The formation mechanism of hollow spherulites and molecular conformation of curcumin and solvate

Abstract

In this study, curcumin 1,4-dioxane solvates (CUR-DIO) in two molecular ratios of 1:1.5(CUR-DIO-1.5) and 1:1(CUR-DIO-1) were obtained at different temperature. In single crystal structure, curcumin molecules differ from planar structure...

Reversible Intramolecular Proton Transfer in Curcumin Crystals and Nonlinear Size Correlation

“…As shown in Figure c, the removal of 1,4-dioxane solvent molecules (accompanied by phase transition) was accomplished in the range of 30–130 °C for all the CUR-DIO crystals of different particle sizes. The weight loss did not show a significant difference with the variation of crystal size, all around 19.2%, which is highly consistent with the mole ratio from single-crystal data (1:1 molar ratio of solute to solvent) . Noteworthily, influenced by the heat transfer efficiency of the crystals, the temperature interval during desolvation was wider, and the desolvation temperature was higher for the large-size crystals compared to the small-size crystals.…”

“…The detailed data of crystal structures of CUR-Form I, CUR-DIO, and CUR-ACE are shown in Table S3. In this paper, the crystal structures of curcumin solvate CUR-ACE are reported for the first time, and those of CUR-DIO been reported in our previous article …”

“…The proton transfer process in solid- state conditions is accompanied by phase transitions and changes in the vibrational frequency of functional groups, and single- crystal structure analysis is the most ideal visualization method at the molecular level. Solution crystallization was used to obtain 1,4-dioxane solvate (CUR-DIO) crystals, acetone solvate (CUR-ACE). and stable polymorph Form I (CUR-Form I) crystals of curcumin.…”

Cocrystallization of Curcuminoids with Hydroxybenzenes Pyrogallol and Hydroxyquinol: Investigations of Binary Thermal Phase Behaviors

“…Form 2 and form 3 build an orthorhombic crystal lattice in space groups Pca 2 1 and Pcba , respectively. Three solvates with 1,4-dioxane, methyl acetate, and dichloromethane and several cocrystals, e.g., with resorcinol, catechol, hydroquinone, pyrogallol, hydroxyquinol, and nicotinamide have been discovered to date. − For BDMC, only one crystal structure in the monoclinic space group P 2/ c is known . Besides that, six solvates with acetone, methanol, isopropanol, tetrahydrofuran, 1,4-dioxane, and dimethyl sulfoxide and two cocrystals with pyrogallol and hydroxyquinol were discovered. − So far, there are no crystal structure data available for DMC.…”