Europium(III) Ion-Based photoluminescence complexes of Indole-Derivative β-diketone dominated by ancillary ligands

A series of five β-diketone ligand EIFD complexes served as a promising luminescence material sensitizer on Eu(III) center by substituent group of the oxygen and nitrogen ancillary ligands donors. [Display omitted] •One pot reaction of β-diketone EIFD, EuCl3·6H2O and ancillary ligand yields a series of β-diketone europium complexes.•Their photoluminescence performances show EIFD is an effective material sensitizer in luminescence of center ions.•Incorporation of the oxygen and nitrogen ancillary ligands can significantly improve the yield of luminescence quantum. One pot reaction of β-diketone EIFD, EuCl3·6H2O and ancillary ligand yield a sequence of five luminescence β-diketone EIFD europium complexes, including Eu(EIFD)3(H2O)·CH2Cl2 (1), Eu(EIFD)3(DMSO) (2), Eu(EIFD)3(DMF)·CH2Cl2 (3), Eu(EIFD)3(phen)·CH2Cl2 (4) and Eu(EIFD)3(bpy) (5) (EIFD: 1-(1-ethyl-1H-indol-3-yl)-4,4,4-trifluorobutane-1,3-dione, phen = 1, 10-phenanthroline, bpy = 2,2′-bipyridine,). The molecular crystals reveal five mononuclear structures with the central Eu(III) ions of seven/eight coordination configuration furnished by three EIFD ligands and ancillary ligands for complexes 1–5. All the five complexes display room-temperature strong characteristic photoluminescence emissions of Eu(III) ions. The coordination environment of Eu(III) ion is a crucial factor in the optical performance of the complex. Herein, the way to introduce of oxygen and nitrogen ancillary ligands plays an important role in characteristic photoluminescence. The luminescence lifetime and quantum yields of the complexes can vary essentially by substituting the solvent molecules with oxygen and nitrogen ligands, leading to a strong luminescence intensity, as observed experimentally.