Solvent-Induced\nMagnetic Properties of a Series of\nDy-Based MOFs from Two Different Precursor Complexes

It is still challenging for Dy-MOFs to modulate the single-molecule\nmagnet (SMM) behavior through guest molecules. Dy-MOFs with different\nguest molecules, secondary building units, and linkers were synthesized\nby precursors and bridging carboxylic acid ligands, and the magnetic\nproperties of Dy-MOFs were regulated by guest molecules. These differentiated\nDy-MOFs are [Dy<sub>2</sub>(C<sub>9</sub>H<sub>4</sub>Cl<sub>2</sub>NO)<sub>2</sub>(L1)<sub>2</sub>(H<sub>2</sub>O)(DMA)]<sub>n</sub>·DMA (<b>MOF-3</b>, L1 = terephthalate), [Dy­(C<sub>9</sub>­H<sub>4</sub>­Cl<sub>2</sub>­NO)<sub>2</sub>­(L1)­(DMSO)(H<sub>2</sub>O)]<sub>n</sub> (<b>MOF-4</b>), [Dy<sub>2</sub>­(C<sub>9</sub>­H<sub>4</sub>­Br<sub>2</sub>­NO)<sub>2</sub>­(L1)<sub>2</sub>­(H<sub>2</sub>O)­(DMA)]<sub>n</sub>·DMA (<b>MOF-5</b>), [Dy­(C<sub>9</sub>­H<sub>4</sub>­Cl<sub>2</sub>­NO)<sub>2</sub>­(L2)­(H<sub>2</sub>O)]<sub>n</sub>·DMA (<b>MOF-6</b>, L2 = iso­phthalate), and [Dy­(C<sub>9</sub>­H<sub>4</sub>­Cl<sub>2</sub>­NO)<sub>2</sub>­(L2)­(H<sub>2</sub>O)]<sub>n</sub>·DMF (<b>MOF-7</b>), [Dy­(C<sub>9</sub>­H<sub>4</sub>­Br<sub>2</sub>­NO)<sub>2</sub>­(L2)­(H<sub>2</sub>O)]<sub>n</sub>·DMA (<b>MOF-8</b>). The single-crystal X-ray diffraction showed that <b>MOF-3</b> and <b>MOF-5</b> are two-dimensional MOFs with square holes. <b>MOF-4</b> is a two-dimensional MOF formed by hydrogen–halogen\nbonds, and <b>MOF-6</b>, <b>MOF-7</b>, and <b>MOF-8</b> are one-dimensional chains. The magnetic test results show that <b>MOF-4</b>, <b>MOF-6</b>, and <b>MOF-8</b> show SMM\nbehavior under zero field, and <b>MOF-3</b> and <b>MOF-5</b> exhibit field-induced SMM behavior. In the zero field, the effective\nenergy bases of <b>MOF-4</b>, <b>MOF-6</b>, and <b>MOF-8</b> are 37.09, 19.56, and 15.73 K, and relaxation times\nτ<sub>0</sub> were 4.66 × 10<sup>–6</sup>, 2.35\n× 10<sup>–6</sup>, and 9.95 × 10<sup>–6</sup> s, respectively. This work provides a vivid example of regulating\nthe molecular magnetism of Dy-MOFs and promotes the progress of Dy-MOF\ncrystal engineering.