Han Y, Dong S, Shao J, Fan W, Chi C. Synthesis of a Sidewall Fragment of a (12,0) Carbon Nanotube.
Angew Chem Int Ed Engl 2020;
60:2658-2662. [PMID:
33047813 DOI:
10.1002/anie.202012651]
[Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Indexed: 11/11/2022]
Abstract
Synthesis of a carbon nanobelt (CNB) is a very challenging task in organic chemistry. Herein, we report the successful synthesis of an octabenzo[12]cyclacene based CNB (6), which can be regarded as a sidewall fragment of a (12,0) carbon nanotube. The key intermediate compound, a tetraepoxy nanobelt (5), was first synthesized by Diels-Alder reaction, and subsequent reductive aromatization gave the fully conjugated CNB 6. X-ray crystallographic analysis unambiguously confirmed the belt-shaped structure of 6. 1 H NMR spectrum and theoretical calculations (ACID, NICS, and 2D/3D ICSS) revealed localized aromaticity and stronger shielding chemical environment in the inner region of the belt. The optical properties (absorption and emission) of 6 were studied and correlated to its electronic structure. Strain analysis indicates that the phenyl substituents at the zigzag edges are crucial to the successful synthesis of 6. This report presents a new strategy towards highly strained CNBs.
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