Effect of solvent and pH on the stability and chemical reactivity of the delphinidin molecule

Abstract

The study of the stability in different solvents and its effect on the chemical reactivity for the delphinidin molecule is presented, using molecular modeling as a tool. The structural modeling of delphinidin in the different solvents (water, methanol, ethanol and acetone) was carried out based on the predominant structures of delphinidin in different pHs (1, 4.5, 5.5 and 7). Quantum mechanical studies were performed using density functional theory (DFT) with a B3LYP level and a base set 6-11+g(d,p). The solvation energies of the delphinidin molecule were obtained, finding that methanol is where the molecule dissolves best. Besides, The chemical reactivity indices for the molecule were obtained due to the effect of the solvent, finding that when it is found in water as a solvent, it acquires a lower hardness, making it more susceptible, that is, more reactive. The results also showed that at pH < 2 using methanol as solvent, the hydrogen atom of the hydroxyl group attached to the 4' carbon is the most prone to donate hydrogen.