pH dependency of the structural and photophysical properties of the atypical 2',3-dihydroxyflavone.

2',3-Dihydroxyflavone (2'3HF) is a natural flavonol that has barely ever been studied, however the scarce studies of its physico-chemical properties have highlighted its atypical behaviour. We present a structural and spectral study of 2'3HF, performed using UV-visible absorption and fluorescence spectroscopies, coupled with DFT and TD-DFT calculations. Although its structure is close to that of 3-hydroxyflavone, 2'3HF shows a much lower p value.

Spectroscopic and theoretical study of the pH effect on the optical properties of the calcium-morin system.

Morin (2-(2,4-dihydroxyphenyl)-3,5,7-trihydroxychromen-4-one) is an abundant flavonoid with various pharmacological and biological activities. Considering the ubiquitous presence of calcium cations in biological systems, it seems relevant to study the interaction of this ion with morin and the influence of pH on this system. In a first step, among the four hypothetical chelation sites, the preferential fixing site, its protonation state and the Ca environment have been determined by combining electronic spectroscopies and density functional theory (DFT) and time-dependent DFT calculations.