Synthesis, Structures, and Magnetic Properties of Two Coordination Assemblies of Mn(III) Single Molecule Magnets Bridged via Photochromic Diarylethene Ligands

摘要

Two new coordination assemblies were prepared by combining the open and close forms of 1,2-bis(5-carboxyl-2-methyl-3-thienyl)perfluorocyclopentene (H(2)dae) with [Mn-2(saltmen)(2)(H2O)(2)](PF6)(2), where H(2)saltmen = 2,2'-((1E,1'E)-((2,3-dimethylbutane-2,3-diyl)bis(azaneylylidene)) bis-(methaneylylidene))diphenol. From X-ray diffraction analyses, the complexes had the following formula: [Mn-2(saltmen)(2)(dae-open)] (1 (open)) and [Mn(saltmen)(dae-close)]center dot H2O center dot Et3N (1 (close)). Both complexes crystallized in the C2/c monoclinic space group. In 1(open), dae-o(2-) behaves as a bidentate ligand attached to the outer Mn-saltmen monomer via the oxygen atom of carboxylato groups, whereas in 1(close), the dae-c(2-) ligand behaves as a monodentate ligand attached to the external Mn-saltmen dimer by only one carboxylato group of the photochromic ligand. The complexes showed reversible photochromic responses to UV/vis light and showed single-molecule magnet-like behavior. The relaxation times and energy barriers of the metal complexes are clearly affected by UV/vis irradiation.