A new Cu3Al-layered double hydroxide heterogeneous catalyst for azide-alkyne [3 + 2] cycloaddition reaction in water

A new Cu3Al-layered double hydroxide (LDH) compound that contains Cu2+ and Al3+ in a 3:1 copper to aluminum molar ratio was synthesized by a coprecipitation method at constant pH and characterized by various methods. Cu3Al-LDH was efficiently used as a catalyst for the regioselective click of 1,4-disubstituted-1,2,3-triazoles by [3 + 2] cycloaddition of several azides and alkynes in water under ambient conditions. The investigated heterogeneous Cu3Al-LDH catalyst was used in lower copper catalyst loading in absence of any additive reducing agent, showing good stability in terms of copper species leaching as well as reusability associated to the loss of the layered structure to some extent during the process of filtration-dehydration.