Conformational Preference of Oxybis(methylene-1,3- dioxane-5,5-diil)dimethanol in Solvents of Various Nature

The conformational preference of oxybis(methylene-1,3-dioxane-5,5-diyl)dimethanol in various solvents was studied by NMR. According to the data of two-dimensional spectroscopy (NOESY), the bis(chair) form with diaxial oxymethyl groups is dominated in С6D6 and CDCl3, while the form with axial and equatorial oxymethyl groups at С5 and С5' atoms of the ring is dominated in DMSO-d6 and CD3CN solvents. The results of computer simulation of the conformational transformation of molecules of the studied diformal within the DFT approximation PBE/def2-SVP in these solvents (cluster model) are in complete agreement with the NMR results. It is shown that the optimal number of solvent molecules in the nearest solvate shell of the studied diformal varies from five to seven depending on the nature of solvent.