Syntheses, structures and catalytic properties of one-dimensional lanthanide-dotp compounds [dotpH8 = 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetrakis-(methylenephosphonic acid)]

Based on 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetrakis-(methylenephosphonic acid) (dotpH8), compounds [Ln(dotpH7)(H2O)2]Cl2 · xH2O (1 · Ln) (Ln = La, Nd, Sm, Eu, Gd, Tb) and [Ln(dotpH7)(H2O)2](ClO4)2 · xH2O (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 {LnO8} polyhedra are doubly bridged by {CPO3} 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 ClO4- counterions fill in the inter-layer spaces. The catalytic and luminescent properties are investigated.

Complexes [Ln(dotpH7)(H2O)2]Cl2 · xH2O (1 · Ln) (Ln = La, Nd, Sm, Eu, Gd, Tb) and [Ln(dotpH7)(H2O)2](ClO4)2 · xH2O (2 · Ln) (Ln = Nd, Sm, Eu, Gd, Tb) [dotpH8 = 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetrakis-(methylenephosphonic acid)] show chain structures with interesting catalytic and luminescent properties.Figure optionsDownload as PowerPoint slide