From unsaturated dodecahedranes to C40 cages?

Weber, Klaus; Voss, Thorsten; Heimbach, Dirk; Weiler, Andreas; Keller, Manfred; Wörth, Jürgen; Knothe, Lothar; Exner, Kai S.; Prinzbach, Horst

doi:10.1016/j.tetlet.2005.06.072

Cited by 11 publications

(8 citation statements)

References 27 publications

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“…[103][104][105] Alternatively, Prinzbach et al were able to dimerize C 20 dodecahedranes by the formation of two CAC bonds in the way to a C 40 cage. [106] Our results are also in good agreement with the short exocyclic CAC bond distances observed in this type of species (1.42-1.46 Å), for example the synthesized trimethylsilyl-substituted tetrahedranyltetrahedrane [107] (CAC distance 1.436 Å), in comparison with typical values for linear or branched alkanes (1.53 -1.59 Å). This effect has been explained in terms of hyperconjugation on the tetrahedranyl groups and also of the high s character of the exocyclic CAC bond.…”

Section: Covalently Bonded Polyhedrasupporting

confidence: 89%

“…In fact, the stability of covalently bonded cubanes was experimentally proved through the synthesis and crystallographic characterization of cubylcubane in 1988 . Alternatively, Prinzbach et al were able to dimerize C 20 dodecahedranes by the formation of two CC bonds in the way to a C 40 cage . Our results are also in good agreement with the short exocyclic CC bond distances observed in this type of species (1.42–1.46 Å), for example the synthesized trimethylsilyl‐substituted tetrahedranyltetrahedrane (CC distance 1.436 Å), in comparison with typical values for linear or branched alkanes (1.53 – 1.59 Å).…”

Section: Computational Analysissupporting

confidence: 85%

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Intermolecular interactions in group 14 hydrides: Beyond CH···HC contacts

2017

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In line with previous work in which we established the factors that enhance attractive CH···HC dihydrogen interactions in alkanes, an extended theoretical analysis of noncovalent intermolecular interactions in group 14 hydrides is presented here. Remarkably, these weak interactions may play a major role in determining the crystal structures adopted by several families of molecules. A combined structural and computational analysis at the MP2 level allowed us to identify and characterize different interactions of the type EH···HE and E···HE (E = Si, Ge, Sn, and Pb), and to find also the most suitable scenario for the establishment of each particular type. The nature of the interactions has been analyzed in terms of natural charges of the atoms involved and a topological analysis of the electron density of several dimers confirms the existence of H···H and H···E attractive contacts. We have observed that the interaction strength increases when descending down the periodic group and that silicon has a marked tendency to establish Si···HSi interactions. A size‐dependent backbone effect that reinforces H···H dihydrogen interactions in polyhedral systems has also been found.

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Section: Covalently Bonded Polyhedrasupporting

confidence: 89%

Section: Computational Analysissupporting

confidence: 85%

Intermolecular interactions in group 14 hydrides: Beyond CH···HC contacts

2017

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“…0 .0 4,20 .0 5,18 .0 6,16 .0 8,15 . 0 (C-4,-7,-8,-10,-13,-18 4) .0 6,16 .0 8,15 .0 10,14 .0 12,19 .0 13,17 ]icosa-1,3-/ 1,3(7)-dienes (41/42): A solution of 10 (22 mg, 0.05 mmol) and [D 36 ]P 2 F (80 mg, 0.2 mmol) in C 6 D 6 (5 mL) was stirred at room temperature until complete conversion (ca. 1 min).…”

Section: Bromination Ofmentioning

confidence: 99%

“…Dimerization, [10] extremely rapid in similarly bent cycloalkenes, is efficiently inhibited by the four allylic hydrogen atoms. As Appendix a brief account is given of the radical bromination of 1,6-dibromododecahedrane and of experiments directed at (conjugated) Abstract: As part of a study to achieve selective oligoA C H T U N G T R E N N U N G (poly)bromination-ultimately perbromination-of the dodecahedral C 20 skeleton, the extent and direction of the ionic bromination of dodecahedrene and 1,16-dodecahedradiene were explored.…”

Section: Introductionmentioning

confidence: 99%

Bromination of Unsaturated Dodecahedranes—En Route to C₂₀ Fullerene

Sackers¹,

Osswald²,

Weber³

et al. 2006

Chemistry A European J

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As part of a study to achieve selective oligo(poly)bromination-ultimately perbromination-of the dodecahedral C(20) skeleton, the extent and direction of the ionic bromination of dodecahedrene and 1,16-dodecahedradiene were explored. Along sequences of Br(+) additions/deprotonations and allylic rearrangements, up to ten hydrogen atoms were substituted (traces of C(20)H(x)Br(10)). Tetrabromododecahedrenes obtained under defined conditions in up to 50 % total yield with three and four allylic bromine substituents protecting the extremely bent C==C bonds, proved highly unreactive even towards oxygen but reacted rapidly with CH(2)N(2). Upon electron impact ionization (MS) of the newly secured oligo(poly)bromododecahedra(e)nes, sequential loss of the substituents ended generally in polyunsaturated dodecahedranes (in the extreme C(20)H(4), "tetrahydro-C(20) fullerenes"). Only subsequently did skeletal fragmentations occur. From X-ray crystal-structure analyses, more information was obtained on the structural response of the dodecahedral skeleton to the strain induced by the voluminous substituents. As Appendix, the forcing radical bromination of 1,6-dibromododecahedrane and exploratory cis-beta-HBr/cis-beta-Br(2) eliminations in bromododecahedranes with [Fe(2)(CO)(9)], P(2)F/[FeCp(2)] and [Fe(tmeda)Cp*Cl] (in situ protection) are presented.

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“…Further work produced other less positively curved and less symmetrical allotropes such as C 70 , as well as linearly-extended nanotubes. Additionally, theoretical papers have subsequently described smaller, higher-energy fullerene-like molecules such as C 20 , C 36 , and C 48 [3][4][5][6] (the most symmetrical isomer of which is analogous to Archimedean solid A3, the great rhombicuboctahedron, with 48 vertices and Oh symmetry), though no reasonable strategy for their synthesis has been forthcoming [7][8][9][10][11].…”

Section: Introductionmentioning

confidence: 99%

Polyhedral Phenylacetylenes: The Interplay of Aromaticity and Antiaromaticity in Convex Graphyne Substructures

Sebastiani

Parker

2009

Symmetry

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Abstract:We have studied a series of bridged phenylacetylene macrocycles with topologies based on Platonic and Archimedean polyhedra, using density functional calculations to determine both their molecular structure and their electronic response to external magnetic fields (NICS maps). We are able to elucidate the interplay of aromaticity and anti-aromaticity as a function of structural parameters, in particular the symmetry properties of the intramolecular bond connectivities, in these compounds.

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From unsaturated dodecahedranes to C40 cages?

Cited by 11 publications

References 27 publications

Intermolecular interactions in group 14 hydrides: Beyond CH···HC contacts

Intermolecular interactions in group 14 hydrides: Beyond CH···HC contacts

Bromination of Unsaturated Dodecahedranes—En Route to C₂₀ Fullerene

Polyhedral Phenylacetylenes: The Interplay of Aromaticity and Antiaromaticity in Convex Graphyne Substructures

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From unsaturated dodecahedranes to C40 cages?

Cited by 11 publications

References 27 publications

Intermolecular interactions in group 14 hydrides: Beyond CH···HC contacts

Intermolecular interactions in group 14 hydrides: Beyond CH···HC contacts

Bromination of Unsaturated Dodecahedranes—En Route to C20 Fullerene

Polyhedral Phenylacetylenes: The Interplay of Aromaticity and Antiaromaticity in Convex Graphyne Substructures

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Product

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Bromination of Unsaturated Dodecahedranes—En Route to C₂₀ Fullerene