Benzene-hydrogen halide interactions: Theoretical studies of binding energies, vibrational frequencies, and equilibrium structures

Abstract

High level ab initio calculations have been performed on the benzene-HCl and benzene-HF systems using the second-order Mo/ller-Plesset perturbation theory. In contrast to existing theoretical studies, the calculated binding energies indicate that HCl binds more strongly to benzene than HF. This is in accordance with the limited experimental data available on these systems. An explanation has been forwarded for the above observation by performing a molecular orbital analysis of both C6H6⋯HF and C6H6⋯HCl. In the global minimum of C6H6⋯HF, HF lies inclined to the benzene ring with the hydrogen atom pointing either towards a benzene carbon or the center of carbon-carbon bond. In the C6H6⋯HCl complex, HCl is found to lie along the C6 axis of the benzene ring for smaller basis sets, but it also tends to lie inclined to the benzene ring for a very large basis set. The quantum mechanical probabilistic characterization of the structure of the C6H6⋯HCl complex provides a more realistic description of the experimental equilibrium structure. The van der Waals modes have also been characterized, and the modulation of these modes as one progresses from HF to HCl has also been studied.

Functional molecules and materials by π‐Interaction based quantum theoretical design

“…Structures of nucleobases on graphene: a) Gua, b) Ade, c) Thy, d) Cyt; [89] e) schematic of GNR nanochannel design for DNA sequencing and snapshot from a p-p interaction simulation in nanochannel device, where d, stacking distance; h, tilt angle; f ) transmission (in G 0 ) with respect to energy E-E F (E F : Fermi energy) of the GNR device with DNA bases stacked, which show strong Fano resonance at the molecular orbital energies of each nucleobase. [5] Reproduced from Refs. [83] and [88], with permission from Nature Publishing Group and American Chemical Society, respectively).…”

“…The addition of flaps on the rim of the bowl part of receptor was suggested as the critical factor in designing of receptors. [81] Moreover, the quintuply charged calix [5]-imidazolium recognizes the neutral C 60 fullerene in water that could be valuable in aqueous fullerene chemistry. This recognition is confirmed by both theoretical calculations, fluorescence, and NMR spectroscopies.…”

“…This recognition is confirmed by both theoretical calculations, fluorescence, and NMR spectroscopies. [82] The cavity size of calix [5]imidazolium and the strong p 1 -p interaction between positively charged imidazolium ring and aromatic rings of fullerene explain the water solubility of fullerene. The calculated binding energy of calix [5]imidazolium with C 60 fullerene at B97-D3/TZV2P changes from 21.0 kcal/mol in gas phase to 14.0 kcal/mol in aqueous solution using conductor-like screening model (COSMO).…”

“…[82] The cavity size of calix [5]imidazolium and the strong p 1 -p interaction between positively charged imidazolium ring and aromatic rings of fullerene explain the water solubility of fullerene. The calculated binding energy of calix [5]imidazolium with C 60 fullerene at B97-D3/TZV2P changes from 21.0 kcal/mol in gas phase to 14.0 kcal/mol in aqueous solution using conductor-like screening model (COSMO). [76] Recognition of aromatic molecules and nucleobases using pstacking interactions is of particular interests for researches in DNA sequencing, [83,84] DNA sensing, [85] and drug delivery fields.…”

“…[2][3][4] p-Systems can noncovalently bind to diverse molecular systems. Various types of p-interactions include Hp, [5,6] p-p, [7][8][9] p 1 -p, [10] p 1 -p 1 , [11] cation-p, [7,[12][13][14] p --p, p --p -, [15] and anion-p [16][17][18][19][20][21] interactions (Fig. 1).…”