Crystal structures and stereochemical properties of lanthanide(III) complexes with ethylenediamine- N,N,N′,N′-tetraacetate

Abstract

Seven (ethylenediamine- N,N,N′,N′-tetraacetato)lanthanide(III) type compounds, M[Ln(edta)(H 2O) m ] · nH 2O (M–Ln=Na–Er, K–Ho, Cs–Nd, Cs–Sm, Cs–Gd, Cs–Dy, and Cs–Ho) have been synthesized and their crystal structures have been determined by single crystal and powder X-ray diffractions. The Na–Er, K–Ho, Cs–Nd, Cs–Sm, and Cs–Gd complexes exhibit nine-coordination geometry, while the Cs–Dy and Cs–Ho complexes contain eight-coordinate Ln atoms. The coordination modes for the Ln–edta complexes depend not only on the ionic radii for the lanthanide ions but also on the sizes for the counter cations. The electronic absorption behaviors in solid and aqueous solution are also discussed in relation to their geometries.