Self-assembly of a catechol-based macrocycle at the liquid–solid interface: experiments and molecular dynamics simulations

J. Saiz-Poseu, A. Martínez-Otero, Th.Roussel, J. Faraudo, J.K.-H. Hui, M. L. Montero, R. Urcuyo, M. J. MacLachland, D. Ruiz-Molina

Phys. Chem. Chem. Phys., 14, 11937-11943, (2012)
DOI: 10.1039/C2CP41407D

http://pubs.rsc.org/en/content/articlehtml/2012/cp/c2cp41407d

Abstract: This combined experimental (STM, XPS) and molecular dynamics simulation study highlights the complex and subtle interplay of solvent effects and surface interactions on the 2-D self-assembly pattern of a Schiff-base macrocycle containing catechol moieties at the liquid–solid interface. STM imaging reveals a hexagonal ordering of the macrocycles at the n-tetradecane/Au(111) interface, compatible with a desorption of the lateral chains of the macrocycle. Interestingly, all the triangular-shaped macrocycles are oriented in the same direction, avoiding a close-packed structure. XPS experiments indicate the presence of a strong macrocycle–surface interaction. Also, MD simulations reveal substantial solvent effects. In particular, we find that co-adsorption of solvent molecules with the macrocycles induces desorption of lateral chains, and the solvent molecules act as spacers stabilizing the open self-assembly pattern.

Self-assembly of a catechol-based macrocycle at the liquid–solid interface: experiments and molecular dynamics simulations
Snapshots from MD simulations S4A and S4B. In this figure, (a) and (c) panels correspond to lateral and top views of a snapshot from the simulations performed in the absence of solvent, whereas the (b) and (d) panels correspond to simulations in the presence of n-tetradecane. In (b) all solvent molecules are shown (yellow translucent lines), whereas in (d) we shown those solvent molecules adsorbed onto the gold surface.