Concerted dehydrogenation reactions of magnesium borohydride with oxygen and nitrogen heterocyclic compounds

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dc.contributor.advisorJensen, Craig M.
dc.contributor.authorPrager, McKinley A.
dc.contributor.departmentChemistry
dc.date.accessioned2025-09-30T22:32:27Z
dc.date.available2025-09-30T22:32:27Z
dc.date.issued2025
dc.description.degreePh.D.
dc.identifier.urihttps://hdl.handle.net/10125/111302
dc.subjectChemistry
dc.subjectInorganic chemistry
dc.titleConcerted dehydrogenation reactions of magnesium borohydride with oxygen and nitrogen heterocyclic compounds
dc.typeThesis
dcterms.abstractThis dissertation focuses on work resulting from the progress in developing a two-way hy-drogen carrier system consisting of solutions of furans and pyrroles containing Mg(BH4)2 and an irridum pincer complex catalyst. Previous studies have focused on magnesium borohy- dride (Mg(BH4)2) due to its high hydrogen content and favorable thermodynamics. Further studies have shown the kinetic enhancement of the addition of sub-stoichiometric amounts of Lewis bases on cycling. While the kinetic enhancement of the addition of O-heterocycles has been explored the effects of N-heterocycles have not been. Since the discovery in 1997 of the first reported homogeneous catalyst for the dehydrogenation cycloalkanes to arenes, the “pincer” complex IrH2(2,6 -C6H3-(CH2PtBu2)2) and related pincer complexes, are known to be highly active catalysts for the dehydrogenation of heterocyclic liquid or- ganic hydrogen carriers (LOHC). While attempting the tandem dehydrogenation of magne- sium borohydride and pyrrolidine, we found Mg(BH4)2 reacts with pyrrolidine to produce tris(pyrrolidino)borane and bis(pyrrolidino)borane, irreversibly releasing up to 6 wt% H2. The proportions of the pyrrolidino boranes are highly dependent on reaction times and conditions. We have also observed that the iridium pincer complex catalyzes the direct de- hydrogenation of tris(pyrrolidino)borane to tris(1H-pyrrole-1-yl)borane, a significant finding in view of its theoretical, 5.2 wt% gravimetric and >80 g/L volumetric hydrogen capacities. Full characterization of the products along with their hydrogen cycling behavior is discussed.
dcterms.extent128 pages
dcterms.languageen
dcterms.publisherUniversity of Hawai'i at Manoa
dcterms.rightsAll UHM dissertations and theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission from the copyright owner.
dcterms.typeText
local.identifier.alturihttps://www.proquest.com/LegacyDocView/DISSNUM/32169194

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