Structurally Precise Silver Sulfide Nanoclusters Protected by Rhodium(III) Octahedra with Aminothiolates.

A 60-nuclear silver sulfide nanocluster with a highly positive charge (1) has been synthesized by mixing an octahedral RhIII complex with 2-aminoethanethiolate ligands, silver(I) nitrate, and d-penicillamine in water under mild conditions. The spherical surface of 1 is protected by the chiral octahedral RhIII complex, with cleavage of the C-S bond of the d-penicillamine supplying the sulfide ions. Although 1 does not contain d-penicillamine, it is optically active because of the enantiomeric excess of the RhIII molecules induced by chiral transfer from d-penicillamine. 1 can accommodate/release external Ag+ ions and replace inner Ag+ ions by Cu+ ions. The study demonstrates that a thiolato metal complex and sulfur-containing amino acid can be used as cluster-surface-protecting and sulfide-supplying regents, respectively, for creating chiral, water-soluble, structurally precise silver sulfide nanoclusters, the properties of which are tunable through the addition/removal/exchange of Ag+ ions.