The Department of Functional Materials and Catalysis invites to a seminar with

Ass. Prof. Dr. Heidi Schwartz:

Transferring optical properties to the solid state – utilizing porous MOFs as nano-vessels for dye molecules

Abstract:

Since the publication of MOF-5 in 1999[1], the class of metal-organic frameworks (= MOFs) has been intensively studied regarding numerous applications, which are due to their porosity. Among those, their exploitation as host matrices for photoactive dye molecules is very attractive. Here, photochromic molecules are of special interest, as their light induced structural transformation requires a certain degree of sterical freedom, which is not given in the pristine solid. The MOF pores do not only separate these molecules from each other to enable the photoswitching process, but also specifically interact with them. That way, the occurring interaction motifs can directly be related to the optical properties of the overall material. A wide range of photochromic molecules such as fluorinated azobenzenes[2,3], spiropyrans[4–6], spirooxazines[7], diarylethenes[8], fulgides[9] and dihydroazulenes[10] has been embedded in various MOFs and the occurring properties have been studied in detail. The resulting switch@MOF systems do not only show photochromic, but also solvatochromic response and host- as well as guest- dependent optical response. Additionally, luminescence of thioindigo[11] was studied as a function of local environment: when inserted inside MOFs of varying polarity, an enhanced fluorescence is found with short decay times. The insertion of dye molecules as non-covalently bound guests inside MOF paves the way to unprecedented properties, which are of high interest in applications such as data storage or memory devices, optoelectronics or even battery materials.

[1]    H. Li, M. Eddaoudi, M. O’Keeffe, O. M. Yaghi, Nature 1999, 402, 276–279.
[2]    M. Rödl, S. Kerschbaumer, H. Kopacka, L. Blaser, F. R. S. Purtscher, H. Huppertz, T. S. Hofer, H. A. Schwartz, RSC Adv. 2021, 11, 3917–3930.
[3]    M. Rödl, A. Reka, M. Panic, A. Fischereder, M. Oberlechner, T. Mairegger, H. Kopacka, H. Huppertz, T. S. Hofer, H. A. Schwartz, Langmuir 2022, 38, 4295–4309.
[4]    H. A. Schwartz, S. Olthof, D. Schaniel, K. Meerholz, U. Ruschewitz, Inorg. Chem. 2017, 56, 13100–13110.
[5]    S. Kremer, I. Ober, V. Greussing, H. Kopacka, H. G. Gallmetzer, D. Demmel, S. Olthof, H. Huppertz, H. A. Schwartz, Langmuir 2021, 37, 7834−7842.
[6]    V. Greussing, J. M. Gallmetzer, H. Huppertz, T. S. Hofer, H. A. Schwartz, J. Phys. Chem. C 2022, 2022, 10923–10931.
[7]    H. A. Schwartz, M. Werker, C. Tobeck, R. Christoffels, D. Schaniel, S. Olthof, K. Meerholz, H. Kopacka, H. Huppertz, U. Ruschewitz, ChemPhotoChem 2020, 4, 195–206.
[8]    H. A. Schwartz, H. Laurenzen, S. Kerschbaumer, M. Werker, S. Olthof, H. Kopacka, H. Huppertz, K. Meerholz, U. Ruschewitz, Photochem. Photobiol. Sci. 2020, 19, 1730–1740.
[9]    C. Eichler, A. Rázková, F. Müller, H. Kopacka, H. Huppertz, T. S. Hofer, H. A. Schwartz, Chem. Mater. 2021, 33, 3757–3766.
[10]    K. Küssner, R. V. Listyarini, M. Rödl, S. Olthof, K. Meerholz, T. S. Hofer, H. A. Schwartz, Chem. Mater. 2023, 35, 6953–6865.
[11]    A. Fischereder, M. Rödl, M. Suta, T. S. Hofer, H. A. Schwartz, J. Phys. Chem. C 2023, 127, 127–15657.