Quantum-mechanical computations on the electronic structure of trans-resveratrol and trans-piceatannol: a theoretical study of the stacking interactions in trans-resveratrol dimers

Abstract

Accurate quantum-chemical calculations based on the second-order Møller-Plesset perturbation method (MP2) and density functional theory (DFT) were performed for the first time to investigate the electronic structures of trans-resveratrol and trans-piceatannol, as well as to study the stacking interaction between trans-resveratrol molecules. Ab initio MP2 calculations performed with using standard split-valence Pople basis sets led us to conclude that these compounds have structures that deviate strongly from planarity, whereas the DFT computations for the same basis sets revealed that the equilibrium geometries of these bioactive polyphenols are planar. Furthermore, the results obtained at the MP2(full)/aug-cc-pVTZ and B3LYP/aug-cc-pVTZ levels indicated that the geometries of trans-resveratrol and trans-piceatannol are practically planar at their absolute energy minima. The relative energies of the equilibrium geometries of trans-resveratrol on its potential energy surface were computed at the MP2(full)/aug-cc-pVTZ level. According to the results obtained, a T-shaped (edge-to-phase) conformer of trans-resveratrol dimer is the most stable in vacuum. This T-shaped conformer is mainly stabilized by strong hydrogen bonding and weak C-H...π interactions. Stacked structures with parallel-displaced trans-stilbene skeletons were also found to be energetically stable. The vertical separation and twist angle dependencies of the stacking energy were investigated at the MP2(full)/aug-cc-pVTZ, B3LYP/aug-cc-pVTZ, and HF/aug-cc-pVTZ levels. The standard B3LYP functional and the Hartree-Fock method neglect long-range attractive dispersion interactions. The MP2 computations revealed that the London dispersion energy cannot be neglected at long or short distances. The stacked model considered here may be useful for predicting the quantum nature of the interactions in π-stacked systems of other naturally occurring stilbenoids, and can help to enhance our understanding of the antioxidant and anticancer activities of trans-resveratrol.

Quantum Chemical Study on the Antioxidation Mechanism of Piceatannol and Isorhapontigenin toward Hydroxyl and Hydroperoxyl Radicals

“…The optimized structures of PIC and ISO with atom labels are shown in Fig 1 . By our calculation with the method of M05-2X/6-311++G(d,p), the dihedral angle between two benzene rings of PIC is 179.95°, which is similar with the value of 179.50°calculated by MP2/6-311G(d,p) method [ 31 ]. The theoretical results are in agreement well with the corresponding experimental value of 179.23° [ 30 ].…”

“…Rossi et al performed a theoretical investigation on the structural features of PIC and the effect of water using DFT method and COSMO solvation model [ 30 ]. Mikulski et al first completed a theoretical research of the electronic structural feature of PIC using MP2 and DFT method [ 31 ]. Perez-Gonzalea et al investigated the free radical scavenging activity of a series of polyphenols.…”

Theoretical study of the interaction energy of benzodifuranone dye molecule rings

“…Both the bond angles and the dihedral angles show that the six‐benzene ring and five‐furanone rings of the benzodifuranone molecule have better coplanarity. Better planarity of dye molecules provides better π‐electron distributions and larger π–π stacking interaction . Coplanar dye molecules come more easily into contact with linear PET molecules along their entire length than non‐planar molecules.…”