Homoleptic Lanthanide 1,2,3-Triazolates _∞^2–3[Ln(Tz*)₃] and Their Diversified Photoluminescence Properties

The series of homoleptic lanthanide 1,2,3-triazolates _∞³[Ln­(Tz*)₃] (Ln³⁺ = lanthanide cation, Tz*^– = 1,2,3-triazolate anion, C₂H₂N₃^–) is completed by synthesis of the three-dimensional (3D) frameworks with Ln = La, Ce, Pr, Nd, and Sm, and characterization by X-ray powder diffraction, differential thermal analysis-thermogravimetry (DTA/TG) investigations and molecular vibration analysis. In addition, α-_∞²[Sm­(Tz*)₃], a two-dimensional polymorph of 3D β-_∞³[Sm­(Tz*)₃], is presented including the single crystal structure. The 3D lanthanide triazolates form an isotypic series of the formula _∞³[Ln­(Tz*)₃] ranging from La to Lu, with the exception of Eu, which forms a mixed valent metal organic framework (MOF) of different structure and the constitution _∞³[Eu­(Tz*)_6+<i>x</i>(Tz*H)_2–<i>x</i>]. The main focus of this work is put on the investigation of the photoluminescence behavior of lanthanide 1,2,3-triazolates _∞³[Ln­(Tz*)₃] and illuminates that six different luminescence phenomena can be found for one series of isotypic compounds. The luminescence behavior of the majority of these compounds is based on the photoluminescence properties of the organic linker molecules. Differing properties are observed for _∞³[Yb­(Tz*)₃], which exhibits luminescence properties based on charge transfer transitions between the linker and Yb³⁺ ions, and for _∞³[Ce­(Tz*)₃] and _∞³[Tb­(Tz*)₃], in which the luminescence properties are a combination of the ligand and the lanthanide metal. In addition, strong inner-filter effects are found in the ligand emission bands that are attributed to reabsorption of the emitted light by the trivalent lanthanide ions. Antenna effects of varying efficiency are present indicated by the energy being transferred to the lanthanide ions subsequent to excitation of the ligand. _∞³[Ce­(Tz*)₃] shows a 5d-4f induced intense blue emission upon excitation with UV light, while _∞³[Tb­(Tz*)₃] shows emission in the green region of the visible spectrum, which can be identified with 4f-4f-transitions typical for Tb³⁺ ions

Metal–Organic Framework Luminescence in the Yellow Gap by Codoping of the Homoleptic Imidazolate _∞³[Ba(Im)₂] with Divalent Europium

The rare case of a metal-triggered broad-band yellow emitter among inorganic–organic hybrid materials was achieved by in situ codoping of the novel imidazolate metal–organic framework _∞³[Ba­(Im)₂] with divalent europium. The emission maximum of this dense framework is in the center of the yellow gap of primary light-emitting diode phosphors. Up to 20% Eu²⁺ can be added to replace Ba²⁺ as connectivity centers without causing observable phase segregation. High-resolution energy-dispersive X-ray spectroscopy showed that incorporation of even 30% Eu²⁺ is possible on an atomic level, with 2–10% Eu²⁺ giving the peak quantum efficiency (QE = 0.32). The yellow emission can be triggered by two processes: direct excitation of Eu²⁺ and an antenna effect of the imidazolate linkers. The emission is fully europium-centered, involving 5d <b>→</b> 4f transitions, and depends on the imidazolate surroundings of the metal ions. The framework can be obtained by a solvent-free in situ approach starting from barium metal, europium metal, and a melt of imidazole in a redox reaction. Better homogeneity for the distribution of the luminescence centers was achieved by utilizing the hydrides BaH₂ and EuH₂ instead of the metals

NGO assessment study report (Yellow Book)

http://sci.esa.int/science-e/www/object/index.cfm?fobjectid=49839#The NGO (New Gravitational wave Observatory) concept results from the reformulation of the LISA mission into a European-led mission. This report, the so-called Yellow Book, contains the results of ESA's assessment study (Phase 0/A) of the candidate L-class Cosmic Vision mission NGO

Genome-wide meta-analysis of over 29,000 people with epilepsy reveals 26 loci and subtype-specific genetic architecture

AbstractEpilepsy is a highly heritable disorder affecting over 50 million people worldwide, of which about one-third are resistant to current treatments. Here, we report a trans-ethnic GWAS including 29,944 cases, stratified into three broad- and seven sub-types of epilepsy, and 52,538 controls. We identify 26 genome-wide significant loci, 19 of which are specific to genetic generalized epilepsy (GGE). We implicate 29 likely causal genes underlying these 26 loci. SNP-based heritability analyses show that common variants substantially close the missing heritability gap for GGE. Subtype analysis revealed markedly different genetic architectures between focal and generalized epilepsies. Gene-set analysis of GGE signals implicate synaptic processes in both excitatory and inhibitory neurons in the brain. Prioritized candidate genes overlap with monogenic epilepsy genes and with targets of current anti-seizure medications. Finally, we leverage our results to identify alternate drugs with predicted efficacy if repurposed for epilepsy treatment