title: Visible and near-infrared emission by samarium(III)-containing ionic liquid mixtures.
abstract: Highly luminescent anionic samarium(III) beta-diketonate and dipicolinate complexes were dissolved in the imidazolium ionic liquid 1-hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, [C(6)mim][Tf(2)N]. The solubility of the complexes in the ionic liquid was ensured by a careful choice of the countercation of the samarium(III) complex. The samarium(III) complexes that were considered are [C(6)mim][Sm(tta)(4)], where tta is 2-thenoyltrifluoroacetonate; [C(6)mim][Sm(nta)(4)], where nta is 2-naphthoyltrifluoroacetonate; [C(6)mim][Sm(hfa)(4)], where hfa is hexafluoroacetylacetonate; and [choline](3)[Sm(dpa)(3)], where dpa is pyridine-2,6-dicarboxylate (dipicolinate) and [choline](+) is (2-hydroxyethyl)trimethyl ammonium. The crystal structures of the tetrakis samarium(III) beta-diketonate complexes revealed a distorted square antiprismatic coordination for the samarium(III) ion in all three cases. Luminescence spectra were recorded for the samarium(III) complexes dissolved in the imidazolium ionic liquid as well as in a conventional solvent, that is, acetonitrile or water for the beta-diketonate and dipicolinate complexes, respectively. These experiments demonstrate that [C(6)mim][Tf(2)N] is a suitable spectroscopic solvent for studying samarium(III) luminescence. High-luminescence quantum yields were observed for the samarium(III) beta-diketonate complexes in solution.
authors.affiliation: Katholieke Universiteit Leuven, Department of Chemistry, Laboratory of Coordination Chemistry, Celestijnenlaan 200F bus 2404, B-3001 Leuven, Belgium.
authors.forename: Kyra
authors.initials: K
authors.lastname: Lunstroot
authors.forename: Peter
authors.initials: P
authors.lastname: Nockemann
authors.forename: Kristof
authors.initials: K
authors.lastname: Van Hecke
authors.forename: Luc
authors.initials: L
authors.lastname: Van Meervelt
authors.forename: Christiane
authors.initials: C
authors.lastname: Görller-Walrand
authors.forename: Koen
authors.initials: K
authors.lastname: Binnemans
authors.forename: Kris
authors.initials: K
authors.lastname: Driesen