New routes developed recently to overcome the difficulties usually associated with the sequential introduction of Te centers into polytelluroethers and the introduction of tellurium into macrocyclic compounds are described, including the synthesis of the first facultative telluro-ethers, RTe(CH 2 ) 3 Te(CH 2 ) 3 TeR, R = Me or Ph, and the first tridentate S 2 Te-donor macrocycles and a tetradentate S 3 Te-donor macrocycle.
The first systematic investigations into the preparation and characterization of coordination complexes of MX 3 (M = As, Sb, Bi; X = Cl, Br, I) involving polydentate and macrocyclic thio-and seleno-ether ligands are then discussed. The structures of examples of each class of compound are described, including the first examples of seleno-ether adducts of the group 15 acceptors. A more limited range of telluroether derivatives has been identified and the structure of the first example of this type is included. These species serve to demonstrate the wide structural diversity exhibited by these systems and the factors directing the assembly of these structures are highlighted.