The incorporation of heteroatoms into carbon nanohoops can significantly overcome aromatic stabilization energy and enrich their physicochemical properties depending on the positions and numbers of the doped atoms.Uti...The incorporation of heteroatoms into carbon nanohoops can significantly overcome aromatic stabilization energy and enrich their physicochemical properties depending on the positions and numbers of the doped atoms.Utilizing a V-shaped dipyreneo[c,e]dihydrophenazine as the building block,herein we report a novel kind of axially N-embedded quasi-carbon nanohoops by integratingπ-extended dihydropyrazine and para-phenylene subunits.Singlecrystal X-ray diffraction analyses revealed that their geometrical structures varied from droplet-shaped geometry for DPP-M and suppressed elliptical cross-section configuration for DPP-D to triangularly prismatic configuration for DPP-T.Spectroscopic measurements confirmed rich electronic properties,especially multioxidation behaviors due to the embedding of graphitic-N atoms,which are not observed in carbonaceous nanohoops and other analogs.Further investigations,including electron spin resonance spectroscopy,theoretical calculations,and single-crystal structure analyses,on the oxidized species of both DPP-D and DPP-T demonstrated their tunable open-shell ground states for the dications.This work provides a new synthetic strategy to axially N-embedded quasi-carbon nanohoops and gives insights into the design of structure-precise segments of graphitic-N-doped single-walled carbon nanotubes.展开更多
基金financially supported by the National Natural Science Foundation of China(grant nos.22235005,21871084,and 21790361)the Shanghai Municipal Science and Technology Major Project(grant no.2018SHZDZX03)+3 种基金the Fundamental Research Funds for the Central Universities,the Programme of Introducing Talents of Discipline to Universities(grant no.B16017)the Program of Shanghai Academic/Technology Research Leader(grant no.19XD1421100)the Shanghai Science and Technology Committee(grant no.17520750100)the China Postdoctoral Science Foundation(grant no.2020M671018).
文摘The incorporation of heteroatoms into carbon nanohoops can significantly overcome aromatic stabilization energy and enrich their physicochemical properties depending on the positions and numbers of the doped atoms.Utilizing a V-shaped dipyreneo[c,e]dihydrophenazine as the building block,herein we report a novel kind of axially N-embedded quasi-carbon nanohoops by integratingπ-extended dihydropyrazine and para-phenylene subunits.Singlecrystal X-ray diffraction analyses revealed that their geometrical structures varied from droplet-shaped geometry for DPP-M and suppressed elliptical cross-section configuration for DPP-D to triangularly prismatic configuration for DPP-T.Spectroscopic measurements confirmed rich electronic properties,especially multioxidation behaviors due to the embedding of graphitic-N atoms,which are not observed in carbonaceous nanohoops and other analogs.Further investigations,including electron spin resonance spectroscopy,theoretical calculations,and single-crystal structure analyses,on the oxidized species of both DPP-D and DPP-T demonstrated their tunable open-shell ground states for the dications.This work provides a new synthetic strategy to axially N-embedded quasi-carbon nanohoops and gives insights into the design of structure-precise segments of graphitic-N-doped single-walled carbon nanotubes.
