Lanthanide(III) complex metal-organic frameworks with a phenanthroline-carboxylate derivate and 2,5-thiophenedicarboxylate coligand: hydrothermal synthesis, crystal structure, and high thermostability

Based on 2-(4-carboxyphenyl)imidazo[4,5-f]-1,10-phenanthroline (HNCP) and 2,5-thiophenedicarboxylate (TDC2−) ligands, three new lanthanide-containing (Sm, Nd, and Pr) compounds, [Sm(NCP)(TDC)] n (1), [Nd(NCP)(TDC)] n ·2n(H2O)0.5 (2), and [Pr(NCP)(TDC)] n ·n(H2O)0.5 (3), have been synthesized using the hydrothermal method and structurally characterized using single-crystal X-ray diffraction. Structural analyses have revealed that compounds 1–3 are 3D isostructural metal-organic frameworks in which the [Ln2(COO)4] dimers can be regarded as 6-connecting nodes, and the TDC2− and NCP− ligands are simplified as connectors to achieve the double interspersed 3D networks with the point symbol {412·63}. Thermogravimetric analysis has illustrated that the rigid architecture contributes to superior thermal stability with a thermal decomposition temperature of more than 400°C for the resulting metal-organic frameworks.