Synthesis of a Series of a Few Hydrosulfide Complexes of Cu(I). A μ3-SH-Bridged Rare Cubane-like Tetramer Showing Efficient Catalytic Activity toward Azide-Alkyne Cycloaddition

A cubane-like tetranuclear hydrosulfido complex of Cu(I), [Cu₄(SH)₄(PPh₃)₄] (1), has been synthesized by the reaction of Cu(NO₃)₂·3H₂O, NaSCOPh, and Cu(PPh₃)₂NO₃ and characterized structurally. Complex 1 represents the first example of crystallographically characterized μ₃-SH-bridged cubanoid hydrosulfide. By direct reactions of [(PPh₃)₂Cu(NO₃)] and NaSH, neutral hydrosulfide complexes [Cu(SH)(PPh₃)₂]·C₆H₆ (2), [Cu₂(SH)₂(PPh₃)₃] (3), and [Cu₂(SH)₂(PPh₃)₄] (4) have also been synthesized and structurally characterized. Complex 2 is monomeric with a terminal hydrosulfide ligand. The other two, 3 and 4, are μ₂-SH-bridged unsymmetrical and symmetrical dinuclear complexes, respectively. In the symmetric one (4), both Cu(I) ions are tetrahedrally coordinated while in the unsymmetric one (3), 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 1 is found to be an efficient catalyst for the regioselective synthesis of glycoconjugate triazoles.

Synthesis and structural studies of an electron deficient hexatitanium cluster dication stabilized by novel tritin anions

A reaction of Cp(2)Ti(SH)(2) with n-BuSnCl(OH)(2) gave two unusual ionic compounds; the cation in both is a hexatitanium cluster, [Cp(6)Ti(6)O(8)](2+), while the anion is a six membered cyclic (chair form) [n-Bu(3)Sn(3)Cl(SH)(3)(S)(3)](-) in one and acyclic [n-Bu(3)Sn(3)Cl(3)(SH)(3)(S)(2)](-) in the other. Besides X-ray crystallography, theoretical studies have also been completed to understand the structures of these complexes.