The Magnitude of the CH/π Interaction between Benzene and Some Model Hydrocarbons (original) (raw)
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Non-covalent interaction in benzene and substituted benzene: A theoretical study
Computational and Theoretical Chemistry, 2018
Non-covalent interaction is believed to play a vital role in stabilizing various complex chemical species. Herein, we have undertaken a theoretical study to understand the nature and extent of non-covalent interaction between the aromatic surfaces of benzene and its substituted derivatives with hydrogen bond donors as well as lone pair containing molecules. Molecular electrostatic potential (MESP) calculation has been used to identify the attractive zones of the aromatic surface. Symmetry adopted perturbation theory (SAPT) calculations reveal that the stability of these interactions is dominated by both electrostatic as well as dispersion interaction. Non-covalent interaction plot (NCI) analysis provided the qualitative visualization of the interaction while quantum theory of atoms in molecules (QTAIM) proved the existence of this interaction through the formation of bond and cage critical points.
A Molecular Electrostatic Potential Analysis of Hydrogen, Halogen, and Dihydrogen Bonds
Hydrogen, halogen, and dihydrogen bonds in weak, medium and strong regimes (<1 to ∼60 kcal/mol) have been investigated for several intermolecular donor−acceptor (D-A) complexes at ab initio MP4//MP2 method coupled with atoms-in-molecules and molecular electrostatic potential (MESP) approaches. Electron density ρ at bond critical point correlates well with interaction energy (E nb ) for each homogeneous sample of complexes, but its applicability to the entire set of complexes is not satisfactory. Analysis of MESP minimum (V min ) and MESP at the nuclei (V n ) shows that in all D-A complexes, MESP of A becomes more negative and that of D becomes less negative suggesting donation of electrons from D to A leading to electron donor−acceptor (eDA) interaction between A and D. MESP based parameter ΔΔV n measures donor−acceptor strength of the eDA interactions as it shows a good linear correlation with E nb for all D-A complexes (R 2 = 0.976) except the strongly bound bridged structures. The bridged structures are classified as donor−acceptor−donor complexes. MESP provides a clear evidence for hydrogen, halogen, and dihydrogen bond formation and defines them as eDA interactions in which hydrogen acts as electron acceptor in hydrogen and dihydrogen bonds while halogen acts as electron acceptor in halogen bonds. − (electron donors) with different electron acceptors. Throughout this paper, E nb represents the interaction energy calculated at MP4//MP2 method and the standard notations ρ and ∇ 2 ρ are used to indicate the electron density at the bond critical point (bcp) of the electron donor−acceptor bond and the Laplacian of the electron density at the bcp. Figure 7. Change in V min upon bond formation in electron donor−acceptor−donor complexes (a) F − ...IF and (b) F − ...IBr. The black dots represent the location of the most negative MESP-valued point and the corresponding V min values in kcal/mol are also depicted.
Mutual influence of parallel, CH/O, OH/π and lone pair/π interactions in water/benzene/water system
Computational and Theoretical Chemistry, 2013
The mutual influence of OH/p, CH/O, parallel alignment (all attractive) and lone pair/p (repulsive) water/ benzene interactions was studied with ab initio calculations on water/benzene/water systems. The energies of the systems containing two water molecules on the opposite sides of benzene molecule or as far as possible from each other were calculated using Møller-Plesset perturbation theory of the second order and cc-pVTZ and cc-pVQZ basis sets. The synergetic effects in those systems were shown to be related to direction and amount of electron transfer. The results showed that OH/p and CH/O interactions strengthen each other for 0.42-0.44 kcal/mol. Similar effect is also present in the system containing LP/p and OH/p interaction, that strengthen each other for 0.42-0.46 kcal/mol. In contrast, two OH/p interactions weaken each other for 0.40 kcal/mol, two CH/O interactions weaken each other for 0.31 kcal/mol, while two LP/p interaction weaken each other by 0.40 kcal/mol. Weakening is also present in the system containing LP/p and CH/O interaction, that weaken each other by 0.43 kcal/mol. Parallel alignment water/benzene interactions, where one water OH bond is parallel to benzene ring and out of benzene ring and C-H bond region, do not have a significant influence on the energy of other interactions or on each other.
2013
The performance of the DFT/B-97-D and ωB97-D methods to reproduce the isotropic non-bonded interaction and the electric response properties in the benzene-argon and the π-π interaction in the benzene dimer have been studied. The PES for the interaction of benzene and argon with all possible Ar n-benzene (n = 1, 2) conformations has been explored. Results indicate that the ωB97-XD method is capable of reproducing well positions and depths for the studied benzene-Ar and benzene-benzene clusters to a high degree of accuracy and compare well with the experimental and best benchmark calculations. Satisfactory results have also been obtained for the benzene-X (X = He, Ne and Kr) clusters. The features of the charge density distributions of the studied benzene-Ar van der Waal complexes have been analyzed by calculating the dipole and higher multipole moments and the static polarizibility, its anistropic part and the interaction polarizibility. Trends and relationships to the dispersion interaction energy are suggested. Natural bond orbital analyses of the benzene-Ar n vdw complexes show clearly that all carbon valence orbitals are over-populated by about 21% at the expense of the hydrogen atoms valence orbitals. These data also indicate that argon behaves as electron donor in the Ar-benzene vdw complex, and hence, the slight positive charge on argon is at on the expense of its valence (non-bonding) p-orbitals.
An electrostatic approach for the interaction between molecules
Zeitschrift für Physikalische Chemie, 1981
In this paper we present an analysis of the electrostatic interaction between a solute molecule and its environment in non-reactive systems. The model has been applied in some calculations for the methane, ethane, methanol and hydrogen fluoride as solutes and water as a solvent. The results for the electrostatic interaction are compared with the corresponding ones obtained with the use of semi-empirical methods. The agreement is very satisfactory, and since the method developed here does not take a lot of computational time, it is quite suitable to predict stable configurations for the relative orientations of the solute and solvent molecules.
Exploring Orthogonality between Halogen and Hydrogen Bonding Involving Benzene
Molecules, 2021
The concept of orthogonality between halogen and hydrogen bonding, brought out by Ho and coworkers some years ago, has become a widely accepted idea within the chemists’ community. While the original work was based on a common carbonyl oxygen as acceptor for both interactions, we explore here, by means of M06-2X, M11, ωB97X, and ωB97XD/aug-cc-PVTZ DFT calculations, the interdependence of halogen and hydrogen bonding with a shared π-electron system of benzene. The donor groups (specifically NCBr and H2O) were placed on either or the same side of the ring, according to a double T-shaped or a perpendicular geometry, respectively. The results demonstrate that the two interactions with benzene are not strictly independent on each other, therefore outlining that the orthogonality between halogen and hydrogen bonding, intended as energetical independence between the two interactions, should be carefully evaluated according to the specific acceptor group.
Journal of Physical Chemistry A, 2002
Intermolecular interaction of the propane dimer was calculated with the MP2 level electron correlation correction using several basis sets up to the cc-pVQZ. The calculated interaction energy greatly depends on the basis set. Small basis sets underestimate the attraction considerably. The effects of electron correlation beyond MP2 are not large. Intermolecular interaction energies of 23 orientations of propane dimers were calculated at the MP2 level with a large basis set including multiple polarization functions. In all dimers, the inclusion of electron correlation considerably increases the attraction. The dispersion interaction is found to be the major source of attraction, whereas the electrostatic interaction is very small. The C 2h dimer in which the two C 2 axes of propane monomers have antiparallel orientation has the largest binding energy. The separation between the two methylene carbon atoms at the potential minimum in this dimer is the shortest among the 23 dimers. The short separation, which increases the dispersion energy, is the cause of the large binding energy of the C 2h dimer. The estimated MP2 and CCSD(T) interaction energies of the propane dimer at the basis set limit are -1.99 and -1.94 kcal/mol, respectively.
Aliphatic C−H/π Interactions: Methane−Benzene, Methane−Phenol, and Methane−Indole Complexes
Journal of Physical Chemistry A, 2006
Noncovalent C-H/π interactions are prevalent in biochemistry and are important in molecular recognition. In this work, we present potential energy curves for methane-benzene, methane-phenol, and methaneindole complexes as prototypes for interactions between C-H bonds and the aromatic components of phenylalanine, tyrosine, and tryptophan. Second-order perturbation theory (MP2) is used in conjunction with the aug-cc-pVDZ and aug-cc-pVTZ basis sets to determine the counterpoise-corrected interaction energy for selected complex configurations. Using corrections for higher-order electron correlation determined with coupled-cluster theory through perturbative triples [CCSD(T)] in the aug-cc-pVDZ basis set, we estimate, through an additive approximation, results at the very accurate CCSD(T)/aug-cc-pVTZ level of theory. Symmetry-adapted perturbation theory (SAPT) is employed to determine the physically significant components of the total interaction energy for each complex.