Collect. Czech. Chem. Commun. 1981, 46, 1722-1733

Conformational dependence of solvation energy of phosphates

Tomáš Blehaa, Ján Mlýneka and Igor Tvaroškab

a Polymer Institute, Slovak Academy of Sciences, 809 34 Bratislava
b Institute of Chemistry, Slovak Academy of Sciences, 809 33 Bratislava


Conformational dependence of solvation energy has been calculated for dimethyl phosphate, its monoanion and ion pair with the proton considering rotation about P-O bonds in the molecules. The solvent (water) effect has been expressed using the continuous model according to Sinanoglu. Contribution of individual terms (electrostatic, dispersion and cavity) of the solvation energy in the stabilization of individual conformers has been analyzed. Some of methodical problems of the calculation of solvation energy have been discussed and particularly the inevitability of reliable determination of torsional dependence of molecular volume has been stressed. A comparison of the three molecules has shown that different character of the solvation energy dependences is due to the electrostatic term and is connected with orientation of the group dipole moment of the central PO2 group in the individual molecules.