The reaction of [phenylthallium(III)(18-crown-6)] diperchlorate, [PhTl(III)(18-crown-6)](ClO4)2 (1a), with phenol gives [phenyl(4'-hydroxyphenyl)thallium(III)(18-crown-6)] perchlorate (2), the phenolic OH having remained intact. The complex 1a reacts also with alkylphenols, methoxyphenols, catechol, resorcinol, and pyrogallol to give thallated products exclusively at the para position of the electron-donating group (OH or OCH3) without suffering from reduction of thallium(III). No reaction takes place with benzene, toluene, and tert-butylbenzene.
Monophenylthallium(III) complexes with a Tl–I or Tl–SR bond were prepared in the presence of dibenzo-18-crown-6. These complexes are stable in the air and to heat to their melting points. In the hydrogen sulfide complex, ν(S–H) band was found at 2570 cm−1 and δ(Tl–SH) was observed at 1.15 ppm with 2J(Tl-SH) = 405 Hz in CH2Cl2 solution.