π-Expanded oligothienylene macrocycle with a large inner cavity incorporates fullerenes such as methano[60]fullerene (C₆₁H₂) and [70]fullerene (C₇₀) inside to form Saturn-like complexes.[1] Although the oligothiophene macrocycle weakly interacts with fullerenes in solution, it forms stable Saturn-like fullerene complexes in the solid state. X-ray analysis of the Saturn-like complexes exhibited short contacts between the sulfur atoms of the oligothiophene macrocycle and fullerene carbons, which hinder the rotation of fullerenes. As a result, the non-covalent interaction between the oligothiophene macrocycle and fullerenes was employed in crystal structure determination of fullerenes. UV–vis–NIR spectra of the Saturn-like complexes showed weak donor–acceptor interaction between the oligothiophene macrocycle and fullerenes.

[1] M. Iyoda, H. Shimizu, S. Aoyagi, H. Okada, B. Zhou, Y. Matsuo, Can. J. Chem. 95 (2017) 315-319.