Sulfide-Induced Dimerization Versus Demetallation of Tricopper(I) Clusters Protected by Tris-Thiolato Metalloligands.

Here, we report the reactivity of copper(I) clusters toward sulfide ions; these sulfide copper(I) clusters have attracted much attention due to their relevance to biologically active centers and their fascinating structural and photophysical properties. Treatment of the CuI 3RhIII 2 pentanuclear complex, [Cu3{Rh(aet)3}2]3+ (aet=2-aminoethanethiolate), in which a {CuI 3}3+ cluster moiety is bound by two fac-[Rh(aet)3] metalloligands, with NaSH in water produced the CuI 6RhIII 4 decanuclear complex, [Cu6S{Rh(aet)3}4]4+, accompanied by the dimerization of [Cu3{Rh(aet)3}2]3+ and the incorporation of a sulfide ion at the center. While similar treatment using the analogous CuI 3IrIII 2 complex with fac-[Ir(aet)3] metalloligands, [Cu3{Ir(aet)3}2]3+, produced the isostructural CuI 6IrIII 4 decanuclear complex, [Cu6S{Ir(aet)3}4]4+, the use of the CuI 3RhIII 2 complex with fac-[Rh(apt)3] metalloligands, [Cu3{Rh(apt)3}2]3+ (apt=3-aminopropanethiolate), resulted in the removal of one of the three CuI atoms from {CuI 3}3+ to afford the CuI 2RhIII 2 tetranuclear complex, [Cu2{Rh(apt)3}2]2+.

Heterometallation of Photoluminescent Silver(I) Sulfide Nanoclusters Protected by Octahedral Iridium(III) Thiolates.

The recently-increasing interest in coinage metal clusters stems from their photophysical properties, which are controlled via heterometallation. Herein, we report homometallic AgI 46 S13 clusters protected by octahedral fac-[Ir(aet)3 ] (aet=2-aminoethanethiolate) molecules and their conversion to heterometallic AgI 43 MI 3 S13 (M=Cu, Au) clusters. The reactions of fac-[Ir(aet)3 ] with Ag+ and penicillamine produced [Ag46 S13 {Ir(aet)3 }14 ]20+ ([1]20+ ), where a spherical AgI 46 S13 cluster is covered by fac-[Ir(aet)3 ] octahedra through thiolato bridges. [1]20+ was converted to [Ag43 M3 S13 {Ir(aet)3 }14 ]20+ ([1M ]20+ ) with an AgI 43 MI 3 S13 cluster by treatment with M+ , retaining its overall structure. [1]20+ was photoluminescent and had an emission band ca. 690 nm that originated from an S-to-Ag charge transfer. While [1Cu ]20+ showed an emission band with a slightly higher energy of ca. 650 nm and a lower quantum yield, the emission band for [1Au ]20+ shifted to a much higher energy of ca. 590 nm with an enhanced quantum yield.

Controlled Formation of Thiol-Thiolate Hydrogen versus Disulfide Bonds between Two Iridium(III) Centers.

Here, we report an iridium(III) coordination system with 2-aminoethanethiolate (aet), which shows the formation of S-H⋅⋅⋅S hydrogen and S-S disulfide bonds in a controlled manner. Treatment of fac-[Ir(aet)3 ] with aqueous HBF4 under aerobic conditions gave dinuclear [Ir2 (aet)4 (cysta)]2+ ([1]2+ ; cysta=cystamine) with a single S-S disulfide bond, while dimeric [Ir2 (aet)3 (Haet)3 ](BF4 )3 ([2](BF4 )3 ) with a triple S-H⋅⋅⋅S hydrogen bond was formed by similar treatment under anaerobic conditions. Upon exposure to air, [2]3+ was converted to dinuclear [Ir2 (aet)2 (Haet)2 (cysta)]4+ ([3]4+ ), in which two IrIII centers are spanned by a double S-H⋅⋅⋅S hydrogen bond and a single S-S disulfide bond. Complex [3]4+ was interconvertible with [1]2+ via the removal/addition of protons on S donors, accompanied by the intermolecular exchange of the fac-[Ir(aet)3 ] units. Complexes [1]2+ , [2]3+ , and [3]4+ , isolated as BF4 - salts, were fully characterized by single-crystal X-ray crystallography.

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.