Two 2-D lanthanide coordination polymers constructed from hydroquinone-O,O′-diacetic acid

Abstract

Two new coordination polymers, {Ln₂(hqda)₃(H₂O)₄·6H₂O}_n (H₂hqda = hydroquinone-O,O′-diacetic acid, Ln = Dy, 1; Ho, 2), were prepared and characterized by elemental analysis, IR spectroscopy, TG-DTA, fluorescence spectroscopy, and single-crystal X-ray diffraction. The two complexes are isomorphous with similar crystal structures. In 1 and 2, each Ln(III) ion is nine coordinate with seven oxygen atoms from hqda ligands and two oxygen atoms from water molecules. Two adjacent Ln(III) ions are bridged by–COO⁻ groups from hqda ligands in bidentate-bridging and chelating-bridging modes. These building blocks cross link through ^–OOCCH₂OC₆H₄OCH₂COO⁻ spacers to form a 2–D network structure. The adjacent 2-D layers are further interlinked by hydrogen bonds to form a 3-D supermolecular structure.

Keywords:

• Lanthanide coordination polymers
• Hydroquinone-O,O′-diacetic acid
• Crystal structure

Acknowledgements

We are grateful to the Natural Science Foundation of Beijing (No. 2073022), the Scientific Research Common Program of Beijing Municipal Commission of Education, and the Young Mainstay Teachers Foundation of Beijing Municipal Universities