“…Curcumin (CUR, C 21 H 20 O 6 , CAS registry No. 458-37-7) is a typical organic small molecule with intramolecular hydrogen bonding of enol isomerization and both keto-enol and β-diketone (Scheme ) structures. , In solution, the conversion of the keto-enol molecule of curcumin to the β-diketone form can be achieved by adjusting the pH − and polarity of the solvent. − However, limited by the high energy or fugacity of the β-diketone structure, curcumin is dominated by the keto-enol structure in the solid state . In particular, curcumin in the solid state (crystalline, powder, polymorph, etc.)…”