New Family of Porous Lanthanide-Containing Coordination Polymers: [Ln2(C2O4)3(H2O)6,12H2O]∞ with Ln = La-Yb or Y

Reactions at low temperature in a mixture benzene/water between dimethyloxalate and a lanthanide chloride lead to a family of 3D-coordination polymers with general chemical formula [Ln(2)(C2O4)(3)(H2O)(6)center dot 12H(2)O](infinity), where Ln = La-Yb (except Pm) or Y. All these compounds are isostructural to the already described [Er-2(C2O4)(3)(H2O)(6)center dot 12H(2)O](infinity). Their crystal structure can be described as the juxtaposition of channels with hexagonal cross-section. The channels are filled with crystallization water molecules. Their thermal dehydration produces a collapse of the molecular skeleton leading to amorphous compounds. On the opposite, their dehydration by freeze-drying is possible and the twelve crystallization water molecules can be removed without destruction of the molecular skeleton. The porosity of the dehydrated compounds has been estimated by computational methods to 483 m(2) g(-1). The luminescence properties of the Eu-containing and Tb-containing compounds are also briefly described.