Synthesis, structural characterization and properties of copper(II) and zinc(II) coordination polymers with a new bridging chelating ligand

Two new coordination polymers [Cu-3(cpida)(2)(H2O)(4)](n)(.)4nH(2)O (1) and [Zn(Hcpida)](n)(.)nH(2)O (2) have been synthesized with a new bridging chelating ligand N-(4-carboxyphenyl)iminodiacetic acid (H(3)cpida). X-ray diffraction analysis reveals that complex 1 consists of 1D parallelogram-shaped molecular-box chains constructed from unusual linear trinuclear Cu-II secondary building units (SBUs), which further extend into 2D layers by perfect parallel AA stacking. Complex 2 adopts a 2D framework comprised of tetrahedral Zn-II centres isolated from each other by the bridging bidentate carboxylate groups of the Hcpida(2-) ligands. Compound 2 possesses alternate open and closed channels along the a direction. The dehydation and rehydration experiments showed that compound 2 undergoes a reversible inclusion process to some extent. However, the removal of guest water molecules from 1 results in the collapse of the polymeric networks owing to the loss of the coordinated water molecules. Compound 2 also shows strong photoluminescence and may be a good candidate for a photoactive or porous material. (C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004.