N-Substituted imide-fused corannulenes can be generated from the corresponding tetramethylfluoranthenes. Syntheses, crystal structure and electronic properties are reported. The solid state structure of the pentafluorophenyl derivative shows nearly perfect π-stacking in a convex-concave fashion and is expected to possess useful electronic properties.

A hitherto unprecedented polynuclear phosphinine-Cu(I) complex has been prepared and crystallographically characterized. The molecular structure in the crystal verifies the presence of the heterocubane-type tetrameric cluster [LCuBr]4 (L = 2,4-diphenyl-5-methyl-6-(2,3-dimethylphenyl)phosphinine), which unexpectedly shows in the solid state temperature-independent orange phosphorescence solely from an (3)XMLCT state, in clear contrast to the well-established dual-emissive-state model for luminescent Cu4X4L4 clusters.

In this study, we compare combustion ion chromatography (CIC) and high resolution-continuum source-graphite furnace molecular absorption spectrometry (HR-CS-GFMAS) with respect to their applicability for determining organically bound fluorine sum parameters. Extractable (EOF) and adsorbable (AOF) organically bound fluorine as well as total fluorine (TF) were measured in samples from river Spree in Berlin, Germany, to reveal the advantages and disadvantages of the two techniques used as well as the two established fluorine sum parameters AOF and EOF. TF concentrations determined via HR-CS-GFMAS and CIC were comparable between 148 and 270 μg/L. On average, AOF concentrations were higher than EOF concentrations, with AOF making up 0.14–0.81% of TF (determined using CIC) and EOF 0.04–0.28% of TF (determined using HR-CS-GFMAS). The results obtained by the two independent methods were in good agreement. It turned out that HR-CS-GFMAS is a more sensitive and precise method for fluorine analysis compared to CIC. EOF and AOF are comparable tools in risk evaluation for the emerging pollutants per- and polyfluorinated alkyl substances; however, EOF is much faster to conduct.

For the first time, fluorine K-edge X-ray absorption near-edge structure (XANES) spectroscopy was applied to detect per- and polyfluoroalkyl substances (PFAS) in various soil and sewage sludge samples. The method can be used to determine the speciation of inorganic and organic fluorides, without pre-treatment of solid samples. Therefore, XANES spectra of several inorganic fluorides as well as selected fluorinated organic compounds were recorded. While inorganic fluorides partially exhibit a variety of sharp spectral features in the XANES spectrum, almost all inspected organofluorine compounds show two distinct broad features at 688.5 and 692.0 eV. Moreover, the peak intensity ratio 688.5 eV/692.0 eV in the PFAS XANES spectrum can be inversely correlated to the chain length of the perfluoro sulfonic acid group. The detection of targeted PFAS by bulk-XANES spectroscopy in combination with linear combination fitting in soils and sewage sludges was not applicable due to the low organic fluorine to total fluorine ratio of the samples (0.01–1.84%). Nonetheless, direct analysis of pure PFAS revealed that analysis of organofluorine species might be achieved in higher concentrated samples. Furthermore, quantitative measurements by combustion ion chromatography (CIC) evaluated as sum parameters extractable organically bound fluorine (EOF) and total fluorine (TF) emphasize that besides soils, sewage sludges are a significant source of organic fluorine in agriculture (154–7209 µg/kg).

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A series of isotopologues of the siloxanediol Mes Si(OH)(μ-O)Si(OH)Mes (3 a) (Mes=2,4,6-trimethylphenyl) were synthesized by reactions of the corresponding disiloxane precursors Mes Si(μ-O) SiMes (2 a), Mes Si(μ- O) SiMes (2 b) or Mes Si(μ- O) SiMes (2 c) with an excess of H O, H O or H O. NMR and IR signal assignments for the siloxanediols in benzene are supported by quantum-chemical calculations, which indicate small energy differences between trans and cis conformers, the latter of which exhibits an intramolecular hydrogen bond. H NMR as well as IR data suggest the presence of a mixture of both conformers in C D . Hydrogen-bonded adducts of Mes Si(OH)(μ-O)Si(OH)Mes with ethers such as diethylether, dimethoxyethane or dioxane were observed in the solid state, where they form polymeric chain-like structures. The latter appear to be stable only in the crystal. O{ H} NMR and IR data in THF solution suggest an interaction of 3 a with at least one THF molecule, whereas diethylether appears not to interact. Water adducts form neither in solution nor in the solid state as indicated by NMR and ATR IR data. O{ H} NMR and ESI-MS experiments illustrate the remarkably high stability of the siloxanediols towards water and show no evidence for intra- or intermolecular oxygen-exchange reactions. In marked contrast, a stepwise exchange of all three oxygen atoms-including the one in the Si-O-Si bridge-occurred in the gas phase, when [Mes Si( OH)(μ- O)Si( O)Mes ] was treated with H O in the hexapole of an ESI FT-ICR mass spectrometer. The scrambling between the bridging and the other oxygen atoms likely proceeds through cyclic Si O intermediates.

Over the past two decades, per- and polyfluoroalkyl substances (PFASs) have emerged as worldwide environmental contaminants, calling out for sophisticated treatment, decomposition and remediation strategies. In order to mineralize PFAS pollutants, the incineration of contaminated material is a state-of-the-art process, but more cost-effective and sustainable technologies are inevitable for the future. Within this review, various methods for the reductive defluorination of PFASs were inspected. In addition to this, the role of mechanochemistry is highlighted with regard to its major potential in reductive defluorination reactions and degradation of pollutants. In order to get a comprehensive understanding of the involved reactions, their mechanistic pathways are pointed out. Comparisons between existing PFAS decomposition reactions and reductive approaches are discussed in detail, regarding their applicability in possible remediation processes. This article provides a solid overview of the most recent research methods and offers guidelines for future research directions.

The Lewis acid B(C6F5)3 and the cyclic silane (ArN2Si)3 (1) (ArN=o‐(CH3)2NCH2C6H4) are useful precursors to access the silylene(II)–borane adduct ArN2Si‐B(C6F5)3 (2). Treatment of 2 with water led to coordination and gave the Lewis pair (ArN2H2O)Si‐B(C6F5)3 (3) that exhibits a hydrogen‐bond‐stabilized silanol unit. It can be converted into the siloxane [(HArN)2SiOB(C6F5)3]2O (6) by dehydrogenation in the presence of a base. Heteronuclear NMR spectroscopic data to characterize the compounds were supported by quantum‐chemical calculations.