Blue-light excitable europium(III) complex based on deprotonated 1-(9-ethyl-6,8-dimethyl-9H-carbazol-2-yl)-4,4,4-trifluorobutane-1,3-dionate and 1,10-phenanthroline

Abstract

A new β-diketone ligand, 1-(9-ethyl-6,8-dimethyl-9H-carbazol-2-yl)-4,4,4-trifluorobutane-1,3-dione was synthesized by four step reaction (Suzuki–Miyaura cross-coupling, Cadogan cyclization, N-ethylation and Claisen condensation reaction) from 1-(4-bromo-3-nitrophenyl)ethanone and 3,5-dimthylphenylboronic acid. Deprotonated 1-(9-ethyl-6,8-dimethyl-9H-carbazol-2-yl)-4,4,4-trifluorobutane-1,3-dionate (L−1) and 1,10-phenanthroline (phen) coordinated to europium ion to yield a new europium(III) complex, EuL3[phen]. The Eu(III) complex was characterized by elementary analysis, IR, 1H NMR, 13C NMR , UV–Vis absorption spectroscopy, thermogravimetric analysis (TGA) and photoluminescence measurements. TGA shows that the decomposition temperature of the complex EuL3[phen] is up to 320°C. Photoluminescence measurement results indicate that the Eu(III) complex exhibits intense red emission and extends its excitation band blue light region. Red emission LEDs were successfully fabricated by precoating complex EuL3[phen] onto 460nm blue-emitting InGaN chip. The europium complex based on depronated 1-(9-ethyl-6,8-dimethyl-9H-carbazol-2-yl)-4,4,4-trifluorobutane-1,3-dionate is a very interesting blue light excitable red emission material, which can be applied in many fields without UV radiation.