Four Distinctively Different Decomposition Pathways of Metastable Supermesityltellurium(IV) Trichloride

Abstract

Chlorination of bis(supermesityl)ditelluride RTeTeR (R = 2,4,6-t-Bu3C6H2) with 3 equiv of sulfuryl chloride SO2Cl2 provided the intrinsically unstable supermesityltellurium(IV) trichloride RTeCl3 (1) as bright yellow crystals. Severe repulsion between the equatorial Cl atom and one tert-butyl group in an ortho position in the supermesityl ligand is the reason for the extreme reactivity of 1, which is in contrast to that of all previously known monoorganotellurium trihalides. In the solid state at room temperature, (the triclinic modification of) 1 reacts slowly under HCl elimination and intramolecular Te-C bond formation to give the bicyclic 5,7-di-tert-butyl-2-hydro-3,3-dimethylbenzo[b]tellurophene-1,1-dichloride (2), which was originally obtained as a colorless amorphous solid. On one occasion, when the solid-state reaction was allowed to occur under air conditions, compound 2 and a colorless crystalline byproduct, namely, trans-supermesityltellurium hydroxide dichloride (3), had formed, from which a few crystals were hand-selected. The formation of 3 has been tentatively rationalized by a solid-state hydrolysis of a second (monoclinic?) modification present in the bulk material of 1. In diethyl ether, THF, or carbon disulfide, a redox equilibrium exists between yellow supermesityltellurium(IV) trichloride RTeCl3 (1), deep blue supermesityltellurenyl(II) chloride RTeCl (4), and chlorine gas, which can be shifted to 4 when the reaction vessel is purged with argon to remove the chlorine gas. Compound 4 was also obtained by the reaction of RTeTeR (R = 2,4,6-t-Bu3C6H2) with 1 equiv of SO2Cl2. When a solution of 1 was stored with an excess of SO2Cl2 for a prolonged amount of time, Te-C bond cleavage occurred and [(Et2OH)2Te2Cl10].2Et2O (5) was formed. Compounds 1-5 have been characterized by X-ray crystallography.

Synthesis of Ferrocenyl-Substituted Organochalcogenyldichlorogermanes

“…While 2b exhibits head-to-tail-type interactions, 2a shows head-to-head-type interactions, albeit that the intramolecular interactions should be negligible due to the long intramolecular Ch···Ch, Ch···Cl, and Cl···Cl distances. In addition, the 77 Se (907 ppm) and 125 Te NMR chemical shifts (1756 ppm) are consistent with those of previously reported monomeric chalcogenenylhalides [8][9][10]. group.…”

“…The molecular structures of TrpSeCl (2a) and TrpTeCl (2b) were unambiguously determined by X-ray diffraction (XRD) analyses, which delivered C-Ch-Cl angles of 99.93(6) • (Ch = Se) and 96.38 (9) • (Ch = Te), as well as Ch-Cl bond lengths of 2.1860(7) Å (Ch = Se) and 2.348(1) Å (Ch = Te). These structural parameters are similar to those of previously reported stable selenenyl-and tellurenyl-chlorides [8][9][10], indicating negligible electronic perturbations from the Trp group toward the Ch-Cl moieties. The packing structures of 2a and 2b suggest that these compounds are monomeric in the crystalline state ( Figure 1).…”

“…To isolate stable chalcogenenyl halides, it is necessary to introduce sterically demanding substituents on the Ch atom [8][9][10]. We have decided to use the 9-triptycyl (Trp) group as a steric protection group, as the simple synthesis of the corresponding dichalcogenides (1a,b) has already been reported [11][12][13].…”

Intramolecularly Coordinated Telluroxane Clusters and Polymers

“…The average Te À Cl bond length of 1 (2.536(2) ) is significantly longer than that of the kinetically stabilised aryltellurenyl chloride, 2,4,6-tBu 3 C 6 H 2 TeCl (2.334(1) ), [11] which points to a considera- Te NMR spectroscopic chemical shifts of the sterically encumbered aryltellurenyl chloride 2,4,6-tBu 3 C 6 H 2 TeCl (d = 1791.0 ppm) and the aryltellurium trichloride 2,4,6-tBu 3 C 6 H 2 TeCl 3 (d = 1179.0 ppm) were observed significantly more highfield. [11] While the solution and solid-state 125 Te NMR spectroscopic chemical shifts of 2 are reasonably similar, the large discrepancy of 1 is highly unusual. In the absence of another explanation, we tentatively attribute this large chemical-shift discrepancy to the absence and presence of the Te···Te secondary interactions in solution and in the solid state, respectively.…”

Aryltellurenyl Cation [RTe(CR′2)]+ Stabilized by an N‐Heterocyclic Carbene

“…For instance, the diaryl ditelluride RTeTeR (e.g., R = 2,4,6-tBu 3 C 6 H 2 [1] ) and the series of aryltellurenyl halides RTeX (X = I, [2,3] Br, [2,4] Cl [5] ) closely resemble molecular iodine I 2 or the related interhalides IBr and ICl, while RTeCl 3 [5] can be regarded as being an analogue of ICl 3 . The tritelluride anions (RTe) 3 -(e.g., R = Ph, [6] CF 3 [7] ) and the related diiodotelluride anion (RTeI 2 ) -(e.g., R = CF 3 [7] ) exhibit characteristics very similar to the triiodide ion I 3 -.…”