Dichotomous On-Surface Self-Assembly of Tripod Molecules with Anchor Like Interaction Pattern

Abstract

Recent development of methods to fabricate low dimensional molecular structures has enabled tailoring their architecture using building blocks with suitably encoded structural and chemical properties. In this contribution we study structure formation in adsorbed assemblies comprising model tripod molecules equipped with terminal arm segments providing short-range directional interactions. The interaction directions were assigned in a specific anchor like pattern which enabled the creation of diverse intermolecular connections. To explore the on-surface self-assembly of these functional units the coarse grained lattice Monte Carlo simulation method was used in which the molecules were represented as collections of interconnected segments adsorbed on a triangular lattice. Our theoretical investigations focus on the effect of symmetry and size of molecular backbone on the outcome of the 2D self-assembly. The simulations revealed the formation of complex superstructures of two types including porous networks with diverse nanocavities and nanoribbons characterized by a constant width. Occurrence of these different assemblies was found to be strongly dependent on the molecular symmetry and aspect ratio, highlighting the decisive role of the arm length distribution in the tripod building block. The theoretical results of this study can be helpful in designing new low-dimensional superstructures which are stabilized be weak intermolecular interactions as well as by covalent bonds formed in on-surface reactions such as the Ullmann coupling.

On-Surface Self-Assembly of Metal-Organic Architectures: Insights from Computer Simulations

“…To conclude, the structures obtained in nonracemic assemblies comprising star-shaped ligands A – E and metal atoms M II are very similar (in terms of topology) to the structures simulated in our previous contributions, where hydrogen-bonding molecular entities with the same size, shape, and distribution of active centers were considered. , For the racemic metal-organic overlayers shown in Figure , the similarities to analogous supramolecular structures stabilized by linear hydrogen bonds are also noticeable and manifest itself in the formation of ordered, chiral, ladder-like patterns, which are randomly distributed among disordered molecular connections . Interestingly, the topology of the racemic mixture comprising surface enantiomers D R ⋮ D S and metal atoms M II (Figure a) is also very similar to its simulated counterpart cemented by the linear hydrogen bonds …”

Effect of an axial ligand on the self-assembly of molecular platforms

“…20 Plenty of other triangular, but essentially planar, molecules have been studied. [26][27][28][29][30][31][32][33] For example, trimesic acid (TMA) molecules form various porous networks with honeycomb or hexagonal symmetries. [34][35][36][37] As an exception from this rule, a structure of alternating stripes of TMA molecules was reported from a liquid-solid interface.…”