Mechanically‐Driven Vase–Kite Conformational Switch in Cavitand Cross‐Linked Polyurethanes
Martina Torelli, Francesca Terenziani, Alessandro Pedrini, Francesca Guagnini, Ilaria Domenichelli, Chiara Massera, Enrico Dalcanale
Abstract
Abstract The eligibility of tetraquinoxaline cavitands (QxCav) as molecular grippers relies on their unique conformational mobility between a closed ( vase ) and an open ( kite ) form, triggered in solution by conventional stimuli like pH, temperature and ion concentration. In the present paper, the mechanochemical conformational switching of ad hoc functionalized QxCav covalently embedded in an elastomeric polydimethylsiloxane and in a more rigid polyurethane matrix is investigated. The rigid polymer matrix is more effective in converting mechanical force into a conformational switch at the molecular level, provided that all four quinoxaline wings are covalently connected to the polymer.