Solvent influence on intramolecular interactions and aromaticity in meta and para nitroanilines

Abstract

Theoretical density functional theory (B3LYP/6-31G**) was used to study the intra- and intermolecular interactions of nitrobenzene, aniline, and meta and para nitroaniline in various solvation models. The studied molecules were solvated by one or two water molecules in the presence of continuum solvation (the PCM model) or without it. Finally, the studied molecules were surrounded by a cluster of water molecules. For comparison, calculations were also made for separated molecules. Geometries, energies, hydrogen bonding between solutes and solvent molecules, atomic charges, and aromaticity were examined. The analysis was based on the Atoms in Molecules methodology and the Harmonic Oscillator Model of Aromaticity (HOMA) index. As a result, an extensive description of the solvation of nitro and amino groups and the effect of solvation on mutual interactions between these groups in meta and para nitroanilines is provided. It was found that in general, the PCM description of the hydration effect on the electronic structure of the studied systems (substituents) is consistent with the approach taking into account all individual interactions (cluster model).

Chemical Absorption of CO2 Enhanced by Solutions of Alkali Hydroxides and Alkoxides at Room Temperature

“…The inclusion of the water dielectric constant in the medium by the PCM approach slightly decreases the R 1 O—CO 2 bond length. This is in line with the principle that the intermolecular interactions that involve charge or proton transfers and even hydrogen bonds between low molecular weight organic molecules are more strongly stabilized under the effect of implicit solvent [42–45] . The PCM‐water curves in Figure 1 show that the electronic stabilization of the formed products varies from −34 kcal mol −1 (isopropyl and tert‐butyl carbonates, Figures 1(c)–(d) to −38 kcal mol −1 (methyl carbonate, Figure 1(a)).…”

“…This is in line with the principle that the intermolecular interactions that involve charge or proton transfers and even hydrogen bonds between low molecular weight organic molecules are more strongly stabilized under the effect of implicit solvent. [42][43][44][45] The PCM-water curves in Figure 1 show that the electronic stabilization of the formed products varies from À 34 kcal mol À 1 (isopropyl and tert-butyl carbonates, Figures 1(c)-(d) to À 38 kcal mol À 1 (methyl carbonate, Figure 1(a)). These results suggest that the increase of the carbonic chain decreases the nucleophilicity of the alkoxide and reduces its basicity, due to the steric hindrance.…”

Empirical Hydrogen Bonding Donor (HBD) Parameters of Organic Solvents Using Solvatochromic Probes – A Critical Evaluation

“…Further analysis of the KAT α ‐values is not useful, as they were determined with B30 and push‐pull substituted nitroaromatics. Hence, reported α values are physically questionable mixtures of several effects, as the nitro group of the π*‐probe also interacts specifically with HBD solvents [82,83] . See also explanation in SI part 3 (Figure S10, p. S13).…”

Pyrrole and Pyridine in the Water Environment—Effect of Discrete and Continuum Solvation Models

“…8 In particular, the noticeable aromaticity of benzene in the GP was proven to persist under a polarizable continuum model of solvation (PCM), as well as with discrete solvation by a cluster of water molecules. More recently, 9 on the aromaticity of aniline, nitrobenzene, as well as para-and meta-nitroanilines in water was considered. In contrast to benzene, these compounds possess group(s) that can effectively interact with water molecules through the formation of hydrogen bond(s) between solute and solvent molecules.…”