_**Organometallics: Materials & Catalysis**_ _(_[_OMC_](https://iscr.univ-rennes.fr/organometallics-materials-catalysis-omc)_) team_

_**Abstract**_
Single-chain magnets exhibit magnetic bistability at the molecular scale and hold promise for high-density information storage. Controlling them with light would provide an additional level of control. This work combines dithienylethene photochromic units, nitronyl-nitroxide radicals, and lanthanide(III) ions, with photoisomerization intended to modulate both magnetic exchange interactions and the ligand field around the metal.
Four dithienylethene–nitronyl-nitroxide diradicals and three monoradical analogs were synthesized and characterized. The most compact diradical, previously unreported, exhibits an antiferromagnetic exchange interaction multiplied by a factor of 100 upon ring closure—the strongest reported to date for this family—as well as the first ON/OFF photomodulation of the luminescence of a nitronyl-nitroxide radical.
The coordination of these ligands to lanthanide(III) ions led to the first complexes integrating dithienylethene–nitronyl-nitroxide units, in both open and closed forms. Their photochromic and magnetic properties were studied, particularly using torque magnetometry.
These results lay the foundation for the development of photocommutable single-chaine magnets based on radicals.

_**Jury**_
**Jennifer Molloy,** CNRS researcher, University Grenoble Alpes
**Ie-Rang Jeon**, CNRS researcher, University of Bordeaux
**David Canevet**, Professor, University of Angers
**Mauro Perfetti**, Professor, University of Florence
**Lucie Norel**, Professor, ISCR, University of Rennes / PhD Director
**Kevin Bernot**, Professor, INSA Rennes, ISCR, University of Rennes / PhD Co-Director

_**Contacts**_
[Louis Caussin](https://iscr.univ-rennes.fr/louis-caussin), _[Louis.caussin@univ-rennes.fr](mailto:Louis.caussin@univ-rennes.fr)_
[Lucie Norel](https://iscr.univ-rennes.fr/lucie-norel), _[lucie.norel@univ-rennes.fr](mailto:lucie.norel@univ-rennes.fr)_
[Kevin Bernot](https://iscr.univ-rennes.fr/kevin-bernot), _[kevin.bernot@univ-rennes.fr](mailto:kevin.bernot@univ-rennes.fr)_