Effect of the Methanol Molecule on the Stabilization of C₁₈H₁₈O₄ Crystal: Combined Theoretical and Structural Investigation

Abstract

The ability of the chalcone, C18H18O4, to form solvates was theoretically and experimentally investigated. The unit cell with Z' > 1, composed of two independent chalcone molecules (α and β), shows the formation of a stable molecular complex which is related with the presence of methanol in this crystal lattice. Aiming to understand the process of crystal lattice stabilization, a combination of techniques was used, including X-ray diffraction (XRD), computational molecular modeling, and an ab initio molecular dynamic. The results show that α and β molecules are sterically barred from forming a direct hydrogen bond with one other. In addition, the presence of the methanol molecule stabilizes the crystal structure by a bifurcated O-H···O interaction acting as a bridge between them. The theoretical thermodynamic parameter and the rigid potential energy surface scan describe the role of methanol in the energy stabilization of the crystal. The absence of the methanol compound in the asymmetric unit destabilizes the crystalline structure, making the formation process of the asymmetric unit nonspontaneous. The energy difference between α and β molecules is around 0.80 kcal·mol(-1), indicating that both are stable and equally possible in the crystal lattice. The analysis of the energy profile of the C14-O2···H1-O3 and O2-H1···O3-C17 torsion angles in the crystal packing shows that the α and β molecules are confined in the stable potential region, in agreement with the two conformers in the asymmetric unit. The Molecular Electrostatic Potential (MEP) shows that the methanol has no steric effects, which prevents small motion around the torsion angles.

Methanol Solvation Effect on the Proton Rearrangement of Curcumin’s Enol Forms: An Ab Initio Molecular Dynamics and Electronic Structure Viewpoint

“…However, there is a preference for the O6 site, and this solvation process induces asymmetric behavior from the energy wells. The symmetric methanol distribution around the β-diketone group needs an organized and specific anchoring, and the polarity of methanol is not enough to stabilize this interaction . Furthermore, the degree of organization necessary for symmetric methanol interaction requires a considerable negative entropy (a nonspontaneous process).…”

“…The symmetric methanol distribution around the β-diketone group needs an organized and specific anchoring, and the polarity of methanol is not enough to stabilize this interaction. 49 Furthermore, the degree of organization necessary for symmetric methanol interaction requires a considerable negative entropy (a nonspontaneous process). In contrast, the disorder provided by the dynamic evolution solvates one of the carboxyls better than the other, stabilizing the structure with hydrogen on the other carboxyl.…”

Explicit Aqueous Solvation Treatment of Epinephrine from Car–Parrinello Molecular Dynamics: Effect of Hydrogen Bonding on the Electronic Absorption Spectrum

“…Guided by our interest in ab initio molecular dynamics, − the solvent’s effects on optical and spectroscopic properties − prompted us to investigate these subjects in the case of the neurotransmitter EPN in the aqueous medium. In this paper, our goal is to account for the effects of the explicit water solvation on EPN’s geometry and absorption spectrum to highlight the importance of an atomistic treatment of the solvent when the accuracy of continuum approximations is not attainable.…”

The Influence of Methoxy and Ethoxy Groups on Supramolecular Arrangement of Two Methoxy-chalcones

“…[1][2][3][4][5][6][7][8][9] Chemically, the molecular skeleton is characterized by aromatic rings moieties connected through three-carbon bridge having a keto carbonyl group and one α,β-unsaturation ( Figure 1). 5,[10][11][12][13] Chalcones and chalcone derivatives are often obtained from natural or synthetic sources. 8,14 By synthesis perspective, the Claisen-Schmidt condensation of aromatic aldehyde and aromatic acetophenone under either base or acid catalysis is a widely employed method to the synthesis of chalcones.…”

“…8,14 By synthesis perspective, the Claisen-Schmidt condensation of aromatic aldehyde and aromatic acetophenone under either base or acid catalysis is a widely employed method to the synthesis of chalcones. 5,[10][11][12][13] The versatility of class is evident from its wide-ranging biological activities; in particular, antiviral, anthelmintic, amoebicidal, antibacterial, antiprotozoal, antiulcer, cytotoxic, insecticidal, and anticancer. 13,[15][16][17][18] Also, due to its chemical structure, several chalcones have been reported to exhibit non-linear optical (NLO) properties that turn these compounds into potential functional materials.…”