还原反应中和厚朴酚得到4e和4H⁺,使两个烯丙基饱和,计算结果较好地说明了实验事实.     

Electrochemical Reduction of Zearalenone

Zearalenone1isolatedfromthemycelliaofthefungusGibberallazeae(FusariumGraminearum)isasubstanceofstrikingphysiologicalactivityexhibitingantibioticestrogenicandantibacterialactivitiesinvitroandinvivol.Itsreducedproduct,a-zearalanol2,hasbeenusedasananabolicagentincattIeandsheepunderthecommercialnameRalgro.Accordingtothereducingagentusedtheb-resorcyclicl4-memberedmacrolide1gavedifferentproducts'.Reductionof1withsodiumborohydrideinmethanolgaveamixtureoftwodiastereomericzearalenols3.Catalytichydrog…     

Synthesis and Electrochemical Reduction of Nitro-Alkanephosphonates

Abstract

As a continuation of our research program [l, 2], directed to the synthesis of aminoalkanephosphonates, we present here the synthesis of 1-amino-nitroalkanephosphonid acids 5, prepared according to eq. 1. The electrochemical reduction of amino acids 5 to the derivatives 6 and 7 (eq. 2) have been investigated.     

Electrochemical Reduction of Arylxenon Tetrafluoroborates

Reduction potentials of arylxenon(II) tetrafluoroborates have been measured by cyclic voltammetry method on platinum disc and ultramicro electrodes. The electrochemical properties of the arylxenon(II) tetrafluoroborates are quite different to those of corresponding arylperfluoralkyliodine(III) salts.     

Preparative Electrochemical Reduction of Decafluorobenzil

Preparative electrochemical reduction of decafluorobenzil in DMF on a platinum electrode at the potential of the first peak afforded decafluorobenzophenone as the principal product. The reaction mixture lacked products of hydrodefluorination of the decafluorobenzil or of its reduction at the C=O group.     

Electrochemical Synthesis of Isoxazolines: Method and Mechanism

An electrochemical method for the green and practical synthesis of a broad range of substituted isoxazoline cores is presented. Both aryl and more challenging alkyl aldoximes are converted to the desired isoxazoline in an electrochemically enabled regio- and diastereoselective reaction with electron-deficient alkenes. Additionally, in-situ reaction monitoring methods compatible with electrochemistry equipment have been developed in order to probe the reaction pathway. Supporting analyses from kinetic (time-course) modelling and density functional theory support a stepwise, radical-mediated mechanism, and discounts hypothesised involvement of closed shell [3+2] cycloaddition pathways.     

Electrochemical Reduction of Arsenic Acid

It is found that arsenic acid in aqueous solutions is reduced chiefly to arsine, whose yield substantially depends on the cathode material nature and electrolysis conditions. The yield increases with the acid concentration and catholyte temperature. The maximum yield (current efficiency of about 50%) is obtained on a cadmium cathode. Hydrochloric acid or cationic surface-active substances present in the catholyte raise the arsine yield on a copper cathode by more than two times and make no impact on the yield on a cadmium cathode. A possible mechanism of the observed phenomena is discussed.     

锗硅烯与CH3OH加成反应机理及区域选择性

采用密度泛函理论方法,在B3LYP/6-311++G(d, p)水平,研究了几种锗硅烯与CH₃OH的加成反应的微观机理和势能剖面,分析了锗硅烯中Si=Ge双键的极性对加成反应区域选择性的影响.研究结果表明,锗硅烯可分别与CH₃OH的单聚体或二聚体发生加成反应.所有加成反应均从初始亲核或亲电复合物的形成开始.母体锗硅烯H₂Si=GeH₂与CH₃OH二聚体的加成反应比其与CH₃OH单聚体的相应反应在动力学上更容易些,但在其它锗硅烯与CH₃OH的反应中情况则相反.用Ph或SiMe₃基团取代H₂Si=GeH₂中的H原子在动力学上使反应变得不利且SiMe₃基团的影响更显著.加成反应的区域选择性与锗硅烯中Si=Ge双键的极性以及Si-O(Ge-H)和Ge-O (Si-H)键的相对强弱都有关.     

电化学还原处理对碳纸形貌和电化学电容的影响

对电化学还原处理过程中碳纸的形貌和电容的变化进行了研究. 扫描电子显微镜观测结果显示电还原使碳纤维分解为碳颗粒, 并且表面粗糙度增加. 拉曼光谱结果显示I_D/I_G的比值在还原处理1 min后即出现改变, 表明碳纸无序度增加. BET测试结果显示电还原处理后碳纸的比表面积明显增加. X射线光电子能谱结果表明还原处理后碳纸表面羟基的数量随之增加. 此外, 在-1.6 V下还原5 min后碳纸电容增加到原来的15倍, 并在1500个循环的稳定性测试中保持不变, 显示出良好的稳定性.     

Electrochemical Reduction of Phosphaallenes: Electron Spin Resonance and Theoretical Studies

Abstract

In order to check to what extent allenic systems containing one or two phosphorus atoms are likely to accept an electron, solutions of ArP?C?Cφ₂ (Ar Phenyltributyl; φ benzene) and ArP?C?PAr have been electrochemically and chemically reduced. Cyclic voltammetry shows that ArP?C?Cφ₂ undergoes irreversible reduction at -2266mV in THF while an irreversible reduction takes place at - 1900 mV (THF) for ArP?C?PAr.     

CoTPP电化学催化原溴代环己烷的机理

以电化学循环伏安、现场ＥＳＲ电化学以及现场薄层电化学方法研究了电生Ｃｏ（Ｉ）ＴＰＰ与溴代五己烷的反机制。在ＤＭＦ中，Ｃｏ（Ⅱ）／Ｃｏ（Ⅰ）的氧化还原有明显的催化溴代环己烷还原的特片，反现场有自由基生成，反应产物之一是Ｃｏ－Ｃ键化合物，可以在１．３０Ｖ（ＳＣＥ）－电子还原，当存在ＣＨ２－ＣＨＣＮ时，。生成另一种Ｃｏ－Ｃ键化合物，该化合物在－１．１０Ｖ（ＳＣＥ）处一电子还原，证明溴代环己烷与Ｃｏ（Ｉ）     

Electrochemical Reduction of 1,4-Disubstituted Phthalazines

Electrochemical reduction in dimethylformamide of unsymmetrical 1-Cl-4-X-phthalazines and symmetrical 1,4-X₂-phthalazines (X = Cl, PhO, MeO, EtO, i-PrO) was studied by voltammetry and electrolysis-ESR. The electron trasfer on 1,4-dichlorophthalazine and unsymmetrical 1-Cl-4-X-phthalazines induces anionoid elimination of Cl and X, pyridazine ring cleavage, and phthalonitrile formation. In this previously unknown process the transfer of two electrons induces cleavage of three bonds and formation of two new bonds. The reduction of 1,4-dialkoxy(diaryloxy)phthalazines involves formation of stable radical anions which undergo no heteroring cleavage. Possible mechanisms of the processes studied were discussed. It was assumed that the same mechanism with pyridazine ring cleavage may be realized with other phthalazine derivatives and heteroannelated pyridazines containing readily leaving nucleofuge groups to nitrogens.