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Sodium naphthalenide, also known as sodium naphthalide, is an organic salt with the chemical formula Na+C10H8. In the research laboratory, it is used as a reductant in the synthesis of organic, organometallic, and inorganic chemistry. It has not been isolated as a solid, but it is usually prepared fresh before use.[1]

Sodium naphthalenide
Sodium naphthalenide.svg
Names
Preferred IUPAC name
Sodium naphthalenide
Systematic IUPAC name
Sodium naphthalen-1-ide
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.020.420
EC Number 222-460-3
Properties
C10H8Na
Molar mass 151.164 g·mol−1
Related compounds
Other anions
Sodium cyclopentadienide
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

Preparation and propertiesEdit

The alkali metal naphthalenides are prepared by stirring the metal with naphthalene in an ethereal solvent, usually as tetrahydrofuran or dimethoxyethane. The resulting salt is dark green.[2][3][4] The anion is a radical, giving a strong EPR signal near g = 2.0, with a reduction potential near -2.5 V vs NHE. Its deep green color arises from absorptions centered at 463, 735 nm.[1]

The anion is strongly basic, and a typical degradation pathway involves reaction with water and related protic sources. These reactions afford dihydronaphthalene:

2 NaC10H8 + 2 H2O → C10H10 + C10H8 + 2 NaOH

Related reagentsEdit

For some synthetic operations, sodium naphthalenide is excessively reducing (too negative) or too insoluble. In such cases, alternative reductants are selected.

  • Sodium acenaphthalenide is milder by about 0.75 V, reflecting the milder reduction potential of polycyclic aromatic compounds.
  • Lithium biphenyl is a THF-soluble species related to lithium naphthalenide except that it is a poorer ligand.[5]
  • Sodium 1-methylnaphthalenide is more soluble than sodium naphthalenide, which is useful for low-temperature reductions.[6]
 
A solution of lithium naphthalenide, a related compound, in tetrahydrofuran

ReferencesEdit

  1. ^ a b N. G. Connelly and W. E. Geiger, "Chemical Redox Agents for Organometallic Chemistry", Chem. Rev. 1996, 96, 877-910. doi:10.1021/cr940053x
  2. ^ Corey, E. J.; Gross, Andrew W. (1993). "tert-Butyl-tert-octylamine". Organic Syntheses.; Collective Volume, 8, p. 93
  3. ^ Cotton, F. Albert; Wilkinson, Geoffrey (1988), Advanced Inorganic Chemistry (5th ed.), New York: Wiley-Interscience, p. 139, ISBN 0-471-84997-9
  4. ^ Greenwood, Norman N.; Earnshaw, Alan (1984). Chemistry of the Elements. Oxford: Pergamon Press. p. 111. ISBN 978-0-08-022057-4.
  5. ^ Rieke, Reuben D.; Wu, Tse-Chong & Rieke, Loretta I. (1995). "Highly Reactive Calcium for the Preparation of Organocalcium Reagents: 1-Adamantyl Calcium Halides and Their Addition to Ketones: 1-(1-Adamantyl)cyclohexanol". Org. Synth. 72: 147. doi:10.15227/orgsyn.072.0147.
  6. ^ Liu, X.; Ellis, J. E. (2004). "Hexacarbonylvanadate(1−) and Hexacarbonylvanadium(0)". Inorg. Synth. 34: 96–103. doi:10.1002/0471653683.ch3. ISBN 0-471-64750-0.