Syntheses, structures and catalytic properties of one-dimensional lanthanide-dotp compounds [dotpH 8 = 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetrakis-(methylenephosphonic acid)

Abstract

Based on 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetrakis-(methylenephosphonic acid) (dotpH 8), compounds [Ln(dotpH 7)(H 2O) 2]Cl 2 · xH 2O ( 1 · Ln) (Ln = La, Nd, Sm, Eu, Gd, Tb) and [Ln(dotpH 7)(H 2O) 2](ClO 4) 2 · xH 2O ( 2 · Ln) (Ln = Nd, Sm, Eu, Gd, Tb) are synthesized in aqueous solutions at low pH. Compounds within each kind are isostructural. Both show chain structures where the neighboring {LnO 8} polyhedra are doubly bridged by {CPO 3} tetrahedra through corner-sharing. The packing of chains, however, are different in the two cases. In 1 · Ln, each chain is surrounded by six equivalent chains, with the Cl − counterions and the lattice water molecules locating between the chains. In 2 · Ln, neighboring chains are connected via strong hydrogen bond interactions to form a supramolecular layer in the ab plane. The ClO 4 - counterions fill in the inter-layer spaces. The catalytic and luminescent properties are investigated.