Spin Frustration from cis-Edge or -Corner Sharing Metal-Centered Octahedra

摘要

A new strategy using cis-edge or -corner sharing metal-centered octahedra is described which enables interesting frustrated spin lattices to be targeted. The examination of "CuV_2" triangular motifs in the two new compounds [enH_2]Cu(H_2O)_2[V_2O_2F_8] (1) and [Cu(H_2O)(2,2'-bpy)]_2[V_2O_2F_8] (2) (where enH_2 = ethylenediammonium and 2,2'-bpy =2,2'-bipyridyl) reveals that the [VOF_4]~(2-) anions, which exhibit cis structure directing properties, lead to frustrated lattices owing to the competing ferro and antiferromagnetic interactions. There is direct coordination through two cis F~- ligands (i.e., the F~- ligand trans to O~(2-) and one equatorial F~- ligand) in both 1 and 2 owing to the significant π-bonding between the vanadium and the oxide ligand. We emphasize that most of triangular motifs reported in the literature are built of cis-edge or -corner sharing metal-centered octahedra, thus they can be used to target new materials exhibiting interesting magnetism such as spin frustration.