Preparation and crystal structures of two dimeric lanthanoid (III) complexes containing pyridinioacetate and 2,2'-bipyridine ligands: [Ln2 (bpy)2 (pybet)4 (H2O)4] (bpy)3 (ClO4)6.H2O (Ln= Eu and Tb)
[en] Two dimeric lanthanoid(III) complexes, [Ln2 (bpy)2 (pybet)4(H2O)4] (bpy)3 (ClO4)6.H2O (bpy = 2,2'-bipyridine, pybet = pyridinioacetate, and Ln = Eu and Tb), have been prepared and characterized by X-ray crystallography. The complexes are isostructural, each comprising a quadruply carboxylato-bridged, centrosymmetrical dimeric cation, six perchlorate anions, three uncoordinated bpy molecules and a lattice water molecule. Each Ln ion is surrounded in a distorted square-antiprismatic environment by four carboxylato oxygen atoms, two nitrogen atoms of the bidentate bpy ligand and two aqua ligands. The Ln-O bond lengths range from 2.33 to 2.44 Angstroms, and Ln-N bond lengths from 2.55 to 2.64 Angstroms. The uncoordinated bpy molecules are linked to the aqua ligands by hydrogen bonds. 17 refs., 2 tabs.,2 figs
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