Preparation and X-ray Structure Analysis of 1,1,5,5,9,9-Hexachloro-1,5,9-tritelluracyclododecane (Cl6([12]aneTe3)) and Its Redox Behavior

The first synthesis and structure determination of 1,1,5,5,9,9-hexachlorotritelluracyclododecane ( 1 ), a monocyclic multitellurium moiety which is composed of three hypervalent tellurium(IV) atoms, along with redox studies were presented. The pyrolysis of ditellurane ( 2 ) in dimethylformamide at 160 °C afforded the ring-expansion products 1, Cl 6 ([12]aneTe 3 ), in 44% yield. The structure of 1 was determined by X-ray diffraction analysis. Each tellurium atom is involved in four bonding contacts, and with the lone pair of electrons the central atoms exhibit a trigonal bipyramidal geometry (TBP). The more electronegative chloride atoms are located in the apical positions, while the lone pair and the two alkyl carbons are in the equatorial position. Compound 1 (1 equiv) reacted with thiophenol (6 equiv) in the presence of triethylamine in dimethyl sulfoxide (DMSO) under an Ar atmosphere at 50 °C for 10 min to give neutral 1,5,9-tritelluradodecane ( 3 ), [12]aneTe 3, in 90% yield. Compound 3 reacted with Cl 2 in CH 2 Cl 2 at room temperature to afford the tris(tellurane) 1 in quantitative yield. The results described herein show a new type of chlorine adduct of a telluromacrocycle, as organotellurium compounds consisting of three hypervalent telluriums are hitherto unknown.