Spontaneous Chiral Resolution of a Mn III Spin-Crossover Complex with High Temperature 80 K Hysteresis

• Published in: Chemistry : a European journal 2023-07, Vol.29 (37), p.e202300275
• Main Authors: Kelly, Conor T, Jordan, Ross, Felton, Solveig, Müller-Bunz, Helge, Morgan, Grace G
• Format: Article
• Language: English
• ISSN: 0947-6539; 1521-3765
• DOI: 10.1002/chem.202300275

Non-centrosymmetric spin-switchable systems are of interest for their prospective applications as magnetically active non-linear optical materials and in multiferroic devices. Chiral resolution of simple spin-crossover chelate complexes into the Δ and Λ forms offers a facile route to homochiral magnetic switches, which could be easily enantiomerically enriched. Here, we report the spontaneous resolution of a new hysteretic spin-crossover complex, [Mn (sal 323)]SCN ⋅ EtOH (1), into Δ and Λ forms, without the use of chiral reagents, where sal 323 is a Schiff base resulting from condensation of 1,2-bis(3-aminopropylamino)ethane with 2-hydroxybenzaldehyde. The enantiopurity of the Δ and Λ isomers was confirmed by single crystal X-ray diffraction and circular dichroism. Quantum chemistry calculations were used to investigate the electronic structure. The opening of a wide 80 K thermal hysteresis window at high temperature highlights the potential for good magneto-optical function at ambient temperature for materials of this type.