Impact of the Position of the Hydroxyl Group in Monohydroxy Chalcones with 2-Hydroxypropyl-β-Cyclodextrin on Their Spectral, Biological, and Theoretical Properties

Abstract

3-Hydroxychalcone (3HOCH) and 4-hydroxychalcone (4HOCH) compounds were synthesized from the reaction between acetophenone and either 3-hydroxybenzaldehyde or 4-hydroxy benzaldehyde, using KOH as a catalyst. Then the synthesized compounds were further reacted with two cyclodextrins (CDs) (2-hydroxypropyl-β-cyclodextrin and β-cyclodextrin), by a co-precipitation method to investigate their spectral (absorption, fluorescence, and Fourier transform infrared), biological, and theoretical properties. Two absorption maximums appeared at 307 and 253 nm for 3HOCH and 346 and 254 nm for 4HOCH in aqueous solution by absorption spectrophotometry. In the excited state, dual emission was observed at 362 nm and 426 nm for 3HOCH and 360 nm and 486 nm for 4HOCH in the same medium of H2O by fluorescence spectrophotometry. The apparent changes in the absorption and emission spectra were the result of the inclusion complex with a 1:1 molar stoichiometric ratio. The interaction of 3HOCH, 4HOCH, and the CDs in the solid state was characterized by Fourier-transform infrared spectroscopy (FTIR), powder X-ray diffraction patterns (PXRD), scanning electron microscopy (SEM), antioxidant and antibacterial studies concerning the position of the hydroxyl (-OH) group at the m- or p-positions in chalcone. The optimized highest occupied molecular orbital (HOMO) diagram, lowest unoccupied molecular orbital (LUMO) diagram and molecular electrostatic potential (MEP) map for the isolated molecules and their inclusion complexes were done by Becke’s three-parameter (B3) hybrid functional method using the Lee-Yang-Parr (LYP) correlation levels of density functional theory (DFT) method with 3-21 G basis set.