Branched Nanotubes Inspire Nanocages

Researchers in Japan have achieved an innovation in nanoarchitecture by preparing the first all-benzene nanocages (Chem. Sci., DOI: 10.1039/c2sc21322b). A team led by Yasutomo Segawa and Kenichiro Itami of Nagoya University in collaboration with Kenji Kamada of the National Institute of Advanced Industrial Science & Technology created a cyclic precursor by cobbling together six cyclohexane-based L-shaped units and two benzene-based three-way units via cross-coupling and homocoupling reactions. The team used acid-mediated aromatization of the cyclohexane rings to reach the final cage structure. The researchers had initially recognized the nanocage structure as a junction unit in branched carbon nanotubes. They were inspired to try to make it by analogy to carbon nanoring units in straight carbon nanotubes. In addition to the aesthetic appeal, the nanocage could find application in logic gates or transistors and in host-guest chemistry. The researchers note that the high fluorescence quantum yield and large two-photon absorption cross section of the nanocage could be useful in optoelectronic applications.