New insights into the comprehension of the magnetic properties of dinuclear Mn-III compounds with the general formula [{MnL(NN)}(2)(mu-O)(mu-n-RC6H4COO)(2)]X-2

作者：Escriche Tur Luis^*; Font Bardia Merce; Albela Belen; Corbella Montserrat^*

来源：Dalton Transactions, 2016, 45(29): 11753-11764.

DOI：10.1039/c6dt01097k

Five new dinuclear Mn(III) compounds with benzoato derivative bridges [{Mn(bpy)L}(2)(mu-O)(mu-n-RC6H4COO)(2)]X-2 (n-R = 3-MeO, 4-MeO and 4-tBu, X = NO3- and ClO4-) were synthesised and characterised. According to X-ray diffraction, the X anions tend to be coordinated to the Mn ions and may occupy the place of the monodentate ligand L. Two structural isomers that only differ in one of their monodentate ligands have been obtained with the 3-MeOC6H4COO- bridges. For all compounds, the Mn( III) ions display elongated octahedra with a pronounced rhombic distortion. To quantify these distortions separately, the elongation and rhombicity parameters Delta and rho have been defined. The magnetic study shows a good relationship between the distortion of the coordination polyhedra and the zero field splitting parameters (D-Mn and E-Mn). From the magnetic data of a powder sample, it is possible to determine the sign and magnitude of DMn for ferromagnetic systems or weak antiferromagnetic systems with D-Mn < 0. For this kind of dinuclear compound, the R group at the meta position, the rhombic distortion of the octahedra, and large torsion angles between the Jahn-Teller axes lead to ferromagnetic interactions.

• 出版日期2016