Perfluoroalkyl(dithiocarbamato) tellurium(ii) compounds

Abstract

[NMe₄][R_fTe(SC(S)NR₂)₂] derivatives are selectively formed by the oxidation of [NMe₄]TeR_f (R_f = CF₃, C₂F₅) with [R₂NC(S)S]₂ (NR₂ = NEt₂, NBz₂, N(CH₂)₄) in almost quantitative yields. An alternative route to obtain the dithiocarbamato complex anions offer reactions of Te[SC(S)NR₂]₂ (NR₂ = NEt₂, NBz₂) with equimolar amounts of Me₃SiR_f and [NMe₄]F. Some of the derivatives were recrystallized with bulky cations in order to determine the crystal structures. Structural elucidation by diffraction methods exhibit the structural feature of a distorted pentagonal planar environment (resembling “butterflies”) around the tellurium centres. The carbamato tellurates can be transferred easily into the neutral derivatives, R_fTeSC(S)NR₂, upon treatment with Ag[BF₄]. In solution they equilibrate with Te₂(R_f)₂ and [R₂NC(S)S]₂ and finally are transformed into Te(R_f)₂, Te[SC(S)NR₂]₂, and Te[SC(S)NR₂]₄, respectively. All compounds are fully characterized by NMR spectroscopic methods (¹H, ¹³C, ¹⁹F, ¹²⁵Te). Additionally, synthesis and characterization of the hitherto unknown derivative [NMe₄]TeC₂F₅ are described.