Comparative insight into the halogen bonding of 4-chloropyridine and its metal [CuI, ZnII] coordinations with halide ions: A theoretical study on M-C-X⋯X′

► The metal coordination promotes an interaction of chloropyridine to halide anions. ► The increase of halogen bonding focuses mainly on the electrostatic component. ► The metal coordination to heterocycles can lead to a novel M-C-X⋯X′ synthon.