Anion-directed assemblies of europium(III) coordination polymers based on 1H-benzimidazole-5,6-dicarboxylate: structures and luminescence properties

Abstract

n (2), have been synthesized via the hydrothermal method and structurally characterized. CP 1 shows a three-dimensional network, in which the oxalate ligand acts as a pillar, while CP 2 has a two-dimensional network based on a europium(III)-sulfate skeleton, further extended into a three-dimensional framework by hydrogenbonding interactions. The structural diversity in the two compounds can be attributed to the different acidification abilities and geometries of the anionic ligands. The luminescence properties of 1 display the characteristic europium red emission with CIE chromaticity coordinates (2/3, 0.34). Interestingly, CP 2 shows the characteristic red emission with CIE chromaticity coordinates (0.60, 0.34) when excited at 280 nm and a near-white emission with CIE chromaticity coordinates (0.38, 0.29) when excited at 340 nm.