Switchable Self-Assembly of a Bioinspired Alkyl Catechol at a Solid/Liquid Interface: Competitive Interfacial, Noncovalent, and Solvent Interactions

J Saiz-Poseu, J. Faraudo, A. Figueras, R. Alibes, F. Busqué and D. Ruiz-Molina

Chemistry - A European Journal, 18, 3056 - 3063, (2012)
DOI: 10.1002/chem.201101940

http://onlinelibrary.wiley.com/doi/10.1002/chem.201101940/abstract

Abstract: The large tendency of catechol rings to adsorb on surfaces has been studied by STM experiments with molecular resolution combined with molecular-dynamics simulations. The strong adhesion is due to interactions with the surface and solvent effects. Moreover, the thermodynamic control over the differential adsorption of 1 and the nonanoic solvent molecules has been used to induce a new temperature-induced switchable interconversion. Two different phases that differ in their crystal packing and the presence of solvent molecules coexist upon an increase or decrease in the temperature. These results open new insight into the behavior of catechol molecules on surfaces and 2D molecular suprastructures.

Switchable Self-Assembly of a Bioinspired Alkyl Catechol at a Solid/Liquid Interface: Competitive Interfacial, Noncovalent, and Solvent Interactions
A 3D representation of the tentative mechanism proposed for the transition from the α to β phase. a) Molecules in solution; b) arrangement of the molecules in the α-phase unit cell; c) the coadsorbed solvent molecules are desorbed from the surface during annealing to leave voids in the monolayer; d) the 4-heptadecylcatechol molecules rearrange to fulfill the free room, thus giving rise to the β phase.