Modeling in Structure Analysis of Vanadyl Phosphate Intercalated with 1-Alkanols

Abstract

Molecular mechanics simulations supported by X-ray powder diffraction measurements have been used to investigate the structure of vanadyl phosphate intercalated with 1-alkanols C_nH_2n+1OH for n = 2, 3, 4. Modeling revealed the specific features and differences in arrangement of alkanol molecules with different chain length, depending on the relation between the parameters of active sites network and size of guest molecules. This result enabled us to explain the irregularities in dependence of basal spacing on the chain length. The comparison of experimental d_exp and calculated d_calc values of basal spacing showed the good agreement of modeling with x-ray powder diffraction. While we obtained d_calc(Univ) = 13.05 Å for vanadyl phosphate-ethanol using the Universal force field (d_exp=13.17 Å), for vanadyl phosphate-propanol and vanadyl phosphate-butanol better agreement with experiment was obtained using the Tripos force field. In the case of vanadyl phosphate-propanol the calculated basal spacing d_calc(Tripos) = 14.49 Å, compared with an experimental value of d_exp=14.36 Å. For vanadyl phosphate-butanol d_calc(Tripos) = 17.71 Å and d_exp=17.90 Å.