C–H…S Hydrogen Bond Assisted Supramolecular Encapsulation of Fullerenes with Nanobelts

Hydrogen-bonded capsules have been widely employed as supramolecular hosts for organic molecular guests.Encapsulation of fullerenes by capsules is relatively scarce,especially those that utilize sulfur atoms as hydrogen-bond acceptors.Herein,we describe,in both solution and solid state,a bowl-shaped nanobelt[8]cyclophenoxathiin 1a and its tetra-methylated derivative 1b that can form C–H⋯S hydrogen-bonded capsules induced by complexation with suitable fullerenes.1a strongly encapsulates C60,C70,or 6,6-phenyl-C61-butyric acid methyl ester(PC61BM)to form a 2∶1 ternary complex featuring 16 equatorial(sp2)C–H⋯S hydrogen bonds.A pseudorotaxane structure was further obtained for the complex of 1a with PC61BM.Conversely,a 1∶1 inclusion complex was observed for binding C60 or PC61BM with 1b indicating the reduced tendency to form capsules by introducing methyl groups into the belt.Surprisingly,the capsule-like structure was retained for the 1:2 complex of C70 with 1b as observed by the presence of multiple(sp3)C–H⋯S hydrogen bonds.The strong binding affinity and tailorable complexation mode enable further applications of nanobelts in fullerene chemistry.