“…Usually, metal-based complexes display higher reactivity than organocatalysts for the coupling reaction. As a result of the diversity of the metal across the periodic table and the organic ligands of different structures, miscellaneous metal complexes based on aluminum , magnesium [33][34][35][36], chromium [37][38][39][40][41][42], cobalt [43][44][45][46][47][48], iron [49][50][51][52][53], and rare earth metals [54,55] have been innovated for the coupling reaction of CO 2 with epoxides. Of many metal complexes, aluminum complexes have been drawing attention due to their low price, easy availability, and the superior selectivity for the cyclic carbonate over polymeric products [56].…”