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

Abstract

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 Cu(i) methylthiosalicylate complexes and their catalytic application in thiol-yne click reaction

“…It is worth mentioning here that several methods have been developed for the stereoselective synthesis of ( E )-vinyl sulfides. 42 In contrast, it has been challenging to prepare Z -isomers. 74,75 Kondoh et al 76 have reported the synthesis of ( Z )-1-alkenyl sulfides; however, their synthetic strategy was only applicable to alkyl thiols.…”

“…It is interesting to note that the azide-alkyne click reaction is one of the most studied Cu( i ) catalyzed reactions and we have recently reported several homogeneous azide-alkyne cycloaddition reactions catalyzed by Cu( i ) complexes stabilized by phosphine ligands. 41–43 However, a search of the available literature reveals that reports on Cu( i ) catalyzed hydrothiolation are scanty. 44–46 Notably, Cu + ions are unstable under ambient conditions and require special care while being used as a catalyst.…”

Azide–Alkyne “Click” Reaction in Water Using Parts-Per-Million Amine-Functionalized Azoaromatic Cu(I) Complex as Catalyst: Effect of the Amine Side Arm

“…We explored the reaction of 2,3,4,6-tetra- O -acetyl-β- d -glucopyranosylazide with various kinds of alkynes (Table ). Glycoconjugates are being used as a drug molecule, and they are the integral parts of the living cells, playing an essential role at the intracellular and intercellular level. Moreover, triazole appended glycoconjugates act as enzyme inhibitors used to study carbohydrate–protein interaction, sensing for the detection of analytes, gelation, chelation, catalysis, etc .…”

“…Glycoconjugates are being used as a drug molecule, and they are the integral parts of the living cells, playing an essential role at the intracellular and intercellular level. Moreover, triazole appended glycoconjugates act as enzyme inhibitors used to study carbohydrate–protein interaction, sensing for the detection of analytes, gelation, chelation, catalysis, etc . The CuAAC reaction with this catalytic protocol is indeed a superb synthetic tool.…”

Synthesis and structural features of a series of Cu(i) furan-2-thiocarboxylate complexes: efficient “click” catalysts for the synthesis of glycoconjugates and glycocluster

“…19 N donor ligands, such as tris(2-dioctadecylaminoethyl)amine, tristriazolylamines, tris(benzimidazolylmethyl)amines, 20,21 and ligands with C donating capacity, particularly NHC ligands 22 have exhibited outstanding activity towards CuAAC, whereas O/S donor ligands remain merely investigated. 13,23–26 With the turn of the 21st century, there has been an increasing interest in the synthesis of “pre-formed” copper( i ) complexes acting as catalysts in CuAAC reactions. 23–26 Recently, a number of Cu( i ) complexes were synthesized in our laboratory, which showed excellent compatibility with CuAAC reaction conditions to generate triazolylglycoconjugates in high yields.…”