Cation effect on the crystal structure of polynuclear complexes with 2,2′-oxydiacetate as bridging ligand

Using the flexible ligand oxydiacetic acid (H2oda), nine heterodimetallic polymers [{Ca(H2O)6}{CaLn(oda)3}2]·xH2O (Ln = Y, Eu, Tb, Dy, Ho, Er, Tm, Yb, Lu) were synthesized and structurally characterized. The syntheses were performed in aqueous solution by reaction of the ligand and salts of the two ions. They are isostructural and possess a highly ordered 3D structure with [CaLn(oda)3]− as building blocks. The charge is balanced with [Ca(H2O)6]2+ ions which occupy the holes of the anionic framework. The complexes are thermally stable up to 250 °C. Magnetic susceptibility measurements of Yb and Eu complexes show deviations from the Curie law mainly owing to the split of the ground term due to the ligand field and to the depopulating of paramagnetic excited states in the Yb and Eu compounds, respectively.