Polysulfide ligands mononuclear

Monocyclic MS units are known for n = 3-7 and 9. Among the mononuclear complexes there is also an example where a polysulfide acts as a tridentate ligand, namely the 87 ion in (Mc3P)3M(S7) (M = Ru, Os). The OSS7 bicycle shows a similar exo-endo conformation as the ion in Sg(AsF6)2 (58). ... 

There are large numbers of compounds with the simple sulfide ion (S2 ) as a ligand comparable to O2- that are mononuclear like S=WC13 or bi- or polynuclear with sulfur bridges. These and related species derived from polysulfide ions (S2 ) have been intensively studied in part because sulfur bridged species occur in Nature in ferredoxins and related compounds. 

The presence of the pyramidal [M(82)2E] (E=0, 8) intermediate seems to be a general feature in the acidification of M84, since this fragment was also trapped and characterized with [V04] " in a polysulfide-containing medium. This intermediate readily reacts with chelating ligands and is stabilized as a mononuclear spe-... 

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