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

Abstract

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-hexafluoroacetylacetonate 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 molecules to the Dy^III 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.