Novel lanthanide–iminodiacetate frameworks with hexagonal pores

A new family of lanthanide complexes with open-framework structures has been prepared and characterized by X-ray diffraction. The structure of the polymers with general formula [Ln(Hida)3] · xH2O (Ln = La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Yb; H2ida = iminodiacetic acid) presents large hexagonal channels with more than 11 Ǻ diameter, and houses the crystallization water molecules. These molecules can be reversibly removed upon heating. This is the first example of this kind of structure with ida as bridging ligand.