Gas Phase Acidities of Organic Acids Based on 9H-Fluorene Scaffold: A DFT Study

The density functional theory (DFT) calculations have been performed on a new set of organic Brønsted acids based on 9H-fluorene scaffold. The optimal structures and acidity of the compounds have been calculated by using DFT/B3LYP/6-31++G(d,p) computational method. The acidity of the designed compounds was obtained in the range of 276-328 kcal/mol that the fluorene scaffold bearing ketenimine group 17 and trifilic group 20 with ΔHacid of 276.3 and 285.4 kcal/mol, respectively were found to be within the range of superacids, being more acidic than simple fluorene and mineral acids. The designed compounds and the corresponding conjugate bases were also examined from the aromaticity indices point of view. The tautomerization process for some designed structures was investigated by DFT calculations. Molecular electrostatic potential analysis for the designed acids and the corresponding conjugate bases were also used for charge distribution analysis.

Quantum key distribution with two-way authentication

Quantum key distribution uses the principle of quantum physics to realize unconditionally secure key distribution protocol. But this kind of security needs to be based on the authenticated classical channel. Although there are quantum key distribution protocols without classical channel, authentication is still needed. In the process of key distribution, authentication is not considered, which is also a problem of quantum key distribution protocol. In this paper, a quantum key distribution protocol with two-way authentication is proposed. Identity authentication is carried out at the same time of key distribution. If the identity authentication fails, the key distribution protocol cannot be carried out. If the key distribution protocol is aborted, the identity authentication is not successful. The conclusion of this paper is based on a central authentication system supported by symmetric encryption theory, which uses pseudo-random functions, multiple sets of quantum conjugate bases and Measurement-device-independent technology to simultaneously achieve two-way authentication and key distribution.

Glass Surface as Strong Base, ‘Green’ Heterogeneous Catalyst and Degradation Reagent

Systematic screening of accelerated chemical reactions at solid/solution interfaces has been carried out in high-throughput fashion using desorption electrospray ionization mass spectrometry and it provides evidence that glass surfaces accelerate various base-catalyzed chemical reactions. The reaction types include elimination, solvolysis, condensation and oxidation, whether or not the substrates are pre-charged. In a detailed mechanistic study, we provide evidence using nanoESI showing that glass surfaces can act as strong bases and convert protic solvents into their conjugate bases which then act as bases/nucleophiles when participating in chemical reactions. In aprotic solvents such as acetonitrile, glass surfaces act as ‘green’ heterogeneous catalysts that can be recovered and reused after simple rinsing. Besides their use in organic reaction catalysis, glass surfaces are also found to act as degradation reagents for phospholipids with increasing extents of degradation occuring at low concentrations. This finding suggests that the storage of base/nucleophile-labile compounds or lipids in glass containers should be avoided. <br>

Glass Surface as Strong Base, ‘Green’ Heterogeneous Catalyst and Degradation Reagent

Systematic screening of accelerated chemical reactions at solid/solution interfaces has been carried out in high-throughput fashion using desorption electrospray ionization mass spectrometry and it provides evidence that glass surfaces accelerate various base-catalyzed chemical reactions. The reaction types include elimination, solvolysis, condensation and oxidation, whether or not the substrates are pre-charged. In a detailed mechanistic study, we provide evidence using nanoESI showing that glass surfaces can act as strong bases and convert protic solvents into their conjugate bases which then act as bases/nucleophiles when participating in chemical reactions. In aprotic solvents such as acetonitrile, glass surfaces act as ‘green’ heterogeneous catalysts that can be recovered and reused after simple rinsing. Besides their use in organic reaction catalysis, glass surfaces are also found to act as degradation reagents for phospholipids with increasing extents of degradation occuring at low concentrations. This finding suggests that the storage of base/nucleophile-labile compounds or lipids in glass containers should be avoided. <br>

Effects of overliming on the nutritional status of grapevines with special reference to micronutrient content

Aluminium plays a central role in soil acidity, which is one of the main constraints on grape production in humid, northern temperate viticultural regions. To decrease the acidity of vineyard soil, it is usually amended with alkaline materials that provide conjugate bases to weak acids (liming). However, one practical consideration is the danger of overliming, which has potential implications in terms of yield reduction and decreased bioavailability of several mineral nutrients. The main aim of this study was to evaluate the effects of overliming using dolomitic lime on grapevines growing on acid soil. The effects on the topsoil fertility parameters (0–30 cm), petiole and berry nutrient levels, berry weight and must quality properties were studied in a vineyard planted with Vitis vinifera L. cv. Mencía for three years (2014–2016). Data analysis performed using a mixed model that took into account both random effects (year of sampling) and fixed effects (liming treatments) showed that overliming decreased the manganese content in both leaf and berry tissues. Until now, nothing was known about the effects of overliming on both vine nutritional status and harvest quality properties, thus this study fills an important knowledge gap.

Photoelectron-photofragment coincidence spectroscopy of aromatic carboxylates: benzoate and p-coumarate

Photoelectron-photofragment coincidence spectroscopy was used to study the dissociation dynamics of the conjugate bases of benzoic acid and p-coumaric acid. Upon photodetachment at 266 nm (4:66 eV) both aromatic carboxylates...

Protic Ionic Liquids Can Be Both Free Proton Conductors and Benign Superacids .

<div>Superacids have been the source of much spectacular chemistry, but very little interesting physics despite the fact that the states of cations formed by transfer of the superacid proton to molecular bases, can approach that of the cations in free space. Indeed some of the very strongest acids, such as HPF6 and HAlCl4, have no independent existence due to lack of screening of the bare proton self-energy: their acidities can only be assessed by study of the conjugate bases. Here we show that, by allowing the protons of transient HAlCl4 and HAlBr4 to relocate on pentafluoropyridine, PFP - a very weak base that is stable to superacids - we can create glassforming protic ionic liquids (PILs) which are themselves superacids but, being free of superacid vapors, are of benign character. At Tg, conductivities exceed “good” ionic liquid values by 9 decades, so must be superprotonic. Anomalous Walden plots confirm superprotonicity.</div>

Protic Ionic Liquids Can Be Both Free Proton Conductors and Benign Superacids .

<div>Superacids have been the source of much spectacular chemistry, but very little interesting physics despite the fact that the states of cations formed by transfer of the superacid proton to molecular bases, can approach that of the cations in free space. Indeed some of the very strongest acids, such as HPF6 and HAlCl4, have no independent existence due to lack of screening of the bare proton self-energy: their acidities can only be assessed by study of the conjugate bases. Here we show that, by allowing the protons of transient HAlCl4 and HAlBr4 to relocate on pentafluoropyridine, PFP - a very weak base that is stable to superacids - we can create glassforming protic ionic liquids (PILs) which are themselves superacids but, being free of superacid vapors, are of benign character. At Tg, conductivities exceed “good” ionic liquid values by 9 decades, so must be superprotonic. Anomalous Walden plots confirm superprotonicity.</div>