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Amine Hydration: A United‐Atom Force‐Field Solution
Author(s) -
Oostenbrink Chris,
Juchli Daniel,
van Gunsteren Wilfred F.
Publication year - 2005
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.200400542
Subject(s) - solvation , force field (fiction) , chemistry , atom (system on chip) , chloroform , polar , amine gas treating , computational chemistry , field (mathematics) , molecule , chemical physics , thermodynamics , physics , organic chemistry , mathematics , quantum mechanics , astronomy , computer science , pure mathematics , embedded system
The free energies of hydration for ammonia and mono‐, di‐, and trimethylated amines experimentally show an unexpected trend that has, in the past, been difficult to reproduce computationally. Absolute and relative free energies of hydration of these compounds were calculated using the OPLS all‐atom and the united‐atom GROMOS force fields. Both force fields reproduce the relative free energy of hydration, but the absolute free energies of hydration were only reproduced within k B T when using the recently developed GROMOS parameter set 53A6. Relative free energies of solvation in chloroform could also be reproduced indicating a proper partitioning of the compounds between polar and apolar media. Overall we conclude that it is possible to resolve the amine hydration problem using a simple united‐atom force field.