Spaltung sperriger Diarylditelluride mit Brom und Iod[1]; Strukturbestimmung an Et₄N+ 2,4,6‐(<i>i</i>‐C₃H₇)₃C₆H₂TeI⁻₂

Abstract

Cleavage of Bulky Diaryl Ditellurides with Bromine and Iodine; Crystal Structure of Et 4 N + 2,4,6‐( i ‐C 3 H 7 ) 3 C 6 H 2 TeI − 2 Bis(2,4,6‐triisopropylphenyl) ditelluride ( 1a ), obtained from 2,4,6‐triisopropylphenylmagnesium bromide with tellurium followed by oxidation with oxygen, and bis(2,4,6‐tri‐ tert ‐butylphenyl) ditelluride ( 1b ) react with equimolar amounts of bromine and iodine to provide new monomeric arenetellurenyl halides 2,4,6‐R 3 C 6 H 2 TeX ( 2a, b, 3a, b : R = i ‐C 3 H 7 , t ‐C 4 H 9 ; X = Br, I). Both tellurenyl iodides are thermally more stable than the corresponding bromides. Green 2,4,6‐( i ‐C 3 H 7 ) 3 C 6 H 2 TeI ( 3a ) reacts with Et 4 N + I − to give the stable, red adduct Et 4 N + 2,4,6‐( i ‐C 3 H 7 ) 3 C 6 H 2 TeI − 2 ( 4a ). An X‐ray crystal structure determination of 4a revealed a T‐shaped structure of the hypervalent aryldiiodotellurate(II) anion. Iodide‐ion transfer between aryldiiodotellurate(II) and arenetellurenyl iodide is a fast process ( 1 H‐NMR time scale). 125 Te‐NMR data of this anion and of tellurenyl halides are compared with those of the ditellurides and of lithium benzenetellurolates (LiTeR·(THF) x ).