Synthesis and structural characterization of lanthanide oxalate–oxydiacetate mixed-ligand coordination polymers {[Ln(oda)(H₂O)_x]₂(ox)}_n (x = 3 for Ln = La, Ce, Pr, Gd, Tb and x = 2 for Ln = Er)

Abstract

Reactions of oxydiacetic acid (H₂oda) with lanthanide oxide, nitrate, chloride, and carbonate gave six lanthanide oxalate–oxydiacetate mixed-ligand coordination polymers {[Ln(oda)(H₂O) _x ]₂(ox)} _n [x = 3 for Ln = La, Ce, Pr, Gd, Tb, (1–5), and x = 2 for Ln = Er (6)]. Oxydiacetic acid is decomposed into oxalic acid in this reaction. In the crystal structures of 1–6, oxydiacetate and the lanthanides build a chain, and the oxalate groups bridge two chains to form 1-D double-chain ladder-shaped structures, connected by intermolecular hydrogen bonds to form a 2-D network structure. These compounds contain approximately 3.0 × 6.4 Ų channels along the c-axis. The infrared spectra and thermal behaviors of 1–6 are also investigated.

Keywords:

• Oxydiacetate
• Oxalate
• Lanthanide coordination polymers
• Crystal structures

Acknowledgements

This work was supported by the Outstanding Adult-young Scientific Research Encouraging Foundation of Shandong Province (No. 2006BS03049), the Natural Science Foundation of Shandong Province (Z2006B01), and the Program for New Century Excellent Talents in Universities (No. NCET-04-0649).