First-principle study of the hydrogen bonds in a thin film of phthalocyanine molecules

The nature and the strength of intermolecular contacts involved in molecular self-assemblies on a substrate strongly depend on the surrounding functional atoms. Recently, it has been shown that deposition of chlorine-zinc-phthalocyanine (ZnPcCl₈) molecules on Ag(1 1 1) leads to a compact arrangement governed by the activation of a Cl ? H-C bond network. A detailed theoretical study of these contacts based on first-principle density functional calculations and topological analysis of the electron density is reported in this paper. This study reveals that the mechanism of the Cl ? H-C contacts is similar to that of weak hydrogen bonds.