New lanthanide coordination polymers of 1,2,4,5-benzenetetracarboxylic acid and 4,4-bipyridine with 1D channels

Three new lanthanide coordination polymers with 1,2,4,5-benzenetetracarboxylic acid, Pr-2(betc)(2)(4,4'-bpyH(2)).0.25H(2)O (1), Ln(2)(betc)(2)(4,4'-bpyH(2)) (Ln = Eu (2), Gd (3)) were hydrothermally prepared. The crystallographic data of 1-3 show that they are isostructural, and possess 3D framework with 1D rhomboid channels, where the 4,4-bipyridine molecules exist steadily via hydrogen bonds. Meanwhile, a supramolecular structure of (4,4-bpyH(2))(2)(betc) (4) was also obtained by hydrothermal reaction. The results of 1-4 indicate that 4,4'-bipyridine molecule acting as a template plays an important role in the formation of complexes 1-3, and thus has a synergistic action in the construction of 3D framework with large channels. (C) 2004 Elsevier B.V. All rights reserved.