Conférence LCC
Dr Rodolphe Clérac
Université de Bordeaux
Optical and Magnetic Molecular Switches: from Solid State to Solution
Vendredi 25 janvier 2019 à 11h00 Auditorium Fernand Gallais
Campus CNRS 205
205, route de Narbonne, Toulouse
Contact LCC: Dr Eric Manoury , [email protected]
Retrouvez le programme complet des séminaires sur le site web du LCC : http://www.lcc-toulouse.fr/
Optical and Magnetic Molecular Switches: From Solid State to Solution
From Dr. Hab. Rodolphe Clérac
a CNRS, CRPP, UMR 5031, 115 Avenue du Dr. A. Schweitzer, Pessac, F-33600, France
b Université de Bordeaux, CRPP, UMR 5031, Pessac, F-33600, France Email: [email protected]
The design of molecule-based systems displaying tunable optical and/or magnetic properties under external stimuli received a great deal of attention in the past few years. This interest is driven by the potential applications in high-performance molecule-based electronics. As an example, 3D Fe/Co Prussian blue compounds exhibit a concomitant change in magnetic and optical properties due to a temperature- or light- induced metal-to-metal electron transfer (ET). The foregoing remarkable properties in Prussian blues prompted us to design soluble molecular fragments of these coordination networks through a rational building- block approach in order to mimic their properties on a single molecule (See Figure).[1-5] With a judicious choice of the ligands for metal ion precursors, we prepared a octanuclear,[1] tetranuclear[2] and recently dinuclear[3] cyanido-bridged Fe/Co complexes. In the solid state, while an intramolecular ET is observed for the [Co4Fe4] and [Co2Fe2] complexes,[1,2] the Co ion of our first dinuclear complex exhibits a spin crossover (SCO) involving a [FeIIILS-CN-CoIILS] ground state and a thermally populated [FeIIILS-CN-CoIIHS] state.[3] To our knowledge, this compound is the only example of a heterobimetallic complex exhibiting a CoII SCO.
Remarkably, our studies of these [ConFen] complexes in solution reveal important optical and magnetic changes induced by an intramolecular metal-to-metal ET triggered and modulated by a controlled protonation of the complex, by the solvent nature or by temperature. Therefore, these molecules act as different molecular switches depending on their physical state and external stimuli.[3] These results motivated us to design new
dinuclear [FeCo] complexes
exhibiting both thermally
and light induced electron
transfer in solid state. Learning
from these previous systems,
new dinuclear
complexes[4] have been
designed by a rational
building-block approach.[5]
Combined structural,
spectroscopic, magnetic
and photomagnetic studies reveal that a metal-to-metal electron transfer that can be triggered by light, temperature and lattice contents is observed for the first time in solid state for a dinuclear cyanido-bridged Fe/Co complex.[4]
Acknowledgements. We thank the Centre National de la Recherche Scientifique (CNRS), the Conseil Regional de Nouvelle Aquitaine, the University of Bordeaux and the ANR for financial support.
[1]. D. Li et al., J. Am. Chem. Soc. 130, 252-258 (2008).
[2]. Y. Zhang et al., Angew. Chem. Int. Ed. 49, 3752-3756 (2010) ; D. Siretanu, et al., Chem. Eur. J. 17, 11704-11708 (2011) ; Y. Zhang et al., J. Am. Chem. Soc. 136, 16854-16864 (2014).
[3]. I.-R. Jeon, et al., Chem. Sci. 4, 2463-2470 (2013).
[4]. E. S. Koumousi et al., J. Am. Chem. Soc. 136, 15461-15464 (2014).
[5]. D. Aguila, Y. Prado, E. S. Koumousi, C. Mathonière, R. Clérac, Chem. Soc. Rev. 45, 203-224 (2016).
