A Density Functional Theory Investigation of Intramolecular Dispersion Forces in Buckyball-Buckybowl Complexes

The electron-rich, concave face of corannulene makes it an ideal candidate to host electron-deficient fullerenes, such as C60. The host–guest system is dominated by weak van derWaals interactions. Modelling of the C60@corannulene complex was carried out with nine different density functionals: B3LYP, B97-D, BP86, CAM-B3LYP, M06-2X, PW91, t-HCTH, wB97X, and wB97X-D, using the 6-31G(d) basis set. Results indicated that the functionals including an empirical dispersion correction term, B97-D and wB97X-D, gave the most reliable binding energy values when compared with ab initio SCS-MP2 benchmark computations. Additionally, a number of complexes with functionalised corannulene bowls were modelled at the wB97X-D/6-31G(d) level, with NMR calculations performed at the GIAO/wB97X-D/dec-6-31G(d) level. A linear trend was revealed between the number of substituents on corannulene and the strength of binding within complex with C60. Calculated 1H NMR Dd values for methyl groups on methyl substituted corannulene bowls were also linearly dependent on binding energy. Further results are reported here.