Densely Packed CO 2 Aids Charge, Spin, and Lattice Ordering Partially Fluctuated in a Porous Metal-Organic Framework Magnet.

Partial charge fluctuations in the charge-ordered state of a material, often triggered by structural disorders and/or defects, can significantly alter its physical characteristics, such as magnetic long-range ordering. However, it is difficult to post-chemically fix such accidental partial fluctuations to reconstruct a uniform charge-ordered state. Herein, we report CO ₂ -aided charge ordering demonstrated in a CO ₂ -post-captured layered magnet, [{Ru ₂ (o-ClPhCO ₂ ) ₄ } ₂ {TCNQ(OMe) ₂ }] ⋅ CO ₂ (1⊃CO ₂ ; o-ClPhCO ₂ ^- =ortho-chlorobenzoate; TNCQ(OMe) ₂ =2,5-dimethoxy-7,7,8,8-tetracyanoquinodimethane). Pristine porous layered magnet 1 had a partially charge-fluctuated ordered state, which provided ferrimagnetic ordering at T _C =65 K. Upon loading CO ₂ , 1 adsorbed one mole of CO ₂ , forming 1⊃CO ₂ , and raising T _C to 100 K. This was because of the vanishing charge fluctuations without significantly changing the framework structure. This research illustrates the post-accessible host-guest chemistry delicately combined with charge, spin, and lattice ordering in a spongy magnet. Furthermore, it highlights how this innovative approach opens up new possibilities for technology and nanoscale magnetism manipulation.
(© 2023 The Authors. Angewandte Chemie International Edition published by Wiley-VCH GmbH.)