Xiong Wei, Zhang Guang, Bao De-Liang, Lu Jianchen, Gao Lei, Li Yusen, Zhang Hui, Ruan Zilin, Hao Zhenliang, Gao Hong-Jun, Chen Long, Cai Jinming
Faculty of Materials Science and Engineering, Kunming University of Science and Technology, 650093, Kunming, PR China.
Department of Chemistry and Tianjin Key Laboratory of Molecular Optoelectronic Science, Tianjin University, 300072, Tianjin, PR China.
Nat Commun. 2025 Jan 15;16(1):690. doi: 10.1038/s41467-024-55719-4.
Regulating carbon hybridization states lies at the heart of engineering carbon materials with tailored properties but orchestrating the sequential transition across three states has remained elusive. Here, we visiualize stepwise evolution in carbon hybridizations from sp³ to sp² and to sp states via dehydrogenation and elimination reactions of methylcyano-functionalized molecules on surfaces. Utilizing scanning probing microscopy, we distinguish three distinct carbon-carbon bond types within polymers induced by annealing at elevated temperatures. Density-functional-theory calculations unveil the pivotal role of the electron-withdrawing cyano group in activating neighboring methylene to form C(sp)-C(sp) bonds, and in facilitating subsequent stepwise HCN eliminations to realize the transformation across three carbon-carbon bond types. We also demonstrate the applicability of this strategy on one-dimensional molecular wires and two-dimensional covalent organic framework on different substrates. Our work expands the scope of carbon hybridization evolution and serves as an advance in flexibly engineering carbon-material by employing cyanomethyl-substituted molecules.
调控碳的杂化态是设计具有定制特性的碳材料的核心，但协调三种状态之间的连续转变一直难以实现。在这里，我们通过表面上甲基氰基官能化分子的脱氢和消除反应，可视化了碳杂化从sp³到sp²再到sp状态的逐步演变。利用扫描探针显微镜，我们区分了高温退火诱导的聚合物中三种不同的碳-碳键类型。密度泛函理论计算揭示了吸电子氰基在活化相邻亚甲基以形成C(sp)-C(sp)键以及促进随后逐步消除HCN以实现三种碳-碳键类型转变中的关键作用。我们还展示了该策略在不同基底上的一维分子线和二维共价有机框架上的适用性。我们的工作扩展了碳杂化演变的范围，并为通过使用氰甲基取代分子灵活设计碳材料提供了进展。
