C5,5-取代基对海因质子亲合能的影响

Effect on the Proton Affinity of Different Substitution Group of Hyantoin at C5,5

文章对５种碳五位（Ｃ５）的不同取代基海因的质子亲合能（ＰＡ），在亚稳状态采用“动能法”（ｋｉｎｅｔｉｃ ｍｅｔｈｏｄ）进行了研究。以 ５，５－甲基海因作为参照，确定了 ５种样品亲质子能的顺序。

The proton affinities of five kinds of substitution group of hyantoin, i. e. 5, 5- dimethylhyantoin (1) ; 5-methyl, 5-ethyl-hyantoin (2) ; 5-methyl, 5-isobtutyl-hyantoin (3) ; 5-methyl, 5phenyl-hyantoin(4); and pentamethylenehydantoin (5) 3 have been studied using 'kinetic method' with mass spectrometry. By using fast atom bombardment ionization tech- nique, the protonated heterodimer molecular cluster was generated and the heterodimers clevered in metastable to produce two protonic sample ions. From the ion peak intensity ratio of the two sample ions, the effect on the proton affinity can be determined. We found the or- der of their gas-phase acidity was 4<5<3<2<1. That is the larger substitution group at C5,5 the more effect on the proton affinity.