UiO-67-tethered copper(II) complex: a highly efficient and reusable heterogeneous catalyst for CuAAC reactions in aqueous media

The development of catalysts anchored on metal-organic frameworks has drawn significant attention due to their large internal surface areas and provides a solid support, offering the potential for enhanced efficiency in heterogeneous catalysis. Among these reactions, the copper-catalyzed azide-alkyne cycloaddition (CuAAC), a key transformation in click chemistry, stands out for its versatility in synthesizing 1,4-disubstituted-1,2,3-triazole derivatives. Despite the popularity of CuAAC, no MOF-tethered Copper complex for this reaction has been reported to date. In this study, we synthesized a Zr(IV)-based UiO-67 MOF tethered Cu complex (UiO-67-BT-Cu(II)) using biphenyl-4,4′-dicarboxylic acid-functionalized bis thiophene (BDA-BT) via a solvothermal method and comprehensively characterized. Notably, UiO-67-BT-Cu(II) exhibited good catalytic activity and recyclability for azide-alkyne cycloaddition compared to BDA-BT-Cu(II). The copper moieties on the MOF framework efficiently catalyzed the formation of 1,4-disubstituted-1,2,3-triazole derivatives in water, a green solvent, achieving a high yield of 94 % with no detectable leaching of the Cu species from UiO-67-BT-Cu(II).