Stimuli-responsive 2D assemblies of nitrogen-functionalized tris-stilbene derivatives

1,3,5-Tris[(E)-2-(3,5-didodecyloxyphenyl)-ethynyl]-benzene (TSB) and its derivatives are valuable molecules due to their ability to self-assemble on solid substrates and to act as templates for the organization of functional molecules or nano-objects. Although TSB has been extensively studied as a supramolecular seed, the description of new derivatives bearing functional groups remains scarce and investigations into their responsiveness to various stimuli are still limited. In this work, we report the preparation of a new TSB derivative functionalized with pyridine groups on the peripheral rings. Its responsiveness to different stimuli, such as temperature and chemical activation, is studied and compared with that of a TSB derivative based on a central triazine core. The latter undergoes a hexagonal-to-rhombic lattice structural change under annealing, but no structural change occurs with acidic treatment, whereas the TSB derivative with pyridine groups on the peripheral rings shows inertness under annealing and hexagonal-to-rhombic lattice structural rearrangement in the presence of acetic acid. We observe in both cases the emergence of a network with a very large-scale periodicity after the application of stimuli, and notice that molecular functionalization plays a crucial role in the responsiveness of the system.