Direct Experimental Observation of in situ Dehydrogenation of an Amine-Borane System Using Gas Electron Diffraction.
Direct Experimental Observation of in situ Dehydrogenation of an Amine-Borane System Using Gas Electron Diffraction.
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使用气体电子衍射直接实验观察胺-硼烷系统的原位脱氢。
DOI：
10.1021/acs.jpca.9b05522
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发表时间：
2019
期刊：
影响因子：
--
通讯作者：
Ja'o AM
中科院分区：
文献类型：
--
作者：
Ja'o AM
通过严格的结构和热化学研究，观察了氮杂丁- bh3的原位脱氢反应。结构分析采用了气相电子衍射和高能级量子计算，并在CBS-QB3水平上预测了bh3作为双功能催化剂存在和不存在时单分子氢释放反应的途径。催化脱氢途径的势垒低于预测的B-N键离解能，因此有利于脱氢过程而不是配合物的离解。在CCSD(T)/CBS水平上预测的脱氢焓表明，该化合物释放氢需要温和的反应条件，并且比线性胺硼烷更接近热中性。脱氢过程的熵和自由能变化表明，该反应是能工性的、能量上可行的，并且会自发地向氢释放方向进行，这些都是储氢的重要因素。
In situ dehydrogenation of azetidine–BH3, which is a candidate for hydrogen storage, was observed with the parent and dehydrogenated analogue subjected to rigorous structural and thermochemical investigations. The structural analyses utilized gas electron diffraction supported by high-level quantum calculations, while the pathway for the unimolecular hydrogen release reaction in the absence and presence of BH3as a bifunctional catalyst was predicted at the CBS-QB3 level. The catalyzed dehydrogenation pathway has a barrier lower than the predicted B–N bond dissociation energy, hence favoring the dehydrogenation process over the dissociation of the complex. The predicted enthalpy of dehydrogenation at the CCSD(T)/CBS level indicates that mild reaction conditions would be required for hydrogen release and that the compound is closer to thermoneutral than linear amine boranes. The entropy and free energy change for the dehydrogenation process show that the reaction is exergonic, energetically feasible, and will proceed spontaneously toward hydrogen release, all of which are important factors for hydrogen storage.