Redox Switchable Thianthrene Cavitands

• Main Authors: Bertani, Federico (Author), Dalcanale, Enrico (Author), Ong, Wen Jie (Contributor), Swager, Timothy M (Contributor)
• Other Authors: Massachusetts Institute of Technology. Department of Chemistry (Contributor)
• Format: Article
• Language: English
• Published: Thieme Publishing Group, 2018-04-13T18:35:34Z.
• Subjects: Article
• Online Access: Get fulltext

A redox activated vase-to-kite conformational change is reported for a new resorcinarene-based cavitand appended with four quinoxaline-fused thianthrene units. In its neutral state, the thianthrene-containing cavitand was shown by 1H NMR to adopt a closed vase conformation. Upon oxidation the electrostatic repulsion among the thianthrene radical cations promotes a kite conformation in the thianthrene-containing cavitand. The addition of acid produced a shoulder feature below 300 nm in the cavitand's UV-Vis spectrum that we have assigned to the vase-to-kite conformation change. UV-Vis spectroelectrochemical studies of the cavitand revealed a development of a similar shoulder peak consistent with the oxidation-induced vase-to-kite conformation change. To support that the shoulder peak is diagnostic for a vase-to-kite conformation change, a model molecule constituting a single quinoxaline wall of the cavitand was synthesized and studied. As expected UV-Vis spectroelectrochemical studies of the cavitand arm did not display a shoulder peak below 300 nm. The oxidation-induced vase-to-kite conformation is further confirmed by the distinctive upfield shift in 1H chemical shift of the methine signal. Key words: redox active, thianthrene, resorcinarene cavitands, electrochemical switching, conformation change
National Science Foundation (U.S.). Center for Energy Efficient Electronics Science (Award ECCS0939514)
Singapore. Agency for Science, Technology and Research (Graduate Scholarship)