From Lewis Superacidic Aluminum Pentafluoroorthotellurates to Perfluorinated Tritylium and Fluoronium Ions

The properties and reactivity of Lewis superacidic aluminum pentafluoroorthotellurates are investigated. An improved synthesis for the dimeric [Al(OTeF5)3]2 was developed, yielding a pure product with an enhanced thermal stability. Different solvent adducts were synthesized, resulting in monomeric complexes of the Lewis acid with up to three solvent molecules attached. The complexes of Al(OTeF5)3 with toluene, fluorobenzene and sulfuryl chloride fluoride remained Lewis superacidic, as quantum-chemical calculations confirmed. Additionally, the high Lewis acidity of [Al(OTeF5)3]2 and its solvent adducts were further verified by experimental methods. Two different routes for the synthesis of the perfluorinated trityl cation [C(C6F5)3]+ were established. One utilizes the Lewis superacid [Al(OTeF5)3(OSOClF)2], the other the corresponding Brønsted superacid [H–C6H4F2][Al(OTeF5)4]. A crystallographic characterization of this cation in conjunction with the weakly coordinating anion [Al(OTeF5)4]− was achieved for the first time. These routes finally give access to the perfluortrityl cation in SO2ClF and organic solvents such as ortho-difluorobenzene. This improved handling enabled insights into the reactivity of this cation as hydride abstractor and oxidation reagent, which was proven by experimental and theoretical methods. Organic divalent fluoronium ions were only investigated by spectroscopic studies, while a characterization in the solid state so far did not yield success. In this thesis, the synthesis and crystallographic analysis of a symmetrical [C–F–C]+ fluoronium ion is reported. The vibrational spectrum of the fluoronium salt is discussed and the nature of the bonding situation in this type of cations are quantum-chemically studied and compared with heavier halonium homologues. Besides the isolation and characterization of elusive cations with strong Lewis acids, the synthesis of a novel solid Lewis superacid is reported. Hereby, the reaction of a mixture of AlCl3 and [Al(OTeF5)3]2 with CCl3F leads to an anion-doped aluminum chlorofluoride AlCl0.1F2.8(OTeF5)0.1. This material was studied by PDF analysis, EXAFS and MAS NMR spectroscopy, confirming an intact OTeF5 group. A reaction with CD3CN and subsequent IR spectroscopy revealed the Lewis superacidic nature of the material. Lastly, the catalytic activity of the material in dehydrofluorination reactions was tested.Die Eigenschaften und die Reaktivität von Lewis-supersauren Aluminiumpentafluoroorthotelluraten wurden untersucht. Es wurde eine verbesserte Synthese für dimeres [Al(OTeF5)3]2 entwickelt, die ein reineres Produkt mit erhöhter thermischer Stabilität ergibt. Es wurden verschiedene Lösungsmitteladdukte syn- thetisiert, wobei monomere Komplexe der Lewis-Säure mit bis zu drei gebundenen Lösungsmittelmolekülen erhalten wurden. Die Komplexe von Al(OTeF5)3 mit Toluol, Fluorbenzol und Sulfurylchloridfluorid gelten immernoch als Lewis-Supersäuren, was durch quantenchemische Berechnungen bestätigt wurde. Darüber hinaus wurde die hohe Lewis-Azidität von [Al(OTeF5)3]2 und seinen Lösungsmitteladdukten durch experimentelle Methoden weiter verifiziert. Es wurden zwei unterschiedliche Routen zur Synthese des perfluorierten Tritylkations [C(C6F5)3]+ entwickelt. Die erste Route nutzt die Lewis-Supersäure [Al(OTeF5)3(OSOClF)2], während die zweite Route die korrespondierende Brønsted Supersäure [H–C6H4F2][Al(OTeF5)4] verwendet. Das schwach koordinierende Anion [Al(OTeF5)4]− ermöglichte die kristallographische Charakterisierung dieses Kations mittels Einkristall-Röntgenstrukturanalyse. Die vorgestellten Synthesrouten führen so erstmalig zur Handhabung des Perfluortrityl-Kations in SO2ClF und organischen Lösungsmitteln wie ortho-Difluorbenzol. Dies erlaubte Einblicke in die Reaktivität dieses Kations als Hydridabstraktor und Oxidationsreagenz, was mit experimentellen und theoretischen Methoden nachgewiesen wurde. Organische, divalente Fluoroniumionen wurden bisher nur durch spektroskopische Studien untersucht, während eine Charakterisierung im festen Zustand bisher nicht möglich war. In dieser Arbeit wird über die Synthese und kristallographische Analyse eines symmetrischen [C–F–C]+ Fluoroniumions berichtet. Darüber hinaus wird das Schwingungsspektrum des Fluoroniumsalzes diskutiert und die Bindungssituation in dieser Art von Kation quantenchemisch untersucht und mit schwereren Halonium-Homologen verglichen. Neben der Isolierung und Charakterisierung von schwer-fassbaren Kationen mit starken Lewis-Säuren wird über die Synthese einer neuartigen festen Lewis-Supersäure berichtet. Dabei führt die Reaktion einer Mischung aus AlCl3 und [Al(OTeF5)3]2 mit CCl3F zu einem anionen-dotierten Aluminiumchlor-fluorid AlCl0.1F2.8(OTeF5)0.1. Dieses Material wurde mittels PDF-Analyse, EXAFS- und MAS-NMR- Spektroskopie untersucht, wodurch die Intakthaltung der OTeF5 Gruppe bestätigt werden konnte. Eine Reaktion mit CD3CN und anschließende Untersuchung mittels IR-Spektroskopie zeigten die Lewis-supersauren Eigenschaften des Materials. Schließlich wurde die katalytische Aktivität des Materials in Dehydrofluorierungsreaktionen getestet

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−

Unravelling the Role of the Pentafluoroorthotellurate Group as a Ligand in Nickel Chemistry

The pentafluoroorthotellurate group (teflate, OTeF5) is able to form species, for which only the fluoride analogues are known. Despite nickel fluorides being widely investigated, nickel teflates have remained elusive for decades. By reaction of [NiCl4]2− and neat ClOTeF5, we have synthesized the homoleptic [Ni(OTeF5)4]2− anion, which presents a distorted tetrahedral structure, unlike the polymeric [NiF4]2−. This high‐spin complex has allowed the study of the electronic properties of the teflate group, which can be classified as a weak/medium‐field ligand, and therefore behaves as the fluoride analogue also in ligand‐field terms. The teflate ligands in [NEt4]2[Ni(OTeF5)4] are easily substituted, as shown by the formation of [Ni(NCMe)6][OTeF5]2 by dissolving it in acetonitrile. Nevertheless, careful reactions with other conventional ligands have enabled the crystallization of nickel teflate complexes with different coordination geometries, i.e. [NEt4]2[trans‐Ni(OEt2)2(OTeF5)4] or [NEt4][Ni(bpyMe2)(OTeF5)3].Deutsche Forschungsgemeinschaft http://dx.doi.org/10.13039/501100001659Peer Reviewe

Unravelling the Role of the Pentafluoroorthotellurate Group as a Ligand in Nickel Chemistry

The pentafluoroorthotellurate group (teflate, OTeF5) is able to form species, for which only the fluoride analogues are known. Despite nickel fluorides being widely investigated, nickel teflates have remained elusive for decades. By reaction of [NiCl4]2− and neat ClOTeF5, we have synthesized the homoleptic [Ni(OTeF5)4]2− anion, which presents a distorted tetrahedral structure, unlike the polymeric [NiF4]2−. This high‐spin complex has allowed the study of the electronic properties of the teflate group, which can be classified as a weak/medium‐field ligand, and therefore behaves as the fluoride analogue also in ligand‐field terms. The teflate ligands in [NEt4]2[Ni(OTeF5)4] are easily substituted, as shown by the formation of [Ni(NCMe)6][OTeF5]2 by dissolving it in acetonitrile. Nevertheless, careful reactions with other conventional ligands have enabled the crystallization of nickel teflate complexes with different coordination geometries, i.e. [NEt4]2[trans‐Ni(OEt2)2(OTeF5)4] or [NEt4][Ni(bpyMe2)(OTeF5)3]

Air-stable aryl derivatives of pentafluoroorthotellurate

We report on two different sets of air-stable derivatives of pentafluoroorthotellurate containing fluorinated and non-fluorinated aryl groups. The acid cis-PhTeF4OH was obtained in gram scale and further transformed to Ag[cis-PhTeF4O], which was used as a cis-PhTeF4O transfer reagent to obtain [PPh4][cis-PhTeF4O]. Furthermore, the synthesis of trans-(C6F5)2TeF3OH was achieved by a selective hydrolysis of trans-(C6F5)2TeF4 in the presence of KF and subsequent protonation by aHF. Quantum-chemical calculations show a higher acidity and robustness against fluoride abstraction for trans-(C6F5)2TeF3OH compared to cis-PhTeF4OH

An Amorphous Teflate Doped Aluminium Chlorofluoride: A Solid Lewis‐Superacid for the Dehydrofluorination of Fluoroalkanes

An anion-doped aluminium chlorofluoride AlCl0.1F2.8(OTeF5)0.1 (ACF-teflate) was synthesized. The material contains pentafluoroorthotellurate (teflate) groups, which mimic fluoride ions electronically, but are sterically more demanding. They are embedded into the amorphous structure. The latter was studied by PDF analysis, EXAFS data and MAS NMR spectroscopy. The mesoporous powder is a Lewis superacid, and ATR-IR spectra of adsorbed CD3CN reveal a blue-shift of the adsorption band by 73 cm−1, which is larger than the shift for SbF5. Remarkably, ACF-teflate catalyzes dehydrofluorination reactions of monofluoroalkanes to yield olefins in C6D6. In these cases, no Friedel-Crafts products were formed.German Research Foundation http://dx.doi.org/10.13039/501100001659Diamond Light Source http://dx.doi.org/10.13039/100011889German Research Foundation http://dx.doi.org/10.13039/501100001659Peer Reviewe

An Amorphous Teflate Doped Aluminium Chlorofluoride: A Solid Lewis‐Superacid for the Dehydrofluorination of Fluoroalkanes

An anion‐doped aluminium chlorofluoride AlCl0.1F2.8(OTeF5)0.1 (ACF‐teflate) was synthesized. The material contains pentafluoroorthotellurate (teflate) groups, which mimic fluoride ions electronically, but are sterically more demanding. They are embedded into the amorphous structure. The latter was studied by PDF analysis, EXAFS data and MAS NMR spectroscopy. The mesoporous powder is a Lewis superacid, and ATR‐IR spectra of adsorbed CD3CN reveal a blue‐shift of the adsorption band by 73 cm−1, which is larger than the shift for SbF5. Remarkably, ACF‐teflate catalyzes dehydrofluorination reactions of monofluoroalkanes to yield olefins in C6D6. In these cases, no Friedel‐Crafts products were formed

Proteomics as a quality control tool of pharmaceutical probiotic bacterial lysate products

Probiotic bacteria have a wide range of applications in veterinary and human therapeutics. Inactivated probiotics are complex samples and quality control (QC) should measure as many molecular features as possible. Capillary electrophoresis coupled to mass spectrometry (CE/MS) has been used as a multidimensional and high throughput method for the identification and validation of biomarkers of disease in complex biological samples such as biofluids. In this study we evaluate the suitability of CE/MS to measure the consistency of different lots of the probiotic formulation Pro-Symbioflor which is a bacterial lysate of heat-inactivated Escherichia coli and Enterococcus faecalis. Over 5000 peptides were detected by CE/MS in 5 different lots of the bacterial lysate and in a sample of culture medium. 71 to 75% of the total peptide content was identical in all lots. This percentage increased to 87–89% when allowing the absence of a peptide in one of the 5 samples. These results, based on over 2000 peptides, suggest high similarity of the 5 different lots. Sequence analysis identified peptides of both E. coli and E. faecalis and peptides originating from the culture medium, thus confirming the presence of the strains in the formulation. Ontology analysis suggested that the majority of the peptides identified for E. coli originated from the cell membrane or the fimbrium, while peptides identified for E. faecalis were enriched for peptides originating from the cytoplasm. The bacterial lysate peptides as a whole are recognised as highly conserved molecular patterns by the innate immune system as microbe associated molecular pattern (MAMP). Sequence analysis also identified the presence of soybean, yeast and casein protein fragments that are part of the formulation of the culture medium. In conclusion CE/MS seems an appropriate QC tool to analyze complex biological products such as inactivated probiotic formulations and allows determining the similarity between lots

Measurements of branching fraction ratios and CP-asymmetries in suppressed B^- -> D(-> K^+ pi^-)K^- and B^- -> D(-> K^+ pi^-)pi^- decays

We report the first reconstruction in hadron collisions of the suppressed decays B^- -> D(-> K^+ pi^-)K^- and B^- -> D(-> K^+ pi^-)pi^-, sensitive to the CKM phase gamma, using data from 7 fb^-1 of integrated luminosity collected by the CDF II detector at the Tevatron collider. We reconstruct a signal for the B^- -> D(-> K^+ pi^-)K^- suppressed mode with a significance of 3.2 standard deviations, and measure the ratios of the suppressed to favored branching fractions R(K) = [22.0 \pm 8.6(stat)\pm 2.6(syst)]\times 10^-3, R^+(K) = [42.6\pm 13.7(stat)\pm 2.8(syst)]\times 10^-3, R^-(K)= [3.8\pm 10.3(stat)\pm 2.7(syst]\times 10^-3, as well as the direct CP-violating asymmetry A(K) = -0.82\pm 0.44(stat)\pm 0.09(syst) of this mode. Corresponding quantities for B^- -> D(-> K^+ pi^-)pi^- decay are also reported.Comment: 8 pages, 1 figure, accepted by Phys.Rev.D Rapid Communications for Publicatio

Search for the standard model Higgs boson in the H to ZZ to 2l 2nu channel in pp collisions at sqrt(s) = 7 TeV

A search for the standard model Higgs boson in the H to ZZ to 2l 2nu decay channel, where l = e or mu, in pp collisions at a center-of-mass energy of 7 TeV is presented. The data were collected at the LHC, with the CMS detector, and correspond to an integrated luminosity of 4.6 inverse femtobarns. No significant excess is observed above the background expectation, and upper limits are set on the Higgs boson production cross section. The presence of the standard model Higgs boson with a mass in the 270-440 GeV range is excluded at 95% confidence level.Comment: Submitted to JHE