Two New Series of Potentially Triboluminescent Lanthanide(III) β‐Diketonate Complexes

Abstract

Two new series of anionic lanthanide(III) tetrakis(dibenzoylmethanato) complexes of the type [C 4 H 8 NEtH][Ln(dbm) 4 ] [Ln = Pr (2a), Nd (2b), Eu (2c), Tb (2d), Lu (2e); dbm = dibenzoylmethanate anion; [C 4 H 8 NEtH] + = N-ethylpyrrolidinium cation] and [C 5 H 10 NEtH][Ln(dbm) 4 ] [Ln = Pr (3a), Nd (3b), Eu (3c), Tb (3d), Lu (3e); [C 5 H 10 NEtH] + = N-ethylpiperidinium cation]. The results showed that anions of the type [Ln(dbm) 4 ]are accessible for Ln 3+ ions cover-* Prof. Dr. F. T. Edelmann 1177ing a wide range of ionic radii. While neither 2c nor 3c showed the expected triboluminescence (TL) properties, the new TL-active europium(III) complex salt [iPr 2 NH 2 ][Eu(dbm) 4 ] (4) could be isolated in a similar manner. Moreover, the unexpected formation and structural characterization of the nonanuclear europium cluster Eu 9 (μ 4 -OH) 2 (μ 3 -OH) 8 (bnac) 16 (5) (bnac = benzoylacetonate anion) is described. pium(III) chloride with 4 equiv. of dibenzoylmethane and 4 equiv. of triethylamine in ethanol solution. Slow cooling of the reaction mixture affords yellow crystals of 1, while the byproduct [NEt 3 H]Cl remains dissolved in the mother liquid. Upon grinding, large crystals of 1 show very strong orangered Eu 3+ triboluminescence, which can be observed even in daylight ("smash-glow crystals"). [10] Scheme 1. Schematic representation of [NEt 3 H][Eu(dbm) 4 ] (1). Journal of Inorganic and General ChemistryZeitschrift für anorganische und allgemeine Chemie ARTICLE amines such as N-ethylpyrrolidine (C 4 H 8 NEt) or N-ethylpiperidine (C 5 H 10 NEt) (cf. Scheme 2). Furthermore, we have been interested in the preparation and luminescence properties of corresponding complexes of lanthanide metals other than europium. Scheme 2. Schematic representation of (a) triethylamine, (b) N-ethylpyrrolidine, and (c) N-ethylpiperidine.We report herein the synthesis and full characterization of two series of anionic lanthanide(III) tetrakis (dibenzoylmethanato) complexes of the type [C 4 H 8 NEtH][Ln(dbm) 4 ] (2a-2e) (Ln = Pr, Nd, Eu, Tb, Lu) and [C 5 H 10 NEtH][Ln(dbm) 4 ] (3a-3e) (Ln = Pr, Nd, Eu, Tb, Lu) as well as the new TL-active europium(III) complex salt [iPr 2 NH 2 ][Eu(dbm) 4 ] (4).Moreover, the unexpected formation and structural characterization of the nonanuclear europium cluster Eu 9 (μ 4 -OH) 2 (μ 3 -OH) 8 (bnac) 16 (5) (bnac = benzoylacetonate anion) is described. Results and Discussion Preparation and PropertiesAs illustrated in Scheme 3, the preparation of the title complexes [C 4 H 8 NEtH][Ln(dbm) 4 ] (2a-2e) (Ln = Pr, Nd, Eu, Tb, Lu) and [C 5 H 10 NEtH][Ln(dbm) 4 ] (3a-3e) (Ln = Pr, Nd, Eu, Tb, Lu) was carried out in a similar manner as reported for 1. [9a] For these experiments, the lanthanides Nd, Pr, Eu, Tb, and Lu were chosen in order to cover a wide range of ionic radii. The respective lanthanide(III) chlorides (as hexahydrates) were dissolved in absolute ethanol and treated with a mixture of 4 equiv. of dibenzoylmethane and 4 equiv. of either Scheme 3. Synthesis of compounds 2a-2e and 3a-3e.

Effect of single variable factor of electron‐acceptor on the luminescence quantum yield of terbium complex

“…[24,25] BMBA shows three coordination modes of 2.12, 2.11, and 1.11 (Figure S1). Selected bond angles and bond lengths for Tb-Br and Tb-I are in line with reported results [26][27][28][29][30] and are listed in Table S1-S2. Powder X-ray diffraction (PXRD) patterns of assynthesized Tb-Br and Tb-I correspond well with their simulated results, demonstrating high phase purity of the bulk samples (Figures S2, S3).…”

Mechanochemical Syntheses of Ln(hfac)3(H2O)x (Ln = La-Sm, Tb): Isolation of 10-, 9-, and 8-Coordinate Ln(hfac)n Complexes

“…Lanthanide β-diketonate complexes are often studied for their magnetic − and optical properties. − The versatility afforded by the variety of commercially available β-diketone ligands combined with the structurally isomorphous nature of lanthanide cations allows for delineation of structure–function relationships while also facilitating diverse applications . More specifically, the fluorinated β-diketone 1,1,1,5,5,5-hexafluoroacetylacetone (Hhfac) ligand imparts volatility. − Although complexes of the type Ln­(hfac) 3 (H 2 O) x have been known for over 50 years, only the single-crystal structures of the later lanthanides Tb, Ho, Er, and Dy are currently known.…”