Anti and gauche conformers of an inorganic butane analogue, NH3BH2NH2BH3

Chen, Xuenian; Gallucci, Judith C.; Campana, Charles F.; Huang, Zhenguo; Lingam, Hima Kumar; Shore, Sheldon G.; Zhao, Ji‐Cheng

doi:10.1039/c2cc33621a

Cited by 27 publications

(19 citation statements)

References 41 publications

(28 reference statements)

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“…The bulky crown ether at the end of DDAB prevents the formation of intermolecular DHBs, allowing the hydride of the terminal -BH 3 at the other end of DDAB to bend back to interact with a proton of the terminal -NH 3 to form the gauche conformer. 32 Similar influence of inter-and intramolecular DHBs on conformation has been observed in linear ammonia borane oligomers and ammonia triborane by the Sneddon group 33 and in the BÀN cyclohexane analogue, N 3 B 3 H 12 , by the Shore group. 34 In the crystal structure of N 3 B 3 H 12 redetermined recently, its "chair" conformer was found to be stabilized by intermolecular DHBs.…”

Section: Dihydrogen Bond Effects On Conformationmentioning

confidence: 54%

The Roles of Dihydrogen Bonds in Amine Borane Chemistry

Chen

Zhao²,

Shore³

2013

Acc. Chem. Res.

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134

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A dihydrogen bond (DHB) is an electrostatic interaction between a protonic hydrogen and a hydridic hydrogen. Over the past two decades, researchers have made significant progress in the identification and characterization of DHBs and their properties. In comparison with conventional hydrogen bonds (HBs), which have been widely used in catalysis, molecular recognition, crystal engineering, and supramolecular synthesis, chemists have only applied DHBs in very limited ways. Considering that DHBs and conventional HBs have comparable strength, DHBs could be more widely applied in chemistry. Over the past several years, we have explored the impact of DHBs on amine borane chemistry and the syntheses and characterization of amine boranes and ammoniated metal borohydrides for hydrogen storage. Through systematic computational and experimental investigations, we found that DHBs play a dominant role in dictating the reaction pathways (and thus different products) of amine boranes where oppositely charged hydrogens coexist for DHB formation. Through careful experiments, we observed, for the first time, a long-postulated reaction intermediate, ammonia diborane (AaDB), whose behavior is essential to mechanistic understanding of the formation of the diammoniate of diborane (DADB) in the reaction of ammonia (NH3) with tetrahydrofuran borane (THF·BH3). The formation of DADB has puzzled the boron chemistry community for decades. Mechanistic insight enabled us to develop facile syntheses of aminodiborane (ADB), ammonia borane (AB), DADB, and an inorganic butane analog NH3BH2NH2BH3 (DDAB). Our examples, together with those in the literature, reinforce the fact that DHB formation and subsequent molecular hydrogen elimination are a viable approach for creating new covalent bonds and synthesizing new materials. We also review the strong effects of DHBs on the stability of conformers and the hydrogen desorption temperatures of boron-nitrogen compounds. We hope that this Account will encourage further applications of DHBs in molecular recognition, host-guest chemistry, crystal engineering, supramolecular chemistry, molecular self-assembly, chemical kinetics, and the syntheses of new advanced materials.

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Section: Dihydrogen Bond Effects On Conformationmentioning

confidence: 54%

The Roles of Dihydrogen Bonds in Amine Borane Chemistry

Chen

Zhao²,

Shore³

2013

Acc. Chem. Res.

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134

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“…When the DHB is strong enough, dihydrogen elimination occurs, similar to the B−H bond (red) cleaved as in the case ( i ) in Figure . In other cases, the DHB interactions play important roles in the properties and structures of boranes, as well as the mechanisms of their reactions ,–. Recent Reviews have succinctly summarized the highlights in this field, thus they will not be discussed in detail here except for the influence of the formation of DHBs on the mechanisms …”

Section: The Nucleophilicity Of the B−h Bonding Pair Electronsmentioning

confidence: 99%

A New Perspective on Borane Chemistry: The Nucleophilicity of the B−H Bonding Pair Electrons

et al. 2019

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A number of recently discovered nucleophilic boron compounds, such as boryl anions and borylenes, are breaking the rules regarding boron and boron‐containing compounds and their reputation as Lewis acids/electrophiles. In a similar fashion, the B−H bonding pair electrons in boranes also show nucleophilicity which is ascribed to the lower electronegativity of boron relative to that of hydrogen. However, this nucleophilicity of the B−H bond has received far less attention. Explorations of the nucleophilicity of the B−H bonding pair electrons have led to the formation of B−H−B bonded units and B−H⋅⋅⋅H−Y dihydrogen bonds, based on which new chemistry has been uncovered, including the elucidation of the mechanism of formation of aminodiborane (ADB), the diammoniate of diborane (DADB), and lithium or sodium salts of octahydrotriborates (B3H8−), as well as the development of more convenient and straightforward synthetic routes to these reagents. Moreover, the recognition of the nucleophilic properties of the B−H bonding pair electrons will also help to more deeply understand the different mechanisms operating in hydroboration reactions.

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“…ammonia borane). 12,13,14 To achieve fast cycling at accessible conditions, however, requires weak chemical bonds, fast kinetics, and short diffusion lengths. Thus, the concomitant requirement of fast recycling is quite challenging for these high-hydrogen-capacity hydride materials.…”

Section: Introductionmentioning

confidence: 99%

Development of potential organic-molecule-based hydrogen storage materials: Converting C N bond-breaking thermolysis of guanidine to N H bond-breaking dehydrogenation

Zhou

Udovic

et al. 2016

International Journal of Hydrogen Energy

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The small organic molecule guanidine CN 3 H 5 can be anionized via a facile reaction with alkalimetal hydrides or amides with the formation of metal guanidinates (MCN 3 H 4) and their guanidine adducts. The crystal structures and thermal decomposition properties of these oragnicmolecule-based complex hydrides were carefully investigated. Through metallation, MCN 3 H 4 can completely preserve carbon atoms in the system and exhibit a largely improved thermal decomposition compared to CN 3 H 5 regarding the extent of C-N bond breaking. By pairing H + in CN 3 H 5 or MCN 3 H 4 with Hfrom metal hydrides, the resulting composite can further reduce ammonia libration and promote an endothermic dehydrogenation.

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Anti and gauche conformers of an inorganic butane analogue, NH3BH2NH2BH3

Cited by 27 publications

References 41 publications

The Roles of Dihydrogen Bonds in Amine Borane Chemistry

The Roles of Dihydrogen Bonds in Amine Borane Chemistry

A New Perspective on Borane Chemistry: The Nucleophilicity of the B−H Bonding Pair Electrons

Development of potential organic-molecule-based hydrogen storage materials: Converting C N bond-breaking thermolysis of guanidine to N H bond-breaking dehydrogenation

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