Study on Ranking and Characteristic of Vinyl Cations as Carbocation

本研究的目的是二价乙烯基阳离子是如何与三价碳正离子连接的，以及乙烯基阳离子是如何特征的。1）气相中苯乙炔衍生物的质子化产生乙烯基阳离子。用芳香取代反应的线性关系式计算了各种乙烯基阳离子的热力学。b-取代乙烯基阳离子的r值与相应乙烯基阳离子的稳定性呈线性关系，也与三价苄基阳离子相关。2）研究了乙烯基衍生物在乙醇水溶液中溶剂分解的溶剂效应。溶解性的问题通过制备具有亲水性氨基的乙烯基衍生物来克服。3）激光闪光光解芳基取代卤代乙烯可生成乙烯基阳离子。乙烯基阳离子的行为可以通过测量其在各种溶剂分解条件下的衰减速率来跟踪。评价了溶剂混合物的亲核性。α-对甲氧基苯基乙烯基阳离子的β-取代基之间存在很大的差异，这是由于β-取代基与亲核试剂之间的空间排斥作用。

The purpose of this study is how a divalent vinyl cation is connected with trivalent carbocations and how characteristic a vinyl cation is.1) Protonation to phenylacetylene derivatives in gas phase generates vinyl cations. The thermodynamics of various vinyl cations were evaluated with equation of linear relationship of aromatic substitution reaction. The r-values of b-substituted vinyl cations gave linear relationship with stability of the corresponding vinyl cations and also related with trivalent benzylic cations.2) Solvent effect of solvolysis of vinyl derivatives were measured in aqueous ethanol. The problem of solubility was overcome with preparation of vinyl derivatives which have a hydrophilic ammmono group. Further investigation has to be done in extension.3) A vinyl cation can be generated by laser flash photolysis of aryl-substituted vinyl halides. The behavior of a vinyl cation can be followed by measuring its decay rates under various solvolytic conditions. The nucleophilicity of solvent mixture is evaluated. There is large difference between beta-substituents of alpha-p-methoxyphenylvinyl cations due to steric repulsion between the beta-substituent and nucleophiles.