Assembly of three 3-D MOFs from 2-phenyl-4,5-imidazole dicarboxylate and oxalate

Three lanthanide–organic polymers, {[Ln(μ ₃-HPhIDC)(μ ₂-C₂O₄)_0.5(H₂O)]?·?2H₂O} _n (Ln?=?Nd (1), Sm (2), and Tb (3)), have been isolated from the reaction of 2-phenyl-1H-imidazole-4,5-dicarboxylic acid (H₃PhIDC) with equal amount of Ln(III) salts under solvothermal condition with the rigid coligand oxalate. The three polymers, which are isomorphous and isostructural, have been structurally characterized by elemental analyses, IR spectroscopy, and single-crystal X-ray diffraction. Each exhibits a 3-D framework constructed from infinite 2-D layers joined by μ ₂-C₂O₄, which are composed of μ ₃-HPhIDC^2? and trivalent lanthanide. Thermal properties have also been investigated.