Berlin 2018 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 33: Biomedical and molecular magnetism

MA 33.9: Vortrag

Mittwoch, 14. März 2018, 17:15–17:30, H 1012

X-ray magnetic spectroscopy study of switchable photomagnetic cages — •Niéli Daffé¹, Michal Studniarek¹, Juan-Ramón Jiménez², Rodrigue Lescouëzec², and Jan Dreiser¹ — ¹Paul Scherrer Institut, 5232 Villigen PSI, Switzerland — ²Institut Parisien de Chimie Moléculaire, UPMC, F-75252 Paris, France

Molecules exhibiting switchable physical properties as a function of external stimuli have promising applications in molecule-based electronic devices. Therefore, the past decade has witnessed considerable interest in the design of new molecular systems with tunable functionalities. The most encouraging groups of compounds have emerged from the family of Prussian Blue Analogues (PBAs) that are known to exhibit concomitant changes in their magnetic and optical properties based on a metal-to-metal electron transfer when they are submitted to a temperature or light stimulus (D. Aguilà et al., Chem. Soc. Rev. 45, 203-224, 2016). Molecular cubes based on Co and Fe 3d transition ions linked by cyanide bridges are a prime example of a reversible conversion occurring between the diamagnetic (Fe_LS^II-CN-Co_LS^III) pairs and the paramagnetic (Fe_LS^III-CN-Co_HS^II) ones (D. Garnier et al., Chem. Sci. 7, 4825-4831, 2016). However, our understanding of the metal-to-metal charge transfer remains one of the key issues faced when studying PBAs, and it requires better insights on the geometry and the nature of the coordinated atoms. Using X-ray absorption spectroscopy and X-ray magnetic circular dichroism, we shed light onto the electronic and magnetic properties of the Co and Fe ions inside the CoFe photomagnetic cage upon temperature change and light irradiation.