Steering the Surface-Confined Self-Assembly of Multifunctional Star-Shaped Molecules

Directing the self-assembly(SA) of small organic molecules intolow-dimensional porous patterns is a versatile method for the bottom-upfabrication of flat nanomaterials with controllable architecture andfunctions. However, the rational synthesis of the self-assembled monolayers(SAMs) requires carefully choosing the building blocks with a propersize, shape, and functionalization scheme. Among the molecular bricksused for this purpose, especially promising are the (N-hetero)aromatic star-shaped molecules equipped from three to sixelectronegative functional groups, providing anisotropic in-planeintermolecular interactions. Therefore, in this work, the surface-confinedSA of tripodal polytopic molecules was investigated using latticeMarkov chain Monte Carlo (MCMC) computer simulations in the canonicalensemble. Specifically, the simulated building blocks were equippedwith terminal interaction centers providing short-range directionalinteractions and represented on a flat triangular lattice in a simplifiedbut credible way. By altering the number and intramolecular positionof sticky sites attached to these rigid tectons, we observed the emergenceof various supramolecular constructs, including isolated well-shapedaggregates, two-dimensional (2D) open porous networks, and a seriesof hierarchically organized floral phases, which were classified accordingto their morphological properties. Our theoretical findings may behelpful in predicting the SA of pi-aromatic multifunctional tripodmolecules on close-packed crystalline surfaces and relevant to thescanning tunneling microscopy (STM) laboratory experimentalists seekingnew linkers for the construction of novel surface-supported supramolecularconstructs with a predefined topology.

Automated summary

Directing the self-assembly of small organic molecules into low-dimensional porous patterns is a versatile method for fabricating flat nanomaterials with controllable architecture and functions. In this study, the surface-confined self-assembly of tripodal polytopic molecules was investigated using computer simulations. By altering the number and position of sticky sites on the molecules, various supramolecular constructs were observed. These findings are relevant to experimentalists seeking new linkers for constructing surface-supported supramolecular constructs.