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 C-60 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 C-60, 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@C-60 endofullerene. Calculations show that inner-cavity chemical reaction C-60 + H2O can take place if H2O@C-60 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@C-60. Though the calculated heat effect of the mentioned chemical transformation is endothermic, the product of the reaction is a minimum on potential energy surface.