An Organic Molecular Nanobarrel that Hosts and Solubilizes C₆₀

Abstract

Organic cages have gained increasing attention in recent years as molecular hosts and porous materials. Among these, barrel‐shaped cages or molecular nanobarrels are promising systems to encapsulate large hosts as they possess windows of the same size as their internal cavity. However, these systems have received little attention and remain practically unexplored despite their potential. Herein, we report the design and synthesis of a new trigonal prismatic organic nanobarrel with two large triangular windows with a diameter of 12.7 Å optimal for the encapsulation of C60. Remarkably, this organic nanobarrel shows a high affinity for C60 in solvents in which C60 is virtually insoluble, providing stable solutions of C60.

Leveraging Torsional and Steric Strains: A Pre‐macrocyclization Strategy Enables Conformation‐Specific Fullerene Binding in m‐Cyclophanes

“…The emission spectrum of the ground sample in DCM solution displayed a significant bathochromic shift (ca. 50 nm, yellow‐green emission; Figure 6F) accompanied by fluorescence quenching [31a, 33] . This situation was analogous to the toluene‐refluxed sample (Figure 6F).…”

A Saddle‐Shaped Expanded Porphyrinoid Fitting C60**

“…[8] Recently, a molecular nanobarrel was reported to host C 60 . [9] Porphyrins and their expanded derivatives often have a flat, twisted or band-like morphology, which is less suitable for molecular interactions with a ball-shaped molecule like fullerene [10] that prefers a host molecule of a concave design. [5] To realize a suitable binding site for fullerenes nonetheless, aromatic substituents and additional concave structures have been added.…”

An Indacenopicene‐based Buckybowl Catcher for Recognition of Fullerenes

“…Various receptor molecules such as [n]cycloparaphenylenes, [2] calix[n]arenes [3] and porphyrins [4] have been employed for the recognition based on either shape or electronic reciprocities. Such supramolecular complexes possess interesting applications, including the solubilization of pristine fullerenes [5] and the formation of electron transfer complexes using suitable donor molecules [6] . Given the fact that host‐guest interactions strongly profit from a good shape and size complementarity, [7] fullerene receptors employing different types of buckybowls have been demonstrated as a successful approach [8,9,10–12] .…”