Synthesis, structure, and luminescent properties of a family of lanthanide-functionalized peroxoniobiophosphates

Eight new lanthanide derivatives containing 6-peroxoniobio-4-phosphate building block, [Ln(III)(H(2)O)(6)](2)[H(4)(NbO(2))(6)P(4)O(24)]·nH(2)O [Ln = Eu (1), Gd (2), Tb (3), Dy (4), Ho (5), Er (6), Tm (7), Yb (8), 1–5, 7, 8 n = 12; 6 n = 9], have been successfully obtained using an in-situ strategy and fully characterized in the solid state by single-crystal X-ray diffraction, IR spectra, TG-MS, PXRD. Structural analyses indicate that these isostructural polyanions 1–8 consist of one [P(4)(NbO(2))(6)O(24)](10−) (P (4) (NbO (2) ) (6)) clusters and two pendant Ln(3+) cations. In these compounds, P (4)(NbO (2) ) (6) clusters are connected by lanthanide cations to form extended two-dimensional architectures. The approach takes advantage of the ability of in-situ formed P (4)(NbO (2) ) (6) cluster to build frameworks by using it as ligands to lanthanide ions. The photoluminescence (PL) and lifetime decay behaviors of 1, 3 and 4 in solid state have been performed at room temperature. The PL emission of 1, 3 and 4 is mainly derived from the characteristic (5)D(0)→(7)F(J) (J = 1, 2, 3, 4), (5)D(4)→(7)F(J) (J = 6, 5, 4, 3) and (4)F(9/2)→(6)H (J) (J = 15/2, 13/2, 11/2) transitions of the Eu(III), Tb(III) and Dy(III) cations, respectively.