Hydrothermal synthesis and structural characterization of a family of lanthanide tartrates: [Ln2(C4H4O6)3(H2O)3]•1.5H2O (Ln = La, Ce, Pr, Nd, Sm)

Coordination polymers containing lanthanides with tartaric acid [Ln(2)(C4H4O6)(3)(H2O)(3)]center dot 1.5H(2)O (Ln = La, Cc, Pr, Nd, Sm and C4H4O6 = D(-) or L(+) tartrate anion) have been synthesized using hydrothermal techniques and characterized by single crystal X-ray diffraction. The compounds are all isotypic with a monoclinic crystal system in the P2(1)/n space group. The asymmetric units of coordination polymers contain two metal centers having different coordination environments. One metal is bonded to four tartrate groups having three D and one L isomers (or three L and one D isomers), whereas the other metal is bonded to five tartrate groups having two D and three L isomers (or two L and three D isomers). Each trivalent metal center is coordinated to nine oxygen atoms that originate from carboxylate and hydroxyl groups of the tartrate anions and water molecules. These new polymers have three-dimensional structures containing open channels that are occupied by non-coordinating water molecules. Thermogravimetric and differential thermal analyses and adsorption of nitrogen have also been studied for these compounds. (C) 2008 Elsevier Masson SAS. All rights reserved.