Effect of lanthanide contraction on crystal structures of Ln(iii) coordination polymers with dinuclear SBUs based on 3-(4-hydroxypyridinium-1-yl) phthalic acid and oxalic acid

Abstract

A series of lanthanide coordination polymers, {[Ln(L)(OX)_0.5(H₂O)₂]·3H₂O}_n (Ln = La 1, and Ce 2), [Ln₂(L)₂(OX)(H₂O)₃]_n (Ln = Pr 3, Nd 4, Sm 5, Eu 6, Gd 7, Tb 8, Dy 9, Er 10, and Yb 11) (H₂L = (3-(4-hydroxypyridinium-1-yl) phthalic acid, H₂OX = oxalic acid), have been hydrothermally synthesized and characterized by single-crystal X-ray diffraction. The title compounds are crystallized in the same triclinic space group P but display different 2D layer structures with different dinuclear secondary building units (SBUs) due to the effect of lanthanide contraction. Furthermore, X-ray diffraction and thermogravimetric analysis of 1–11 are also studied, which demonstrate their high purities and good thermal stabilities. Luminescent measurements indicate that the Eu (6), Tb (8), and Dy (9) compounds exhibit ligand (L²⁻) sensitized emissions in red, green, and yellow light regions, respectively.