Synthesis and crystal structures of the monomeric organotellurium(IV) trihalides: trans-2-ethoxy-cyclohexyl-tellurium(IV) trichloride, trichloro(2-chlorobicyclo[2.2.1]hept-7-yl)-λ4-tellurane, and mesityltellurium(IV) tribromide

The crystal and molecular structures of trans-2-ethoxy-cyclohexyltellurium(IV) trichloride (1), trichloro(2-chlorobicyclo[2.2.1]hept-7-yl)-λ4-tellurane (2) and mesityltellurium(IV) tribromide (3) have been determined. The structures of 1 and 2 show intramolecular bonding between additional donors resident on the organogroups and the tellurium(IV) centre leading to pseudo-octahedral geometries. The structure of 3 shows no evidence of intra- or inter-molecular bonding, and has clearly a five-coordinate geometry about the tellurium centre, indicating the presence of a stereochemically active lone pair in a trigonal bipyramidal arrangement of electron pairs.