Syntheses and Properties of Heteroatom-Doped Conjugated Nanohoops

As structural models for carbon nanotube segments, radially conjugated carbon nanohoops have received much attention from chemists, which led to a series of bottom-up synthetic strategies.However, most of these nanohoops are composed only of benzene and simple polyaromatic hydrocarbon moieties.Modulation of the optoelectronic properties is mainly dependent on the variation of ring size, which greatly limits the functional development and application of conjugated nanohoops.In recent years, syntheses and property study of heteroatom-doped carbon nanohoops have become a new research hotspot.The design, synthesis and properties of conjugated nanohoops involving heterocyclic subunits such as pyridine, thiophene, furan, carbazole, benzothiadiazole, chrysenylene, 1,2-azaborine heterocycle, diketopyrrolopyrrole, porphyrin, perylene diimide, and naphthodithiophene diimide, etc. are reviewed.Most of these nanohoops have special topological structures.The introduction of heteroatoms not only significantly improves their optoelectronic properties, but also regulates their assembly, leading to new skeletons for multifunctional supramolecular systems and organic materials.