Magnet Creation by Guest Insertion into a Paramagnetic Charge-Flexible Layered Metal-Organic Framework
Jun Zhang1,2, Wataru Kosaka2,3, Hiroyasu Sato4
1Frontier Research Institute for Interdisciplinary Sciences, Tohoku University, 6-3 Aramaki-Aza-Aoba, Aoba-ku, Sendai 980-8578, Japan.
Journal of the American Chemical Society
|April 15, 2021
Summary
Researchers transformed a nonmagnetic material into a bulk magnet by adsorbing guest molecules. This chemical modification creates tunable ferrimagnetic or antiferromagnetic properties in a metal-organic framework, demonstrating postsynthesis magnet creation.
Area of Science:
- Materials Science
- Magnetism
- Supramolecular Chemistry
Background:
- Transforming nonmagnetic materials into spontaneous magnets is a significant challenge in materials science.
- Metal-organic frameworks (MOFs) offer tunable electronic and structural properties.
- Controlling magnetic ordering (ferrimagnetism, antiferromagnetism) is crucial for advanced applications.
Purpose of the Study:
- To demonstrate the chemical modification of a nonmagnetic material into a bulk magnet.
- To investigate the influence of guest molecules on the magnetic properties of a MOF.
- To achieve postsynthesis control over magnetic phases (ferrimagnetic and antiferromagnetic).
Main Methods:
- Synthesis of a layered metal-organic framework, [{Ru2(2,4-F2PhCO2)4}2TCNQ(EtO)2] (1).
- Adsorption of various organic guest molecules (e.g., benzene, CS2) into the MOF framework.
- Characterization of structural and magnetic properties of the guest-free and guest-loaded MOFs.
Main Results:
- The guest-free MOF (1) is paramagnetic and undergoes a thermally driven electron transfer at 380 K.
- Guest molecule accommodation at room temperature induces intralattice electron transfer, forming ferrimagnetically ordered layers.
- The magnetic phase transitions to ferrimagnetism with guests like benzene and 1,2-dichloroethane, and to antiferromagnetism with carbon disulfide.
Conclusions:
- This study presents the first demonstration of postsynthesis creation of bulk magnets using guest-molecule accommodations in MOFs.
- The magnetic behavior (ferrimagnetism or antiferromagnetism) can be precisely tuned by selecting specific guest molecules.
- This approach offers a novel strategy for designing switchable magnetic materials with tailored properties.
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