Theoretical study on the solvent influence on 1,2,3-triazole tautomeric equilibrium. A comparison of incremental microsolvation and continuum solvation model approaches

Tautomeric Equilibrium in 1-Benzamidoisoquinoline Derivatives

In this study, the tautomeric equilibrium of a sequence of 1-benzamidoisoquinoline derivatives was investigated with the tools of NMR spectroscopy and computational chemistry. The equilibrium between different tautomers in these systems could be controlled via the substitution effect, and the relative content of the amide form varied from 74% for the strong electron-donating NMe2 substituent to 38% for the strong electron-accepting NO2 group in the phenyl ring. In contrast to the previously investigated 2-phenacylquinoline derivatives, the most stable and thus most abundant tautomer in the 1-benzamidoisoquinoline series except the two most electron-accepting substituents was an amide. The intramolecular hydrogen bond present in the enol tautomer competed with the intermolecular hydrogen bonds created with the solvent molecules and thus was not a sufficient factor to favor this tautomer in the mixture. Although routinely computational studies of tautomeric equilibrium are performed within the continuum solvent models, it is proven here that the inclusion of the explicit solvent is mandatory in order to reproduce the experimental tendencies observed for this type of system, facilitating strong intermolecular hydrogen bonds.

ExcelAutomat 1.4: generation of supporting information

Quantum chemical computations generate output files with data. The processing of these data generates results which are presented in a target document, such as a manuscript or supporting information (SI). Several tools and techniques can be employed to facilitate the transfer of data which, otherwise, can be time-consuming with a large number of files. However, depending on the user’s technical knowledge or expertise with the software, additional time has to be invested to set up the software or use the tools. In addition, to the best of the authors’ knowledge, the tools currently available do not provide an option to transfer the data from the output files directly to the target document without the use of custom scripts. The ExcelAutomat tool (Laloo et al., J. Comput. Aided Mol. Des. 2017, 31, 667 and Laloo et al., J. Comp. Chem. 2019, 40, 3) is spreadsheet-based and was developed in-house to facilitate the steps involved in the processing of computational files. The tool was adapted to facilitate the generation of SI in an update of ExcelAutomat 1.4. A graphical user interface was designed where the options for the generation of SI can be defined. ExcelAutomat 1.4 is compatible with Microsoft Excel and the open-source LibreOffice Calc. The extensible tool supports various software packages and parameters by interfacing with the cclib library and through built-in codes. The tool provides a method to transfer data from output files directly to a Microsoft Word or LibreOffice Writer document and can reduce the number of steps, tools or technical knowledge needed to generate SI, especially for users who are familiar with Microsoft Excel or LibreOffice Calc.

Corrosion inhibition of copper in aqueous chloride solution by 1H-1,2,3-triazole and 1,2,4-triazole and their combinations: electrochemical, Raman and theoretical studies

Triazoles are well-known organic corrosion inhibitors of copper. 1H-1,2,3-Triazole and 1,2,4-triazole, two very simple molecules with the only difference being the positions of the nitrogen atoms in the triazole ring, were studied in this work as corrosion inhibitors of copper in 50 mM NaCl solution using a set of electrochemical and analytical techniques. The results of electrochemical tests indicate that 1H-1,2,3-triazole exhibited superior inhibitor properties but could not suppress anodic copper dissolution at moderate anodic potentials (>+300 mV SCE), while 1,2,4-triazole, although it exhibited higher anodic currents, suppressed anodic copper dissolution at very anodic potentials. Density functional theory calculations were also performed to interpret the measured data and trends observed in the electrochemical studies. The computational studies considered either the inhibitors isolated in the gaseous phase or adsorbed onto Cu(111) surface models. From the calculations, the mechanisms of the inhibitive effects of both triazoles were established and plausible mechanisms of formation of the protective films on the Cu surface were proposed. The results of this study hold positive implications for research in the areas of catalysis, and copper content control in water purification systems.