10.1002/chem.201101266
The study presents the design, synthesis, and characterization of a tetrathiafulvalene-calix[4]pyrrole receptor, which can be controlled by external acid/base inputs to regulate its molecular recognition of guest molecules. The receptor, named ouroboros due to its self-complexation property, is composed of three identical tetrathiafulvalene (TTF) units and a fourth TTF unit appended with a phenol moiety. The phenol group allows for the receptor to switch between a locked (ouroboros) and unlocked state through deprotonation/protonation, thereby controlling the binding and release of guest molecules like 1,3,5-trinitrobenzene (TNB). The chemicals used in the study include tetrathiafulvalene derivatives, phenol, and various reagents for synthesis such as CsOH·H2O, 4-(3-bromopropyl)phenol, NaOMe, and tetrabutylammonium chloride (TBACl). These chemicals served the purpose of constructing and modifying the receptor molecule, as well as studying its interactions with TNB guests through absorption and 1H NMR spectroscopy, which revealed the receptor's ability to switch conformations and control guest binding based on pH changes.