The first ladder-like lanthanide double chain complex [Tm(NTA)(H2O)2]·2H2O (H3NTA=nitrilotriacetic acid)

The title complex has been synthesized in aqueous solution and its crystal structure was determined by X-ray diffraction. It consists of a one-dimensional ladder-like chain. One carboxyl group bridges the adjacent Tm ions giving rise to the edge of the ladder, a second one links the Tm ions from the neighboring edge in zigzag form to act as the rung of the ladder, and a third one monodentately coordinates with Tm to serve as the pendant of the ladder. Each Tm ion is eight coordinated by one nitrogen atom, five oxygen atoms from three NTA molecules and two oxygen atoms from H2O.