Magnetic Tuning of an Anionic CoII -MOF through Deionization of the Framework: Spin-Canting, Spin-Flop, and Easy-Plane Magnetic Anisotropy.

An anionic CoII -MOF, (Me2 NH2 )[Co3 (Me2 NH)3 (OH)(SDBA)3 ] (1) (H2 SDBA=4,4'-sulfonyldibenzoic acid) consisting of highly symmetric CoII3 (µ3 -OH) triangles exhibits spin-canting, spin-flop, and easy-plane magnetic anisotropy. Measurement on a single crystal shows that the ab plane of 1 is the easy magnetization plane. After structural modification through simultaneous removal of the coordinated dimethylamine (DMA) molecule at the Co center and the ionic groups DMA+ and OH- , the resulting neutral amorphous framework 2 displays an enhanced spin frustration effect. The deionization of 1 does not result in the collapse of the framework, showing the high stability of the backbone structure.