Direct observation of charge transfer and magnetism in Fe&lt;sub&gt;4&lt;/sub&gt;Co&lt;sub&gt;4&lt;/sub&gt; cyanide-bridged molecular cubes

Daffé, Niéli; Jiménez, Juan-Ramón; Studniarek, Michał; Benchohra, Amina; Arrio, Marie-Anne; Lescouëzec, Rodrigue; Dreiser, Jan

doi:10.1021/acs.jpclett.8b03839

Direct observation of charge transfer and magnetism in Fe₄Co₄ cyanide-bridged molecular cubes

Daffé N, Jiménez J-R, Studniarek M, Benchohra A, Arrio M-A, Lescouëzec R & Dreiser J

Citation

Daffé, N., Jiménez, J. R., Studniarek, M., Benchohra, A., Arrio, M. A., Lescouëzec, R., & Dreiser, J. (2019). Direct observation of charge transfer and magnetism in Fe₄Co₄ cyanide-bridged molecular cubes. Journal of Physical Chemistry Letters, 10(8), 1799-1804. https://doi.org/10.1021/acs.jpclett.8b03839

Persistent URL https://www.dora.lib4ri.ch/psi/islandora/object/psi:21655

We have studied the zero-dimensional cubane molecular correspondent of a Prussian blue analogue Cs–Fe₄Co₄ at low temperature and high magnetic field by means of L-edge X-ray absorption spectroscopy and X-ray magnetic circular dichroism. We probe the magnetic and electronic structures of Fe and Co separately upon light irradiation, which allows us to observe directly the electron transfer coupled to a spin transition phenomenon within the molecular cubes and to investigate the nature of the metastable photoexcited state. The magnetic moments in the photoexcited state are found to be M = 1.3μ_B (M_spin = 0.59μ_B with large orbital moment, M_orbit = 0.74μ_B) for low-spin Fe^III and M = 1.5μ_B (M_spin = 1.08μ_B with orbital moment, M_orbit = 0.41μ_B) for high-spin Co^II at 2 K and 6.8 T. From our results, we evidence that a strong antiferromagnetic coupling between the metal ions can be ruled out.