Influence of Substitution on the Supramolecular Chemistry of Cycloparaphenylene-Fullerene Complexes

Abstract

We present a comprehensive host-guest study of four substituted and unsubstituted [10]cycloparaphenylenes with the fullerenes C60 and C70. Within this study, the influence on the complexation behavior was investigated experimentally and computationally. Due to the increased steric demand the substitution on the nanohoop results in an energetic penalty, which could be partially compensated by additional substituent-fullerene interactions. These attractive interactions are intensified in the C70 complexes and with an increased degree of substitution. For the computational investigation conformer ensembles were taken into account, providing reliable structures with Boltzmann weighted energies. An analysis of the noncovalent interactions elucidated the origin of the enhanced substituent-C70 interaction. The ellipsoid fullerene C70 can be considered as a π-extended version of C60, which is able to increase the attractive van der Waals interactions within these supramolecular complexes.