Oohashi K, Takiguchi H, Morikawa N
Radioisotopes. 1984 Nov;33(11):747-53. doi: 10.3769/radioisotopes.33.11_747.
Recoil tritium reactions in the aromatic ring were investigated with toluene and benzonitrile in the moderator-free and the C6F6-moderated systems in terms of the intramolecular tritium distribution, the relative tritiation rate, and the isotope effect in toluene. The reactions free from hexafluorobenzene are in essential agreement with non-selective nature shown in hot atom reactions. The addition of the moderator to the systems changes more markedly the uniform labeling to o,p-orientation in toluene than in benzonitrile, and the 1.17 PhCH3/PhCN tritiation rate (in PhCH3-d8/PhCN, 0.942) to the 1.89 PhCH3/PhCN one (in PhCH3-d8/PhCN, 1.51) when the mole ratio of C6F6/substrate is about 100. These findings agree with the electrophilic nature of the tritium at lower energies. The H/D isotope effect in the moderated system is given as 1.89/1.51 or 1.25 and is substantially the same as that (1.24) in the moderator-free system.
在无慢化剂和六氟苯（C6F6）慢化体系中，以甲苯和苯甲腈为研究对象，从分子内氚分布、相对氚化速率以及甲苯中的同位素效应等方面对芳环中的反冲氚反应进行了研究。无六氟苯参与的反应与热原子反应中显示的非选择性本质一致。向体系中添加慢化剂，相比于苯甲腈，甲苯中从均匀标记到邻位、对位取向的变化更为显著，当C6F6/底物的摩尔比约为100时，氚化速率从1.17 PhCH3/PhCN（在PhCH3-d8/PhCN中为0.942）变为1.89 PhCH3/PhCN（在PhCH3-d8/PhCN中为1.51）。这些发现与较低能量下氚的亲电性质相符。慢化体系中的H/D同位素效应为1.89/1.51或1.25，与无慢化剂体系中的效应（1.24）基本相同。
