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Phenyl(trichloromethyl)mercury

Phenyl(trichloromethyl)mercury is an organomercury compound with the formula C6H5HgCCl3. It is a white solid that is soluble in organic solvents. The compound is used as a source of dichlorocarbene, e.g. in cyclopropanation reactions, because the products are particularly easy to extract from the reaction mixture. Strong nucleophiles may catalyze the reaction by displacing CCl−
3 from mercury, although the free ion is not believed to form in the process. Unusually, the pure organomercury compound reacts with electron-poor alkenes, converting tetrachloroethylene to hexachlorocyclopropane:[1]

C6H5HgCCl3 → C6H5HgCl + CCl2
CCl2 + Cl2C=CCl2 → C3Cl6

The compound is prepared by treating phenylmercuric chloride [fi] with sources of dichlorocarbene. These include the base/haloform reaction and thermolysis of sodium trichloroacetate:[2][3]

NaO2CCCl3 + C6H5HgCl → C6H5HgCCl3 + NaCl + CO2

Closely related compounds include phenyl(bromodichloromethyl)mercury (CAS registry number 3294-58-4) and phenyl(tribromomethyl)mercury (CAS registry number 3294-60-8).[4] According to X-ray crystallography, the former has nearly linear coordination geometry at mercury, with a C-Hg-C angle of 179° and Hg-C distances of 2.047 Å.[5]

Also known is bis(trichloromethyl)mercury, Hg(CCl3)2.

References

  1. ^ José Barluenga; Miguel Tomás; José M. González (2001). "Phenyl(trichloromethyl)mercury". Encyclopedia of Reagents for Organic Synthesis. e-EROS Encyclopedia of Reagents for Organic Synthesis. doi:10.1002/047084289X.rp141. ISBN 0-471-93623-5.
  2. ^ Ted J. Logan (1966). "Phenyl(trichloromethyl)mercury". Organic Syntheses. 46: 969. doi:10.15227/orgsyn.046.0098.
  3. ^ Seyferth, D.; Lambert, R. L. (1969). "Halomethyl-metal compounds XX. An improved synthesis of phenyl(trihalomethyl)mercury compounds". Journal of Organometallic Chemistry. 16: 21–26. doi:10.1016/S0022-328X(00)81631-9.
  4. ^ Shipman, Michael (2001). "Phenyl(tribromomethyl)mercury". Encyclopedia of Reagents for Organic Synthesis. doi:10.1002/047084289X.rp140. ISBN 0-471-93623-5.
  5. ^ R. E. Bachman; B. R. Maughon; D. J. McCord; K. H. Whitmire; W. E. Billups (1995). "Bromodichloromethyl)phenylmercury". Acta Crystallogr. C. 51 (10): 2033–2035. doi:10.1107/S0108270195004501.