Photocatalytic copper-catalyzed azide-alkyne cycloaddition click reaction with Cu(II) coordination polymer

A two dimensional Cu(II) coordination sheet has been developed. By incorporating well-designed chromophore linkers into the coordination polymer, the long conjugated system caused the maximum UV-vis absorption wavelength red shift to the visible area (up to 550 nm). Adjacent sheets were assembled in an ABAB fashion via pi...pi stacking and C-H...pi interactions to form a three-dimensional structure. The interlayer stacking mode is important because its liability allows for exfoliation of the material which results in the dispersion of the active sites and the enhancement of the visible-light trapping capacity. Using this copper(II) coordination polymer, a series of click reactions were successfully conducted under household light irradiation in the air at room temperature. And 1,4-substituted triazoles were the single products in good yields. Moreover, the catalyst can be easily removed from the reaction mixture.