A computational study of the ground and excited state acidities of synthetic analogs of red wine pyranoanthocyanins

摘要: The color of mature red wines is due in large part to the chemical transformation grape anthocyanins into pyranoanthocyanins. Given difficulties isolation and purification pyranoanthocyanins from wines, experimental investigations have focused on pyranoflavylium cations, synthetic analogs that contain basic chromophoric moiety Quantum methodologies been extensively employed predict physical, spectroscopic photophysical properties and, more recently, cations. In present work, we employ TD-DFT with B3-LYP functional def2-TZVP basis set, combined estimation solvation free energies via COSMO, estimate a priori pKa values ground state lowest excited singlet triplet states series seven substituted hydroxypyranoflavylium For first state, quantum results compare favorably for most these compounds. Although there are currently no data acidity predicted be similar than as generally found experimentally photoacids.