Elevation of the Energy Threshold for Isomerization of 5-Hydroxyindole-(tert-butyl alcohol)1 Cluster Cations
Elevation of the Energy Threshold for Isomerization of 5-Hydroxyindole-(tert-butyl alcohol)1 Cluster Cations
复制标题
提高 5-羟基吲哚-(叔丁醇)1 簇阳离子异构化的能量阈值
DOI：
10.1021/acs.jpca.7b05434
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发表时间：
2017
期刊：
影响因子：
2.9
通讯作者：
Hiroshi Sekiya
中科院分区：
文献类型：
--
作者：
Takamasa Ikeda;Kenji Sakota;Hiroshi Sekiya
Isomerization between two hydrogen-bonded (H-bonded) isomers of 5-hydroxyindole-(tert-butyl alcohol)1cluster cations ([5HI-(t-BuOH)1]+) was investigated in the gas phase. In the S0state, jet-cooled 5HI-(t-BuOH)1has two structural isomers, 5HI(OH)-(t-BuOH)1and 5HI(NH)-(t-BuOH)1, in which thet-BuOH molecule is bound to the OH or the NH group of 5HI. The IR photodissociation spectrum of [5HI-(t-BuOH)1]+generated by two-color resonant two-photon ionization (2C-R2PI) via the S1–S0origin of 5HI(NH)-(t-BuOH)1provided evidence of both [5HI(OH)-(t-BuOH)1]+and [5HI(NH)-(t-BuOH)1]+coexisting in the D0state, indicating that [5HI(NH)-(t-BuOH)1]+isomerizes to [5HI(OH)-(t-BuOH)1]+after 2C-R2PI of 5HI(NH)-(t-BuOH)1. The lower limit of the energy threshold for the isomerization of [5HI(NH)-(t-BuOH)1]+to [5HI(OH)-(t-BuOH)1]+was experimentally determined to be 3362 ± 30 cm–1, and the corresponding energy threshold for the isomerization of [5HI(NH)-(H2O)1]+to [5HI(OH)-(H2O)1]+has been reported to be 2127 ± 30 cm–1. Thus, the energy threshold for the isomerization is elevated by at least 1200 cm–1when the solvent molecule changes from H2O tot-BuOH. The elevation of the energy threshold is explained by the difference in the stabilization energies of [5HI-(t-BuOH)1]+and [5HI-(H2O)1]+in the initial and transition states owing to the larger proton affinity oft-BuOH than H2O.
