Theoretical Investigation of the Structure and Physicochemical Properties of Alkaline and Alkaline Earth Metal Perchlorate Solutions in Sulfolane

To assess the possibility of using solutions of perchlorates of alkali and alkaline earth metals in sulfolane as electrolytes for electrochemical energy storage devices with metal negative electrodes, the physicochemical properties of 0.5 M solutions of Me(ClO4)n (Me = Li, Na, K, Mg, and Ca) in sulfolane were simulated by the method of molecular dynamics. The density, viscosity, conductivity, self-diffusion coefficients, and transport numbers are calculated. Satisfactory agreement between the calculated and experimentally measured properties of 0.5 M solutions of LiClO4 and NaClO4 in sulfolane suggests that the calculated values of the physicochemical properties of solutions of K, Mg, and Ca perchlorates are also close to real values. The study of the structure of solvate complexes of salts of alkali and alkaline earth metals with sulfolane by quantum chemical and molecular dynamics modeling showed that the first solvate shell of metal cations consists of sulfolane molecules. Regardless of the nature of the cation, sulfolane is coordinated to the metal cation by only one oxygen atom. Based on the analysis of the calculated values of the physicochemical properties of solutions of metal perchlorates in sulfolane, it can be concluded that they can be used as electrolyte systems of electrochemical energy storage devices with negative electrodes made of alkali and alkaline earth metals

Interplay of Conformational and Chemical Transformations of Ortho-Substituted Aromatic Nitroso Oxides: Experimental and Theoretical Study

The mechanism of the photooxidation of aromatic azides containing a substituent at one of the ortho positions (2,4-dimethoxyphenyl azide (<b>1a</b>) and 2-methyl-4-[(2<i>E</i>)-1-methylbut-2-en-1-yl]­phenyl azide (<b>1b</b>)) was studied in acetonitrile. The electronic spectra and the kinetic regularities of the consumption of corresponding nitroso oxides, which are the reaction intermediates, were investigated by flash photolysis. Owing to the one-and-a-half order of the C–N and N–O bonds and asymmetric molecule structure these nitroso oxides exist as four conformers (cis/syn, cis/anti, trans/syn, and trans/anti). The conformers differ in the spectral properties and in the reactivity in various irreversible transformations. The only product, (2<i>Z</i>,4<i>E</i>)-4-methoxy-6-oxohepta-2,4-dienenitrile oxide (<b>7a</b>), was observed during photooxidation of <b>1a</b>, whereas transformations of the nitroso oxide isomers derived from <b>1b</b> led to a set of stable products: the cis/anti isomer was transformed into (3,4,7-trimethyl-3a,4-dihydro-2,1-benzisoxazol-5­(3<i>H</i>)-ylidene)­ethanal (<b>10</b>), the trans isomers recombined forming the corresponding nitro and nitroso compounds, and the most reactive cis/syn isomer was transformed into <i>ortho</i>-nitrosobenzyl alcohol <b>11</b>. The last was oxidized slowly to the corresponding benzaldehyde <b>12</b>. Interaction of <b>11</b> and <b>12</b> led to the formation of (<i>Z</i>)-1,2-bis­(2-formyl-4-((2<i>E</i>)-1-methylbut-2-en-1-yl)­phenyl)­diazene-1-oxide (<b>13</b>). The DFT simulation and kinetic modeling of the nitroso oxide transformations as well as the product analysis allowed revealing the fine details of the mechanism of decay for these species