Construction of 2D metal-organic precursor networks with tunable porosity: A Monte Carlo simulation approach

Abstract

Two-dimensional network structures comprising functional organic building blocks have been recently recognized as promising platforms for various physio-chemical processes running in confined spaces. In this study, we present theoretical results of the self-assembly of metal-organic precursor networks on a crystalline surface and provide quantitative characteristics of these planar architectures. To that end, a coarse-grained model of the adsorbed overlayer comprising halogenated polyaromatic aromatic hydrocarbon (PAH) molecules and bivalent metal atoms was used in combination with the equilibrium Monte Carlo (MC) simulation method. Our calculations focused on the effect of molecular features, such as size, shape and distribution of halogen substituents in the PAH monomer, on the quality and morphology of the networks formed on a model (111) crystalline surface. For the simulated porous assemblies, representing the precursor stage of the surface-assisted Ullmann coupling reaction, such descriptors as the unit cell parameters, radial distribution functions, pore size distributions and structure factors were determined. The obtained results demonstrated that fine-tuning of the monomeric PAH units enables the creation of periodic and aperiodic networks having diverse porous properties, ranging from monoporous to heteroporous with bi- and multimodal pore-size distributions. The findings of our theoretical investigations, apart from the potential application in the optimization of 2D polymeric networks, can also be helpful in designing real confined nanoenvironments for selective capture and immobilization/transformation of guest species.