Crystal and molecular structure and luminescence properties of the europium trifluoroacetate complex with dipyridyl

The crystal structure of [Eu(Dipy)(TFA)3(H2O)3] · Dipy (where TFA− is the trifluoroacetate anion and Dipy is, 2,2′-dipyridyl) has been studied by X-ray diffraction. The coordination polyhedron of the europium atom is a distorted square antiprism [EuO6N2] with the nonplanar quadrilateral faces. The coordinated and non-coordinated dipyridyl molecules are linked pairwise through π stacking interactions into an infinite pile with an overlap of up to 50% of the molecular surface areas. An increase in the luminescence intensity of the compound upon its UV irradiation is explained.