Selective cycloaddition of ethylene oxide to CO₂ within the confined space of an amino acid-based metal–organic framework

Host-guest chemistry within the confined space of metal-organic frameworks (MOFs) offers an almost unlimited myriad of possibilities, hardly accessible with other materials. Here we report the synthesis and physical characterization, with atomic resolution by single-crystal X-ray diffraction, of a novel water-stable tridimensional MOF, derived from the amino acid <i>S</i>-methyl-L-cysteine, {SrZn₆[(<i>S</i>,<i>S</i>)-Mecysmox]₃(OH)₂(H₂O)}·9H₂O (1), and its application as a robust and efficient solid catalyst for the cycloaddition reaction of ethylene/propylene oxide with CO₂ to afford ethylene/propylene carbonate with yields of up to 95% and selectivity of up to 100%. These results nicely illustrate the great potential of MOFs to be game changers for the selective synthesis of industrially relevant products, representing a powerful alternative to the current heterogeneous catalysts.