Organomercury compounds. Part I. Mercury pentafluorobenzoates and their decarboxylation to pentafluorophenylmercury compounds

The preparations of some mercury derivatives of pentafluorobenzoic acid and their decarboxylation to give pentafluorophenylmercury compounds are described. Mercuric pentafluorobenzoate and C ₆F ₅CO ₂HgR (R = Ph, p-MeC ₆H ₄, or p-MeOC ₆H ₄) have been prepared by reaction of pentafluorobenzoic acid with mercuric acetate and RHgOAc, respectively, and methylmercuric pentafluorobenzoate has been made from methylmercuric iodide and silver pentafluorobenzoate. The complexes (C ₆F ₅CO ₂) ₂HgL (L = 2,2′-bipyridyl, 1,10-phenanthroline, or 1,2-bisdiphenylphosphinoethane) were obtained from reactions of these ligands with mercuric pentafluorobenzoate. The pentafluorobenzoates are monomeric and have low conductances in acetone. Conductances of representative compounds in methanol and pyridine have also been measured. Infrared data suggest that the compounds may contain unidentate pentafluorobenzoate groups. Mercuric pentafluorobenzoate and 2,2′-bipyridylmercuric pentafluorobenzoate decarboxylate at their melting points and the other pentafluorobenzoates decarboxylate on heating in dry pyridine to give the corresponding pentafluorophenylmercury compounds. In acetone and benzene, the complexes (C ₆F ₅) ₂HgL dissociate into L and and bispentafluorophenylmercury.