Synthesis, structure and luminescence of three europium complexes with 2,4-dimethylbenzoic acid

Three different complexes of europium with 2,4-dimethylbenzoic acid (2,4-HDMBA), [Eu(2,4-DMBA)3] n (1), [Eu(2,4-DMBA)3 · (2,2′-bpy)]2 · 6H2O (2) (2,2′-bipy = 2,2′-bipyridine), and [Eu(2,4-DMBA)3 · phen]2 (3) (phen = 1,10-phenanthroline) were synthesized. Complex 1 is in an infinite one-dimensional polymer chain. Complex 2 is a dimeric unit, in which Eu(III) is nine-coordinate in a distorted monocapped square-antiprism arrangement. Complex 3 is also a dimeric unit, in which the Eu(III) ion is eight-coordinate and is in a distorted square antiprism arrangement. The three complexes displayed luminescence properties. The luminescence spectra correspond to the characteristic emission 5D0 → 7FJ (J = 0–4) transition of Eu(III).