Carbon nanotubes (CNTs) interlocked by cyclic compounds through supramolecular interaction are promising rotaxane-like materials applicable as 2D and 3D networks of nanowires and disease-specific theranostic agents having multifunctionalities. Supramolecular complexation of CNTs with cyclic compounds in a "ring toss'' manner is a straightforward method to prepare interlocked CNTs; however, to date, this has not been reported on. Here, the "ring toss" method to prepare interlocked CNTs by using π-conjugated carbon nanorings: [8]-, [9]-, and [10]cycloparaphenyleneacetylene (CPPA) is reported. CPPAs efficiently interact with CNTs to form CNT@CPPA complexes, while uncomplexed CPPAs can be recovered without decomposition. CNTs, which tightly fit in the cavities of CPPAs through convex-concave interaction, efficiently afford "tube-in-ring"-type CNT@CPPA complexes. "Tube-in-ring"-type and "ring-on-tube"-type complexation modes are successfully distinguished by spectroscopic, thermogravimetric, and microscopic analyses.

In article number https://doi.org/10.1002/smll.201800720, Koji Miki, Kouichi Ohe, and co‐workers report the “ring toss” method, throwing carbon nanorings onto carbon nanotubes, to prepare “tube‐in‐ring” supramolecular complexes. Carbon nanorings, [n]cycloparaphenyleneacetylenes, are utilized to demonstrate the formation of “tube‐in‐ring” complexes. The good size fit between the concave inner surface of the carbon nanorings and the convex outer surface of carbon nanotubes is important for the efficient production of rotaxane‐like complexes. This work provides a strategy to prepare interlocked carbon nanotubes for next‐generation electric devices and theranostic agents.