Spectroscopy of triplet-excited complexes of oxygen with spruce cone molecules extract from picea abies in AOT micelles under combined photoexcitation

Abstract

The paper presents a method for obtaining an extract from the cones of Picea Abies spruce and fabrication a microemulsion based on it, which has an absorption spectrum in the UV region and luminescence in the red region (680-720 nm). A spectral study of a microemulsion with an extract containing polyphenols and phenolic acids (vanillic, protocatechuic, oxybenzoic) in the visible and IR spectral regions has been carried out. On the basis of time-resolved spectral data, the possibility of formation of reactive oxygen species, in particular, singlet oxygen, in a microemulsion under the action of UV radiation has been proved. A technique for oxygen saturation of microemulsions with an extract has been developed. The quantum efficiency of singlet oxygen generation upon absorption of light at a wavelength of 400 nm by an extract with different concentrations of molecular oxygen inside reverse micelles has been determined. It has been established that the quantum yield of singlet oxygen (1Δg) in a microemulsion with an extract can be increased by a factor of 9.5 and this value can be controlled by changing the oxygen accumulation time inside the micelle. It was found that with the oxygen concentration grow, both extract fluorescence intensity and optical density increase, and long-lived delayed fluorescence appears. A controlled concentration process of oxygen complexation with extract molecules accompanied by chemiluminescence in the red region of the spectrum has been studied. The rate constants of energy deactivation in the contact complex after photoexcitation during quenching of triplet states of the extract molecules have been determined