A new 4c–2e bond in B6H7−

Hofmann, Kathrin; Prosenc, Marc H.; Albert, Barbara

doi:10.1039/b704944g

Cited by 31 publications

(34 citation statements)

References 18 publications

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“…[23] Multipole refinements of the crystal structure based on diffraction data gained from single crystals at low temperature were recently performed for the closo-B 6 H 6 2À ion and the B 6 H 7 À ion; the experimental electron density distributions (static deformation density) were also analysed. [27][28][29] The picture of multicenter bonds as found for closo-clusters in textbooks was confirmed without reserve for B 6 H 6 2À (Figure 11 a). For B 6 H 7 À , a new type of 2e4c bond was found with ring-critical points in the B 3 H rhomboids.…”

Section: 2supporting

confidence: 67%

“…The partial occupation of the so-called B11 site is known from several compounds described in the literature. It, therefore, seems confirmed that the B 28 unit of the elemental structure mentioned in Section 2.2.2 should be denoted as a B 27 unit. This also means that B1 is subject to a distorted tetrahedral coordination not by six, but only by four atoms in the B11 position.…”

Section: General Observationsmentioning

confidence: 92%

“…The concept of polycentric bonding has also been proven experimentally in recent experimental determinations of the electron density in closo-clusters. [27][28][29] However, the bridge from molecules to solids-that is, from borane to boron-rich boride-remains one of the great current challenges. [30] The production of boron and borides in the form of nanomaterials-nanotubes, nanowires, nanoparticular, nanostructured, or in the form of nanolayers-is yet another current challenge.…”

Section: àmentioning

confidence: 99%

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Boron: Elementary Challenge for Experimenters and Theoreticians

Albert¹,

Hillebrecht²

2009

Angew Chem Int Ed

558

436

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Many of the fundamental questions regarding the solid-state chemistry of boron are still unsolved, more than 200 years after its discovery. Recently, theoretical work on the existence and stability of known and new modifications of the element combined with high-pressure and high-temperature experiments have revealed new aspects. A lot has also happened over the last few years in the field of reactions between boron and main group elements. Binary compounds such as B(6)O, MgB(2), LiB(1-x), Na(3)B(20), and CaB(6) have caused much excitement, but the electron-precise, colorless boride carbides Li(2)B(12)C(2), LiB(13)C(2), and MgB(12)C(2) as well as the graphite analogue BeB(2)C(2) also deserve special attention. Physical properties such as hardness, superconductivity, neutron scattering length, and thermoelectricity have also made boron-rich compounds attractive to materials research and for applications. The greatest challenges to boron chemistry, however, are still the synthesis of monophasic products in macroscopic quantities and in the form of single crystals, the unequivocal identification and determination of crystal structures, and a thorough understanding of their electronic situation. Linked polyhedra are the dominating structural elements of the boron-rich compounds of the main group elements. In many cases, their structures can be derived from those that have been assigned to modifications of the element. Again, even these require a critical revision and discussion.

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Section: 2supporting

confidence: 67%

Section: General Observationsmentioning

confidence: 92%

Section: àmentioning

confidence: 99%

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Boron: Elementary Challenge for Experimenters and Theoreticians

Albert¹,

Hillebrecht²

2009

Angew Chem Int Ed

558

436

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“…Even though Ca is farther away from B 12 H 12 cage than Mg, due to lower ionization energy, Ca forms a stronger bond with B 12 H 12 complex. Note that the Mg atom has the highest ionization energy, 7.65 eV, 29 in comparison with Li (5.39 eV), Na (5.14 eV) and Ca (6.11 eV 20 have reported a systematic study of the atomic structure and stability of B n H n and B n H n -(n ) 5-13, 16,19,22) clusters and have shown that with the exception of B 12 H 12 2-, loss of one electron from B n H n 2-(n ) 5-13) is exothermic. Note that according to the Wade-Mingos rule described earlier (n + 1) electron pairs are needed to stabilize closo-borane polyhedra with n vertices.…”

Section: Resultsmentioning

confidence: 97%

Reaction Intermediates during the Dehydrogenation of Metal Borohydrides: A Cluster Perspective

Willis

Jena

2010

J. Phys. Chem. C

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Complex light metal hydrides such as alanates, amides, and borohydrides have among the highest hydrogen storage capacities of any materials investigated thus far. However, their use in the transportation industry is plagued by poor thermodynamics and kinetics as well as lack of reversibility at ambient pressure and temperature. To achieve a fundamental understanding of the properties of these materials, considerable efforts have been made to study the reaction intermediates as hydrogen continues to desorb. Recent experiments 1 have confirmed the formation of [B 12 H 12 ] 2-complexes during the dehydrogenation of metal tetrahydroborates. We show that the existence of these complexes can be understood by studying the stability of borane clusters and their interaction with metal atoms. We further examine the possibility that other reaction intermediates with different B and H stoichiometry may be present during the dehydrogenation process. Study of the interaction of boron-hydrogen complexes with various metal cations also permits us to illustrate which of the metal borohydrides may be better suited for hydrogen storage. The results are obtained from first principles cluster calculations using density functional theory.

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“…KCl precipitates and can be filtered off. 2-, [20] and is also borne out by the ease with which H-D exchange can be achieved with DCl. [21] The melting points of the compounds (Table 1) are highest when tetramethylammonium serves as the counterion.…”

Section: Resultsmentioning

confidence: 95%

N‐Alkylation of Ammonioundecahydro‐closo‐dodecaborate(1–) for the Preparation of Anions for Ionic Liquids

2008

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Different N‐alkylated derivatives of ammonioundecahydro‐closo‐dodecaborate(1–), [B12H11NH3]–, were prepared. Strategies for the introduction of one alkyl chain or two equal alkyl chains and the trisubstitution by two different alkyl chains were developed. Several of the resulting salts have low melting points and are examples of a new class of ionic liquids.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)

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A new 4c–2e bond in B₆H₇⁻

Abstract: For N(C(4)H(9))(4)B(6)H(7) a proton is shown to be localised above one of the faces of the distorted octahedron, and rhomboid rings are formed as shown by topological analysis of charge densities.

Cited by 31 publications

References 18 publications

Boron: Elementary Challenge for Experimenters and Theoreticians

Boron: Elementary Challenge for Experimenters and Theoreticians

Reaction Intermediates during the Dehydrogenation of Metal Borohydrides: A Cluster Perspective

N‐Alkylation of Ammonioundecahydro‐closo‐dodecaborate(1–) for the Preparation of Anions for Ionic Liquids

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