Charged Forms of Diacetone Diperoxide - DFT Treatment

Diacetone diperoxide (DADP) is one of the sensitive and powerful organic peroxide explosives like its trimeric analogue TATP. Presently, some ionic forms of it have been investigated within the limitations of density functional theory at the level of UB3LYP/6-311++G(d,p). Various properties (including structural, electronic, spectral and quantum chemical) have been obtained and discussed. The studied mono and dianions having different multiplicity states have been found to be stable but monocation form decomposed.

Some Ions of TNAZ - A DFT Study

TNAZ is a thermally stable high energy explosive molecule. In the present study, some ionic forms of it have been investigated within the limitations of density functional theory at the level of UB3LYP/6-311++G(d,p). Various properties (including structural, electronic, spectral and quantum chemical) are obtained and discussed.

Modeling of sorption kinetics of U(VI) micro-quantities nanostructured materials with anatase mesoporous structures

The sorption kinetics of uranyl ions micro-quantities from fluoride solutions by nanostructured materials with anatase mesoporous structures has been studied. Using the model of competitive sorption of ions and positively charged complexes of uranyl ion on deprotonated hydroxyl groups of an anatase, kinetic curves of changes in the ratio of ionic forms of uranium in solution were calculated. Modeling was carried out under the assumption of a two-stage mechanism of uranium complex ions sorption. The modeling considered the influence of the uranyl ion carbonate complexes formation. The shift in equilibrium among ionic forms of uranyl correlates with the stability of the complexes in solution.

Effect of galena contained in dust from Zn–Pb metallurgical processes on environment

This paper assesses the effect of galena emitted with dust from an electrostatic precipitator at Miasteczko Śląskie Zinc Smelting Plant (Poland) onto a soil and water environment. The Eh–pH diagrams plotted in the temperature range of − 3 to 25 °C serve to determine the conditions of PbS stability and conditions under which its decomposition may occur, resulting in the release of ionic forms of lead into the soil and water environment. Determination of the mobility of galena emitted with metallurgical dust is a current and important issue in view of the geochemistry of mineral components in the environment.

Isomers of (L)-Diiodotyrosine - A DFT Treatise

(L)-Diiodotyrosine isomers are considered within the realm of density functional theory at the level of B3LYP/6-311+G(d,p). Their zwitter ionic forms are considered as well. All the structures are electronically stable, have exothermic heat of formation and favorable Gibbs free energy of formation values. Within the limitations of the method the zwitter ionic forms are not different from the corresponding parent structures in the vacuum conditions and no hydrogen bonding seems to exist between the NH2 and COOH groups. Some structural, quantum chemical and spectral data have been collected and discussed.

An HPLC and UHPLC-HRMS approach to study PSMA-11 instability in aqueous solution

Background The stability of precursors and reagents is of utmost importance for developing a robust radiolabelling method that provides high and constant radiochemical yield and radiochemical purity. While performing the QC of the [68Ga]Ga-PSMA-11 injectable solutions according to Ph. Eur. Monograph that has recently been published, a trend to the instability of the standard PSMA-11, the same used as a precursor for [68Ga]Ga-PSMA-11 radiosynthesis, has been observed. This instability led to the formation of a side product in a time-dependent manner. The formation of this compound, besides making the implementation of the Ph. Eur. analytical method more difficult, negatively influenced the radiochemical yield and the radiochemical purity by increasing gallium-68 in colloidal and ionic forms. Results The nature of the side product was investigated by adding chelators, such as EDTA, to PSMA-11 solutions and using the combination of UHPLC-HRMS. The results led to the definition of the side product structure, as natFe-PSMA-11, from the combination of the high-affinity chelator HBED-CC, present in the molecule of PSMA-11, and environmental Fe (III). Conclusions Strategies to reduce the risk of low radiolabeling yields and to increase the stability of the PSMA-11 in an aqueous solution were also discussed.

Спектрально-люминесцентные свойства и фотолиз заряженных форм бисфенола А

The spectral luminescent properties and photolysis of the ionic forms (neutral, cationic and anionic) of bisphenol A have been studied experimentally and by methods of quantum chemistry. Calculations and experiment have shown that, in comparison with a neutral form, no new absorption bands appear in the absorption spectra of ionic form in the range 200–600 nm. The polar solvent (water) shifts the absorption spectrum bands of ionic forms towards low energies. In this case, the shift of the absorption spectrum of the cation is insignificant, and the shift of the anion is significant with an increase in the intensity of the absorption bands. The low quantum yield of fluorescence of ionic form is explained by the prevalence of the efficiency of singlet-triplet conversion over the efficiency of the radiation channel of decay of the fluorescent state. The low quantum yield of fluorescence of the anionic form is due not only to the effective singlet-triplet conversion, but also to the low efficiency of the radiative decay of the fluorescent state of the anion caused by a change in its orbital nature. Calculations have shown that the potential curves of the excited states of bisphenol A and its ionic forms have a significant potential barrier to photolysis. The increase in the efficiency of the process of photodissociation of the bisphenol A anion is caused by a noticeable decrease in the potential barrier and an increase in the overlap of the absorption spectra of the bisphenol A anion and solar radiation.

Theoretical Description for Sunset Yellow Electrochemical Determination in Food, Assisted by Poly(3,4-ethylenedioxypyrrole) – VO(OH) Composite

In this work, the possibility for sunset yellow electrochemical determination, assisted by the composite of VO(OH) with conducting polymer, has been evaluated theoretically. The correspondent balance equation model of three variables has been developed and analyzed by means of linear stability theory and bifurcation analysis. The oscillatory and monotonic instabilities are shown to be manifested more probably than for the simplest case. The double electric layer (DEL) is influenced by the cyclic changes of ionic force observed during ionic forms' chemical transformation. Nevertheless, the CP – VO(OH) composite may be considered an efficient electrode modifier for yellow sunset determination.