Big Borane Assemblies, Macropolyhedral Species and Related Chemistry

Kennedy, John D.

doi:10.1007/978-3-319-22282-0_6

Cited by 4 publications

(3 citation statements)

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“…19 Here it may be noted that macropolyhedral thiaboranes and transition-element metallaboranes have proved to be more flexible than corresponding binary boranes in their reaction chemistry and structural variants, a versatility probably facilitated by the flexible valency states of sulphur and of transition-element centres. 20,21 It also may be noted in this context that attempts to make the purely binary boron hydride analogue of 2, viz. the [B18H22] 2 dianion, by reduction of anti-B18H22 1, surprisingly led instead in the isolation of the macropolyhedral [OB18H21]  oxaborane monoanion .…”

Section: IVmentioning

confidence: 99%

Substitution of the laser borane anti-B₁₈H₂₂ with pyridine: a structural and photophysical study of some unusually structured macropolyhedral boron hydrides

et al. 2018

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Reaction of anti-BH1 with pyridine in neutral solvents gives sparingly soluble BH-3',8'-Py3a as the major product (ca. 53%) and BH-6',9'-Py2 (ca. 15%) as the minor product, with small quantities of BH-8'-Py 4 (ca. 1%) also being formed. The three new compounds 2, 3a and 4 are characterized by single-crystal X-ray diffraction analyses and by multinuclear multiple-resonance NMR spectroscopy. Compound 2 is of ten-vertex nido:ten-vertex arachno two-atoms-in-common architecture, long postulated for a species with borons-only cluster constitution, but previously elusive. Compound 3a is of unprecedented ten-vertex nido:eight-vertex arachno two-atoms-in-common architecture. The single-crystal X-ray diffraction analysis for the picoline derivative BH(NCHMe)3b, similarly obtained, is also presented. BHPy 4 is also previously unreported but is of known ten-vertex nido:ten-vertex nido two-atoms-in-common architecture of anti configuration, but now with the pyridine ligand positioned differently to other reported examples of BHL compounds. Factors behind the remarkably low solubility of 3a and 3b are elucidated in terms of electrostatic potential (ESP) calculations, polarity, and van der Waals complementarities. In view of contemporary developing high interest in the fluorescent properties of macropolyhedral boron-containing species, a detailed assessment of the photophysical characteristics of 3a and 4 is also presented. In contrast to the thermochromic fluorescence of 2 (from 620 nm brick-red at room temperature to 585 nm yellow at 8 K, quantum yield 0.15), compound 3a is only weakly phosphorescent in the yellow region (590 nm, quantum yield 0.01), whereas compound 4 exhibits no luminescence. The far more photoactive nature of compound 2 is associated with S excited-state minima structures that differ from each other only by the relative rotational positions of the pyridine substituents on its disubstituted ten-vertex {arachno-BPy}-subcluster. The wavelength and relative intensity of fluorescence from these structures depends on the rotational positions of the pyridine ligands, which in turn are influenced by temperature and/or rotational inhibition in the solid-state.

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Section: IVmentioning

confidence: 99%

Substitution of the laser borane anti-B₁₈H₂₂ with pyridine: a structural and photophysical study of some unusually structured macropolyhedral boron hydrides

et al. 2018

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“…Fusion reactions of neutral boranes such as the one shown in eq have been observed experimentally, where the two boranes are linked by a single B–B bond. This coupled-cage borane can then “undergo coupled-cage to single-cage condensations producing important higher cage materials, such as B 9 H 14 – , B 9 H 13 ·SMe 2 , B 8 H 10 ·NEt 3 , 1,2-R 2 C 2 B 8 H 8 , and B 12 H 12 2– .”…”

Section: Introductionmentioning

confidence: 91%

“…Fusion reactions of neutral boranes 39 such as the one shown in eq 1 , is obtained. 41 Reactions 1 and 2 illustrate that, in the presence of metal cations, mediumsized neutral boranes or borohydride anions are capable of fusion to form larger clusters.…”

Section: ■ Introductionmentioning

confidence: 99%

Exploring Detailed Reaction Pathways for Hydrogen Storage with Borohydrides Using DFT Calculations

et al. 2022

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Borohydrides have seen renewed interest due to their ability to store and carry a high weight percentage of hydrogen, making them desirable materials for large-scale and long-duration energy storage applications. In this work, we present a systematic computational study of the thermochemical feasibility of a series of mechanistic pathways that can lead to the formation of the observed boron clusters. This allowed us to identify predominant pathways for buildup, following a complex network of pathways. We find that the preferred mechanisms are different for smaller and larger clusters. The primary mechanism for buildup in clusters up to ∼5 boron atoms is by addition of BH4 –/BH3 species, followed by loss of H2 or H–. For larger clusters, fusion reactions dominate, again followed by the loss of H2 or H–. A few species were identified as possible branching points, where the trends for favorability change; B2H7 – as an initiation step and B4H7 –, B3H8 –, and B9H13 2– as minima on the potential energy surface are most notable. This work demonstrates that borohydride clusters feature a wealth of pathways for realizing the desired products (B10H10 2– or B12H12 2–), the redundancy of which may help avoid energetic sinks or kinetic bottlenecks. This robustness in reactivity has the potential to make them a versatile H2 storage material.

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Expanding Luminescence Horizons in Macropolyhedral Heteroboranes

Bould,

Ehn,

Tok

et al. 2024

Angewandte Chemie

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Luminescence is observed in three novel macropolyhedral nineteen‐ and eighteen‐vertex chalcogenaboranes: Se2B17H17 (1), SeB17H19 (3) and SeB18H20 (4). This led us to the recognition that previously published macropolyhedral heteroborane species might also exhibit luminescence. Thus, the known nineteen‐ and eighteen‐vertex dithiaboranes S2B17H17 (2), n‐S2B16H16 (5) and i‐S2B16H16 (6) were synthesised and also found to exhibit a range of luminescent properties. These macropolyhedral species are very different from the previously unique fluorescent binary borane B18H22 in terms of their structural architectures, by the presence of borane cluster hetero atoms, and, as in the cases of 5 and 6, that their synthetic origins are not derived simply through the modification of B18H22 itself. They consequently greatly expand the possibilities of finding new luminescent inorganic borane species.

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Big Borane Assemblies, Macropolyhedral Species and Related Chemistry

Cited by 4 publications

References 135 publications

Substitution of the laser borane anti-B₁₈H₂₂ with pyridine: a structural and photophysical study of some unusually structured macropolyhedral boron hydrides

Substitution of the laser borane anti-B₁₈H₂₂ with pyridine: a structural and photophysical study of some unusually structured macropolyhedral boron hydrides

Exploring Detailed Reaction Pathways for Hydrogen Storage with Borohydrides Using DFT Calculations

Expanding Luminescence Horizons in Macropolyhedral Heteroboranes

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Big Borane Assemblies, Macropolyhedral Species and Related Chemistry

Cited by 4 publications

References 135 publications

Substitution of the laser borane anti-B18H22 with pyridine: a structural and photophysical study of some unusually structured macropolyhedral boron hydrides

Substitution of the laser borane anti-B18H22 with pyridine: a structural and photophysical study of some unusually structured macropolyhedral boron hydrides

Exploring Detailed Reaction Pathways for Hydrogen Storage with Borohydrides Using DFT Calculations

Expanding Luminescence Horizons in Macropolyhedral Heteroboranes

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Substitution of the laser borane anti-B₁₈H₂₂ with pyridine: a structural and photophysical study of some unusually structured macropolyhedral boron hydrides

Substitution of the laser borane anti-B₁₈H₂₂ with pyridine: a structural and photophysical study of some unusually structured macropolyhedral boron hydrides