Ln[(μ 2-H)(H-mpdc) 2](H-mpdc) 2: Lanthanide infinite architectures with symmetric O [sbnd]H [sbnd]O hydrogen bonds (mpdc = 2,6-dimethylpyridine-3,5-dicarboxylate)

Abstract

Three isostructural lanthanide coordination polymers Ln III[(μ 2-H)(H-mpdc) 2](H-mpdc) 2, (mpdc = 2,6-dimethylpyridine-3,5-dicarboxylate, Ln = Nd( 1), Eu( 2) and Ce( 3)) were synthesized from lanthanide nitrates and H 2dmpdc under solvothermal conditions. H 2dmpdc is a new multifunctional ligand. Of particular interest is that there are the strongest types of O H O hydrogen bonds with a symmetric character (O ⋯ O, 2.487–2.493 Å; O H, 1.247–1.257 Å and O H O, 165–180°) in these polymeric compounds revealed by X-ray crystal diffraction analyses. The symmetric O H O hydrogen bonding in infinite polymeric architectures provides a new proof of proton transfer. Moreover, 3-D supramolecular architectures were self-assembled from 2-D grids with symmetric O H O hydrogen bonds.