Article in Chemical Communications (2024)

03 09 2024

A paper, co-authored by the PhD student Kinga Potempa and Prof. Katarzyna N. Jarzembska with her team, was published in the Chemical Communications journal (Royal Society of Chemistry). The investigations published in the article entitled “Pressure-induced single-crystal-to-single-crystal nitrite ligand isomerisation accompanied by a piezochromic effect” were conducted thanks to the access to the European Synchrotron Radiation Facility (ESRF) in Grenoble, France. The published article was awarded the issue front cover.

Materials that respond to external stimuli (light pulse, pressure, temperature) and change their properties under their influence have been continuously attracting great interest. This is due to their potential wide application as various types of sensors, catalysts, optoelectronic switches, etc. Changes in the properties of materials often result from changes in their structure at the molecular level.

For several years, Katarzyna Jarzembska’s research group has been designing and researching new photoswitchable systems based on nitrite transition metal coordination compounds. The NO2 group bind to a metal centre in several ways, and the change of such a binding mode (usually nitro to nitrito) can be often induced by a light pulse of an appropriately selected wavelength. In the presented article it was checked whether it is possible to force switching between isomers by applying high pressure. It turns out that in the case of the most common nickel nitro complexes, isomerization does not occur under such conditions. However, by carefully selecting of the nitrite-nickel(II) complex with a specific molecular structure, it was possible to obtain a crystal in which the complex molecules adopt a rare (and energetically less stable) exo-nitrito form. As a result, the photoswitchable properties of the obtained material were limited, but the possibility of mechanically stimulated isomerization of the nitrite ligand opened up. Indeed, the applied pressure caused the most significant structural changes along the direction parallel to the exo-nitrito moiety, causing its isomerization. This is the first observation of pressure-induced nitrite group isomerization to date. Structural changes, including two phase transitions (0−6 GPa), are accompanied by a change in the colour of the crystal. These results open up new interesting perspectives for the applications of nitrite-based molecular switches

The research, the results of which were published in the September issue of the journal Chemical Communications, was carried out as part of the NCN projects SONATA BIS (2020/38/E/ST4/00400) and PRELUDIUM BIS (2019/35/O/ST4/04197).

Bibliographic data and link to the article:

Potempa, D. Paliwoda, K. N. Jarzembska, R. Kamiński, A. Krówczyński, P. Borowski, M. Hanfland, Chemical Communications 2024, 60, 9194

https://doi.org/10.1039/D4CC02898H