In this study, the complicated solvation behaviors of arbutin were studied from both experiment investigations and theoretical calculations. Six solid forms of arbutin including anhydrous Form I and five solvates...

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Most organic crystals are brittle, which greatly restricts their applications in flexible smart materials. Herein, we reported two multi-flexible organic crystals. One of them exhibits two-dimensional (2D) elasticity, while the other one exhibits dual plasticity and elasticity along different directions. Their brittle polymorphs were also prepared to establish the correlations of the structure-property of flexible organic crystals from the perspective of crystal engineering. These flexible crystals can be manually twisted without fracture. Therefore, it was verified that manually twisted crystals can also be prepared from 1D plastic and elastic crystals, which has not been reported before. Detailed crystallographic analyses, energy framework calculations and nanoindentation tests were used to reveal the mechanism of the multiple mechanical responses of these crystals. It was found that these properties can be ascribed to the large differences in strength and orientation between the intermolecular interactions, together with the unique molecular arrangement in the crystals. Finally, the application of these flexible crystalline materials in the field of the optical waveguide was developed.

The solubility of 3,5-dinitrobenzoic acid in 13 solvents (methanol, ethanol, n-propanol, i-propanol, n-butanol, 2-butanol, i-butanol, n-pentanol, methyl acetate, ethyl acetate, n-propyl acetate, n-butyl acetate, and acetonitrile) was tested by gravimetry from 283.15 to 323.15 K under atmospheric pressure. The results showed that the solubility of 3,5-dinitrobenzoic acid increased with the increasing temperature in all pure solvents. Besides, the experimental solubility results of 3,5-dinitrobenzoic acid was fitted with thermodynamic equations like modified Apelblat equation, van’t Hoff equation, λh equation and the nonrandom two liquid equation. The results of average relative deviation, root-mean-square deviation, and coefficient of determination showed that the modified Apelblat equation correlates best of all models. Moreover, solvent effects and density functional theory (DFT) were introduced to demonstrate the dissolution properties of 3,5-dinitrobenzoic acid in the above solvents. At last, the dissolution process of 3,5-dinitrobenzoic acid in selected solvents was spontaneous according to the results of the mixing Gibbs free energy change (Δmix G).