Construction of 2-D lanthanide coordination frameworks: syntheses, structures and luminescent property

Abstract

A series of layered lanthanide coordination frameworks [Ln₄(NIPH)₆(H₂O)₄]·(4,4′-bipy) [Ln = La (1), Pr (2)], [La(NIPH)₂(H₂O)₂]·0.5(4,4′-H₂bipy) (3), Ln(NIPH)₂(H₂O)₂]·0.5(4,4′-H₂bipy)·2H₂O [Ln =Pr (4), Nd (5)], and [Ln(NIPH)₂]·0.5(4,4′-H₂bipy) [Ln = Sm (6), Eu (7), Tb (8), Ho (9), Yb (10)] (NIPH = 5-nitroisophthalate and 4,4′-bipy = 4,4′-bipyridine) have been synthesized under hydrothermal conditions and characterized by single-crystal X-ray diffraction. All the coordination frameworks display identical crystal system (triclinic) and space group (P). Compounds 1 and 2 are isostructural, their coordination sheets are constructed by polynuclear helical-like chains. Compounds 3–5 are extremely similar in structure, in which Ln atoms are bridged into rod-shaped chains by carboxylate groups. For compounds 6–10, the coordination layers are built up from 1-D zig-zag chains. The 3-D supramolecular frameworks of 1–10 are finally formed through the alternate stack of Ln coordination layers and 4,4′-bipy layers based on hydrogen bonding interactions. Compound 7 displays luminescent property.