Ln-MOF Pseudo-Merohedral Twinned Crystalline Family as Solvent-Free Heterogeneous Catalysts

Hydrothermally promoted assembly of the multifunctional 3,5-disulfobenzoic acid (3,5-DSB) ligand with the lanthanide series and the 1,10-phenanthroline as a secondary ligand gives rise to the formation of 2D coordination polymers. The isostructural RPF-20-Ln series, with formula [Ln­(3,5-DSB)­(Phen)­(H₂O)]·H₂O (Ln = Sm, Eu, Gd, Tb, Dy, Ho, Er, and Yb), present pseudomerohedral twinned crystals. The polymeric network consists of uninodal 2D net (4³·6³) layers perpendicular to the [010] direction. π–π Stacking interactions between them gives rise to the tridimensional supramolecular framework. The new compounds were tested as catalysts in acid Lewis reactions. A comparative study with other lanthanide MOFs inside the systems Ln/DSB and Ln/DSB/Phen reveals some structural facts that could improve the catalytic behavior of this kind of material.