Paramagnetische organothalliumverbindungen in lösung: I. Esr-untersuchungen von diphenyl-thallium(III)-tonenpaaren mit brenzcatefechinen,pyrogallolen und 1,2-diketonen

Diphenylthallium hydroxide reacts very smoothly in organic solvents with catechols, pyrogallols and 1,2-diketones to stable paramagnetic diphenylthalliumsemiquinone and diphenylthalliumsemidione complexes respectively. This reaction has been investigated with 43 different ligands in numerous solvents. Therefore its general application is proofed.The ESR-spectra of these solutions show the hydrogen hyperfine structure of the ligands and an unusual large coupling which we assign to magnetic interaction of the free electron with the ²⁰³Tl and ²⁰⁵Tl nuclei. The thallium splittings observed depend remarkably on the ligands used. We refer this to different solvation phenomena.Semiquinones of the pyrogallol type show on principle two different radical types. Small concentrations of diphenylthallium hydroxide produce $\text{1}\text{1}$ complexes. These can be converted into $\text{1}\text{2}$ complexes by addition of further amounts of diphenyl thallium hydroxide.The ESR-spectra of the semiquinone-and the semidione-thallium complexes exhibit an unusually strong solvent dependence of the thallium coupling and of the g-factor. It is possible to explain both variations uniformly by the different donor ability of the solvents used.All complexes investigated indicate remarkable temperature dependence of the thallium splitting and the g-factor. The thallium couplings show a positive temperature gradient whereas the g-factor decrease with increasing temperature as expected.Based on the sum of the observed effects, we assume that the radicals observed by us are ion pairs in which a diphenylthallium cation interacts with the semiquinone- or semidione-anion, respectively.