Coordination-induced Spin State Switching in Redox-responsive Viologen-based Metalloporphyrins

Shaymaa Al-Shehimy (1) , Elise Dumont (1) , Denis Frath (1) , Floris Chevallier (1) , Christophe Bucher (1)

1 LC - Laboratoire de Chimie - UMR5182

The control of magnetic properties by external stimuli has attracted much interest over the past few decades and tremendous work has been achieved thereafter.1 Our contribution to this field is based on the Coordination-induced Spin State Switching approach (CiSSS)2 which, as its name implies, aims at changing the spin state of a porphyrin-complexed metal center by modifying its coordination sphere. Therefore, based on our expertise in supramolecular chemistry and with the help of theoretical calculations, a well-suited model system was designed and eventually synthesized. In this presentation, the targeted tweezer-like molecule features a redox-responsive viologen-based hinge tethering a high affinity ligand to a magnetically active metal center. In agreement with the concept depicted below, the electrical stimulation of the hinge is expected to trigger a large amplitude molecular motion driven by the reversible, intramolecular π-dimerization of the electrochemically-generated viologen cation radicals.3,4 This fully reversible back and forth self-locking process will enable to control the coordination/dissociation of the ligand to/from the metalloporphyrin and, consequently, the metal’s spin state. The switching process will be discussed on the grounds of spectroscopic, electrochemical and spectro-electrochemical data supported by quantum calculations.

Domaines: Chimie

Shaymaa Al-Shehimy, Elise Dumont, Denis Frath, Floris Chevallier, Christophe Bucher. Coordination-induced Spin State Switching in Redox-responsive Viologen-based Metalloporphyrins. journée Scientifiques du GDR MAPYRO (Macrocycles Pyrroliques), May 2021, web meeting, France. ⟨hal-03435816⟩