Oxygen Quenching of Room-Temperature Phosphorescence of 1-Bromonaphthalene in a Solid β-Cyclodextrin–Cyclohexane Matrix
摘要
The oxygen quenching of phosphorescence of 1-bromonaphthalene–β-cyclodextrin–cyclohexane ternary complexes localized in a crystalline β-cyclodextrin–cyclohexane matrix has been studied in an aqueous suspension of crystal hydrates and in a powder formed by drying the crystal hydrates. In the case of the suspension, the phosphorescence kinetics are monoexponential and the bimolecular rate constant for phosphorescence quenching by oxygen is kq = 2 × 103 L mol−1 s−1. The phosphorescence kinetics in powder cannot be described by a single exponential function, which is likely due to heterogeneity of the environment of 1-bromonaphthalene molecules. The bimolecular quenching rate constant in powder is 1.33 × 103 L mol−1 s−1. The quenching rate constant values for powders differ only slightly from those for suspensions, indicating that the oxygen diffusion rate is maintained during the decomposition of 1-bromonaphthalene–β-cyclodextrin–cyclohexane crystal hydrates.