Department of Chemistry, University of California, Berkeley, Berkeley, California 94720, United States.
Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States.
J Am Chem Soc. 2021 Jun 16;143(23):8619-8624. doi: 10.1021/jacs.1c04037. Epub 2021 Jun 4.
Carbon nanobelts are molecules of high fundamental and technological interest due to their structural similarity to carbon nanotubes, of which they are molecular cutouts. Despite this attention, synthetic accessibility is a major obstacle, such that the few known strategies offer limited structural diversity, functionality, and scalability. To address this bottleneck, we have developed a new strategy that utilizes highly fused monomer units constructed via a site-selective [2 + 2 + 2] cycloaddition and a high-yielding zirconocene-mediated macrocyclization to achieve the synthesis of a new carbon nanobelt on large scale with the introduction of functional handles in the penultimate step. This nanobelt represents a diagonal cross section of an armchair carbon nanotube and consequently has a longitudinally extended structure with an aspect ratio of 1.6, the highest of any reported nanobelt. This elongated structure promotes solid-state packing into aligned columns that mimic the parent carbon nanotube and facilitates unprecedented host-guest chemistry with oligo-arylene guests in nonpolar solvents.
碳纳米带因其结构类似于碳纳米管而具有很高的基础和技术价值，它们是碳纳米管的分子切出物。尽管受到了广泛关注，但合成的可及性仍是一个主要障碍，因为少数已知的策略提供的结构多样性、功能性和可扩展性有限。为了解决这一瓶颈，我们开发了一种新的策略，该策略利用通过位点选择性[2 + 2 + 2]环加成和高产锆介导的大环化构建的高度融合单体单元来实现具有最后一步中引入功能手柄的新碳纳米带的大规模合成。这条纳米带代表了扶手椅碳纳米管的对角横截面，因此具有纵向延伸的结构，纵横比为 1.6，是所有报道的纳米带中最高的。这种拉长的结构促进了固态组装成类似于母体碳纳米管的对齐柱，并促进了在非极性溶剂中与寡芳基客体的前所未有的主客体化学。
