Macrocyclic tetranuclear copper (I) complex bearing a N-heterocyclic carbene ligand: Synthesis, structure, and catalytic properties

A rare macrocyclic tetranuclear copper (I) complex ([Cu-4(2)(2)](PF6)(4)) of phenanthroline-based NHC ligand has been prepared and characterized by NMR, ESI-MS spectroscopy, and X-ray diffraction analysis. The complex displays a novel twisted macrocyclic conformation and weak intramolecular Cu-Cu interactions. The complex is found to exhibit high catalytic activity in the Cu-catalyzed azide-alkyne cycloaddition (CuAAC) reaction in an air atmosphere at room temperature in a MeCN/H2O mixture solution. (C) 2012 Elsevier B.V. All rights reserved.