Perfluoroalkyl(dithiocarbamato) tellurium(ii) compounds

Abstract

[NMe(4)][R(f)Te(SC(S)NR(2))(2)] derivatives are selectively formed by the oxidation of [NMe(4)]TeR(f) (R(f) = CF(3), C(2)F(5)) with [R(2)NC(S)S](2) (NR(2) = NEt(2), NBz(2), N(CH(2))(4)) in almost quantitative yields. An alternative route to obtain the dithiocarbamato complex anions offer reactions of Te[SC(S)NR(2)](2) (NR(2) = NEt(2), NBz(2)) with equimolar amounts of Me(3)SiR(f) and [NMe(4)]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(f)TeSC(S)NR(2), upon treatment with Ag[BF(4)]. In solution they equilibrate with Te(2)(R(f))(2) and [R(2)NC(S)S](2) and finally are transformed into Te(R(f))(2), Te[SC(S)NR(2)](2), and Te[SC(S)NR(2)](4), respectively. All compounds are fully characterized by NMR spectroscopic methods ((1)H, (13)C, (19)F, (125)Te). Additionally, synthesis and characterization of the hitherto unknown derivative [NMe(4)]TeC(2)F(5) are described.

Synthesis and Characterization of Methyl(perfluoroalkyl)Tellurium(II) Compounds, MeTeRf (Rf = CF3, C2F5), the Corresponding Tellurium(IV) Dihalides, MeTe(Rf)X2 (X = F, Cl, Br, I), and Bis(trifluoroacetates), MeTe(Rf)(OCOCF3)2

“…General: The following derivatives were prepared according to literature procedures: [NMe 4 ]TeCF 3 ,5 [NMe 4 ]TeC 2 F 5 ,26 and XeF 2 27. The synthetic procedure and characterization for 4‐MeC 6 H 4 I(OCOCF 3 ) 2 is outlined below.…”

“…Due to the sensitivity of NMR parameters to concentration for tellurium compounds, all NMR experiments were performed with saturated solutions. Sign determination was performed in a similar manner as described in reference 26…”

Heterovalent chalcogen bonding: supramolecular assembly driven by the occurrence of a tellurium(ii)⋯Ch(i) (Ch = S, Se, Te) linkage

“…To distinguish the heterovalent Ch II ⋯Ch I , Ch II ⋯Ch IV and other relevant cases from various homovalent Ch⋯Ch short contacts, we limited our CSD search to intermolecular contacts between the chalcogenides(II) and di-, tri-chalcogenides or with chalcogen species, where the central Ch atom forms 3 or more single bonds with other nonmetal atoms such as O, N, P, Si, Ge, Sb, F, Cl, Br, and I. The abundant and well-documented class of tellurium(IV) dithiocarbamates and related thiocarbonyl species known for their Te-S intermolecular interactions 71,72 were excluded. The structures with R > 0.100, disordered structures, and polymeric species were also excluded, as in ref.…”

Synthetic Approaches to Fluoroalkyltelluryl‐Substituted Compounds

“…The addition of Ag[BF 4 ] onto these complexes led to the formation of corresponding {[(trifluoromethyl)tellanyl]sulfanyl} carbothioamide (Scheme 47a). [ 55 ] However these compounds couldn't be isolated due to their decomposition in solution.…”