Host-guest binding triggered visual detection of p-toluenesulfonic acid

ABSTRACT Visual detection of p-toluenesulfonic acid (pTSA) is very important due to its health-harmful effects, but remains less investigated. In this study, a TGM (Triethylene Glycol Monomethyl ether) derived calix [4] carbazole was found to be able to selectively encapsulate pTSA by its cone conformation, thus specifically detecting it visually. To the best of our knowledge, it is the first case of pTSA visual detection based on host-guest binding triggered charge transfer.