Studies of solvent effects. 1. Discrete, continuum, and discrete-continuum models and their comparison for some simple cases: ammonium(1+) ion, methanol, and substituted ammonium(1+) ion

Abstract

structure, led Srivastava19 to assign a planar structure to anthrone. Therefore, the enthalpy of formation (Table III) and resonance energy (Table IV) of anthrone were estimated and compared with those of xanthone. The resonance stabilization energy of xanthone falls between those of anthraquinone and anthrone, both of which are known to be planar molecules. These findings suggest that xanthone may also be planar. The somewhat greater resonance energy of xanthone, when compared with that of anthrone, may be due to the contribution of the unshared electrons of the ether oxygen atom to the resonance conjugation. This is consistent with the reported results20-22 that the xanthone molecules, to which the 7-pyrone ring is coupled, are aromatic.

Solvation of alkane and alcohol molecules. Energy contributions

“…4 in the cyclic compound as compared with A 2 173. 7 for the linear one. When we compare cyclohexane A 2 with the most stable geometry for cyclohexanol, the di †erence in solvation energy is related essentially to the increase in the absolute value of the polarization energy (ca.…”

Addressing the Issues of Non-isotropy and Non-additivity in the Development of Quantum Chemistry-Grounded Polarizable Molecular Mechanics

“…For that purpose, five, six, or seven waters were located in the complexes between each ligand and a reduced model of FAK limited to the recognition site shown in Figure 22. They were initially located thanks to a procedure [96] which minimizes with a simplified energy function a limited number of discrete waters around the accessible hydrophilic sites of the solute. The same conclusions hold with 6 and 7 discrete waters.…”

Some Critical Aspects of Molecular Interactions Between Drugs and Receptors

“…The explicit treatment of water molecules together with the continuum solvent model has been demonstrated to improve the pKa predictions with thermodynamic cycles by including the real quantum hydrogen bond interactions and by breaking the artificial boundary delimited by the dielectric continuum and therefore reducing the influence of the solute-continuum electrostatic interaction [210][211][212][213][214][215][216][217][218]. Since the artificial interaction between the dielectric continuum and the solute also limits the performance of the aqueous isodesmic reaction, a similar behavior is expected when explicit water molecules are included.…”