Syntheses and structural analyses of four isostructural lanthanide dimers derived from thiourea-based carboxylato ligands

From the reactions of 2-(3-benzoylthioureido)ethanoic acid (H3L) and 1,10-phenanthroline (phen) with lanthanide ions, four crystalline isostructural homodinuclear complexes [Ln2(μ2–η2-H2L)2(μ2-H2L)2(phen)2(NO3)2] 2CH3OH (Ln = Eu (1), Sm (2), Tb (3) and Dy (4)) have been produced. In these complexes, two neighboring lanthanide ions are connected by carboxylate groups in μ2–η2- or μ2-bridging modes. The four complexes present similar themostabilities. Their solid-state fluorescence properties have been investigated at room temperature.