Synthesis and properties of the ditelluroethers m- and p-C6H4(CH2TeMe)2 and their Te(IV) derivatives: crystal structures of PhTeI2(CH2)3TeI2Ph, m-C6H4(CH2TeI2Me)2 and p-C6H4(CH2TeI2Me)2

The new ditelluroethers m-C6H4(CH2TeMe)2 and p-C6H4(CH2TeMe)2 have been prepared in good yield from nucleophilic reaction of m- or p-C6H4(CH2Br)2 and LiTeMe in THF solution. Reaction of the new ditelluroethers with MeI or I2 affords the light yellow m- or p-C6H4(CH2TeMe2I)2 or the red/orange m- or p-C6H4(CH2TeI2Me)2, respectively in high yield. These compounds have been characterised by IR, 1H, 13C{1H} and 125Te{1H} NMR spectroscopy and EI mass spectrometry as appropriate. The crystal structures of the di-iodo derivatives m-C6H4(CH2TeI2Me)2, p-C6H4(CH2TeI2Me)2 and the related PhI2Te(CH2)3TeI2Ph (prepared from PhTe(CH2)3TePh and diiodine in THF solution) are described. In each compound the TeI2 units are axial and significant intermolecular Te⋯I secondary contacts (≈3.6–4.1 Å) are evident, which link these covalent compounds into extended networks with each Te atom in a distorted 6-coordinate environment.