Direct Experimental Observation of in situ Dehydrogenation of an Amine-Borane System Using Gas Electron Diffraction

Aliyu M. Ja'O, Sarah L. Masters*, Derek A. Wann, Conor D. Rankine, João P.F. Nunes, Jean Claude Guillemin

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


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 BH3 as 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.

Original languageEnglish
Pages (from-to)7104-7112
Number of pages9
JournalJournal of Physical Chemistry A
Issue number32
Early online date17 Jul 2019
Publication statusPublished - 15 Aug 2019

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