Hybrid NS ligands supported Cu(I)/(II) complexes for azide-alkyne cycloaddition reactions

Three copper complexes of nitrogen-sulfur donor ligands, [CuBr2(L1)] (1), [CuCl2(L2)(2)] (2) and [Cu2I2(L3)](n) (3) (L1 = bis(2-cyclohexylsulfanylethyl)amine, L2 = 2-(benzylsulfanylmethyl)pyridine and L3 = 2-(4-pyridylsulfanylmethyl)pyridine), have been synthesized and characterized by single-crystal X-ray diffraction (XRD), powder XRD and TGA analysis. Complexes 1 and 2 are mononuclear Cu(II) complexes and are EPR active with distorted square-pyramidal and octahedral geometry, respectively. Complex 3 is a two-dimensional tetrahedral Cu(I) coordination polymer with 16- and 20-membered metallocycles. These complexes show good catalytic activities for one-pot azide-alkyne cycloaddition reactions in CH3OH-H2O.