A multifunctional MOF as a recyclable catalyst for the fixation of CO2 with aziridines or epoxides and as a luminescent probe of Cr(VI)
A multifunctional metal–organic framework (1) containing 24-nuclear zinc nanocages shows high solvent- and pH-stability. Compound 1 can be employed as a catalyst for the conversion of CO2 with aziridines or epoxides, which can be reused at least ten times just by a simple and rapid method. The PXRD of compound 1 after ten recyclings remains well consistent with the original one. The inductively coupled plasma measurement of a reaction filtrate revealed that only trace amount leakage of Zn2+ was observed, indicating that the framework did not collapse after recyclings. Compound 1 can effectively catalyze the cycloaddition reaction of CO2 and five aziridines or five epoxides with different substituent groups. To our knowledge, this is the first multifunctional MOF-based catalyst used for the conversion of CO2 with aziridines or epoxides. Furthermore, luminescence investigations reveal that compound 1 can also act as a luminescent probe for chromium(VI) anion species, which is seriously harmful to humans and the environment. After five cycle tests, the PXRD of compound 1 is still in accordance with the original one, indicating that compound 1 can serve as a circulatory luminescent probe for Cr(VI) anions.