Affiliation:
1. Collaborative Innovation Center for Advanced Organic Chemical Materials Co‐constructed by the Province and Ministry Ministry‐of‐Education Key Laboratory for the Synthesis and Application of Organic Functional Molecules Hubei Key Laboratory of Polymer Materials College of Chemistry and Chemical Engineering Hubei University Wuhan 430062 P. R. China
Abstract
Abstract2D materials have attracted great interest since the report of graphene. However, because of the fragile stability of ultra‐thin nanosheets, most studies are restricted to sheets maintained by strong covalent or coordination bonds. The research on which kind of bonds can maintain the free‐standing existence of 2D nanosheets is still of great significance. Recently, 2D ionic salts are successfully synthesized on substrates, but whether 2D ionic salts can free‐stand is still a problem. Herein this problem is addressed by a free‐standing 2D ionic salt (thickness: ≈2 nm) exfoliated from a 4,4′‐bipyridinium hydrochloride salt crystal. The stability of this 2D salt is supported by a strong NH···Cl hydrogen (H)‐bonding assisted ionic interaction (17.99 kcal mol−1), which is verified by density functional theory calculation and natural bond orbital analysis. The salt crystal has strong air‐stable radicals inside and the 2D ionic salt exhibits red fluorescence in solution and in solid‐state, especially in solution the stokes shifts are very large (≈ 386 nm). This breakthrough work is not only beneficial for the construction of novel 2D materials but also for the understanding of H‐bonding interactions.
Funder
National Natural Science Foundation of China
Natural Science Foundation of Hubei Province
Subject
Biomaterials,Biotechnology,General Materials Science,General Chemistry