Excited-state dynamics of bis-dehydroxycurcumin carboxylic acid, a water-soluble derivative of the photosensitizer curcumin

Bis-dehydroxycurcumin carboxylic acid (K2A23) is a synthetic curcuminoid designed to exhibit enhanced water solubility and photosensitizing potential with respect to natural curcumin. In this work, the tendency of the compound to form intra- and intermolecular hydrogen bonds in the ground state is studied by UV-visible absorption and by nuclear magnetic resonance (NMR). The excited-state dynamics of the drug are probed in different environments by means of time-correlated single-photon counting measurements and related to its hydrogen bonding affinity in the excited state.