Building new discrete supramolecular assemblies through the interaction of iso-tellurazole N-oxides with Lewis acids and bases

The supramolecular macrocycles spontaneously assembled by iso-tellurazole N-oxides are stable towards Lewis bases as strong as N-heterocyclic carbenes (NHC) but readily react with Lewis acids such as BR₃ (R = Ph, F). The electron acceptor ability of the tellurium atom is greatly enhanced in the resulting O-bonded adducts, which consequently enables binding to a variety of Lewis bases that includes acetonitrile, 4-dimethylaminopyridine, 4,4′-bipyridine, triphenyl phosphine, a N-heterocyclic carbene and a second molecule of iso-tellurazole N-oxide.