Aggregation of octahedral thiolato complexes by forming sulfur-bridged structures with transition metal ions

The main developments in rational construction of chiral metallo-aggregates based on octahedral metal complexes with 2-aminoethanethiolate (aet) or L-cysteinate (L-cys), as well as their functionality as an S-donating chiral metalloligand are reviewed in this paper. The reactions of the tris(thiolato)-type fac(S )-[M(aet or L-cys-N,S)(3)](0) (or 3-) (M = Co-III, Rh-III, Ir-III) with transition metal ions gave a variety of S-bridged metallo-aggregates, the structures and chiral properties of which are highly dependent on the nature of the reacting metal ions. The aggregation of the bis(thiolato)-type cis(S)-[Co(aet)(2)(en )(2+)] was also performed through the replacement of a Ni-II ion in [Ni{Co(aet)(2)(en)}(2)](4+) by other transition metal ions. While aggregation of these tris(thiolato)- and bis(thiolato)-types of octahedral units commonly produced discrete S-bridged polynuclear structures, one-dimensional and two-dimensional extended polymeric structures, besides a discrete trinuclear structure, were constructed by the reactions of the mono(thiolato)-type [Co(aet or L-cys-N,S)-(en)(2)](2+ or divided by) with silver(l) ion, because of the adoption of mu(3)-thiolato bridging mode and/or the coordination ability of the free carboxylate group.