Title : From magnetic anisotropy to molecular magnets: A journey into the coordination chemistry of pentagonal bipyramidal complexes.
Speaker : Prof. Jean-Pascal Sutter, Laboratoire de Chimie de Coordination du CNRS, Toulouse, France.
Date : 17/08/2022, 05:30 PM , Online Mode.
Magnetic anisotropy plays an important role in the behavior of magnetic materials. For instance, the hardness (i.e. coercive field) of bulk magnets is mainly proportional to the magnetic anisotropy, and the energy barrier for magnetization reversal of molecular nanomagnets, such as Single-Molecule Magnets (SMM) and Single-Chain Magnets (SCM), is intimately related to the zero-field splitting characteristics (D) of its individual building units. However, it is still challenging for chemists to control the actual magnetic anisotropy of the complexes, all the more so when they get involved in the construction of heterometallic magnets.
In this context, seven-coordinated 3d ion complexes with pentagonal bipyramidal (PBP) geometry (for example, as depicted in Figure 1) have been found of great relevance. Small or large ZFS D values (up to about +/- 30 cm-1) with a positive or negative sign can be rationally obtained simply by selecting the appropriate metal center;1 and these complexes can be used as basic units for the construction of heterometallic SMMs and SCMs.2
1 J.-P. Sutter, et al. Chem. Soc. Rev. 2022, 51, 3280.
2 C. Pichon, et al. Chem. Eur. J., 2021, 27, 15484; K. Bretosh, et al. Inorg. Chem. Front. 2020, 7, 1503; C. Pichon, et al. J. Am. Chem. Soc. 2018, 140, 7698; A. K. Bar; N. Gogoi, et al. Chem. Eur. J. 2017, 23, 4380; A. K. Bar, et al. Chem. Comm. 2015, 51, 3616; T. S. Venkatakrishnan, et al. J. Am. Chem. Soc., 2010, 132, 6047.