Dihydrogen Bonding under High Pressure:  A Raman Study of BH<sub>3</sub>NH<sub>3</sub> Molecular Crystal

Custelcean, Radu; Dreger, Zbigniew A.

doi:10.1021/jp035267+

Cited by 90 publications

(111 citation statements)

References 40 publications

(32 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…As shown in Fig. 3 B and C, the N-H stretching frequency of lithium amidoborane shows blue shift with increasing pressure, in contrast to its parent compound ammonia borane (25)(26)(27)30). The observation of blueshift of N-H stretching frequency with pressure indicates a likely absence of dihydrogen bond in lithium amidoborane as illustrated by Lipincott's model, unless there is an extremely strong symmetric dihydrogen bonding.…”

Section: −δmentioning

confidence: 83%

“…Raman spectra ( Fig. 1) of ammonia borane (25)(26)(27)(28)(29)(30) and lithium amidoborane (31) at ambient condition have been well documented, and the major Raman modes can be described by their molecular nature: N-H stretching, B-H stretching, and B-N stretching modes. In the Raman spectra, B-H stretching modes of lithium amidoborane appear at lower wavenumbers compared with those of ammonia borane ( Fig.…”

Section: Resultsmentioning

confidence: 99%

“….H δ− distance. So, if there is any dihydrogen bonding in the material, the N-H stretching should exhibit redshift with pressure (25)(26)(27)30) with some exceptions that have very strong symmetric dihydrogen bonding (39)(40)(41)(42)(43)(44)(45)(46). As shown in Fig.…”

Section: −δmentioning

confidence: 94%

“…High-pressure study of molecular crystals can provide unique insight into the intermolecular bonding forces, such as hydrogen bonding and phase stability in hydrogen storage materials and thus provides insight into the improvement of design (22)(23)(24)(25)(26)(27)(28)(29)(30). For instance, Raman spectroscopic study of ammonia borane at high pressure provided insight about its phase transition behavior and the presence of dihydrogen bonding in its structure (25)(26)(27)(28)(29)(30).…”

mentioning

confidence: 99%

“…For instance, Raman spectroscopic study of ammonia borane at high pressure provided insight about its phase transition behavior and the presence of dihydrogen bonding in its structure (25)(26)(27)(28)(29)(30). We have investigated LiNH 2 BH 3 at high pressure using Raman spectroscopy.…”

mentioning

confidence: 99%

See 4 more Smart Citations

High-pressure study of lithium amidoborane using Raman spectroscopy and insight into dihydrogen bonding absence

Najiba

Chen

2012

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

One of the major obstacles to the use of hydrogen as an energy carrier is the lack of proper hydrogen storage material. Lithium amidoborane has attracted significant attention as hydrogen storage material. It releases ∼10.9 wt% hydrogen, which is beyond the Department of Energy target, at remarkably low temperature (∼90°C) without borazine emission. It is essential to study the bonding behavior of this potential material to improve its dehydrogenation behavior further and also to make rehydrogenation possible. We have studied the high-pressure behavior of lithium amidoborane in a diamond anvil cell using in situ Raman spectroscopy. We have discovered that there is no dihydrogen bonding in this material, as the N-H stretching modes do not show redshift with pressure. The absence of the dihydrogen bonding in this material is an interesting phenomenon, as the dihydrogen bonding is the dominant bonding feature in its parent compound ammonia borane. This observation may provide guidance to the improvement of the hydrogen storage properties of this potential material and to design new material for hydrogen storage application. Also two phase transitions were found at high pressure at 3.9 and 12.7 GPa, which are characterized by sequential changes of Raman modes.H ydrogen economy has been considered as potentially efficient and environmental friendly alternative energy solution (1). However, one of the most important scientific and technical challenges facing the "hydrogen economy" is the development of safe and economically viable on-board hydrogen storage for fuel cell applications, especially to the transportation sector. Ammonia borane (BH 3 NH 3 ), a solid state hydrogen storage material, possesses exceptionally high hydrogen content (19.6 wt%) and in particular, it contains a unique combination of protonic and hydridic hydrogen, and on this basis, offers new opportunities for developing a practical source for generating molecular dihydrogen (2-5). Stepwise release of H 2 takes place through thermolysis of ammonia borane, yielding one-third of its total hydrogen content (6.5 wt%) in each heating step, along with emission of toxic borazine (6-8). Recently, research interests are focusing on how to improve discharge of H 2 from ammonia borane, including lowering the dehydrogenation temperature and enhancing hydrogen release rate using different techniques, e.g., nanoscaffolds (9), ionic liquids (10), acid catalysis (11), base metal catalyst (12), or transition metal catalysts (13, 14). More recently, significant attention is given to chemical modification of ammonia borane through substitution of one of the protonic hydrogen atoms with an alkali or alkaline-earth element (15-21). Lithium amidoborane (LiNH 2 BH 3 ) has been successfully synthesized by ball milling LiH with NH 3 BH 3 (15-18). One of the driving forces suggested for the formation of LiNH 2 BH 3 is the chemical potential of the protonic H δ+ in NH 3 and the hydridic H δ− in alkali metal hydrides making them tend to combine, producing H 2 + LiNH 2 BH 3 ....

show abstract

Section: −δmentioning

confidence: 83%

Section: Resultsmentioning

confidence: 99%

Section: −δmentioning

confidence: 94%

mentioning

confidence: 99%

mentioning

confidence: 99%

See 3 more Smart Citations

High-pressure study of lithium amidoborane using Raman spectroscopy and insight into dihydrogen bonding absence

Najiba

Chen

2012

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

show abstract

Thermal Decomposition of T‐Butylamine Borane Studied by in Situ Solid State NMR

Feigerle¹,

Smyrl²,

Morrell³

et al. 2010

Ceramic Transactions Series

View full text Add to dashboard Cite

Amine boranes are a class of hydrogen storage materials which release significant yields of hydrogen gas upon heating to temperatures relevant for automotive applications. The fhermodynamic stability of this class of amine boranes is correlated with the extensive dihydrogen bonding between hydrides bound to boron and amine protons. Further, the hydrogen evolution follows a bimolecular pathway via the di-hydrogen bonding network. The thermal decomposition of t-butylamine borane (tBuAB), (CH 3 )3CNH 2 BH3, has been studied in order to understand the reaction pathway of hydrogen sorption and the impact of the t-butyl substitution dehydrogenation thermodynamics. Ή , U B , and l3 C solid state nuclear magnetic resonance (NMR) spectroscopy has revealed that heating initiates two separate reaction pathways: isomerization and hydrocarbon abstraction resulting in varying yields of isobutane and hydrogen. It is also possible that tBuAB dissociates about the N-B bond giving rise to borane stretching modes in the gas FTIR. Trapped t-butylamine (tBuA) which slowly diffuses from the tBuAB solid in 13 C NMR studies appears to be present; however, this spectral region is convoluted by other decomposition products. n B NMR indicates that the major reaction pathway results in hydrogen evolution with isobutane formation being present in smaller yields. The t-butyl substitution lowers the thermodynamic stability -compared to NH3BH3-but results in impure hydrogen gas stream and lowered capacity due to isobutene evolution. INTRODUCTIONDevelopment of suitable materials to store hydrogen for automotive use has received pointed attention over the past decade [1], Significant progress has been made with the discovery of novel chemical hydrides, complex metal hydrides, and adsorption substrates which continue to optimize both thermodynamics and kinetics of hydrogen sorption [2]. Chemical hydrides typically offer the largest theoretical gravimetric capacities. Autrey et al. [3] have recently shown that mechanical milling of alkali metal hydrides with ammonia borane can further lower the decomposition temperature. In all cases, however, many challenges remain in order to meet the current US DOE performance targets [4].Amine boranes are being considered for hydrogen storage materials since they contain significant quantities of hydrogen which potentially can be released at low temperatures (80-150 °C) via chemical reactions. Ammonia borane, NH3BH3, is one of the most promising in this class as it decomposes to release greater than two moles of pure hydrogen gas (14 wt %) below 160 °C [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19], Although isoelectronic to ethane, NH3BH3 is a solid at room temperature due to the di-hydrogen bonding network formed between the amine protons and boron hydrides in the solid state lattice. Further, it has been shown that the hydrogen release mechanism involves transformation and isomerization to an ionic dimer where a hydride migrates from one boron to the adjacent boron in the dimer [20]. The greatest ch...

show abstract

Raman Spectroscopy of Ammonia Borane at Low Temperature and High Pressure

Najiba¹,

Chen²,

Drozd³

et al. 2012

Energy Technology 2012

View full text Add to dashboard Cite

Dihydrogen Bonding under High Pressure: A Raman Study of BH₃NH₃ Molecular Crystal

Cited by 90 publications

References 40 publications

High-pressure study of lithium amidoborane using Raman spectroscopy and insight into dihydrogen bonding absence

High-pressure study of lithium amidoborane using Raman spectroscopy and insight into dihydrogen bonding absence

Thermal Decomposition of T‐Butylamine Borane Studied by in Situ Solid State NMR

Raman Spectroscopy of Ammonia Borane at Low Temperature and High Pressure

Contact Info

Product

Resources

About

Dihydrogen Bonding under High Pressure: A Raman Study of BH3NH3 Molecular Crystal

Cited by 90 publications

References 40 publications

High-pressure study of lithium amidoborane using Raman spectroscopy and insight into dihydrogen bonding absence

High-pressure study of lithium amidoborane using Raman spectroscopy and insight into dihydrogen bonding absence

Thermal Decomposition of T‐Butylamine Borane Studied by in Situ Solid State NMR

Raman Spectroscopy of Ammonia Borane at Low Temperature and High Pressure

Contact Info

Product

Resources

About

Dihydrogen Bonding under High Pressure: A Raman Study of BH₃NH₃ Molecular Crystal