Synthesis and Structural Characterization of Tetraalkylammonium Salts of the Weakly Coordinating Anion [Al(OTeF5)4]–

The weakly coordinating properties of the [Al(OTeF5)4]– anion were studied by the synthesis and characterization of its tetraalkylammonium salts [NAlk4][Al(OTeF5)4] [Alk4 = –(CH3)4, –(C2H5)4, –(C2H5)3CH3, –(C3H7)4, –(C4H9)4]. The one‐pot synthesis includes formation of the Brønsted acid in 1,2–difluorobenzene, H[Al(OTeF5)4](solv.), and its reaction with [NAlk4]Cl [Alk4 = –(CH3)4, –(C2H5)4, –(C2H5)3CH3, –(C3H7)4, –(C4H9)4] to the corresponding salts. Single crystals were obtained for [N(C4H9)4][Al(OTeF5)4] and characterized by X‐ray diffraction analysis

Insights on the Lewis Superacid Al(OTeF5)3: Solvent Adducts, Characterization and Properties

Preparation and characterization of the dimeric Lewis superacid [Al(OTeF5)3]2 and various solvent adducts is presented. The latter range from thermally stable adducts to highly reactive, weakly bound species. DFT calculations on the ligand affinity of these Lewis acids were performed in order to rank their remaining Lewis acidity. An experimental proof of the Lewis acidity is provided by the reaction of solvent‐adducts of Al(OTeF5)3 with [PPh4][SbF6] and OPEt3, respectively. Furthermore, their reactivity towards chloride and pentafluoroorthotellurate salts as well as (CH3)3SiCl and (CH3)3SiF is shown. This includes the formation of the dianion [Al(OTeF5)5]2−

[P4H]+[Al(OTeF5)4]−: protonation of white phosphorus with the Brønsted superacid H[Al(OTeF5)4](solv)

A sustainable transformation of white phosphorus (P4) into chemicals of higher value is one of the key aspects in modern phosphorus research. Even though the chemistry of P4 has been investigated for many decades, its chemical reactivity towards the simplest electrophile, the proton, is still virtually unknown. Based on quantum-chemical predictions, we report for the first time the successful protonation of P4 by the Brønsted acid H[Al(OTeF5)4](solv). Our spectroscopic results are in agreement with acid-mediated activation of P4 under protonation of an edge of the P4-tetrahedron and formation of a three-center two-electron P–H–P bond. These investigations are of fundamental interest as they permit the activation of P4 with the simplest electrophile as a new prototype reaction for this molecule

Universitätsbibliothek Kiel: Jahresbericht 2017

Der Jahresbericht informiert über die wichtigsten Aktivitäten der Universitätsbibliothek Kiel und stellt ausgewählte Daten, Zahlen und Fakten zur Verfügung. Er beschreibt unser vielfältiges Spektrum an Services und Projekten

Universitätsbibliothek Kiel: Jahresbericht 2018

Der Jahresbericht informiert über die wichtigsten Aktivitäten der Universitätsbibliothek Kiel und stellt ausgewählte Daten, Zahlen und Fakten zur Verfügung. Als wichtiger Eckpfeiler im Berichtswesen der Bibliothek beschreibt er unser vielfältiges Spektrum an Services und Projekten

Insights on the Lewis Superacid Al(OTeF5)3: Solvent Adducts, Characterization and Properties

The improved preparation of the Lewis superacid Al(OTeF5)3 and several solvent adducts is presented. These range from thermally stable adducts to highly reactive, weakly bound species. DFT calculations on the ligand affinity of this Lewis acids were performed in order to rank their remaining Lewis acidity. An experimental proof of the Lewis acidity is provided by the reaction of Al(OTeF5)3 with [PPh4][SbF6] and OPPh3. Furthermore, reactivities towards chloride salts as well as CH3SiCl and CH3SiF are shown

Structural proof of a [C–F–C]+ fluoronium cation

Organic fluoronium ions can be described as positively charged molecules in which the most electronegative and least polarizable element fluorine engages in two partially covalent bonding interactions to two carbon centers. While recent solvolysis experiments and NMR spectroscopic studies on a metastable [C–F–C]+ fluoronium ion strongly support the divalent fluoronium structure over the alternative rapidly equilibrating classical carbocation, the model system has, to date, eluded crystallographic analysis to confirm this phenomenon in the solid state. Herein, we report the single crystal structure of a symmetrical [C–F–C]+ fluoronium cation. Besides its synthesis and crystallographic characterization as the [Sb2F11]− salt, vibrational spectra are discussed and a detailed analysis concerning the nature of the bonding situation in this fluoronium ion and its heavier halonium homologues is performed, which provides detailed insights on this molecular structure

Don't fear 'fear conditioning': Methodological considerations for the design and analysis of studies on human fear acquisition, extinction, and return of fear

The so-called 'replicability crisis' has sparked methodological discussions in many areas of science in general, and in psychology in particular. This has led to recent endeavours to promote the transparency, rigour, and ultimately, replicability of research. Originating from this zeitgeist, the challenge to discuss critical issues on terminology, design, methods, and analysis considerations in fear conditioning research is taken up by this work, which involved representatives from fourteen of the major human fear conditioning laboratories in Europe. This compendium is intended to provide a basis for the development of a common procedural and terminology framework for the field of human fear conditioning. Whenever possible, we give general recommendations. When this is not feasible, we provide evidence-based guidance for methodological decisions on study design, outcome measures, and analyses. Importantly, this work is also intended to raise awareness and initiate discussions on crucial questions with respect to data collection, processing, statistical analyses, the impact of subtle procedural changes, and data reporting specifically tailored to the research on fear conditioning