Hrudya Pariyacheri Padikkal PhD defense

Présentation

**Condensed Matter and Electroactive Systems** (MaCSE) team

**Abstract** Redox-active electron-rich molecules have raised a strong interest for their promising applications in organic electronics. In addition to their conducting properties, introducing paramagnetic metal complexes like FeCl4– or FeBr4– can extend their functionalities. In this thesis, we take advantage of an intermolecular interaction called chalcogen bonding (ChB), to induce such magnetic interactions. We focus on selenium-based organic electron donors different from tetraselenafulvalenes, and characterized, in their cation radical state, by a strong spin density in positions readily available for interactions with magnetic anions. Moreover, these molecules in their radical state develop around the Se atoms, electron deficient regions called σ-holes, able to interact through ChB with counter ions. This thesis focuses on the activation of σ-holes in the cation radical salts and charge-transfer omplexes (with TCNQFn, n = 0, 1, 2, 4 as electron acceptors) of selenium-rich electron donors such as 1,2 diselenoles (naphthalene peri-diselenides and tetraselenides), and selenanthrenes. It highlights the potential of σ-hole engineering as a bridge between molecular, electronic structure and material properties.

**Jury** Piétrick HUDHOMME, Professor, University of Angers / Reviewer Enrique ESPINOSA, Professor, University of Lorraine / Reviewer Flavia POP, CNRS Researcher, University of Angers / Examiner Fabrice POINTILLART, CNRS Research Director, University of Rennes, ISCR / Examiner Marc FOURMIGUE, CNRS Research Director, University of Rennes, ISCR / PhD Director Ie-Rang JEON, CNRS Researcher, University of Bordeaux, CRPP / PhD Co-Director

**Invited** Olivier JEANNIN, Research Engineer, University of Rennes, ISCR

**Contacts** Hrudya Pariyacheri Padikkal, hrudya.pariyacheri@univ-rennes.fr Marc Fourmigué, marc.fourmigue@univ-rennes.fr Olivier Jeannin, olivier.jeannin@univ-rennes.fr