Cyclooctatetraene-Embedded Carbon Nanorings

With the prosperity of the development of carbon nanorings, certain topologically or functionally unique units-embedded carbon nanorings have sprung up in the past decade. Herein, we report the facile and efficient synthesis of three cyclooctatetraene-embedded carbon nanorings (COTCNRs) that contain three (COTCNR1 and COTCNR2) and four (COTCNR3) COT units in a one-pot Yamamoto coupling. These nanorings feature hoop-shaped segments of Gyroid (G-), Diamond (D-), and Primitive (P-) type carbon schwarzites. The conformations of the trimeric nanorings COTCNR1 and COTCNR2 are shape-persistent, whereas the tetrameric COTCNR3 possesses a flexible carbon skeleton which undergoes conformational changes upon forming host-guest complexes with fullerenes (C60 and C70), whose co-crystals may potentially serve as fullerene-based semiconducting supramolecular wires with electrical conductivities on the order of 10-7 S cm-1 (for C60 subset of COTCNR3) and 10-8 S cm-1 (for C70 subset of COTCNR3) under ambient conditions. This research not only describes highly efficient one-step syntheses of three cyclooctatetraene-embedded carbon nanorings which feature hoop-shaped segments of distinctive topological carbon schwarzites, but also demonstrates the potential application in electronics of the one-dimensional fullerene arrays secured by COTCNR3. Molecular Nanorings Featuring Hoop-Shaped Segments of Carbon Schwarzites. We describe three cyclooctatetraene-embedded carbon nanorings (COTCNRs) which can be recognized as hoop-shaped segments of distinctive carbon schwarzites. COTCNR3 complexes with fullerenes (C60 and C70) and forms one-dimensional supramolecular wires with ambient electrical conductivities of up to (7.11 +/- 0.14)x10-7 S cm-1. image