Synthesis of Defect-Engineered Homochiral Metal-Organic Frameworks Using L-Amino Acids: A Comprehensive Study of Chiral Catalyst Performance in CO2 Fixation Reaction

摘要

In this work, a novel homochiral zinc-containing metal-organic framework (MOF) was achieved via defect engineering strategy and characterized by various techniques including X-ray powder diffraction (XRD), Brunner-Emmett-Teller surface area analysis (SBET), field-emission scanning electron microscopy (FE-SEM), thermal gravimetric analysis (TGA), circular dichroism (CD), and nuclear magnetic resonance (NMR) spectroscopy. Results showed that the importing defects in the structure of zinc-containing MOF did not only significantly affect the basic properties of parent MOF (MOF-5), including stability, morphol-ogy, and crystallinity, but have introduced new features such as chirality in its framework. Subsequently, this new defect-engineered material was used as a catalyst in the CO2 fixation process and overcame the essential limitations present in this reaction by providing the synergistic and cooperative effect between Lewis acidic centers (Zn2+) and imidazolium iodide salt on a united catalytic system. These features are present MOF-5@imidazolium iodide as a reusable heterogeneous catalyst for the efficient chemical conversion of carbon dioxide with non-bulky epoxides into cyclic carbonates under mild conditions without utilizing any solvent or cocatalyst.