Cubane
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Names | |||
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Preferred IUPAC name
Cubane[1] | |||
Systematic IUPAC name
Pentacyclo[4.2.0.02,5.03,8.04,7]octane | |||
Identifiers | |||
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Properties | |||
C8H8 | |||
Molar mass | 104.15 g/mol | ||
Appearance | Transparent[2] crystalline solid | ||
Density | 1.29 g/cm3 | ||
Melting point | 133.5 °C (272.3 °F; 406.6 K)[3] | ||
Boiling point | 161.6 °C (322.9 °F; 434.8 K)[3] | ||
Related compounds | |||
Related hydrocarbons
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Prismane C8
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Related compounds
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Octafluorocubane Octanitrocubane Octaazacubane | ||
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Cubane is a synthetic
Having high potential energy and kinetic stability makes cubane and its derivative compounds useful for controlled energy storage. For example, octanitrocubane and heptanitrocubane have been studied as high-performance explosives. These compounds also typically have a very high density for hydrocarbon molecules. The resulting high energy density means a large amount of energy can be stored in a comparably smaller amount of space, an important consideration for applications in fuel storage and energy transport. Furthermore, their geometry and stability make them suitable isosteres for benzene rings.[7]
Synthesis
The classic 1964 synthesis starts with the conversion of
The construction of the eight-carbon cubane framework begins when 2-bromocyclopentadienone undergoes a spontaneous
In the next step, the endo isomer 3 (with both
A more approachable laboratory synthesis of disubstituted cubane involves bromination of the ethylene ketal of cyclopentanone to give a tribromocyclopentanone derivative. Subsequent steps involve dehydrobromination, Diels-Alder dimerization, etc.[9][10]
The resulting cubane-1,4-dicarboxylic acid is used to synthesize other substituted cubanes. Cubane itself can be obtained nearly quantitatively by photochemical decarboxylation of the thiohydroxamate ester (the Barton decarboxylation).[11]
Derivatives
The synthesis of the octaphenyl
In 2022, both
8F−
8, with a free electron trapped inside the cube, in effect making it the world's smallest box.[21]
Cubylcubanes and oligocubanes
Cubene (1,2-dehydrocubane) and 1,4-cubanediyl(1,4-dehydrocubane) are enormously strained compounds which both undergo
Reactions
With a rhodium catalyst, it first forms syn-tricyclooctadiene, which can thermally decompose to cyclooctatetraene at 50–60 °C.[27]
See also
References
- ISBN 978-0-85404-182-4.
The retained names adamantane and cubane are used in general nomenclature and as preferred IUPAC names.
- ^ "Start".
- ^ PMID 26102302.
- ^ .
- ^ Teachers, University of New South Wales Summer School for Chemistry (1963). Approach to Chemistry: Lectures and Workshop Reports of the ... Summer School for Chemistry Teachers. The University. p. 98. "This compound was described only a few months ago and, curiously enough, it is quite easy to make, although only a year ago I would have predicted that it would be difficult, or even impossible, to synthesize."
- ISBN 978-0-03-032011-8. "This sharp bond angle creates severe bond strain in cubane, a compound thought previously impossible to synthesize because of the required 90° bond angles."
- PMC 10680098.
- .
- doi:10.1071/C97021.
- ^ Fluorochem, Inc (July 1989). "Cubane Derivatives for Propellant Applications" (PDF). Archived (PDF) from the original on 2021-07-09.
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- ^ "Hypercubane: DFT-based prediction of an Oh-symmetric double-shell hydrocarbon".
- .
- ISBN 9783527627141.
- S2CID 251515925.
- S2CID 251517529.
- ISSN 0002-7863.
- ISSN 1521-3773.
- S2CID 210870993.
- ISBN 0-471-58589-0.
- .
- ISSN 0002-7863.