Synthesis, Crystal Structures, and Luminescent Properties of Two Series' of New Lanthanide (III) Amino-Carboxylate-Phosphonates

Hydrothermal reactions of lanthanide(III) chlorides with 4-HOOC−C6H4−CH2NHCH2PO3H2 (H3L) at different ligand-to-metal (L/M) ratios afforded nine new lanthanide(III) carboxylate-phosphonates with two types of 3D network structures, namely, LnCl(HL)(H2O)2 (Ln = Sm, 1; Eu, 2; Gd, 3; Tb, 4; Dy, 5; Er, 6) and [Ln2(HL)(H2L)(L)(H2O)2]·4H2O (Ln = Nd, 7; Sm, 8; Eu, 9). Compounds 1−6 are isostructural and feature a 3D network in which the LnO7Cl polyhedra are interconnected by bridging CPO3 tetrahedra into 2D inorganic layers parallel to the bc plane. These layers are further cross-linked by organic groups of the carboxylate-phosphonate liagnds via the coordination of the carboxylate groups into a pillared-layered architecture. Compounds 7−9 are also isostructural and feature a 3D open-framework composed of 1D lanthanide(III) phosphonate inorganic slabs which are further bridged by organic groups of the carboxylate-phosphonate liagnds via the coordination of the carboxylate groups, forming large 1D tunnels along the b-axis which are filled by lattice water molecules. Luminescent measurements indicate that compounds 2, 4, and 5 show strong emission bands in red, green, and yellow light region, respectively. Magnetic properties of 2, 3, 5, and 7 have also been studied.