Water-mediated intermolecular interactions in 1,2-O-cyclohexylidene-myo-inositol: a quantitative analysis

The syntheses of new myo-inositol derivatives have received much attention due to their important biological activities. 1,2-O-Cyclohexylidene-myo-inositol is an important intermediate formed during the syntheses of certain myo-inositol derivatives. We report herein the crystal structure of 1,2-O-cyclohexylidene-myo-inositol dihydrate, C<inf>12</inf>H<inf>20</inf>O<inf>6</inf>·2H<inf>2</inf>O, which is an intermediate formed during the syntheses of myo-inositol phosphate derivatives, to demonstrate the participation of water molecules and hydroxy groups in the formation of several intermolecular O - H...O interactions, and to determine a low-energy conformation. The title myo-inositol derivative crystallizes with two water molecules in the asymmetric unit in the space group C2/c, with Z = 8. The water molecules facilitate the formation of an extensive O - H...O hydrogen-bonding network that assists in the formation of a dense crystal packing. Furthermore, geometrical optimization and frequency analysis was carried out using density functional theory (DFT) calculations with B3LYP hybrid functionals and 6-31G(d), 6-31G(d,p) and 6-311G(d,p) basis sets. The theoretical and experimental structures were found to be very similar, with only slight deviations. The intermolecular interactions were quantitatively analysed using Hirshfeld surface analysis and 2D (two-dimensional) fingerplot plots, and the total lattice energy was calculated.In 1,2-O-cyclohexylidene-myo-inositol, the hydroxy groups at positions 4 and 5 are in a trans configuration and a rationale is suggested for the difficulties in synthesizing 1,2;4,5-di-O-cyclohexylidene-myo-inositol. The calculated structure was very similar to that of the experimental structure. Hirshfeld surface analysis with fingerprint plots demonstrated that the O - H...O interactions are the major intermolecular interactions. Lattice energy calculations suggested that dispersion is the major contributor to the crystal packing.