Mechanism of Solid-State Thermolysis of Ammonia Boraine: 15N NMR Study Using Fast Magic-Angle Spinning and Dynamic Nuclear Polarization

Journal Article · Thu Aug 28 00:00:00 EDT 2014 · Journal of Physical Chemistry. C

DOI:https://doi.org/10.1021/jp504328x· OSTI ID:1166713

Kobayashi, Takeshi ^[1]; Gupta, Shalabh ^[1]; Caporini, Marc A ^[2]; Pecharsky, Vitalij K ^[1]; Pruski, Marek ^[1]

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1. Ames Laboratory
2. Bruker BioSpin Corporation

The solid-state thermolysis of ammonia borane (NH3BH3, AB) was explored using state-of-the-art 15N solid-state NMR spectroscopy, including 2D indirectly detected 1H{15N} heteronuclear correlation and dynamic nuclear polarization (DNP)-enhanced 15N{1H} cross-polarization experiments as well as 11B NMR. The complementary use of 15N and 11B NMR experiments, supported by density functional theory calculations of the chemical shift tensors, provided insights into the dehydrogenation mechanism of AB—insights that have not been available by 11B NMR alone. Specifically, highly branched polyaminoborane derivatives were shown to form from AB via oligomerization in the “head-to-tail” manner, which then transform directly into hexagonal boron nitride analog through the dehydrocyclization reaction, bypassing the formation of polyiminoborane.

• Research Organization: Ames Lab., Ames, IA (United States)
• Sponsoring Organization: USDOE Office of Science (SC)
• DOE Contract Number: DE-AC02-07CH11358
• OSTI ID: 1166713
• Report Number(s): IS-J 8452
• Journal Information: Journal of Physical Chemistry. C, Vol. 118, Issue 34; ISSN 1932-7447
• Publisher: American Chemical Society
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
Catalysis, Reaction Kinetics, and Inorganic Reaction Mechanisms