Research Progress on Organic Nanohoops/Nanogrids

Radial conjugated carbon nanohoops, as nanofragments of carbon nanotubes, have attracted great attention in the fields of synthetic chemistry, stereochemistry, supramolecular chemistry and materials science.The structure of nanohoops can be divided into monocyclic and multicyclic nanohoops according to the geometric angle.The main building blocks of monocyclic nanohoops are benzene, polycyclic aromatic hydrocarbons and macrocycles, the monocyclic nanohoops with macrocycle as the building blocks and multicyclic nanohoops not only have special topological structure but also have the characteristics of high fluorescence quantum yield and large cavity.At present, such nanohoops with topological structure have important research value in the fields of host-guest doping, energy storage materials, porous and organic optoelectronic materials.Therefore, this review will focus on the synthetic methods of porphyrin monocyclic nanohoops with macrocycle as building blocks, figure-of-eight nanohoops and nanogrids, and more complex carbon nanocages.