MS32-P11 Altering the solid-state photochromic behavior of N-salicylideneanilines molecular switches by co-crystallization Andrea Carletta (Namur Institute of Structured Matter (NISM), University of Namur, 61 rue de Bruxelles, Namur, Belgium) Nikolay Tumanov (Namur Institute of Structured Matter (NISM), University of Namur, 61 rue de Bruxelles, Namur, Belgium) Tom Leyssens (Institute of Condensed Matter and Nanosciences, Université Catholique de Louvain, Louvain-La-Neuve, Belgium) Benoît Champagne (Namur Institute of Structured Matter (NISM), University of Namur, 61 rue de Bruxelles, Namur, Belgium) Johan Wouters (Namur Institute of Structured Matter (NISM), University of Namur, 61 rue de Bruxelles, Namur, Belgium)email: andrea.carletta@unamur.beN-salicylideneaniline derivatives are among the most studied man-made thermo- and photo-switchable systems. These systems can switch between three different colored forms: an enol colorless form, a yellow cis-keto form and a red trans-keto form. A thermal tautomeric equilibrium between the enol and cis-keto form accounts for their thermochromism, whereas a cis-trans photoisomerization between the cis-keto form and the trans-keto form is the mechanism behind their photochromism. Photochromism can lead to a broad range of applications, i.e. in information storage and electronic display systems or in optical switching devices like ophthalmic glasses. However, due to the volume requirements of the cis-trans photoisomerization, photochromism is not easily encountered in the solid state. For this reason, we have used co-crystallization with the aim to induce photochromism in a non-photochromic N-salicylideneaniline chromophore. Our results (single-crystal structures and UV-vis diffusion reflectance) reveal how co-crystallization can be successfully employed for this purpose due to the fact that it changes both the free available volume of each molecule in the crystal and the intermolecular interactions.[1,2] 
 
References:

[1] Carletta, A, et al. (2017). Chem. - A Eur. J., 23, 5317–5329.

[2] Carletta, A, et al. (2016) J. Phys. Chem. C, 120, 10001–10008.

Keywords: Co-crystals, photochromism, N-salicylideneanilines