Synthesis and structural characterization of new lanthanide coordination polymers with nitrilotriacetic acid

Reported herein are the hydrothermal synthesis and crystal structures of four lanthanide coordination polymers with nitrilotriacetic acid (H3NTA) [Ln(NTA)(H2O)]n (Ln ¼ La, 1; Pr, 2; Nd, 3; Eu, 4). Despite similar syntheses, compounds 1 to 4 show transformation in coordination mode of NTA and coordination number of Ln3þ duo to lanthanide contraction. The Ln(III) ions in 1 and 2 are nine-coordinated and connected through octadentate bridging ligands (NTA) to form a three-dimensional network. The Ln(III) ions in 3 and 4 are eightcoordinated and bridged by heptadentate bridging ligands (NTA) to form an extended two-dimensional layer structure, which further construct a three-dimensional supramolecular structure via coordination bond and three-centered hydrogen bonding between adjacent layers. q 2004 Elsevier B.V. All rights reserved