Crystal structure, vibrational spectra and quantum chemical parameters of 2-hydroxy-3,4,6-trimethoxyacetophenone isolated from the Croton anisodontus Müll. Arg. (Euphorbiaceae)

In this paper the isolation of 2-Hydroxy-3,4,6-trimethoxyacetophenone (C11O5H14) from the stem bark of Croton anisodontus Mull. Arg. (Euphorbiaceae) is presented and its structure is characterized using Nuclear Magnetic Resonance and single crystal X-ray diffraction. The crystalline structure of this natural compound, which presents potential antimicrobial activity, was determined at 100 K and 298 K. Additionally, the vibrational properties were characterized through infrared and Raman spectroscopy at room temperature in the spectral regions 400 cm−1 to 4000 cm−1 and 25 cm−1 to 4000 cm−1, respectively. Vibrational wavenumber and wavevector have been predicted using the Density Functional Theory calculations with the hybrid functional B3LYP and the basis set 6–31 G(d,p). Furthermore, the description of the normal modes was furnished in terms of the Potential Energy Distribution. Hirshfeld surface analysis is presented in order to investigate the interactions between the molecules in the crystals. Density Functional Theory calculations were carried out in order to obtain the molecular orbitals and other quantum chemical parameters. Experimental and theoretical UV absorption spectra of 2-Hydroxy-3,4,6-trimethoxyacetophenone are also evaluated from time-dependent density functional theory with the purpose to analyze the energies of the most important molecular orbitals and the transitions modes for this compound. Finally, the electrostatic surface potential map was also constructed to display the charge density distribution and the sites of chemical reactivity.