Infrared studies of matrix isolated species in the hydrogen-boron-nitrogen system

Lory, Earl R.; Porter, Richard F.

doi:10.1021/ja00787a012

Cited by 62 publications

(49 citation statements)

References 2 publications

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“…[58-601 These heterocycles, in turn, readily undergo oxidative ring expansionfs8] with sulfur or selenium to give 68 [Eq. (22)]. 67 68…”

Section: Competing Boration Reactionsmentioning

confidence: 99%

The Chemistry of Amino Imino Boranes

Nöth¹

1988

Angew. Chem. Int. Ed. Engl.

103

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Dicoordinated boron compounds can no longer be considered as "exotic" species in boron chemistry: this is proved by the extensive chemistry of bis(dialkylamino)boron( 1 +) ions, alkylidene boranes, and imino boranes. The latter are characterized by high reactivity and chemical versatility. A special position is taken by amino imino boranes, whose chemistry is reported here. The presence of an amino group enhances the reactivity of imino boranes on the one hand and increases their kinetic stability on the other. New types of diamino boranes accessible via amino imino boranes often undergo intramolecular ring closure. These heterocycles are well suited to generate new types of cations of boron. Cycloaddition reactions using amino imino boranes open up a new heterocyclic chemistry of boron. The chemistry of N-functional amino imino boranes, which is still its infancy, shows much promise.

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“…[58-601 These heterocycles, in turn, readily undergo oxidative ring expansionfs8] with sulfur or selenium to give 68 [Eq. (22)]. 67 68…”

Section: Competing Boration Reactionsmentioning

confidence: 99%

The Chemistry of Amino Imino Boranes

Nöth¹

1988

Angew. Chem. Int. Ed. Engl.

103

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“…The cis-trans isomerization of iminoborane (1 and 2) by transition state (TS 1-2 ) and the internal conversion of (1) and (2) by two planar transition states (TS 1a-1b and TS 2a-2b ) also are considered in the triplet PES. On the other hand, the dissociation product of B-N-H (5) and H atom can be predicted by the dissociation reaction of nonplanar cis-iminoborane (2) and a planar structure aminoboranylidene (3) with the transition states TS [2][3][4][5] and TS [3][4][5] . At the same time, the dissociation product H-B-N (6) and H atom can be predicted by the dissociation reaction of nonplanar cis-iminoborane (2) and a planar structure borylnitrene (4) with the transition states of TS [2][3][4][5][6] and TS 4 -6 .…”

Section: Resultsmentioning

confidence: 99%

“…We now turn our attention to the dissociated products of BNH (5) and HBN (6). They are linear molecules with 2 ⌺ electronic state, in which BNH (5) can be produced from cis-iminoborane (2) or ZHANG, LI, AND ZHANG aminoboranylidene (3) and HBN (6) can be obtained from cis-iminoborane (2) or borylnitrene (4) on the H loss reaction by four different transition states (TS 2-5 , TS 3-5 , TS [2][3][4][5][6] , and TS 4 -6 ,). The boron and nitrogen atom both display sp 1 hybridized to being bonded in these two species; however, their single electron occupied different orbitals.…”

Section: Stationary Pointsmentioning

confidence: 99%

“…Total energies for stationary points (trans-iminoborane (1), cis-iminoborane (2), aminoboranylidene (3), and borylnitrene (4)) and the transition states (TS 1-2 , TS 1a-1b , TS 2a-2b , TS [1][2][3] , and TS 1-4 ) on the triplet potential energy surface of BH 2 N with B3LYP/(AUG-)-cc-pVXZ (XϭD, T, and Q) level of theories are presented in Table III. Considering our computational study, it is obvious that the activation barriers are only 0.48, 0.25, and 0.0032 kcal ⅐ mol -1 for the transformation of triplet trans-iminoborane into triplet cis-iminoborane, and the internal conversion reactions of (1) and (2) with the B3LYP/AUG-cc-pVQZ level of theory.…”

Section: Isomerization Pathwaysmentioning

confidence: 99%

“…Total energies for dissociated products (BNH (5) and HBN (6)) and the transition states (TS 2-5 , TS [2][3][4][5][6] , TS [3][4][5] , and TS 4 -6 ) on the triplet potential energy surface of BH 2 N with B3LYP/(AUG-)-ccpVXZ (XϭD, T, and Q) level of theories are presented in Table IV. The reaction energies (⌬E) and the classical potential barriers(V ) at different levels of theory for all reactions are listed in Table V.…”

Section: Dissociation Channelmentioning

confidence: 99%

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Triplet potential energy surface for BH₂N: A DFT study

Zhang

2005

Int J of Quantum Chemistry

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ABSTRACT:The triplet potential energy surfaces (PES) for the isomerization and dissociation reactions of BH 2 N isomers was investigated using the DFT/B3LYP method of theory. Thirteen BH 2 N isomer species and two dissociated products were identified, in which five isomerization reactions and four dissociation pathways were found. On the triplet PES, the nonplanar trans-iminoborane (1) can isomerize to the lowest triplet state of planar aminoboranylidene (3) and the triplet state planar borylnitrene (4) directly by two three-membered ring transition states (TS 1-3 and TS 1-4 ), respectively. The cis-trans isomerization of iminoborane (1 and 2) by transition state (TS 1-2 ), the internal conversion of 1 and that of 2 by two transition states (TS 1a-1b and TS 2a-2b ) are also considered in the triplet PES. On the other hand, the dissociation product of B-N-H (5) and H atom can be predicted by the dissociation reaction of nonplanar cisiminoborane (2) and a planar structure aminoboranylidene (3) with the transition state of TS 2-5 and TS [3][4][5] . At the same time, the dissociation product H-B-N (6) and H atom can be predicted by the dissociation reaction of nonplanar cis-iminoborane (2) and a planar structure borylnitrene (4) with the transition state of TS 2-6 and TS 4 -6 . By analysis of the whole potential energy surface, we can find the isomerization from planar the triplet state aminoboranylidene (3) to the triplet state planar borylnitrene (4) is not carried out in one step directly, but achieved in multistep reactions of

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Ammonia Borane and Related Compounds as Hydrogen Source Materials

Mertens

Wolf

Baitalow

2010

Handbook of Hydrogen Storage

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Mainly driven by the efforts of the automotive industry, a strong push towards new concepts to store hydrogen has occurred over recent years. Generally, in this framework, high hydrogen content materials have been of great interest for chemical storage concepts.From weight considerations, the most natural choice to develop hydrogen storage and source materials would be the use of first row element hydrides. Since a high valency allows more hydrogen to bond per atom, the mid-first row hydrides borane, methane, and ammonia with 21, 25, and 17.5 wt% are amongst the materials with the highest hydrogen contents. Although the thermodynamics is not favorable, due to the strong bond between carbon and hydrogen, the utilization of methane as a hydrogen source material has been widely investigated and small natural gas reformers for a fueling station to supply polymer electrolyte membrane (PEM) fuel cell vehicles with hydrogen have been developed [1].However, ammonia and boranes alone are also not very attractive as hydrogen source compounds because of thermodynamic considerations and the harm they potentially bring to fuel cell catalysts (PEM). The interesting fact that nitrogen and boron are on opposite sides of the electronegative-electropositive border line that runs through the periodic table, offers attractive new features to the ammonia borane adduct BH 3 NH 3 (AB). Especially, their ability to release hydrogen at low temperatures, combined with the very high hydrogen content, has brought these materials into the focus of recent research efforts.Besides the fact that the known world boron resources are insufficient to permanently fuel a significant portion of the world vehicle fleet, it is very clear from the energy expense needed for AB regeneration and the cost aspects that ammonia borane-based materials are not likely to become a means of mass hydrogen storage. These materials, however, can be of interest for small scale applications demanding very high hydrogen storage density, such as autonomously operated small electrical Handbook of Hydrogen Storage. Edited by Michael Hirscher j215 devices. Research efforts to put AB materials to use primarily encompass the control of the hydrogen release kinetics, the production of AB materials and the rehydrogenation of the spent materials.Since spent ammonia borane, or borazane as it is also called, and most of its derivatives are not easily rechargeable, for thermodynamic reasons, new recycling strategies need to be developed. An essential part of possible recycling schemes is the generation of hydridic, that is, negatively charged, hydrogen located at the boron centers. Because of the importance of borohydrides in organic synthesis and the recent developments in nonmetal-center-based hydrogen activation [2], the relevance of these research efforts is outside the area of hydrogen source and storage materials. Materials Description and Characterization

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Infrared studies of matrix isolated species in the hydrogen-boron-nitrogen system

Cited by 62 publications

References 2 publications

The Chemistry of Amino Imino Boranes

The Chemistry of Amino Imino Boranes

Triplet potential energy surface for BH₂N: A DFT study

Ammonia Borane and Related Compounds as Hydrogen Source Materials

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Infrared studies of matrix isolated species in the hydrogen-boron-nitrogen system

Cited by 62 publications

References 2 publications

The Chemistry of Amino Imino Boranes

The Chemistry of Amino Imino Boranes

Triplet potential energy surface for BH2N: A DFT study

Ammonia Borane and Related Compounds as Hydrogen Source Materials

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Triplet potential energy surface for BH₂N: A DFT study