Research Article: Poly[[dodeca­aqua­bis­(μ3-pyridine-2,6-dicarboxyl­ato)tetra­kis­(μ2-pyridine-2,6-dicarboxyl­ato)tri­calciumdieuropium(III)] 10.5-hydrate]

Date Published: May 01, 2012

Publisher: International Union of Crystallography

Author(s): Fengjuan Shi, Jiguang Deng, Hongxing Dai.


In the title compound, {[Ca3Eu2(C7H3NO4)6(H2O)12]·10.5H2O}n, the EuIII ion is nine-coordinated by three tridentate pyridine-2,6-dicarboxyl­ate (PDA) ligands, forming a [Eu(PDA)3]3− building block. The Ca2+ ions adopt two types of coordination geometries. One Ca2+ ion, lying on a twofold rotation axis, is eight-coordinated by four carboxyl­ate O atoms from four PDA ligands and four water mol­ecules, and the other two Ca2+ ions, each lying on an inversion center, are six-coordinated by two carboxyl­ate O atoms from two PDA ligands and four water mol­ecules. The carboxyl­ate groups bridge the EuIII and Ca2+ ions into a three-dimensional porous framework, with channels extending along [010] and [001] in which lattice water mol­ecules are located. Two of the lattice water mol­ecules are disordered over two sets of sites with equal occupancy and one water mol­ecule is 0.25-occupied. Numerous O—H⋯O hydrogen bonds involving the water mol­ecules and carboxyl­ate O atoms are present.

Partial Text

For 3d–4f and 4d–4f metal complexes with pyridine-2,6-dicarboxyl­ate ligands, see: Zhao et al. (2006 ▶, 2007 ▶, 2011 ▶); Zhao, Zhao et al. (2009 ▶). For Ln–Ba (Ln = lanthanide) complexes with pyridine-2,6-dicarboxyl­ate ligands, see: Zhao, Zuo et al. (2009 ▶).