Phenyl(trichloromethyl)mercury explained

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, illustrated with tetrachloroethylene as a substrate, the product being hexachlorocyclopropane:^[1]

C₆H₅HgCCl₃ → C₆H₅HgCl + CCl₂

CCl₂ + Cl₂C=CCl₂ → C₃Cl₆

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

NaO₂CCCl₃ + C₆H₅HgCl → C₆H₅HgCCl₃ + NaCl + CO₂

Related compounds

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