Multiple C-H⋯anion and N-H⋯anion hydrogen bond directed two-dimensional crystalline nanosheets with precise distance...

Utilizing combined non-covalent interactions and introducing anions as structure-directing factors to build oriented self-assembly and 2D crystalline nanosheet superstructures with precise distance control of surface charges in competitive aqueous solvents still represents a formidable challenge for supramolecular chemists. Here we report a simple, efficient, and general strategy for multiple C-H/N-H⋯anion hydrogen bond enhanced π-π interaction directed 2D oriented self-assembly in water, which is based on the head-to-tail association of perylene monoimide dimers (PMIs) by directing N-H⋯anion interactions to position the anions to the C-H of π systems (PMIs). Interesting, this behavior only occurs for size-matched anions (Cl^- to NO₃^-; <45 ų), while larger anions could not form 2D crystalline nanosheet superstructures. The results show that crystalline nanosheet superstructures with precise distance control of surface charges can effectively capture DNA, possibly due to their high surface charge density and the distance match between the distance of surface charges and the distance between adjacent base pairs.