Structure of aggregate of hydrotropic p-toluene sulfonate and hydroxyacetophenone isomers

The interaction between sodium p-toluene sulfonate (NaPTS) and hydroxyacetophenones (HAPs) was investigated by photoluminescence and Raman spectroscopy methods. Indicative changes of the Raman spectra of NaPTS were observed upon interaction with HAPs. The molecular vibrations associated to the Raman peaks were identified by DFT calculations. Our results highlight that the molecular interactions between the sodium p-toluene sulfonate and hydroxyacetophenone molecules are preferably based on the interaction between the aromatic moieties of the investigated species. Furthermore, the strength of the interaction is moderated by the site of the hydroxy substituent (ortho- or para-) of HAP molecules.