Three-dimensional amino acid backbone Cu-aspartate metal–organic framework as a catalyst for the cycloaddition of propylene oxide and CO 2

Three-dimensional amino acid backbone Cu-aspartate metal organic frameworks {[Cu( l -asp)(1,4-bpy) 0.5 ].H 2 O} n (CuAspBpy) were prepared from copper salt, l -aspartic acid linker, and 4,4′-bipyridyl cross-linker by solvothermal and microwave methods. The synthesized CuAspBpy was characterized and used as a catalyst for the synthesis of propylene carbonate (PC) by the cycloaddition of CO 2 with propylene oxide (PO). An efficient catalytic process for PC synthesis was developed via the synergistic role of CuAspBpy and the quaternary ammonium bromide co-catalyst. Computational studies based on density-functional theory (DFT) were utilized to propose a mechanistic pathway for the reaction. The heterogeneous catalyst was reused four times without any considerable loss in the activity. Graphic abstract