Hydrogen Bonding as a Modulator of Aromaticity and Electronic Structure of Selectedortho-Hydroxybenzaldehyde Derivatives

Abstract

Properties of hydrogen bonds can induce changes in geometric or electronic structure parameters in the vicinity of the bridge. Here, we focused primarily on the influence of intramolecular H-bonding on the molecular properties in selected ortho-hydroxybenzaldehydes, with additional restricted insight into substituent effects. Static models were obtained in the framework of density functional theory at B3LYP/6-311+G(d,p) level. The electronic structure parameters evolution was analyzed on the basis of Atoms In Molecules (AIM) and Natural Bond Orbitals methods. The aromaticity changes related to the variable proton position and presence of substituents were studied using Harmonic Oscillator Model of Aromaticity (HOMA), Nucleus-Independent Chemical Shift (NICS) and AIM-based parameter of Matta and Hernández-Trujillo. Finally, Car-Parrinello molecular dynamics was applied to study variability of the hydrogen bridge dynamics. The interplay between effects of the substitution and variable position of the bridged proton was discussed. It was found that the hydrogen bond energies are ca. 9-10 kcal/mol, and the bridged proton exhibits some degree of penetration into the acceptor region. The covalent character of the studied hydrogen bond was most observable when the bridged proton reached the middle position between the donor and acceptor regions. The aromaticity indexes showed that the aromaticity of the central phenyl ring is strongly dependent on the bridged proton position. Correlations between these parameters were found and discussed. In the applied time-scale, the analysis of time evolution of geometric parameters showed that the resonance strengthening does not play a crucial role in the studied compounds.

Hydrogen bridges of polycyclic aromatic systems with O-H···O bonds — a gas-phase vs. solid-state Car-Parrinello study

“…2) shows for both compounds almost identical curves. The result confirms our previous findings [7] where many electronic-structure related effects were shielded by the presence of a strong intramolecular hydrogen bond. On the other hand, the data show that from the thermodynamical and statistical points of view the inductive and steric effects of the substituents in 2 are subtle and not directly visible in the CPMD trajectory.…”

“Zwitterionic Proton Sponge” Hydrogen Bonding Investigations on the Basis of Car–Parrinello Molecular Dynamics

“…Especially, the presence of the inductive effects has always an impact on the hydrogen bonding. 59 However, the correlations are not strong. In order to trace the correlations fully, the results for the solid state are included here in anticipation.…”

π–π-Induced aggregation and single-crystal fluorescence anisotropy of 5,6,10b-triazaacephenanthrylene

“…3 and S1.1-S1.3). The intramolecular hydrogen bond H10Á Á ÁN11 leads to the formation of an additional quasiaromatic ring (Jezierska-Mazzarello et al, 2012;Krygowski et al, 2014) with the closed-coupled H11 proton and sp 2 hybridization of the N10B atom. That is confirmed by the valence angle sum of 360 at N10B (C3A 1 -N10B-C10A = 116.9, C10A-N10B-C1 = 126.4 and C1-N10B-C3A 1 = 116.7 ).…”