Synthesis and molecular structures of dimeric assemblies of telluronium salts derived from o-C6H4(CH2TeMe)2 and PhMeTe

The ditelluroether, o-C6H4(CH2TeMe)2 reacts with excess MeI in acetone to afford the bis(triorganotelluronium iodide), o-C6H4(CH2TeMe2I)2, in high yield which has been characterised by 1H-, 13C{1H}- and 125Te{1H}-NMR spectroscopy, microanalysis and X-ray crystallography. The crystal structure of this species reveals a weakly associated dimer, assembled through a series of secondary Te⋯I interactions to give a pseudo-cubane Te4I4 core, involving three-coordinate (pyramidal) iodine and six-coordinate (distorted octahedral) tellurium. The o-xylyl backbone units are oriented across the diagonal of two opposite faces of the cubane. This is the first crystallographic study of a triorganotelluronium halide salt derived from a ditelluroether. The crystal structure of PhTeMe2I shows a weakly associated μ2-diiodo bridged dimer, in this case with two-coordinate iodine and five-coordinate, distorted square pyramidal tellurium. The stereochemical activity of the Te-based lone pair is discussed for each system and the structures are compared with other related species.