Temperature-dependent urothermal synthesis of two distinct La(III)-naphthalenedicarboxylate frameworks

Two distinct La(III)-naphthalenedicarboxylate frameworks, namely La2(NDC)3(e-urea)3 (1; H2NDC = 2,6-naphthalenedicarboxylic acid; e-urea = ethyleneurea) and La(NDC)1.5(e-urea) (2), have been successfully synthesized through urothermal synthesis under different temperatures. Single-crystal X-ray structural analysis revealed that both compounds 1 and 2 feature three-dimensional (3D) structures with open channels occupied by the coordinated e-urea molecules. Interestingly, e-urea molecules and NDC ligands adopt distinct coordination modes in two structures. Furthermore, thermal analyses of 1 and 2 were also investigated.