Synthesis of a Series of a Few Hydrosulfide Complexes of Cu(I). A μ-SH-Bridged Rare Cubane-like Tetramer Showing Efficient Catalytic Activity toward Azide-Alkyne Cycloaddition.

A cubane-like tetranuclear hydrosulfido complex of Cu(I), [Cu(SH)(PPh)] (), has been synthesized by the reaction of Cu(NO)·3HO, NaSCOPh, and Cu(PPh)NO and characterized structurally. Complex represents the first example of crystallographically characterized μ-SH-bridged cubanoid hydrosulfide. By direct reactions of [(PPh)Cu(NO)] and NaSH, neutral hydrosulfide complexes [Cu(SH)(PPh)]·CH (), [Cu(SH)(PPh)] (), and [Cu(SH)(PPh)] () have also been synthesized and structurally characterized. Complex is monomeric with a terminal hydrosulfide ligand. The other two, and , are μ-SH-bridged unsymmetrical and symmetrical dinuclear complexes, respectively. In the symmetric one (), both Cu(I) ions are tetrahedrally coordinated while in the unsymmetric one (), one Cu(I) ion is tetrahedral and the other one has a trigonal-planar coordination geometry. The catalytic activity of a hydrosulfido complex in a "click" azide-alkyne cycloaddition reaction has been explored for the first time, and complex is found to be an efficient catalyst for the regioselective synthesis of glycoconjugate triazoles.