Chlorine-assisted fabrication of hybrid supramolecular structures via electrostatic interactions

Supramolecular self-assembly is a spontaneous process relying on non-covalent intermolecular interactions. Among them, electrostatic interactions generated by organic molecules interacting with alkali metals and/or halogens play an important role in structural formation. Herein, we choose cytosine and NaCl as a model system and, from the interplay of STM imaging and DFT calculations, a hybrid network composed of both metal-organic and pure organic motifs interlinked by Cl ions via electrostatic interactions is observed on the Au(111) surface. Moreover, the occasionally missing Cl ions in connections are accompanied by the absence of adjacent organic motifs resulting in defects of the network. This study successfully demonstrates the generality of salt providing both cations and anions simultaneously in the modulation of the structure and provides fundamental knowledge on the formation of hybrid structures as well as the function of halogens in affecting the self-assembly process.