Hydration of Fluorobenzenes: A Molecular Dynamics Simulation Investigation

Abstract

Molecular dynamics simulations of benzene and 12 fluorobenzenes
with various degrees of fluorine substitution in water reveal
that the accumulation of water in the first solvent shell decreases with
increase in number of fluorine atoms relative to benzene, with an exception
of hexafluorobenzene. Further, the solute–solute radial density function
indicates that partially substituted fluorobenzenes sample -stacked
and T-shaped geometries. In contrast benzene and hexafluorobenzene
sample only the T-shaped geometries. Comparison of solute–solute and
solute–solvent radial density functions suggests that solute–solute interactions
is preferred over solute–solvent interaction, which suggests the
hydrophobic nature of fluorobenzenes, which increases with increase
in number of fluorine atoms on the phenyl ring. The spatial distribution
of water around the fluorobenzenes suggests that water avoids the C–F
bond group, which indicates increase in hydrophobicity of fluorobenzenes
with number of fluorine atoms.