Negatively Curved Nanohoops as Cut-Outs of Carbon Toroids and Schwarzites

Nanographenes with negative curvature are often considered as cutouts of proposed new carbon allotropes such as toroids and schwarzites. While the synthesis of cutouts of such structures to date has been limited to smaller areas, here we present the synthesis of negatively curved nanohoops with 152, 228, and 304 toroid or schwarzite resembling carbons. Structural elucidation of two nanohoops by single-crystal X-ray diffraction analysis as well as supramolecular interactions with fullerenes in solution and their structural comparison to the corresponding macrostructures is presented.