An ion-neutral complex (INC)-mediated hydride transfer reaction was observed in the fragmentation of protonated N-benzylpiperidines and protonated N-benzylpiperazines in electrospray ionization mass spectrometry. Upon protonation at the nitrogen atom, these compounds initially dissociated to an INC consisting of [RC(6)H(4)CH(2)](+) (R = substituent) and piperidine or piperazine. Although this INC was unstable, it did exist and was supported by both experiments and density functional theory (DFT) calculations. In the subsequent fragmentation, hydride transfer from the neutral partner to the cation species competed with the direct separation. The distribution of the two corresponding product ions was found to depend on the stabilization energy of this INC, and it was also approved by the study of substituent effects. For monosubstituted N-benzylpiperidines, strong electron-donating substituents favored the formation of [RC(6)H(4)CH(2)](+), whereas strong electron-withdrawing substituents favored the competing hydride transfer reaction leading to a loss of toluene. The logarithmic values of the abundance ratios of the two ions were well correlated with the nature of the substituents, or rather, the stabilization energy of this INC.

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For p-(dimethylamino)chalcone (p-DMAC), the N atom is the most basic site in the liquid phase, whereas the O atom possesses the highest proton affinity in the gas phase. A novel and interesting observation is reported that the N- and O-protonated p-DMAC can be competitively produced in atmospheric pressure chemical ionization (APCI) with the change of solvents and ionization conditions. In neat methanol or acetonitrile, the protonation is always under thermodynamic control to form the O-protonated ion. When methanol/water or acetonitrile/water was used as the solvent, the protonation is kinetically controlled to form the N-protonated ion under conditions of relatively high infusion rate and high concentration of water in the mixed solvent. The regioselectivity of protonation of p-DMAC in APCI is probably attributed to the bulky solvent cluster reagent ions (S(n)H(+)) and the analyte having different preferred protonation sites in the liquid phase and gas phase.

Compared with the organic, ionic liquid, and solid-state electrolytes, aqueous electrolytes have the advantages of good security, environmental friendliness, high ionic conductivity, low cost, and high operability in ordinary environments. [1][2][3][4][5] Therefore, aqueous secondary ion batteries/capacitors are more attractive in large-scale energy storage, and have greater application prospects. [6][7][8][9] However, even so, there still exists several disadvantages as follows: 1) The thermodynamic electrochemical stability window (ESW) of water is as narrow as 1.23 V. Even considering the existence of overpotential, the ESWs of conventional aqueous electrolytes are not higher than 2 V. 2) Usually, the electrode materials cannot form stable interface in water, so it is difficult to ensure the cycling stability. 3) Dissolution and even decomposition of electrode materials and discharge/charge products limit the choice of electrode materials. [10] These factors have limited the improvement of key electrochemical performance indicators such as energy density, output voltage, and cycle life of aqueous energy-storage devices Aqueous energy-storage systems have attracted wide attention due to their advantages such as high security, low cost, and environmental friendliness. However, the specific chemical properties of water induce the problems of narrow electrochemical stability window, low stability of water-electrode interface reactions, and dissolution of electrode materials and intermediate products. Therefore, new low-cost aqueous electrolytes with different water chemistry are required. The nature of water depends largely on its hydroxylbased hydrogen bonding structure. Therefore, the super-concentrated hydroxyl-rich sugar solutions are designed to change the original hydrogen bonding structure of water. The super-concentrated sugars can reduce the free water molecules and destroy the tetrahedral structure, thus lowering the binding degree of water molecules by breaking the hydrogen bonds. The ionic electrolytes based on super-concentrated sugars have the expanded electrochemical stability window (up to 2.812 V), wide temperature adaptability (-50 to 80 °C), and fair ionic conductivity (8.536 mS cm −1 ). Aqueous lithium-, sodium-, potassium-ion batteries and supercapacitors using super-concentrated sugar-based electrolytes demonstrate an excellent electrochemical performance. The advantages of ultralow cost and high universality enable a great practical application potential of the superconcentrated sugar-based aqueous electrolytes, which can also provide great experimental and theoretical assistance for further research in water chemistry.

In this study, the fragmentation reactions of various N-benzylammonium and N-benzyliminium ions were investigated by electrospray ionization mass spectrometry. In general, the dissociation of N-benzylated cations generates benzyl cations easily. Formation of ion/neutral complex intermediates consisting of the benzyl cations and the neutral fragments was observed. The intra-complex reactions included electrophilic aromatic substitution, hydride transfer, electron transfer, proton transfer, and nucleophilic aromatic substitution. These five types of reactions almost covered all the potential reactivities of benzyl cations in chemical reactions. Benzyl cations are well-known as Lewis acid and electrophile in reactions, but the present study showed that the gas-phase reactivities of some suitably ring-substituted benzyl cations were far richer. The 4-methylbenzyl cation was found to react as a Brønsted acid, benzyl cations bearing a strong electron-withdrawing group were found to react as electron acceptors, and parahalogen-substituted benzyl cations could react as substrates for nucleophilic attack at the phenyl ring. The reactions of benzyl cations were also related to the neutral counterparts. For example, in electron transfer reaction, the neutral counterpart should have low ionization energy and in nucleophilic aromatic substitution reaction, the neutral counterpart should be piperazine or analogues. This study provided a panoramic view of the reactions of benzyl cations with neutral N-containing species in the gas phase.

To analyse inner-and inter-annual changes, disaster events of 55 countries in Africa from 1990 to 2014 recorded in the International Disaster Database (EM-DAT) were recounted by year and month and were reorganised in five different regions. Thematic maps of flood disasters in Africa between 1990 and 2014 were drawn using ArcGIS 9.3 to research the spatial distribution patterns of average annual flood frequency, total deaths, total affected, and damage. There were eight natural and socio-economic indicators chosen to explore the main factors influencing the spatio-temporal distribution of flood disasters in Africa, including precipitation, ENSO, runoff, forest coverage rate, reservoir capacity, per capita GDP, population, and urbanisation rate. Studies show that seasonal changes of flood disasters in various regions of Africa, except North Africa, are closely related to precipitation. Annual flood frequencies, from 1990 to 2014, showed a fluctuating upward trend and were in good agreement with ENSO years. In terms of spatial distributions, Ethiopia, Kenya, Somalia, Tanzania in eastern Africa, Nigeria in western Africa, and Libya, and Sudan in northern Arica are flood-prone countries, and main factors influencing spatial disparities include runoff, per capita GDP, population, and urbanisation rate.

In collisional activation of protonated N-benzylaniline, the benzene loss from the benzyl moiety is actually not the result of dissociative proton transfer (PT). In fact, benzyl cation transfer (BCT) from the nitrogen to the anilinic ring (ortho or para position) is the key step for benzene loss. Such dissociation occurs only after the benzyl group migrating from the site with the highest benzylation nucleophilicity (nitrogen) to a different one (aromatic ring carbon), which is described as dissociative benzyl cation transfer.

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