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)

Abstract

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 Ǻ, and Ln-N bond lengths from 2.55 to 2.64 Ǻ. The uncoordinated bpy molecules are linked to the aqua ligands by hydrogen bonds.