Model of 1,1,1,3,3,3-Hexafluoro-propan-2-ol for Molecular Dynamics Simulations

An all-atom model of 1,1,1,3,3,3-hexafluoro-propan-2-ol (HFIP) for use in molecular dynamics simulation studies is proposed. The model was parametrized by fitting to the experimental density, pressure, and enthalpy of vaporization of the pure liquid at 298 K. The model was then tested by comparison against other experimental thermodynamic and kinetic properties of the pure liquid. Mixtures with SPC water were also investigated. Overall, reasonable agreement with the available experimental data for the neat liquid and for mixtures with SPC water was found. A tendency for HFIP to cluster in SPC water was observed in qualitative agreement with experimental observations. The effect of HFIP on the secondary structure of peptides was also studied. Two simulations of the peptide Melittin, in pure water and in 30% v/v HFIP, demonstrate the helix stabilizing effect of HFIP.