Thallium-205 nuclear magnetic resonance spectra of thallium(I) alkoxides

Abstract

Thallium-205 n.m.r. spectra have been determined for toluene solutions of a series of 11 thallium(I) alkoxides including five previously unreported compounds. The observed spectra are consistent with the predominance of tetrameric species, [{Tl(OR)}₄](R = alkyl group), in solution. The essentially three-line spectra arise from thallium-203–thallium-205 spin–spin coupling with J(²⁰³Tl–²⁰⁵Tl) in the range 2 170–2 769 Hz. The thallium-205 chemical shifts span 434 p.p.m. and show some dependence on the nature of the alkyl group. There is no apparent correlation of J(²⁰³Tl–²⁰⁵Tl) with the properties of the alkyl groups. The values of J(²⁰³Tl–²⁰⁵Tl) are compared with those found for dimeric dimethylthallium(III) derivatives and are discussed in terms of the Fermicontact contribution to the coupling mechanism.