Matrix isolation study of the mechanism of the reaction of diborane with ammonia: pyrolysis of the H3B·NH3 adduct

Carpenter, John D.; Ault, Bruce S.

doi:10.1016/0009-2614(92)86042-g

Cited by 26 publications

(15 citation statements)

References 14 publications

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“…144 4.4 Thermolysis-gas phase vs. solid state vs. solution Ammonia-borane releases hydrogen gas when heated, but the reaction rates and products formed depend quite spectacularly on the reaction conditions. In low-pressure, gas-phase thermolysis the primary intermediate of the first dehydrogenation step is aminoborane monomer 4, an observation confirmed by matrix isolation 68 and mass spectrometric studies. 145,146 Building on the calculations mentioned above, Nguyen et al used high-level ab initio calculations to show that the barrier for intramolecular H 2 loss from 1 in the gas phase is actually higher than its B-N bond dissociation energy!…”

Section: Reactions With Strong Oxidantsmentioning

confidence: 71%

Ammonia–borane: the hydrogen source par excellence?

2007

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Ammonia-borane, H3NBH3, is an intriguing molecule for chemical hydrogen storage applications. With both protic N-H and hydridic B-H bonds, three H atoms per main group element, and a low molecular weight, H3NBH3 has the potential to meet the stringent gravimetric and volumetric hydrogen storage capacity targets needed for transportation applications. Furthermore, devising an energy-efficient chemical process to regenerate H3NBH3 from dehydrogenated BNHx material is an important step towards realization of a sustainable transportation fuel. In this perspective we discuss current progress in catalysis research to control the rate and extent of hydrogen release and preliminary efforts at regeneration of H3NBH3.

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Section: Reactions With Strong Oxidantsmentioning

confidence: 71%

Ammonia–borane: the hydrogen source par excellence?

2007

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“…Vibrational frequencies of the monomers and the complexes were calculated at the MP2/aug-cc-pVDZ level and the results are summarized in Table I, along with available experimental frequencies. 58,59,63 The major discrepancy between theory and experiment occurs in the stretching vibration ͑B-N͒ of H 3 BNH 3 . In fact, the experimental 57 B-N stretching frequency estimates vary between 608 and 968 cm Ϫ1 .…”

Section: Spectroscopic Featuresmentioning

confidence: 99%

Comparison between hydrogen and dihydrogen bonds among H3BNH3, H2BNH2, and NH3

Kar¹,

Scheiner²

2003

The Journal of Chemical Physics

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Several possible binary complexes among ammonia-borane, aminoborane, and ammonia, via hydrogen and/or dihydrogen bonds, have been investigated to understand the effect of different hybridization. Møller-Plesset second-order perturbation theory with aug-cc-pVDZ basis set was used. The interaction energy is corrected for basis set superposition error, and the Morokuma-Kitaura method was employed to decompose the total interaction energy. Like H 3 BNH 3 , the sp 2 hybridized H 2 BNH 2 also participates in Hand dihydrogen bond formation. However, such bonds are weaker than their sp 3 analogs. The contractions of BN bonds are associated with blueshift in vibrational frequency and stretches of BH and NH bonds with redshift. The polarization, charge transfer, correlation, and higher-order energy components are larger in dihydrogen bonded complexes, compared to classical H-bonded ammonia dimers.

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“…36 Thus, a tubular and extended conjugated BN structure reduces the binding energy significantly. The newly formed B-N bond lengths are in the range of 1.724-1.733 Å, longer than in H 3 N-BH 3 (1.682 Å at B3LYP/6-31+G*, 1.668 Å at MP2/aug-cc-pVDZ 37 and 1.658 Å (experimental) 38 ). Thus, the method used in the present study seems reasonably accurate in predicting energies and structures but computationally more efficient than expensive correlation methods.…”

Section: Bnnts-nhmentioning

confidence: 81%

Site and chirality selective chemical modifications of boron nitride nanotubes (BNNTs) via Lewis acid–base interactions

Sundaram

Scheiner

Roy

et al. 2015

Phys. Chem. Chem. Phys.

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The pristine BNNTs contain both Lewis acid (boron) and Lewis base (nitrogen) centers at their surface. Interactions of ammonia and borane molecules, representatives of Lewis base and acid as adsorbates respectively, with matching sites at the surface of BNNTs, have been explored in the present DFT study. Adsorption energies suggest stronger chemisorption (about 15-20 kcal mol(-1)) of borane than ammonia (about 5-10 kcal mol(-1)) in both armchair (4,4) and zigzag (8,0) variants of the tube. NH3 favors (8,0) over the (4,4) tube, whereas BH3 exhibits the opposite preference, indicating some chirality dependence on acid-base interactions. A new feature of bonding is found in BH3/AlH3-BNNTs (at the edge site) complexes, where one hydrogen of the guest molecule is involved in three-center two-electron bonding, in addition to dative covalent bond (N: → B). This interaction causes a reversal of electron flow from borane/alane to BNNT, making the tube an electron acceptor, suggesting tailoring of electronic properties could be possible by varying strength of incoming Lewis acids. On the contrary, BNNTs always behave as electron acceptor in ammonia complexes. IR, XPS and NMR spectra show some characteristic features of complexes and can help experimentalists to identify not only structures of such complexes but also the location of the guest molecules and design second functionalizations. Interaction with several other neutral BF3, BCl3, BH2CH3 and ionic CH3(+) acids as well as amino group (CH3NH2 and NH2COOH) were also studied. The strongest interaction (>100 kcal mol(-1)) is found in BNNT-CH3(+) complexes and H-bonds are the only source of stability of NH2COOH-BNNT complexes.

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Matrix isolation study of the mechanism of the reaction of diborane with ammonia: pyrolysis of the H3B·NH3 adduct

Cited by 26 publications

References 14 publications

Ammonia–borane: the hydrogen source par excellence?

Ammonia–borane: the hydrogen source par excellence?

Comparison between hydrogen and dihydrogen bonds among H3BNH3, H2BNH2, and NH3

Site and chirality selective chemical modifications of boron nitride nanotubes (BNNTs) via Lewis acid–base interactions

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