Redox- and solvato-magnetic switching in a tetrathiafulvalene-based triad single-molecule magnet

The first simultaneous redox and solvato-magnetic switching was achieved. The dinuclear complex [Dy2(hfac)6(H2SQ)]CH2Cl2 (Dy2H2SQ) (where hfac = 1,1,1,5,5,5-hexafluoroacethylacetonate and H2SQ = 2,2’-benzene-1,4-diylbis(6-hydroxy-4,7-di-tert butyl-1,3-benzodithiol-2-ylium-5-olate) was reversibly oxidized into the dinuclear complex [Dy2(hfac)6(H2O)2(Q)] (Dy2Q) (where Q = 2,2’-cyclohexa-2,5-diene-1,4-diylidenebis(4,7-di-tert-butyl-1,3-benzodithiole-5,6-dione)) inducing the reversible coordination of water molecule to the DyIII ion. Magnetic susceptibility measurements and ab-initio CASSCF/SI-SO calculations, confirmed by Cantilever Torque Magnetometry measurements, demonstrated that Dy2H2SQ is a Single Molecule Magnet with a magnetic relaxation 7000 times slower than Dy2Q (at 3 K) allowing a “ON-OFF” switching of the magnetic bistability.