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Diamantane

Diamantane
Skeletal formula of diamantane
Ball-and-stick model of the diamantane molecule
Names
IUPAC name
Pentacyclo[7.3.1.14,12.02,7.06,11]tetradecane
Other names
Congressane, diadamantane, decahydro-3,5,1,7-[1,2,3,4]butanetetraylnaphthalene
Identifiers
3D model (JSmol)
1904934
ChemSpider
PubChem CID
Properties
C14H20
Molar mass 188.31 g·mol−1
Appearance solid white crystal
Density 1.092 ± 0.06 g cm−3
Melting point 244.73 °C (472.51 °F; 517.88 K)
Boiling point 269.5 ± 7.0 °C
sparingly soluble (8.1 x 10−4 g L−1)
Solubility in diethyl ether soluble
log P 5.556 ± 0.228
Vapor pressure 0.0120 Torr
Hazards
Main hazards irritant, acute toxcicity to aquatic life
Safety data sheet External MSDS
NFPA 704
Flammability code 0: Will not burn. E.g., water Health code 0: Exposure under fire conditions would offer no hazard beyond that of ordinary combustible material. E.g., sodium chloride Reactivity code 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g., liquid nitrogen Special hazards (white): no codeNFPA 704 four-colored diamond
Flash point 98.1 °C (208.6 °F; 371.2 K)
Structure
D3d
0 D
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Diamantane (also called congressane) is an organic compound that is a member of the diamondoids. These are a cage hydrocarbons with structures similar to a subunit of the diamond lattice. It is a colorless solid that has been a topic of research since its discovery in oil and separation from deep natural gas condensates. Diamondoids such as diamantane exhibit unusual properties, including low surface energies, high densities, high hydrophobicities, and resistance to oxidation.

Diamantane occurs naturally in crude petroleum. It is currently assumed that adamantanes and diamantanes were formed via the catalytic rearrangements of polycyclic naphthenic hydrocarbons. Although present in only trace concentrations in typical oils, due to their great thermodynamic stability, diamondoids such as diamantane are naturally concentrated by catagenesis, becoming important constituents of some natural gas condensates including those from the Norphlet Formation, U.S. Gulf of Mexico, and the Western Canada Basin.

Diamantane was chosen as the Congress Emblem of the 1963 London IUPAC meeting, and was featured as a decoration on the cover of abstracts, program, and publicity material. Congress participants were challenged to synthesize diamantane. The first preparation of this chemical was achieved in 1965 in 1% yield by aluminum halide-catalyzed isomerization of a mixture of norbornene photodimers. Adamantane was the first, and "Congressane", as diamantane came to be known, was only the second member of an entire family of compounds known as the diamandoids. The synthesis of the third member of the series in 1969 emphasized the need for a more general scheme of semitrivial nomenclature. The compound was renamed “diamantane” and the third member designated triamantane.

The year 1966 also marked the isolation of diamantane from the high-boiling fractions of the crude oil of Hodonin (from which adamantane was discovered) and the achievement of a significant improvement in its yield (to 10%). While this permitted a start to be made in the exploration of the chemistry of diamantane, the hydrocarbon was still difficult to obtain in quantity. Diamantane then became as readily available as adamantane and its chemistry could be studied more easily.

Diamantane can be prepared by Lewis acid catalyzed rearrangements of various pentacyclic tetradecanes. The best yield (84%) can obtained from trans-tetrahydro-Binor-S. A convenient synthetic procedure involves rearrangement of a hydrogenated Binor-S compound, which gives diamantane in ~70% yield. Other more highly strained precursors give diamantane in lower yield (1-47%) owing to disproportionation.

The convenient, synthetic route begins with the dimerization of norbornadiene (1) catalyzed by a mixture of cobalt bromide-triphenylphosphine and boron trifluoride etherate. The resulting dimer (2) is hydrogenated to give tetrahydro-binor-S-isomers (3a–3d). As a result of sterical interaction, mainly 3a and 3b are given. The next step is a rearrangement, which occurs in a hot solution of cyclohexane or carbon disulfide with aluminum bromide and forms the main product diamantane (4).


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