Solute-solvent halogen bonding during adsorption on silver nanostructures

► Silver nanoparticles can induce ionization of 4-iodobenzoic acid in mono- and multi-layer. ► Halogen bonds form between 4-iodobenzoate ions and CCl4 in multilayer. ► DFT and SERS suggest strong interaction between CCl4 and benzoate oxygen atoms. ► Halogen bonding was not observed in the system without silver nanoparticles.