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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

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journal contribution
posted on 26.11.1996, 00:00 by Yutaka Takaguchi, Ernst Horn, Naomichi Furukawa
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, Cl6([12]aneTe3), 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]aneTe3, in 90% yield. Compound 3 reacted with Cl2 in CH2Cl2 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.