Halogenated Anthracenes as Building Blocks for the On-Surface Synthesis of Covalent Polymers: Structure Prediction with the Lattice Monte Carlo Method

Functionalized polycyclic aromatic hydrocarbons (PAHs) have been recently recognized as promising building blocks for surface-assisted polymerization reactions producing low-dimensional covalent structures with tailorable properties. In this work, we used the lattice Monte Carlo (MC) simulation method to predict the structure of the labile metal-(halogenated)anthracene connections preceding the formation of covalent polymers in the Ullmann-type coupling reaction occurring on catalytically active metallic surfaces. To that purpose, a coarse-grained model of mono-, di-, and trisubstituted anthracene monomers and two-coordinate metal atoms was proposed, in which these components were adsorbed on a triangular lattice. The formation of metal-organic nodes cementing the resulting superstructures was assumed to be dependent on the directionality of the short-range interactions assigned differently to PAH molecules. Our extensive MC simulations performed for the complete set of 50 positional isomers predicted various organometallic intermediates with morphologies ranging from cyclic oligomers, chains, ladders, ribbons to aperiodic networks and others. These results were compared with the analogous findings obtained for the smaller naphthalene unit. The outcome of the theoretical studies reported herein can be helpful in designing low-dimensional covalent polymers with tunable architecture and functions.

Automated summary

Functionalized polycyclic aromatic hydrocarbons (PAHs) are recognized as promising building blocks for surface-assisted polymerization reactions, and in this study, lattice Monte Carlo (MC) simulations were used to predict the metal-(halogenated)anthracene connections in Ullmann-type coupling reactions on metallic surfaces. By analyzing 50 positional isomers, various organometallic intermediates with different morphologies were identified, providing insights for designing low-dimensional covalent polymers with tunable properties.