Uranocene
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Names | |||
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IUPAC name
Bis(η8-cyclooctatetraenyl)uranium(IV)
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Other names
Uranium cyclooctatetraenide
U(COT)2 | |||
Identifiers | |||
3D model (
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PubChem CID
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CompTox Dashboard (EPA)
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Properties | |||
C16H16U | |||
Molar mass | 446.33 g/mol | ||
Appearance | green crystals[1] | ||
Hazards | |||
Occupational safety and health (OHS/OSH): | |||
Main hazards
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pyrophoric, radioactive, and toxic | ||
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Uranocene, U(C8H8)2, is an
Synthesis, structure and bonding
Uranocene was first described in 1968 by the group of Andrew Streitwieser, when it was prepared by the reaction of dipotassium cyclooctatetraenide and uranium tetrachloride in THF at 0°C:[1]
Uranocene is highly reactive toward oxygen, being pyrophoric in air but stable to hydrolysis. The x-ray crystal structure of uranocene was first elucidated by the group of Ken Raymond.[3] Considering the molecule to be U4+(C8H82−)2, the η8-cyclooctatetraenide groups are planar, as expected for a ring containing 10 π-electrons, and are mutually parallel, forming a sandwich containing the uranium atom. In the solid state, the rings are eclipsed, conferring D8h symmetry on the molecule. In solution the rings rotate with a low activation energy.
The uranium-cyclooctatetraenyl
Spectroscopic properties
Uranocene is
The green color of uranocene is due to three strong transitions in its
Analogous compounds
Analogous compounds of the form M(C8H8)2 exist for M = (Nd, Tb, Yb, Th, Pa, Np, and Pu). Extensions include the air-stable derivative U(C8H4Ph4)2 and the cycloheptatrienyl species [U(C7H7)2]−.[2] In contrast, bis(cyclooctatetraene)iron has a very different structure, with one each of a η6- and η4-C8H8 ligands.
References
- ^ .
- ^ .
- ISSN 0002-7863.
- .
- .
- ^ .
- .
- ISBN 90-277-0990-4.
- .
- doi:10.1063/1.474698.
- ^ Herzberg, G. (1966). Molecular Spectra and Molecular Structure III. Electronic Spectra and Electronic Structure of Polyatomic Molecules. Princeton, New Jersey: D. Van Nostrand. p. 566.
- ^ .
- PMID 15268415.
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Further reading
- The f elements, Nikolas Kaltsoyannis and Peter Scott. ISBN 0-19-850467-5
- Chemistry of the Elements, N. N. Greenwood and A. Earnshaw. ISBN 0-08-022057-6
- Lanthanides & Actinides: Organoactinides