**4. Conclusions**

The molecule's structural geometry was analyzed a generally accepted methodology with a different basis set. Parameters such as relative angles, dihedrals, main features of individual rings, and a discussion on each molecule planarity were included as part of the discussion to relate the main geometry parameters with the molecule behavior and chemical features. Molecules functionalization with COH3 is highlighted as an important feature for the structural and energy gap differences in each molecule geometry structure definition and is directly related with molecular orbital distribution with a direct effect in gap energy.

MOs and spectra results show there is a good fit with TiO2 and concluded these pigments may be good dye sensitizers. Malvidin in its gas phase may be a good option from a gap energy perspective. Solvents increase their gap energy in all cases except with n-hexane which is the narrower followed by petunidin also with n-hexane. A good charge transfer feature is important as well and it was assessed with conceptual DFT. Results show cyanidin, malvidin, and pelargonidin may have a better charge transfer. A lower as possible electron reorganization energy (λe) and a high LHE are desirable since this would benefit charge transfer. Cyanidin has the smaller λ<sup>e</sup> with water, but ethanol and methanol λ<sup>e</sup> resulting values were nearly different. For LHE, the highest were cyanidin, malvidin, and petunidin with similar values between solvents. Based on our analysis of absorption capabilities for the selected pigments, it is corroborated cyanidin, malvidin, and petunidin may be acceptable dye sensitizers for DSSCs and photocatalysis applications.
