3-D supramolecular frameworks assembled by lanthanide binuclear molecules based on 1,2-phenylenedioxydiacetic acid and 1,10-phenanthroline

The complexes [Ln2(PDOA)3(phen)2(H2O)2] · 2H2O (Ln = Eu (1), Tb (2), and Dy (3); H2PDOA = 1,2-phenylenedioxydiacetic acid; phen = 1,10-phenanthroline) have been synthesized and structurally characterized by single crystal X-ray diffraction methods. The three complexes are all binuclear molecules. The two Ln(III) centers are linked by only one PDOA ligand through its two bidentate-chelating carboxylate groups. PDOA also acts as a terminal ligand using one carboxylate oxygen and ether oxygen atoms to chelate the Ln(III) ion. 3-D supramolecular frameworks are built up by the hydrogen bonds and π–π stacking interactions. The fluorescent spectra of the three complexes show the characteristic emission of the Eu(III) for 1, Tb(III) for 2, and Dy(III) for 3, respectively.