2 research outputs found
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]Âphenyl
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-5Â(3<i>H</i>)-ylidene)Âethanal (<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-bisÂ(2-formyl-4-((2<i>E</i>)-1-methylbut-2-en-1-yl)Âphenyl)Âdiazene-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