Transition Metal Polysulfides: Coordination Compounds with Purely Inorganic Chelate Ligands

It has been long known that certain transition metal sulfides dissolve in aqueous ammonium polysulfide. Although it was assumed that they thereby formed metal polysulfides, attention was first paid to such compounds only a few years ago. In recent years a host of new complexes with polysulfido chelate ligands have been isolated and characterized. The complexes are of interest not only regarding their structure and reactivity but also in view of their potential uses; they can be used for the directed preparation of sulfur rings of a given size, and there are indications that they will find applications in catalysis.