Dibenzoa,epentalene (DBP) is a non‐alternant conjugated hydrocarbon with antiaromatic character and ambipolar electrochemical behavior. Upon both reduction and oxidation, it becomes aromatic. We ...herein study the chemical oxidation and reduction of a planar DBP derivative and a bent DBP‐phane. The molecular structures of its planar dication, cation radical and anion radical in the solid state demonstrate the gained aromaticity through bond length equalization, which is supported by nucleus independent chemical shift‐calculations. EPR spectra on the cation radical confirm the spin delocalization over the DBP framework. A similar delocalization was not possible in the reduced bent DBP‐phane, which stabilized itself by proton ion from a solvent molecule upon reduction. This is the first report on structures of a DBP cation radical and dication in the solid state and of a reduced bent DBP derivative. Our study provides valuable insight into the charged species of DBP for its application as semiconductor.
Aromatic character in a dibenzoa,epentalene (DBP) was observed upon chemical oxidation to the cation radical and dication and reduction to the anion radical, as found from solid‐state structures. In a bent DBP‐phane aromaticity could not be reached upon reduction, and stabilization though proton ion occurred.
The coordination chemistry of 2,6‐bis(diazaboryl)pyridine (dab2py) is studied towards selected halides of aluminum(III), gallium(III) and germanium(II). Addition of dab2py to AlBr3 readily yielded ...the salt of ligand induced ionization (dab2py)AlBr2AlBr4. The aluminum atom in the cation is coordinated by the pyridine's nitrogen atom and also by one nitrogen atom of each diazaboryl group, resembling the coordination motif found for tridentate pincer ligands, e.g. 2,6‐diiminopyridines. By NMR spectroscopic measurements a rapid exchange reaction between all four Ndab‐atoms was detected, showing that the tridentate coordination motif of dab2py is less rigid compared with 2,6‐diiminopyridines. The adduct formation of dab2py and GaCl3 does not proceed at room temperature in solution. Addition of GeCl2·dioxane to this mixture gave the salt (dab2py)GeClGaCl4. The germanium atom is coordinated by the pyridine's nitrogen atom and a nitrogen atom of one diazaboryl group. The product of partial hydrolysis of the cation (dab2py)GeCl+ was isolated as single crystals. The structure determination revealed the insertion of an oxygen atom between the germanium atom and a boron atom, showing that the diazaboryl groups do not only provide hemilabile Lewis donor but also weak Lewis acid functionalities that are involved in the stabilization of main group cations.
The coordination chemistry of 2,6‐bis(diazaboryl)pyridine (dab2py) was studied with selected main group compounds. The nitrogen atoms and the boron atom of the diazaboryl groups were found to be involved in the coordination chemistry. The system dab2Py/GaCl3 was identified as a formal FLP at room temperature that allows for the synthesis of cationic main group element adducts.
Invited for the cover of this issue is the group of Tobias Böttcher from Universität Freiburg, Germany. The cover image shows the similarity of the chemistry presented to a game of Tetris.
We think ...that the system dab2py/GaCl3 is a very convenient entry point for the synthesis of cationic complexes …
Read more about the story behind the cover in the Cover Profile and about the research itself in the Full Paper by J. Schröder and T. Böttcher
The synthesis and isolation of a phosphinine selenide was achieved for the first time by reacting red selenium with 2,6‐bis(trimethylsilyl)phosphinine. The rather large coupling constant of ...1JP,Se=883 Hz is in line with a P−Se bond of high s‐character. The σ‐electron donating Me3Si‐substituents significantly increase the energy of the phosphorus lone pair and hence its basicity, making the heterocycle considerably more basic and nucleophilic than the unsubstituted phosphinine C5H5P, as confirmed by the calculated gas phase basicities. NBO calculations further reveal that the lone pairs of the selenium atom are stabilized through donor‐acceptor interactions with antibonding orbitals of the aromatic ring. The novel phosphinine selenide shows a distinct reactivity towards hexafluoro‐2‐butyne, Au(I)Cl as well as iPrOH. Our results pave the way for new perspectives in the chemistry of phosphorus in low coordination.
The synthesis and isolation of a phosphinine selenide was achieved for the first time. The σ‐electron donating Me3Si‐substituents significantly increase the energy of the phosphorus lone pair and hence its basicity, making the heterocycle considerably more basic and nucleophilic than the unsubstituted phosphinine C5H5P, as confirmed by the calculated gas‐phase basicities. The novel phosphinine selenides show a distinct reactivity towards dienophiles, Au(I)Cl as well as alcohols.
Zusammenfassung
Bei der Messung technischer Oberflächen treten insbesondere im Umfeld flexibler Fertigung unterschiedlichste Anforderungen auf. Häufig ist eine schnelle hochgenaue Topographie-Messung ...erwünscht. Durch die Kombination des chromatisch-konfokalen Verfahrens mit der spektralen Interferometrie (Chromatisch-Konfokale Spektral-Interferometrie) ist es möglich, single-shot Messungen mit einem weiten Messbereich und gleichzeitig geringer Unsicherheit zu erzielen. Dabei können ebenso die den beiden einzelnen Verfahren inhärenten Probleme umgangen und so der Einsatzbereich erweitert werden. Mit demselben optischen Aufbau ist es auch möglich, gleichzeitig Brechungsindex und Dicke von Mehrschichtproben mit hoher Auflösung zu vermessen (Chromatisch-Konfokale Kohärenz-Tomographie). Dies ist etwa von Vorteil, wenn das Messobjekt mit funktionalen Schichten versehen ist oder beispielsweise durch eine Ölschicht gemessen werden muss.
Bei der Messung technischer Oberflächen treten insbesondere im Umfeld flexibler Fertigung unterschiedlichste Anforderungen auf. Häufig ist eine schnelle hochgenaue Topographie-Messung erwünscht. ...Durch die Kombination des chromatisch-konfokalen Verfahrens mit der spektralen Interferometrie (Chromatisch-Konfokale Spektral-Interferometrie) ist es möglich, single-shot Messungen mit einem weiten Messbereich und gleichzeitig geringer Unsicherheit zu erzielen. Dabei können ebenso die den beiden einzelnen Verfahren inhärenten Probleme umgangen und so der Einsatzbereich erweitert werden. Mit demselben optischen Aufbau ist es auch möglich, gleichzeitig Brechungsindex und Dicke von Mehrschichtproben mit hoher Auflösung zu vermessen (Chromatisch-Konfokale Kohärenz-Tomographie). Dies ist etwa von Vorteil, wenn das Messobjekt mit funktionalen Schichten versehen ist oder beispielsweise durch eine Ölschicht gemessen werden muss.
Objective: The purpose of this contribution is to determine the ideal near infrared wavelength bands for monochromatic and dual-band remote heartbeat detection using imaging photoplethysmography ...(iPPG) of the forehead. Methods: Experimental data of 38 healthy volunteers has been recorded and analyzed. For the data acquisition, a fast hyperspectral imager has been used. A new combination approach has been implemented that computes the quotient of the bands and, therefore, reduces motion artifacts. Results: With this dual-band method excellent results (1.67 beats per minute mean deviation from electrocardiogram measurements for 73 recordings) have been obtained using a simple algorithm to analyze images at 799 and 861 nm. Conclusion: It can be concluded that excellent imaging photoplethysmography measurements can be performed at low cost using conventional silicon-based image sensors with invisible light in the near infrared region. Significance: This approach is a contribution to the development of non-contact heart rate measurement systems that can be used for medical diagnosis or other applications.
Gaucher disease (GD) is the most common lysosomal storage disorder (LSD). Based on a deficient β-glucocerebrosidase it leads to an accumulation of glucosylceramide. Standard diagnostic procedures ...include measurement of enzyme activity, genetic testing as well as analysis of chitotriosidase and CCL18/PARC as biomarkers. Even though chitotriosidase is the most well-established biomarker in GD, it is not specific for GD. Furthermore, it may be false negative in a significant percentage of GD patients due to mutation. Additionally, chitotriosidase reflects the changes in the course of the disease belatedly. This further enhances the need for a reliable biomarker, especially for the monitoring of the disease and the impact of potential treatments.
Here, we evaluated the sensitivity and specificity of the previously reported biomarker Glucosylsphingosine with regard to different control groups (healthy control vs. GD carriers vs. other LSDs).
Only GD patients displayed elevated levels of Glucosylsphingosine higher than 12 ng/ml whereas the comparison controls groups revealed concentrations below the pathological cut-off, verifying the specificity of Glucosylsphingosine as a biomarker for GD. In addition, we evaluated the biomarker before and during enzyme replacement therapy (ERT) in 19 patients, demonstrating a decrease in Glucosylsphingosine over time with the most pronounced reduction within the first 6 months of ERT. Furthermore, our data reveals a correlation between the medical consequence of specific mutations and Glucosylsphingosine.
In summary, Glucosylsphingosine is a very promising, reliable and specific biomarker for GD.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
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