Nanopumpkins and a sunscreen agent: the inclusion complex of cucurbituril and Tinosorb S

Abstract

The commercial sunscreen agent Tinosorb S (TS) is a promising oil-soluble broad spectrum UV filter. Here, we report for the first time a water-dispersible inclusion complex of TS using cucurbituril. The synthesis was carried out via a supramolecular approach in the solid state by using the high-speed vibration milling technique. The formation and the photophysical properties of the solid inclusion complex were investigated by spectroscopic techniques such as UV–vis spectrophotometry, Fourier-transform infrared and solid-state proton nuclear magnetic resonance spectroscopy as well as by thermal gravimetric analysis and X-ray diffractometry. An increase in the absorbance and a shift of the maximum absorption from 380 nm to 345 nm for the inclusion complex were observed in comparison to the precursor complex TS. The stochiometric ratio of cucurbituril and TS in the inclusion complex was found to be 2:1