Open lanthanide-organic frameworks with intertwined double and triple helical structures

Two new three-dimensional lanthanide coordination complexes, [Ln2(IDC)2(H2O)3] · 1.5H2O (Ln = Sm (1), Eu (2), IDC = 4,5-imidazoledicarboxylate), have been prepared by hydrothermal reaction of Ln2O3, H3IDC at 140 °C and characterized by single-crystal X-ray diffraction analysis. To our knowledge, they represent the first examples of having intertwined lanthanide double and triple helical motifs and nanosized tubular channels. In addition, compound 2 exhibit red photoluminescence at room temperature.