Mitcov Dmitri, Platunov Mikhail, Buch Christian D, Reinholdt Anders, Døssing Anders R, Wilhelm Fabrice, Rogalev Andrei, Piligkos Stergios
Department of Chemistry, University of Copenhagen Universitetsparken 5 DK-2100 Copenhagen Denmark
ESRF - The European Synchrotron CS 40220 38043 Grenoble Cedex 9 France
Chem Sci. 2020 Jul 30;11(31):8306-8311. doi: 10.1039/d0sc02709j.
Magnetochiral dichroism (MΧD) originates in the coupling of local electric fields and magnetic moments in systems where a simultaneous break of space parity and time-reversal symmetries occurs. This magnetoelectric coupling, displayed by chiral magnetic materials, can be exploited to manipulate the magnetic moment of molecular materials at the single molecule level. We demonstrate herein the first experimental observation of X-ray magnetochiral dichroism in enantiopure chiral trigonal single crystals of a chiral mononuclear paramagnetic lanthanide coordination complex, namely, holmium oxydiacetate, at the Ho L-edge. The observed magnetochiral effect is opposite for the two enantiomers and is rationalised on the basis of a multipolar expansion of the matter-radiation interaction. These results demonstrate that 4f-5d hybridization in chiral lanthanoid coordination complexes is at the origin of magnetochiral dichroism, an effect that could be exploited for addressing of their magnetic moment at the single molecule level.
磁手性二色性（MΧD）源于空间宇称和时间反演对称性同时破缺的系统中局部电场与磁矩的耦合。手性磁性材料所表现出的这种磁电耦合可用于在单分子水平上操纵分子材料的磁矩。我们在此展示了在一种手性单核顺磁镧系配位络合物（即氧代二乙酸钬）的对映体纯手性三角单晶中，在Ho L边首次通过实验观测到X射线磁手性二色性。观察到的磁手性效应对于两种对映体是相反的，并基于物质 - 辐射相互作用的多极展开进行了合理化解释。这些结果表明，手性镧系配位络合物中的4f - 5d杂化是磁手性二色性的起源，这种效应可用于在单分子水平上调控其磁矩。
