Reexamination of the conformations of dimethyl phosphate anion in water

by Kamitakahara, Atsushi; Hsu, Chih-Li; Pranata, Julianto

Monte Carlo simulations were employed to calculate the relative free energies of hydration for the gauche-gauche (gg), gauche-trans (gt), and trans-trans (tt) conformers of the dimethyl phosphate anion. Relative to the gg conformer, the free energy of hydration of the gt conformer is 0.2 kcalmol-1higher, while that of the tt conformer is 2.6 kcalmol-1lower. In combination with the free energy differences for the isolated molecules (Liang et al., J. Am. Chem. Soc., 115 (1993) 1537), these results indicate that in aqueous solution the gg conformer is most stable, but the gt and tt conformers have comparable stabilities. The entropic contribution to the free energy of hydration is thought to be an important factor.

Journal
Journal of Molecular Structure-Theochem
Volume
334
Issue
1
Year
1995
Start Page
29
ISBN/ISSN
2210-2728; 0166-1280
DOI
10.1016/0166-1280(94)03966-O