Photocaged Competitor Guests: A General Approach Toward Light-Activated Cargo Release From Cucurbiturils

5 years ago

Photocaged Competitor Guests: A General Approach Toward Light-Activated Cargo Release From Cucurbiturils

José A. González-Delgado, Nuno Basílio, Miguel A. Romero, Artur J. Moro, Jesús F. Arteaga, Mara Domingues, Uwe Pischel

A general approach toward the light-induced guest release from cucurbit[7]uril by means of a photoactivatable competitor was devised. An o-nitrobenzyl-caged competitor is photolyzed to generate a competitive guest that can displace cargo from the host macrocycle solely based on considerations of chemical equilibrium. With this method the release of terpene guests from inclusion complexes with cucurbit[7]uril was demonstrated. The binding of the herein investigated terpenes, all being lead fragrant components in essential oils, has been characterized for the first time. They feature binding constants of up to 108 L mol−1 and a high differential binding selectivity (spanning four orders of magnitude for the binding constants for the particular set of terpenes). By fine-tuning the photoactivatable competitor guest, selective and also sequential release of the terpenes was achieved. The competition is on: The phototriggered generation of competitor guests from o-nitrobenzyl-caged precursors can be used to displace functional guests from the cucurbit[7]uril cavity. This general approach was harnessed for the light-triggered release of terpene fragrances from a supramolecule in a selective and also sequential manner.

Publisher URL: http://onlinelibrary.wiley.com/resolve/doi

DOI: 10.1002/chem.201702185