Udagawa Taro, Tachikawa Masanori
Department of Chemistry and Biomolecular Science, Faculty of Engineering, Gifu University Yanagido 1-1 Gifu 501-1193 Japan
Quantum Chemistry Division, Graduate School of Science, Yokohama City University Seto 22-2, Kanazawa-ku Yokohama 236-0027 Japan.
RSC Adv. 2018 Jan 22;8(7):3878-3888. doi: 10.1039/c7ra13110k. eCollection 2018 Jan 16.
The mechanism of hydrogen-tritium (H-T) exchange reactions between several small organic and HTO molecules have been investigated using M06-2X/6-311++G(d,p) method. The second HTO molecule is taken into account for both direct and addition-elimination H-T exchange reactions. The reactivity of small organic molecules for H-T exchange reactions is in the order of CHCOOH > CHCHOH > CHCHO ≈ CHCOCH ≈ CH and CH > CH, CH, and CH. In particular, the energies of activation in addition-elimination H-T exchange reactions of alkene with two HTO molecules become lower than those of direct H-T exchange ones. Our study reveals that (i) the reactivity of alkene with HTO molecules is comparable to that of aldehyde and ketone when the effect of the second HTO molecule is taken into account and (ii) the H-T exchange reactions between alkene and HTO molecules prefer addition-elimination H-T exchange mechanism, whereas other organic molecules favor a direct one.
使用M06-2X/6-311++G(d,p)方法研究了几种小分子有机物与HTO分子之间的氢-氚（H-T）交换反应机理。在直接和加成-消除H-T交换反应中均考虑了第二个HTO分子。小分子有机物对H-T交换反应的反应活性顺序为：CHCOOH > CHCHOH > CHCHO ≈ CHCOCH ≈ CH以及CH > CH、CH和CH。特别地，烯烃与两个HTO分子发生加成-消除H-T交换反应的活化能低于直接H-T交换反应的活化能。我们的研究表明：（i）当考虑第二个HTO分子的影响时，烯烃与HTO分子的反应活性与醛和酮相当；（ii）烯烃与HTO分子之间的H-T交换反应更倾向于加成-消除H-T交换机理，而其他有机分子则倾向于直接交换机理。
