Copper(I) Complexes of Normal and Abnormal Carbenes and Their Use as Catalysts for the Huisgen [3+2] Cycloaddition between Azides and Alkynes

✍ Scribed by Stephan Hohloch; Cheng-Yong Su; Biprajit Sarkar

• Publisher: John Wiley and Sons
• Year: 2011
• Tongue: English
• Weight: 573 KB
• Volume: 2011
• Category: Article
• ISSN: 1434-1948
• DOI: 10.1002/ejic.201100363

✦ Synopsis

Complexes of general formula [(NHC)Cu(μ-I) 2 Cu(NHC)] (NHC = 1-benzyl-3-butylbenzimidazolin-2-ylidene for 7; NHC = 1-benzyl-3-isopropylbenzimidazolin-2-ylidene for 8 NHC = 1-butyl-3-isopropylbenzimidazolin-2-ylidene for 9) and [(aNHC)CuI] {aNHC = 1-benzyl-3-methyl-4-phenyl-1H-1,2,3-triazol-3-ium-5-ylidene for 10; 3-methyl-1-[2-(methylthio)phenyl]-4-phenyl-1H-1,2,3-triazol-3-ium-5-ylidene for 11} were synthesized from CuI and the corresponding azolium salts. All complexes were fully characterized by spectroscopic methods, and single-crystal X-ray structural analyses were performed for 7 and 11. Complex 7 exhibits an iodidobridged dicopper(I) form in the solid state. The copper centers in 7 adopt a trigonal coordination. The intramolecular Cu-Cu distance is 2.896(2) Å. In contrast to 7, 11 is mononuclear, and the copper center has a linear coordination. All the complexes were tested for their efficiency as catalysts in the [3+2] cycloaddition reaction between azides and alkynes.