A Chiral Prussian Blue Analogue Pushes Magneto-Chiral Dichroism Limits

Matteo Atzori; Ivan Breslavetz; Kévin Paillot; Katsuya Inoue; Geert L J A Rikken; Cyrille Train

doi:10.1021/jacs.9b10970

A Chiral Prussian Blue Analogue Pushes Magneto-Chiral Dichroism Limits

J Am Chem Soc. 2019 Dec 26;141(51):20022-20025. doi: 10.1021/jacs.9b10970. Epub 2019 Dec 10.

Authors

Matteo Atzori¹, Ivan Breslavetz¹, Kévin Paillot¹, Katsuya Inoue², Geert L J A Rikken¹, Cyrille Train¹

Affiliations

¹ Laboratoire National des Champs Magnétiques Intenses (LNCMI) , Univ. Grenoble Alpes, INSA Toulouse, Univ. Toulouse Paul Sabatier, EMFL, CNRS, Grenoble F-38042 , France.
² Department of Chemistry and Center for Chiral Science , Hiroshima University , Hiroshima 739-8524 , Japan.

PMID: 31800226
DOI: 10.1021/jacs.9b10970

Abstract

Here we report on magneto-chiral dichroism (MChD) detected with visible light on the chiral Prussian Blue Analogue [Mn^II(X-pnH)(H₂O)][Cr^III(CN)₆]·H₂O (X = S, R; pn = 1,2-propanediamine). Single crystals suitable for magneto-optical measurements were grown starting from enantiopure chiral ligands. X-ray diffraction and magnetic measurements confirmed the 2D-layered structure of the material, its absolute configuration, and its ferrimagnetic ordered state below a critical temperature T_C of 38 K. Absorption and MChD spectra were measured between 450 and 900 nm from room temperature down to 4 K. At 4 K the electronic spectrum features spin-allowed and spin-forbidden transitions of Cr^III centers, spin-forbidden transitions of the Mn^II centers, and metal-to-metal charge transfer bands. The MChD spectra below the magnetic ordering temperature exhibit intense absolute configuration-dependent MChD signals. The temperature dependence of these signals closely follows the material magnetization. Under a magnetic field of 0.46 T, the most intense contribution to MChD represents 2.6% T^-1 of the absorbed intensity, one of the highest values observed to date.