Metal complexes of thiazyl radicals

Abstract

A diverse variety of thiazyl radicals is known. Intense study of these heterocycles continues in the pursuit of molecule-based materials with novel, academically interesting, and technologically relevant properties. Coordination of these species to metal atoms and ions has focused primarily on the 1,2,3,5-dithiadiazolyl 2 and 1,3,2-dithiazolyl 6. The potential of these two heterocycles as ligand building-blocks has, by no means, been fully exploited. From the structural and electronic similarities between 2 and the verdazyl and nitronyl nitroxide radicals, it is apparent that similar radical ligand designs ought to be achievable. The sulfur atoms of 2 lend a unique feature to this radical that may yet be employed as a means of controlling intermolecular interactions or developing multi-metal species. The recent report of sulfur coordination to 6 demonstrates that there is yet more design flexibility available from this thiazyl as well. Coordination complexes of other radical thiazyls have begun appearing in the literature. This field is currently in its infancy and is starting to be recognized as an enormous source of untapped potential in the future development of molecule-based materials.