Rare-Earth Metal Tetrathiafulvalene Carboxylate Frameworks as Redox-Switchable Single-Molecule Magnets

Using the redox-active tetrathiafulvalene tetrabenzoate (TTFTB4-) as the linker, a series of stable and porous rare-earth metal-organic frameworks (RE-MOFs), [RE9(mu(3)-OH)(13)(mu(3)-O)(H2O)(9)(TTFTB)(3)] (1-RE, where RE=Y, Sm, Gd, Tb, Dy, Ho, and Er) were constructed. The RE9(mu(3)-OH)(13)(mu(3)-O) (H2O)(9)](CO2)(12) clusters within 1-RE act as segregated single-molecule magnets (SMMs) displaying slow relaxation. Interestingly, upon oxidation by I-2, the S=0 TTFTB4- linkers of 1-RE were converted into S=1/2 TTFTB.3- radical linkers which introduced exchange-coupling between SMMs and modulated the relaxation. Furthermore, the SMM property can be restored by reduction in N,N-dimethylformamide. These results highlight the advantage of MOFs in the construction of redox-switchable SMMs.

Automated summary

In this study, stable and porous rare-earth metal-organic frameworks (RE-MOFs) were constructed using redox-active tetrathiafulvalene tetrabenzoate as the linker. The single-molecule magnets (SMMs) displayed slow relaxation and the property was modulated by oxidation and reduction reactions. The results highlight the advantage of MOFs in constructing redox-switchable SMMs.