alpha-Telluration of 2-acetylthiophene: Electronic influence of the heteroaromatic moiety on solid state structures

作者：Chauhan Ashok K S^*; Singh Poornima; Srivastava Ramesh C; Butcher Ray J; Duthie Andrew

来源：Journal of Organometallic Chemistry, 2010, 695(23): 2532-2539.

DOI：10.1016/j.jorganchem.2010.07.025

• Tellurium insertion
• 2-Acetylthiophene
• Sterically hindered organotelluriums
• Dialkyltelluroether
• Intramolecular secondary bonding interactions

Room temperature oxidative addition of alpha-bromo-2-acetylthiophene to elemental tellurium and aryl-tellurium(II) bromide provides direct routes to (2-thiophenoylmethyl)tellurium(IV) dibromides, (2-(C4H3S)COCH2)(2)TeBr2 (1b) and 2-(C4H3S)COCH2ArTeBr2 (Ar = 1-C10H7, Npl, 2b; 2,4,6-Me3C6H2, Mes, 3b). The chloro analogues, 2-(C4H3S)COCH2ArTeCl2 (Ar = Npl, 2a; Mes, 3a) were prepared by the condensation reaction of the parent methyl ketone with NplTeCl(3) or MesTeCl(3). Metathesis of these products with an alkali iodide affords the iodo analogues 1c, 2c and 3c. These diorganotellurium dihalides are reduced with aqueous bisulfite to diorganotellurides 1-3, which can be oxidized readily with dihalogens to the desired diorganotellurium(IV) dihalides. Compound 1 is a rare example of a symmetrical telluroether with C-sp3-Te-C-sp3 grouping that has been characterized by single-crystal diffraction techniques. Preference of the 2-thiophenoylmethyl ligand for small-bite (C, O) chelation over less strained (C, S) coordination is evident in the crystal structures of the Te(IV) compounds 1b, 2a, 2b and 3a. The unexpected transoidal orientation of the two acylmethyl ligands in the solid state molecular configuration of symmetrical diorganotellurium(IV) dibromide 1b appears to be a combined effect of electronic repulsion due to the thiophene moieties and steric repulsion of bromo ligands.

• 出版日期2010-11-1
• 单位迪肯大学