Study of the Electron Transfer Reactions of Organic Anions by Means of Electrochemical and Thermochemical Methods.

该项目的目的是获得不同类型的有机镁试剂与芳香族羰基和硝基底物反应的结构-反应性关系的半定量基础。根据前人的结果，认为电子转移参与了所有反应，这是由于典型的自由基反应产生了副产物。一些镁试剂的给电子能力(EDA)以前也是通过它们的氧化峰电位来估计的，因此，本项目的第一个计划是用电化学方法测量各种底物的还原电位作为它们的电子接受能力(EAA)的估计。以反应物的氧化电位和还原电位之差(&lt；DETA&Gt；E)作为各个反应中电子转移效率的估计值。用极谱分析仪测定了羰基和硝基化合物在四氢呋喃-…中的还原电位更多的Bu_4NC10_4体系，使用双(联苯基)铬(I)四苯基硼酸酯作为内参比由林茨大学G.Gritzner教授提供。所得到的&lt；Delta&Gt；E值与ArMgBr、ArSMgBr、ArNHMgBr、ArN(MgBr)_2和AroMgBr15个反应中正常和异常(自由基)产物的相对产率相关。热化学研究的第二个计划是将丹麦技术大学T.Holm教授建立的格氏反应中电子转移的放热性质应用到我们的新镁试剂的具有镁-N-镁键的反应中。使用Holm的流动技术的机器，由于他所采用的流速不适合我们的反应，所以该计划没有成功。然而，通过使用贝克曼温度计的批量技术，观测到的温度升高与电化学测量的分类几乎完全一致。结果仍然是一个初步的结果，EDA-EAA概念的阐述正在进行中：所获得的关联将有助于机理研究。各类镁试剂的合成应用也在进行中。较少

The purpose of the project is to obtain a semiguantitative basis for the structure-reactivity relationship in the reactions of various types of organomagnesium reagents with aromatic carbonyl and nitro substrates. From the previous results, the involvement of electron transfer in all the reactions is suggested on the basis of the formation of by-products due to typical radical processes. The electron-donating abilities(EDA) of some magnesium reagents was also previously estimated by their oxidation peak potentials.Thus, the first plan of this project is to measure electrochemically the reduction potentials of various substrates as the estimate for their electron accepting abilities(EAA). The value of difference(<DETA>E) between the oxidation and reduction potentials of reactants is taken as the estimate for the efficiency of electron transfer in the individual reactions. By means of a polarographic analyzer, the reduction potentials of carbonyl and nitro compounds were measured in THF- … More Bu_4NC10_4 system by use of bis(biphenyl)chromium(I) tetraphenyl borate as internal reference granted by the courtesy of Prof. G. Gritzner, University of Linz. The obtained<DELTA>E value was correlated to the relative yields of normal and abnormal (radical) products in fifteen reactions of magnesium reagents including ArMgBr, ArSMgBr, ArNHMgBr, ArN(MgBr)_2, and AroMgBr.The second plan of the thermochemical study was to apply the exothermal nature of the electron transfer in Grignard reaction established by Prof. T. Holm, Denmark Technical University, to the reactions of our new magnesium reagent having Mg-N-Mg bond. By use of Holm's machine using flow technigue, the plan was unsuccessful because the flow rate applied by him was not suitable for our reaction. However, by use of a batch technigue using a Beckmann's thermo meter, the observed elevation of temperature was almost completely in accord with the classification proposed on the bais of electrochemical measurements.The result is still a preliminary one, and the elaboration of the EDA-EAA concept is in progress: The obtained correlation will contribute to the mechanistic studies. The synthetic applications of various types of magnesium reagents are also in progress. Less