Buckycatcher polymer versus fullerene‐buckycatcher complex: Which is stronger?

The C 60 H 28 buckycatcher (BC) is an excellent host for fullerenes. This receptor features two corannulene pincers which trap C 60 /C 70 via π stacking interactions. Although, the formation of C 60 @C 60 H 28 complexes is readily observed, the dimerization of C 60 H 28 is not a competitive process, even at high concentrations. By means of first principle calculations, we have studied the thermodynamics of the polymerization of BCs and the formation of fullerene complexes. The results obtained with the M06‐2X, B97‐D, B3LYP‐D3BJ, PBE‐D2, and PBE‐D3 functionals indicated that the interaction energy of (C 60 H 28 ) 2 is larger than the one computed for C 60 @C 60 H 28 , by 8–10 kcal/mol. Because of the greater number of atoms, and due to the presence of more hydrogens, the inclusion of free energy corrections lowers the energetic separation between (C 60 H 28 ) 2 and C 60 @C 60 H 28 , even though the dimer maintains its position as being slightly more bound than that of the C 60 @C 60 H 28 . Our calculations indicated that up to the C 60 H 28 trimer could be formed with a free energy change larger than that corresponding to the dimerization and fullerene complexation processes. Finally, we found that the inversion of the corannulene pincers attached to the cyclooctatetraene core is 2–3 kcal/mol lower than that corresponding to free corannulene. We expect that this work can motivate new investigations that may lead to the observation of C 60 H 28 polymers. © 2015 Wiley Periodicals, Inc.