TY - JOUR A1 - Gers-Panther, C.F. A1 - Fischer, H. A1 - Nordmann, J. A1 - Seiler, T. A1 - Behnke, Thomas A1 - Würth, Christian A1 - Frank, W. A1 - Resch-Genger, Ute A1 - Müller, T.J.J. T1 - Four- and Five-Component Syntheses and Photophysical Properties of Emission Solvatochromic 3‑Aminovinylquinoxalines N2 - 3-Aminovinylquinoxalines are readily accessible from (hetero)aryl glyoxylic acids or heterocyclic π-nucleophiles by consecutive four- and fivecomponent syntheses in the sense of an activation-alkynylation-cyclocondensation-addition sequence or glyoxylation-alkynylation-cyclocondensation-addition sequence in good yields. The title compounds are highly fluorescent with pronounced emission solvatochromicity and protochromic fluorescence quenching. Time-resolved fluorescence spectroscopy furnishes radiative and nonradiative fluorescence decay rates in various solvent polarities. The electronic structure is corroborated by DFT and TD-DFT calculations rationalizing the observed spectroscopic effects. KW - Dye KW - Syntheseis KW - Spectroscopy PY - 2016 DO - https://doi.org/10.1021/acs.joc.6b02581 SN - 0022-3263 VL - 82 SP - 567 EP - 578 PB - ACS Publications AN - OPUS4-39211 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kaltenbach, A. A1 - Nordmann, J. A1 - Görlitz, V. A1 - Pape, C. A1 - Richter, Silke A1 - Kipphardt, Heinrich A1 - Kopp, G. A1 - Jährling, R. A1 - Rienitz, O. A1 - Güttler, B. T1 - Gravimetric preparation and characterization of primary reference solutions of molybdenum and rhodium N2 - Gravimetrically prepared mono-elemental reference solutions having a well-known mass fraction of approximately 1 g/kg (or a mass concentration of 1 g/L) define the very basis of virtually all measurements in inorganic analysis. Serving as the starting materials of all standard/calibration solutions, they link virtually all measurements of inorganic analytes (regardless of the method applied) to the purity of the solid materials (high-purity metals or salts) they were prepared from. In case these solid materials are characterized comprehensively with respect to their purity, this link also establishes direct metrological traceability to The International System of Units (SI). This, in turn, ensures the comparability of all results on the highest level achievable. Several national metrology institutes (NMIs) and designated institutes (DIs) have been working for nearly two decades in close cooperation with commercial producers on making an increasing number of traceable reference solutions available. Besides the comprehensive characterization of the solid starting materials, dissolving them both loss-free and completely under strict gravimetric control is a challenging problem in the case of several elements like molybdenum and rhodium. Within the framework of the European Metrology Research Programme (EMRP), in the Joint Research Project (JRP) called SIB09 Primary standards for challenging elements, reference solutions of molybdenum and rhodium were prepared directly from the respective metals with a relative expanded uncertainty associated with the mass fraction of Urel(w)<0.05 %. To achieve this, a microwave-assisted digestion procedure for Rh and a hotplate digestion procedure for Mo were developed along with highly accurate and precise inductively coupled plasma optical emission spectrometry (ICP OES) and multicollector inductively coupled plasma mass spectrometry (MC-ICP-MS) methods required to assist with the preparation and as dissemination tools. KW - Digestion KW - Rhodium KW - Molybdenum KW - Reference solution KW - Metrological traceability KW - ICP OES KW - MC-ICP-MS PY - 2015 DO - https://doi.org/10.1007/s00216-014-8395-2 SN - 1618-2642 SN - 1618-2650 VL - 407 IS - 11 SP - 3093 EP - 3102 PB - Springer CY - Berlin AN - OPUS4-33065 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -