Experimental and theoretical study on the interaction of an ionic resorcin [4]arene and some pollutants in aqueous solution

The complexation process between an ionic resorcinarene, C-ethyl-tetraminomethylated-resorcin[4]arene hydrochloride, with resorcinol, phenol and potassium cyanide has been studied in aqueous solution using spectroscopic, calorimetric, and computational techniques. The results show the formation of resorcinarene-phenol and resorcinarene-resorcinol inclusion complexes stabilized by means of pi-pi interactions. On the other hand, the interaction between the macrocycle and the cyanide ions is principally mediated by ion pairing and electrostatic interactions. A turn-on effect on the fluorescence intensity is found when resorcinol or phenol is added to the macrocycle. The quantification and detection limits have been calculated and the obtained values are comparable to other sensors reported in the literature. These results extend the use of this type of macrocycles as chemosensors.