Araújo, PaulaMendoza, JohanPina, FernandoPereira, Ana RitaFernandes, Ivade Freitas, VictorOliveira, Joana2021-03-042022-03-242020-11-011010-6030PURE: 28245706PURE UUID: 89b72784-acd9-480f-9604-0752b5c8fcdbScopus: 85089233526WOS: 000582481800022ORCID: /0000-0001-8529-6848/work/89319490http://hdl.handle.net/10362/113070UIDB/50006/2020 UIDP/50006/2020 PTDC/QUI-OUT/29013/2017 SFRH/BD/143309/2019 SFRH/BD/146549/2019 MEX/Ref. 288188 IF/00225/2015The multistate of species originated by the compound 5-hydroxy-4′-dimethylaminoflavylium was studied in the presence of sodium dodecyl sulfate micelles 0.1 M. A series of pH jumps obtained by addition of base to the equilibrated solutions of the flavylium cation results in a metastable equilibrium between the flavylium cation and the quinoidal base with pKa = 7.6. In neutral to moderately basic medium, only at 60 °C and after 5 days a new distribution involving the flavylium cation and trans-chalcones is achieved. On the other hand, the anionic trans-chalcone can be formed in few minutes in very basic medium at room temperature and from this, another meta-stable state constituted by protonated, neutral and anionic trans-chalcones, pKCt+/Ct = 2.6 and pKCt/Ct- = 10.7 is reached. The equilibrium is apparently attained between flavylium cation, neutral and anionic trans-chalcones respectively for pKAH+/Ct = 4.1 and pKCt/Ct- = 10.7. Irradiation of the neutral (stable or metastable) and protonated (meta-stable) trans-chalcones yields to the appearance of the quinoidal base or the flavylium cation in an extended pH region 1 < pH < 10. The peculiar properties of this flavylium based photochromic system are explained by means of an energy level diagram where cis-chalcone and hemiketal lay above the quinoidal base.3109408engAminoflavyliumAnthocyaninsMeta-stabilityPhotochromismQuinoidal baseTrans-ChalconesGeneral ChemistryGeneral Chemical EngineeringGeneral Physics and Astronomyjournal article10.1016/j.jphotochem.2020.112827https://www.scopus.com/pages/publications/85089233526