Off-Lattice Coarse-Grained Model of Surface-Confined Metal–Organic Architectures

Abstract

An off-lattice model of self-assembling surface-confined metal–organic nanostructures (SMONs) comprising tripod molecules has been developed. The model considers the directionality and saturability of coordination bonding. To parametrize the model, density functional theory methods have been used. Self-assembly of the SMONs has been simulated with Metropolis Monte Carlo method in the canonical ensemble. In this paper, we investigate how the directionality of metal–linker bonding and the linker/metal ratio affect the self-assembly of SMONs containing metal centers with different coordination numbers: M(II), M(III), and M(IV). The directionality of coordination bonding is determined by the functional group of the linker molecule and is defined in the model as the angular diameter of the interaction shell. Regardless of the preferred coordination number of the metal center, even a small change in the angular diameter significantly affects the structure of the SMONs. Depending on the angular diameter and composition of the metal–organic layer, various structures can appear. Using our model, we have simulated the self-assembly of the random porous (or defected honeycomb) and triangular structures, the set of hexagonal phases, amorphous structures of different densities, and metal–organic chains. Relative thermal stabilities of clusters of the main structures have been studied. The model reproduces correctly the main SMONs observed by scanning tunneling microscopy.

Two-Dimensional Metal–Organic Framework Self-Assembly and Defect Engineering Studied via Coarse-Grained Simulations

“…The greater apparent definition of the MOF grains is observed qualitatively via the RDF, which has several narrow peaks that propagate beyond 50 au (see Figure i). Incorporating directional bonding and saturability (coordination number) for reagents of MOF simulations produces an assembled framework reflecting the symmetry of the topological net and is in agreement with simulations of surface-confined metal–organic nanostructures (SMONs) . With the finer coarse-grained model allowing for successful self-assembly of the desired MOF structure, further study into how reaction parameters impact the crystallization process, including modulation, is possible.…”

Predicting Organometallic Intermediates in the Surface-Assisted Ullmann Coupling of Chrysene Isomers

“…To facilitate the design of low-dimensional polymeric constructs formed on surfaces, computer-aided methods have recently been used. This refers especially to quantum chemical calculations focusing on bonding mechanisms and reaction paths of polymer formation [15,17] and to more self-assembly-oriented methods, such as the Monte Carlo [18][19][20][21][22] and molecular dynamics [23] simulations. While quantum methods (e.g., density functional theory, DFT) correspond to zero-Kelvin temperature and are usually limited to a few adsorbed molecules (interacting pairs or clusters), MC calculations allow for modeling of large molecular assemblies comprising thousands of units at finite temperatures.…”

Theoretical insights into the interplay between metal–organic and covalent bonding in single-layer molecular networks formed by halogen dissociation

“…17,23 The MC methods were employed to study the metal–organic polymerization of halogenated molecules on solid surfaces. 24–29 Disordered covalent networks were also examined. 30 The assemblies of symmetric tetratopic molecular building blocks were also extensively explored in the MC studies.…”