Endohedral metallofullerenes as nanoreactors: Regulating the ring-opening reaction of m-xylene at a molecular level under pressure

The ring-opening reaction of aromatic molecules is a significant and critical process for the construction of carbon-based and related functional materials with desired structures and properties. However, direct observation and control of such a process at a molecular level remains a challenge. Here, we employed the octahedral voids in endohedral metallofullerene (EMF) crystals as nanoreactors to accommodate aromatic m-xylene molecules and regulate the ring-opening reaction of guest m-xylene by applying a high pressure. We found that the ring-opening reaction of m-xylenes strongly depends on the degree of charge transfer between m-xylene and EMF, which can be tuned by varying the electronegativity of the carbon cages with different endohedral metals. A positive relationship between the electronegativity of fullerenes and the reactivity of m-xylene was revealed. This work demonstrates the potential of tuning the ring-opening reaction of aromatic molecules by charge transfer and manipulates the reaction at a molecule level, providing new insights into the synthesis of carbon materials and fullerene derivatives.