(Magneto)Chiroptical spin crossover switches – from crystals to nanomaterials

The MagChirSwitch MSCA-PF project pioneers cutting-edge chiral Fe(II) and Fe(II)Ln(III) materials, leveraging spin-crossover (SCO) phenomena to achieve unprecedented control over chiroptical and magneto-chiroptical effects. Focusing on magneto-chiral dichroism (MChD) and (magnetic) circularly polarised luminescence ((M)CPL), MagChirSwitch aims to be the first to follow these phenomena over Fe(II) transitions, driven by the design of innovative chiral SCO complexes. The bistability of Fe(II) ions between paramagnetic and diamagnetic states offers breakthrough potential for switching chiroptical properties – an unexplored frontier that could redefine magneto-chiral materials and expand SCO applications.The project unfolds in two phases. The first focuses on the development of chiral SCO crystalline materials and the successful detection of MChD and/or (M)CPL switching, triggered by temperature (thermally-induced SCO) or light (light-induced excited spin-state trapping, LIESST). This molecular approach enables precise design and rapid optimisation of magnetic and chiroptical properties. The second phase pushes the boundaries by transferring these magneto-switching effects to nanomaterials, advancing their real-world application potential. Nanomaterials that retain these switching abilities will enable scalable production, such as thin films for next-generation magneto-chiroptical devices. Additionally, transitioning to nanoparticles may reveal novel phenomena, such as shape changes linked to Fe(II) spin transitions.MagChirSwitch will profoundly enhance the post-doctoral fellow’s expertise by exposing her to advanced synthesis and measurement techniques (including MChD measurements during short visits at LNCMI, CNRS), as well as interdisciplinary collaboration. This experience will be pivotal in launching her academic career, equipping her to lead her own research group at a university in Europe and securing high-impact research funding.