Copper(ii) complexes supported by click generated mixed NN, NO, and NS 1,2,3-triazole based ligands and their catalytic activity in azide-alkyne cycloadditionElectronic supplementary information (ESI) available: Sample 1H and 13C NMR for mono-, bis- and tris-1,2,3-triazoles prepared by the CuAAC process. CCDC 974373-974375 for complexes 5, 6, and 8. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c4dt00323c

The preparation and characterization of four new copper( ii ) complexes supported by click generated mixed NN , NO , and NS 1,2,3-triazoles are reported. The four complexes display a 1 : 2 copper/ligand ratio and give monomeric units in the solid state. Crystal structures demonstrate that depending on the flexibility of the ligand NX (X = O, N, S) pendant arm, the coordination environment around the metal center can feature square planar or octahedral geometries. All four complexes are catalytically active at room temperature in a copper-catalyzed alkyne-azide cycloaddition (CuAAC) reaction using sodium ascorbate as a reducing agent and water-ethanol as a solvent mixture. Complex 8 supported by the NS ligand displayed the best catalytic performance of the series allowing for the easy and high yielding preparation of a variety of mono-, bis- and tris-1,2,3-triazoles under low catalyst loadings. Four copper complexes supported by mixed NO , NN and NS -1,2,3-triazoles are reported. Their catalytic activity in the CuAAC process is demonstrated.