H2S-Responsive Lower Critical Solution Temperature of the Host-Guest Complex Based on Oxatub[4]arene with Tri(ethylene oxide) Moieties.

A water-soluble oxatub[4]arene with tri(ethylene oxide) moieties was synthesized. The lower critical solution temperature (LCST) behavior of this macrocyclic receptor was tunable by changing its concentration or by adding an appropriate guest. Most interestingly, the LCST behavior of the host-guest complex showed a response to the presence of the physiological gasotransmitter H2S through nitro group reduction.