NMR Confirmation for Formation of [B_(12)H_(12)]^(2-) Complexes during Hydrogen Desorption from Metal Borohydrides
Abstract
^(11)B NMR spectroscopy has been employed to identify the reaction intermediates and products formed in the amorphous phase during the thermal hydrogen desorption of metal tetrahydroborates (borohydrides) LiBH_4, Mg(BH_4)_2, LiSc(BH_4)_4, and the mixed Ca(AlH_4)_(2-)LiBH_4 system. The ^(11)B magic angle spinning (MAS) and cross polarization magic angle spinning (CPMAS) spectral features of the amorphous intermediate species closely coincide with those of a model compound, closo-borane K2B_(12)H_(12) that contains the [B_(12)H_(12)]^(2-) anion. The presence of [B_(12)H_(12)]^(2-) in the partially decomposed borohydrides was further confirmed by high-resolution solution ^(11)B and ^1H NMR spectra after dissolution of the intermediate desorption powders in water. The formation of the closo-borane structure is observed as a major intermediate species in all of the metal borohydride systems we have examined.
Additional Information
© 2008 American Chemical Society. Received 14 November 2007. Published online 13 February 2008. Published in print 1 March 2008. The authors express special thanks to Dr. Satish S. Jalisatgi (U. Missouri-Columbia) for generously providing the K_2B_(12)H_(12) and K_2B_(10)H_(10) compounds. This research was partially performed at the Jet Propulsion Laboratory, which is operated by the California Institute of Technology under contract with the NASA. This work was partially supported by DOE through Award Nos. DE-AI-01-05EE11105 and DE-FC3605GO15062. The NMR facility at Caltech was supported by the National Science Foundation (NSF) under Grant No. 9724240 and partially supported by the MRSEC Program of the NSF under Award No. DMR-0520565.Additional details
- Eprint ID
- 79183
- DOI
- 10.1021/jp710894t
- Resolver ID
- CaltechAUTHORS:20170719-065012031
- NASA/JPL/Caltech
- DE-AI-01-05EE11105
- Department of Energy (DOE)
- DE-FC3605GO15062
- Department of Energy (DOE)
- DMR-9724240
- NSF
- DMR-0520565
- NSF
- Created
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2017-07-19Created from EPrint's datestamp field
- Updated
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2021-11-15Created from EPrint's last_modified field