Triphenylmethyl radical

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Triphenylmethyl radical
Kekulé, skeletal formula of the triphenylmethyl radical
Ball-and-stick model of the triphenylmethyl radical
Names
Preferred IUPAC name
Triphenylmethyl
Identifiers
3D model (
JSmol
)
ChemSpider
  • InChI=1S/C19H15/c1-4-10-16(11-5-1)19(17-12-6-2-7-13-17)18-14-8-3-9-15-18/h1-15H checkY
    Key: OHSJPLSEQNCRLW-UHFFFAOYSA-N checkY
  • c1ccc(cc1)[C](c1ccccc1)c1ccccc1
  • C1=CC=C(C=C1)[C](C1=CC=CC=C1)C1=CC=CC=C1
Properties
C19H15
Molar mass 243.329 g·mol−1
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
checkY verify (what is checkY☒N ?)

The triphenylmethyl radical (often shorted to trityl radical) is an

persistent radical. It was the first radical ever to be described in organic chemistry. Because of its accessibility, the trityl radical has been heavily exploited.[1]

Preparation and properties

It can be prepared by

dimer 3 (Gomberg's dimer). In benzene the concentration of the radical is 2%.[2]

Triphenylmethyl radical
Triphenylmethyl radical

Solutions containing the radical are yellow; when the temperature of the solution is raised, the yellow color becomes more intense as the equilibrium is shifted in favor of the radical (in accordance with Le Chatelier's principle).

When exposed to air, the radical rapidly oxidizes to the peroxide, and the color of the solution changes from yellow to colorless. Likewise, the radical reacts with iodine to triphenylmethyl iodide.

tert-butyl groups create a potential minimum that is absent in the unsubstituted molecule.[3][4] Other derivatives have been reported as the quinoid dimer [5]

History

The radical was discovered by Moses Gomberg in 1900 at the University of Michigan.[6][7][8] He tried to prepare hexaphenylethane from triphenylmethyl chloride and zinc in benzene in a Wurtz reaction and found that the product, based on its behaviour towards iodine and oxygen, was far more reactive than anticipated. The discovered structure was used in the development of ESR spectroscopy and confirmed by it.[9][10][11]

The correct

proton NMR data.[13]

See also

References

  1. ISBN 9780470666975
    .
  2. ISBN 978-0-471-72091-1
  3. Bibcode:2008moma.book.....L
  4. PMID 22025456
    .
  5. PMID 25704856
    .
  6. doi:10.1021/ja02049a006
    .
  7. doi:10.1021/ja02033a015
    . (Note: radical is also called a cadicle.)
  8. doi:10.1021/ja02021a001
    .
  9. doi:10.1021/ja01098a522
    .
  10. doi:10.1021/ja01021a004
    .
  11. ^ "ESR spectrum of the triphenylmethyl radical". School of Chemistry, University of Bristol. Retrieved August 5, 2018.
  12. doi:10.1016/S0040-4020(01)97332-6
    .
  13. doi:10.1016/S0040-4039(00)75598-5
    .

External links
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