Intelligent molecular magnetic material devices and extremely low temperature magnetic refrigeration equipment

Molecular magnetism is a frontier interdisciplinary subject that spans synthetic chemistry, quantum chemistry, physical chemistry and condensed matter physics. The magnetic properties of molecules mainly come from the contribution of electron spin and orbital angular momentum of metal ions or free radicals, which is one of the basic properties of matter. One of the focuses of molecular magnetism research is to regulate the spin states, magnetic anisotropy and magnetic interaction of metal ions through molecular structure design and modification, to give molecular materials specific magnetic properties and external field response characteristics, such as molecular magnets, spin variation, magnetic refrigeration and other functions, and reveal the structural performance relationship between molecular spintronic structure and intrinsic physical properties. Promote its application in high-density information storage, molecular magnetic switching and sensing, spintronics, quantum information technology, extremely low-temperature refrigeration and other fields. Since its establishment in 2010, our research group has been committed to researching photoresponsive molecular magnetic materials. Compared with traditional photoresponsive organic molecular systems, photoinduced electron transfer can regulate the spintronic structure of solid molecules at the femtosecond scale and electron level, without causing problems such as low conversion efficiency and poor fatigue resistance caused by violent atomic displacement. Therefore, the research group proposed the use of light-controlled reversible electron transfer of metal ions to regulate magnetism (Nature Chemistry 2021, 13, 698-704; CCS Chemistry 2023, 5, 865-875; Chemical Science 2018, 9, 617-622), Electricity (Angew.chem.in.ed. 2022, 61, e202115367; Angew.Chem.Int.Ed. 2022, 61, e202208208), fluorescence (CCS Chemistry 2023, 5, 915-924; Chemical Science 2023, 14, 6936-6942; Chemical Science 2018, 9, 2892-2897.) and thermal expansion deformation (Angew.chem.in.ed. 2023, 62, e202302815; Angew.chem.in.ed. 2017, 56, 13052-13055) and other functions, forming the characteristic research direction of "electron transfer regulation of light-manipulated metal ions". Based on the above research basis, the research group will continue to focus on the basic research direction of multistage structure design and coupling control of physical properties of photoresponsive molecular magnetic materials, and carry out its application exploration and research in key frontier fields such as nonlinear optics, molecular spintronics, spin quantum devices and extremely low temperature magnetic refrigeration. It mainly includes the following sub-directions:

1. Intelligent manufacturing of photoresponsive molecular magnetic materials and spin quantum devices

2. Study on the structure design and physical property regulation of rare-earth-based molecular polyferric materials;

3. Development of high-performance rare earth magnetic refrigeration materials and extremely low temperature adiabatic demagnetization refrigeration  device.

Magnetic catalytic materials and engineering applications

Electrons have intrinsic spin quantum degrees of freedom, and the physical and chemical reactions in which electron spins participate play a very important role in the natural and living systems. Studies have shown that the annual migration of Arctic terns to and from the North and South Poles (70,000 km) is associated with a spin selective response (quantum compass model). The theory suggests that terns generate radical pairs through the perception of natural light by cryptochrome present in the retina, and the latter changes the quantum entangled state of the singlet-triplet in the presence of the geomagnetic field to obtain orientation information. In addition, the catalytic reaction involving trilinear O2 is also considered to be closely related to the degree of spin polarization of the catalyst material. Magnetic field induced spin polarization on the surface of the ferromagnetic electrode can make the spin of the oxygen intermediates align in parallel, thus reducing and enhancing the oxygen production efficiency of electrocatalytic OER. However, due to the huge differences in energy scales between intrinsic chemical reactions and spin splitting (including but not limited to spin-spin, spin-orbit and spin-Zeeman interactions), chemical reactions related to spin selection are still rarely reported, and the chemical reactions and regulatory mechanisms involved in spin are still unclear. Therefore, in-depth research on the spintronic structure of catalyst materials, spin selectivity in catalytic reactions and the mechanism of magnetic field-assisted photochemical reactions is expected to bring new perspectives for understanding the life chemical activities involved in spin and developing magnetic catalysts with high spin selectivity and product selectivity. And applied to the engineering production of related chemicals. Based on the design concept and control strategy of molecular magnetic materials, the spintronic structure and magnetic structure of the catalyst were reconstructed by magnetic engineering and spin engineering, and chiral structures were introduced by coordination chemistry to generate chiral induced spin selectivity (CISS, chiral-induced spin selectivity). The intrinsic relationship between spin structure and catalytic processes is studied to discover more spin chemical reactions, thus promoting potential applications in engineering scenarios.

Magnetic diagnosis and treatment integrated material and in situ multi-channel molecular optical characterization platform and high resolution spatiotemporal imaging

Research on novel intelligent molecular magnetic materials and magnetic catalytic materials involves collaborative characterization and analysis of multi-weight properties under multiple physical fields, and requires in situ multi-channel spectroscopy characterization platform, molecular device preparation platform and multi-physical field comprehensive physical property measurement system to support relevant research. The research group will build an optical platform of variable temperature ultrafast circular dichroism, expand nonlinear optical response detection by using the output characteristics of double optical paths, realize an ultrafast spectral platform integrating fluorescence, Raman, circular dichroism and nonlinear optical measurement, and develop a multifunctional measurement device of multi-physical field interactive response photoelectric-magnetic-thermal and related functional accessories.