Aqueous photochemistry of bisphenol E in the presence of β-cyclodextrin

Nanosecond laser flash photolysis and time-resolved fluorescence were used to study photochemistry of bis(4-hydroxyphenyl)ethane (Bisphenol E, BPE) and complex of BPE with β-cyclodextrin (BPE-CD) in aqueous solutions. For both systems the primary photochemical process was found to be photoionization with the formation of a hydrated electron—phenoxyl radical pair. Inclusion of BPE in cyclodextrin cavity leads to the increase of photoionization and fluorescence quantum yield (from 0.009 to 0.16) as well as fluorescence lifetime (from 0.07 to 2.5 ns) due to decreasing of the quenching rate of the singlet excited state of complexed BPE by solvent molecules.