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The development and application of nucleobase triplex strategy has gained increasing attention. In this work, we disclose the pioneer use of energy resolved mass spectrometry to investigate A-U and G-C base triplexes with triplex-forming artificial nucleobases. This approach allows us to gain insight into the so-called bond dissociation energetics (BDE). The analysis of two families of nucleobase model frameworks, S (phenylthiazole bisamide) and HB (benzoxazole urea), bearing various substituents has enabled us to probe triplex formation as well as the structure-triplex stabilisation relationship. Moreover, the consistent fragmentation patterns of the triplexes support that CID can be a valuable method to uncover high performance triplex-forming artificial nucleobases. [ABSTRACT FROM AUTHOR]

BACKGROUND The current study presents new insight on the phytochemical content and biological activities of five Prunus domestica L. varieties ('Quetsche blanche de Létricourt', 'Mirabelle de Nancy', 'Perdrigon violet', 'Mirabelle de Provence', 'Reine-claude dorée'). RESULTS The plum leaves were found to possess promising anti-aging activities by their capacity to inhibit 1,1-diphenyl-2-picrylhydrazyl (DPPH), elastase, hyaluronidase and lipoxygenase. After solid phase extraction (SPE), chlorogenic acid, rutin, quercetin and their derivatives were putatively identified by high-performance liquid chromatography coupled with tandem mass spectrometry using an electrospray ionization source (HPLC/ESI-MS/MS). CONCLUSION The plum leaf, a by-product, provides an interesting valuable resource for use as a natural cosmetic product or as a food supplement. © 2017 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

The effect of Cs+ ligation on the decarboxylation of malonic acids (unsubstituted and methyl-, dimethyl-, ethyl-, and phenyl-substituted) in their carboxylate form was studied in the gas phase using tandem mass spectrometry. The study is based on the comparison of the decarboxylation of the bare monoanion (hydrogen malonates) and of the cesium adduct of the cesium salt (Cs+[cesium hydrogen malonates]) under collisional activation. Energy-resolved dissociation curves of the negative and positive ions exhibit major differences. Decarboxylation of the cationic adducts of substituted malonic acid salts occurs at significantly lower collisional activation than for the corresponding bare hydrogen malonate anions. The conclusions from these experiments are supported by DFT calculations. The calculated activation parameters (enthalpy and Gibbs energy) confirm that the cesium cation coordination assists the decarboxylation of the carboxylate form. [ABSTRACT FROM AUTHOR]

The interaction between the cesium cation and fulvic or humic acids is supposed to play a role in cesium mobility in the environment, which is of importance in the context of geographical dispersion or concentration of the corresponding radionuclides. Among the singly charged positive clusters generated by electrospray ionization of mixtures of carboxylic acids (AH) and cesium salts (nitrate, iodide, or trifluoroacetate), the cluster [A−Cs+]Cs+[A′−Cs+] was subjected to collision-induced dissociation. The fragmentation into Cs+[A−Cs+] and Cs+[A′−Cs+] was treated using the kinetic method. A gas-phase basicity ladder was built by a step-by-step addition of the relative basicity data. The relative basicity scale deduced from the kinetic method was calibrated using the affinity and basicity (the enthalpy and Gibbs energy scales, respectively) obtained from DFT calculations. The enhanced basicity of the polyacid salts, relative to their monoacid salts, as well as the substituent effects on aliphatic and aromatic structures, are discussed. [ABSTRACT FROM AUTHOR]

Metal salts of triflic acid, CF3SO2OH and of triflimidic acid, [CF3SO2]2NH, often called 'Lewis superacids', are powerful catalysts for several classes of reactions. Typical applications developed at the Institut de Chimie de Nice during the last decade, mostly in the domain of inter- and intramolecular carbon-carbon, carbon-oxygen and carbon-sulfur bond formation, are illustrated. During the last three years, the characterization of metal triflates and triflimides by electrospray mass spectrometry was also accomplished in our Institute. Displacement of one anion of the salt by strong neutral ligands was developed as a mean for generating characteristic positive ions. In an effort toward the quantitative description of the ligand/metal bonding and the catalytic role of the Lewis acid, a ligand competition method was devised. An exploratory study attests that subtle structural effects on the donor/acceptor interaction can be evidenced using this simple mass spectrometric method. Copyright © 2012 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Humic substances (HS), including humic and fulvic acids, play a significant role in the fate of metals in soils. The interaction of metal cations with HS occurs predominantly through the ionized (anionic) acidic functions. In the context of the effect of HS on transport of radioactive cesium isotopes in soils, a study of the interaction between the cesium cation and model carboxylic acids was undertaken. Structure and energetics of the adducts formed between Cs+ and cesium carboxylate salts [Cs+RCOO−] were studied by the kinetic method and density functional theory (DFT). Clusters generated by electrospray ionization mass spectrometry from mixtures of a cesium salt (nitrate, iodide, trifluoroacetate) and carboxylic acids were quantitatively studied by CID. By combining the results of the kinetic method and the energetic data from DFT calculations, a scale of cesium cation affinity, CsCA, was built for 33 cesium carboxylates representing the first scale of cation affinity of molecular salts. The structural effects on the CsCA values are discussed. [Copyright &y& Elsevier]

Metal triflates, often called Lewis superacids, are potent catalysts for organic synthesis. However, the reactivity of a given Lewis superacid toward a given base is difficult to anticipate. A systematic screening of catalysts is often necessary when developing synthetic methodologies. Presented herein is the development of quantitative reactivity and bond strength scales by using mass spectrometry (MS). By applying a collision-induced dissociation (CID) technique to the adducts formed between Lewis superacids Al(OTf) 3 or In(OTf) 3 with a series of amides bases, including monodentate and bidentate ligands, different dissociation pathways were observed. Quantitative relative energy scales were established by performing energy-resolved mass spectrometry (ERMS) analysis on the adducts. ERMS of the adducts affords a bond strength scale when the fragmentation leads to the loss of a ligand, and reactivity scales when the dissociation leads to the C-F bond activation of one triflate anion or the deprotonation of the ligand. Al(OTf) 3 was found to bind stronger to amides than In(OTf) 3 and to provide the most reactive adducts., (© 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The interaction between the cesium cation and fulvic or humic acids is supposed to play a role in cesium mobility in the environment, which is of importance in the context of geographical dispersion or concentration of the corresponding radionuclides. Among the singly charged positive clusters generated by electrospray ionization of mixtures of carboxylic acids (AH) and cesium salts (nitrate, iodide, or trifluoroacetate), the cluster [A - Cs + ]Cs + [A' - Cs + ] was subjected to collision-induced dissociation. The fragmentation into Cs + [A - Cs + ] and Cs + [A' - Cs + ] was treated using the kinetic method. A gas-phase basicity ladder was built by a step-by-step addition of the relative basicity data. The relative basicity scale deduced from the kinetic method was calibrated using the affinity and basicity (the enthalpy and Gibbs energy scales, respectively) obtained from DFT calculations. The enhanced basicity of the polyacid salts, relative to their monoacid salts, as well as the substituent effects on aliphatic and aromatic structures, are discussed., (Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)