Semiconducting lanthanide polymers of pyridine-2,6-dicarboxylate: Hydrothermal synthesis, structural characterization, electrical conductivity and luminescence properties

Abstract

This paper describes the hydrothermal synthesis of two novel lanthanide coordination polymers (CPs) (H2pip)n[Ln2(pydc)4(H2O)2]n (Ln = La (1) and Nd (2), H2pydc = 2,6-pyridinedicarboxylic acid, H2pip = piperazine). The synthesized polymers were structurally characterized by the elemental analysis, ICP-OES, IR spectroscopy, TGA, single-crystal X-ray diffraction and powder X-ray diffraction (PXRD) analysis. For the morphological analysis field emission scanning electron microscopy (FESEM) was used. CPs are isomorphous, showing three-dimensional Ln–O–Ln chains. Ln(III) ions in 1–2 adopt nine-coordinated mode to construct a mono-capped square antiprism coordination environments. The electrical conductivity and luminescence properties of insoluble 1–2 have been investigated. CPs exhibited luminescence emission bands at 612 nm for 1 and 624 nm for 2 at room temperature when excited at 320 nm.