title: Highly luminescent salts containing well-shielded lanthanide-centered complex anions and bulky imidazolium countercations.
abstract: Four salts containing imidazolium cations and europium(III)- or terbium(III)-centered complex anions have been successfully synthesized from an ethanol/H2O solution. The single-crystal X-ray diffraction analyses reveal that these compounds have a common formula of [R][Ln(DETCAP)4] [R = 1-ethyl-3-methylimidazolium (C2mim), Ln = Eu (1) and Tb (2); R = 1-butyl-3-methylimidazolium (C4mim), Ln = Eu (3) and Tb (4); DETCAP = diethyl-2,2,2-trichloroacetylphosphoramidate], in which the lanthanide centers are chelated by four chelating pseudo-β-diketonate ligands (DETCAP)(-), forming the respective complex anions. Their thermal behaviors and stabilities were also investigated to study the role of the length of the side chain in the cations. Fluorescence measurements at both room temperature and liquid-nitrogen temperature show that these materials show intense characteristic europium(III) or terbium(III) emissions and have long decay times. Their overall quantum yields were determined to be in the range of 30-49%.
authors.affiliation: Key Laboratory of Biofuel, Chinese Academy of Sciences, Qingdao Institute of Bioenergy and Bioprocess Technology , 266101 Qingdao, China.
authors.forename: Si-Fu
authors.initials: SF
authors.lastname: Tang
authors.forename: Chantal
authors.initials: C
authors.lastname: Lorbeer
authors.forename: Xinjiao
authors.initials: X
authors.lastname: Wang
authors.forename: Pushpal
authors.initials: P
authors.lastname: Ghosh
authors.forename: Anja-Verena
authors.initials: AV
authors.lastname: Mudring
mesh_terms: D000838:Anions; D002152:Calorimetry, Differential Scanning; D002412:Cations; D007093:Imidazoles / Q000737:chemistry*; D028581:Lanthanoid Series Elements / Q000737:chemistry*; D049449:Luminescence
chemical_list: D000838:Anions; D002412:Cations; D007093:Imidazoles; D028581:Lanthanoid Series Elements