Adding an explicit solvent molecule to polarized continuum model for computational study on the conformational population of a highly fluorinated hydrazone

摘要

In this work, we examined the conformational population of a highly fluorinated hydrazone, 2H-perfluoro-2-methyl-3-pentanone, by density functional theory computations in four Lewis basic solvents: acetonitrile, diethyl ether, tetrahydrofuran and dimethyl sulfoxide. Various 1:1 hydrogen-bonded clusters of rotamer and solvent were embedded in the solvent employing the polarized continuum model in the computations. The calculated results showed the strength of the intermolecular interaction between the hydrogen bonding acceptor of solvent and the hydrogen atom of amino group in the fluorinated hydrazone played an important role in the experimental observation for the relative population. The combined approach that involves attaching a single explicit solvent molecule to the hydrazone, and then surrounding the resulting 1:1 cluster by a dielectric continuum, significantly improves the agreement between the calculated relative Gibbs energy and experiment, whereas, the implicit treatment of solvent gave an error in the prediction of relative stability for the fluorinated hydrazone in the four Lewis basic solvents.