Cubane-type {M4O4} (M = CoII, ZnII, CuII) clusters: synthesis, crystal structures, and luminescent and magnetic properties†
Abstract
The employment of the hydroxyl-rich ligand (E)-3-((2-hydroxy-3-methoxybenzylidene)amino)propane-1,2-diol (H3L) in the chemistry of cubane-type {M4O4} clusters is reported. Three cubane-type clusters of the formula [M4(HL)4] (M = CoII (1), ZnII (2), CuII (3)) were achieved by reactions of metal acetates with H3L under solvothermal conditions. The structures of 1, 2 and 3 have been established by single-crystal X-ray diffraction studies. The tetranuclear clusters 1–3 have cubane-type [M4(μ3-OR)4]4+ cores with divalent metal atoms and deprotonated oxygen atoms (originating from the HL2− ligands) occupying alternate vertices. The luminescence studies suggest strong emission for 2 in the solid state at room temperature. The magnetic properties of 1 and 3 have been investigated. The variable-temperature dc magnetic susceptibility studies indicate ferromagnetic MII⋯MII exchange interactions for 1 and 3. The ac magnetic susceptibility investigation reveals that complex 1 shows slow magnetic relaxation (SMM) behavior.