Lanthanide Diruthenium(II,III) Compounds Showing Layered and PtS-Type Open Framework Structures

Two types of lanthanide diruthenium phosphonate compounds, based on the mixed-valent metal−metal bonded paddlewheel core of Ru2(hedp)23- [hedp = 1-hydroxyethylidenediphosphonate, CH3C(OH)(PO3)2], have been prepared with the formulas Ln(H2O)4[Ru2(hedp)2(H2O)2]·5.5H2O (1·Ln, Ln = La, Ce) and Ln(H2O)4[Ru2(hedp)2(H2O)2]·8H2O (2·Ln, Ln = La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er). In both types, each Ru2(hedp)2(H2O)23- unit is linked by four Ln3+ions through four phosphonate oxygen (OP) atoms and vice versa. The geometries of the {LnOP4} group, however, are different in the two cases. In 1·Ln, the geometry of {LnOP4} is closer to a distorted plane, and thus a square-grid layer structure is found. In 2·Ln, the geometry of {LnOP4} is better described as a distorted tetrahedron; hence, a unique PtS-type open-framework structure is observed. The channels generated in structures 2·Ln are filled with water aggregates with extensive hydrogen-bond interactions. The magnetic and electrochemical properties are also investigated.