Chirality Induction on a Coordination Capsule for Circularly Polarized Luminescence

Angew Chem Int Ed Engl. 2022 Sep 26;61(39):e202209340. doi: 10.1002/anie.202209340. Epub 2022 Aug 18.

Abstract

By utilizing a confined space inside a coordination capsule consisting of achiral components, we achieve trimeric structures composed of acetic acid and 2,3-disubstituted tartaric acid derivatives. Steric and electronic interactions between the substituents on the tartaric acid and 2,2'-bipyridyl arms of the capsule permit the transfer of the chirality of the tartaric acid to the capsule, resulting in diastereoenrichment of the host-guest complexes of up to 92 % de. The chiral templates can be washed away with diethyl ether, leaving an enantiomerically enriched capsule. The resulting capsule biases the dynamic axial chirality of a 4,4'-diacetoxybiphenyl guest carrying benzothiadiazole units, demonstrating guest-to-capsule and capsule-to-guest chirality transfer. The induced chirality on the bound guest enables it to emit circularly polarized luminescence in the NIR region, demonstrating the application of induced chirality for confined spaces for the generation of chiroptical properties.

Keywords: Capsule; Chirality; Host-Guest; Molecular Recognition; Supramolecular Chemistry.