## 2 Results and Discussion
### Vibrational Analysis  
The chalcones have the molecular formula C\({}_{18}\)H\({}_{17}\)NO\({}_{7}\), and therefore have 43 atoms, allowing 129 degrees of freedom (3N). Therefore, 123 vibrational modes are expected, excluding the three rotation movements and the three translation movements (3N-6). The experimental spectra of FT-Raman of polycrystalline samples of the chalcones are shown in Figure 17, while the experimental ATR-FTIR spectra of these substances are shown in Figure 17. The complete attribution of all theoretical and staggered vibration modes, associated with the wavenumbers observed in the experimental spectra of FT-Raman and ATR-FTIR of the chalcones 1 and 2, respectively, are presented in Tables S1 and S2. In each table, the first and second columns correspond to the calculated (\(\omega\)calc) and staggered (\(\omega\)scal) wavenumbers, respectively. The third and fourth columns correspond to the experimental wave numbers of the FT-Raman (\(\omega_{\rm Raman}\)) and ATR-FTIR (\(\omega_{\rm FTIR}\)) spectra, respectively, and the fifth column shows the assignment of vibration modes along with the contribution of potential energy distribution (PED), with values higher than 10% for each vibration mode. The FT-Raman (Figure 17) and ATR-FTIR spectra (Figure 17) for chalcones 1 and 2 samples present many bands that coincide with those already reported in the literature for chalcones [17], which is expected, since, in these chalcones, the change that occurs is in the B-ring substitution pattern of these derivatives of the natural product 2-hydroxy-3,4,6-trimethoxyactophenone. The assignment for the chalcones 1 and 2 shows that most of the bands observed through FT-Raman and FT-IR spectroscopy (Bruker, Billerica, MA, USA) correspond to a mixture of vibrational modes. In addition, there is a good match between the staggered and experimental Raman and infrared bands. In the step wavenumber region of the Raman and infrared spectra of 14-960 cm\({}^{-1}\) of the vibrational spectra, the presence of torsion modes, out-of-plane deformations, and deformations in the carbon atoms of the aromatic rings and their ligands, as well as of the NO\({}_{2}\) groups, predominates. It should be considered that modes below 100 cm\({}^{-1}\) are associated with external modes, which were not computed because the DFT calculations were performed on isolated molecules, and therefore do not consider the periodicity of the crystalline network. Figure 5: UV-Vis experimental spectra of chalcones 1 and 2 in ethanol solution. The chalcones 1 and 2 ATR-FTIR spectra show more intense absorbance bands in the range from 670-1700 cm\({}^{-1}\). The absorbance bands between 960 and 1671 cm\({}^{-1}\) of the Raman and infrared spectra consist mainly of the stretching modes CC, CO, CN, and NO and deformations of the HCC, CCO, and ONO atoms. It is noted that the intensities of the most infrared bands in the region between 1200 and 1000 cm\({}^{-1}\) are more intense in the chalcone 1 than those observed in the chalcone 2. The differences in the infrared intensities are expected, since this spectral region is within the fingerprint region, which is unique to each one of those chalcones. As the chalcones 1 and 2 are polycrystalline, their molecules are periodically arranged in their crystals. It is known that the intermolecular interactions in molecular crystal depend on how the packing of molecules is arranged within its unit cell, and how the electronegativity affects the intermolecular forces [27 ]. Since the chalcone 2 has higher electronegativity than chalcone 1, it has intermolecular interactions that are more intense than the chalcone 1 (4.30 eV for chalcone 2 against 4.09 eV for chalcone 1).