Fine Tuning the Energy Barrier of Molecular Nanomagnets via Lattice Solvent Molecules

Solvents play important roles in our lives, they are also of interest in molecular materials, especially for molecular magnets. The solvatomagnetic effect is generally used for trigger and/or regulation of magnetic properties in molecule-based systems, however, molecular nanomagnets showing solvatomagnetic effects are very difficult to obtain. Here we report four 3d-4f heterometallic cluster complexes containing ROH lattice solvent molecules, [Cu₃Tb₂(H₃L)₂(OAc)₂(hfac)₄]∙2ROH {H₆L = 1,3-Bis[tris(hydroxymethyl)methylamino]propane, hfac^- = hexafluoroacetylacetonate; R = CH₃, 1; R = C₂H₅, 2; R = C₃H₇, 3; R = H, 4}. Single-molecule magnet (SMM) properties of these four complexes were observed to be dependent on the ROH lattice solvent molecule. There is an interesting magneto-structural correlation: the larger the R group, the higher the energy barrier. For the first time, the solvatomagnetic effect is used for the continuous fine adjustment of the energy barrier of 0D molecular nanomagnets. Additionally, [Cu₃Dy₂(H₃L)₂(OAc)₂(hfac)₄]∙2MeOH (5), an analogue of [Cu₃Tb₂(H₃L)₂(OAc)₂(hfac)₄]∙2MeOH (1), is also reported for comparison.