Frontier Research Institute for Interdisciplinary Sciences
Tohoku University

Metal-organic frameworks (MOFs) are a class of crystalline molecular materials constructed from metal ions and organic ligands. Through rational design and synthesis of novel frameworks, MOFs that combine two functions, the “porosity” and “magnetic ordering”, also referred to as porous magnets, have spurred immense interest due to the potential applications such as magnetic sensors, switches, and separation media. The porosity enables the small molecules to enter the nano-sized pores of MOFs, which may provide electronic interactions or perturbations to the frameworks. On the other hand, the magnetic ordering stems from the coupling interactions of electron spins. Hence, it is promising to reversibly create or eliminate the magnetism of a porous magnet when the adsorption and desorption of guest molecules affect the electronic distribution. While the common gases such as carbon dioxide (CO₂), nitrogen (N₂), and oxygen (O₂), are some of the most attractive targets for adsorption, a large magnetism variation responding to selective gas sorption has rarely been reported, mainly because the gas usually shows weak interaction with the host framework. My research interest focuses on my newly discovered mechanism, i.e. Electronic State Modulation (ESM) to directly manipulate the intrinsic spin states and magnetic correlations of porous magnets by guest sorption especially common gases.