Article in The Journal of Physical Chemistry Letters (2024)
14 10 2024
A paper, co-authored by the PhD student Piotr Łaski and Prof. Katarzyna N. Jarzembska with her team, was published in the The Journal of Physical Chemistry Letters (American Chemical Society). The investigations published in the article entitled “Nanosecond-Lived Excimer Observation in a Crystal of a Rhodium(I) Complex via Time-Resolved X-ray Laue Diffraction” were realised in the cooperation with Prof. Alice Brink’s group from the University of the Free State, RSA. The published article was marked as the ‘Editor’s Choice’.
In-depth research on the interaction of light with matter is necessary to understand, among others: mechanisms of key (bio)chemical processes, the nature of excited states and structural dynamics. This knowledge can be used to design innovative, effective functional materials for applications in optoelectronics, solar batteries, sensors, etc. Since many of such materials are solid materials, crystals are a convenient model systems because they can be relatively easily studied using crystallographic methods. However, in order to track transient species, advanced measurement methods must be used, such as laser-pump / X-ray-probe methods combined with Laue diffraction. To achieve the required high time resolution, such experiments are mostly carried out at synchrotron sources, where short X-ray pulses can be generated. In our research group, we develop tools for processing and analyzing such photocrystallographic data.
In the presented article, using the above-mentioned measurement technique and using our own software, we have determined the structure of the excited state in the crystal of the Rh(I) coordination compound. We have observed the formation of an excimer based on the Rh···Rh interactions in a single crystal upon 390 nm laser pulse. The estimated lifetime of the system in the excited state at 100 K is 2 ns, making it the shortest-lived excited state in a “small molecule” molecular crystal captured experimentally using the laser-pump/X-ray-probe Laue method. After excitation with laser light, the intermolecular Rh···Rh distance shortens from 3.379(4) to 3.19(1) Å, and the metal-metal contact becomes more binding. Based on the experimental results and theoretical modelling, structural changes determined with a time resolution of 100 ps mainly reflect the S0 S1 electronic transition, and after 1 ns these changes are no longer experimentally detectable.
The research, the results of which were published in The Journal of Physical Chemistry Letters, was carried out as part of the NCN SONATA BIS (2020/38/E/ST4/00400) project.
Bibliographic data and link to the article:
P. Łaski, L. Bosman, J. Drapała, R. Kamiński, D. Szarejko, P. Borowski, A. Roodt, R. Henning, A. Brink, K. N. Jarzembska, The Journal of the Physical Chemistry Letters, 2024, 15, 10301