Three dimensional lanthanide-organic frameworks containing tetranuclear Ln (Ln = La, Nd) cluster secondary building blocks

The hydrothermal reactions of Ln2O3, o-phthalic acid (H2L1) and N,N’-Piperazine(bis-methylene phosphonic acid) hydrochloride (H4L2·HCl) yielded two three dimensional (3D) lanthanide-organic frameworks formulated as [Ln4(L1)2(H2L2)3(H3L2)2]·18H2O (Ln = La, 1; Nd, 2). Single-crystal X-ray diffraction revealed that they are isostructural. They feature 3D open framework structures containing rarely observed centrosymmetric tetranuclear lanthanide sub-building units (SBU). The photoluminescence property of 2 has been investigated, and it shows strong solid-emissions in the near-infrared region at room temperature.