From Endohedral Complexes to Endohedral Fullerene Covalent Derivatives: A Density Functional Theory Prognosis of Chemical Transformation of Water Endofullerene H2O@C60 upon Its Compression

Currently, there are no examples of transformation of endohedral C60 complexes, which result in a chemical reaction between the encapsulated molecule and the carbon cage. Such reactions open new opportunities for producing the poorly studied endohedral covalent derivatives of C60, which may be of great interest for fullerene chemistry and material science. In the present work, we have performed accurate theoretical study on the compression of the recently synthesized H2O@C60 endofullerene. Calculations show that inner-cavity chemical reaction C60 + H2O can take place if H2O@C60 is compressed in the direction of two opposite pentagons. In the case of hexagon-to-hexagon compression, there is no chemical reaction, and relaxation of the compressed structure leads to the original H2O@C60. Though the calculated heat effect of the mentioned chemical transformation is endothermic, the product of the reaction is a minimum on potential energy surface.