Three-dimensional ionic frameworks built up from La (III) and Ce (III) succinates

Two three-dimensional ionic open-framework rare-earth succinates have been synthesized. The lanthanum-based compound, 1, was obtained by the silica gel technique and the cerium-based compound, 2, via grown phase under reflux. These two coordination polymers are isostructural. Their layer-type structure is built up from infinite chains of one-edge-sharing polyhedra, discrete chloride ions and lattice water molecules. Strong hydrogen bonds cross link the two-dimensional substructure into a three-dimensional open-framework exhibiting wide channels parallel to [1 0 0] direction. The tetratopic succinate ligand, involved in a syn-anti bridging-chelating mode, links the metal atoms through μ2-oxo bridges. The thermal analysis confirms the high stability of the materials, probably due to the infinite metal-oxygen-metal arrays.