Switching of Chirality by Light

Abstract

Optically active photoresponsive molecules are described by which control of chirality is achieved by light. These chiroptical molecular switches are based on inherently dissymmetric overcrowded alkenes and the synthesis, resolution and dynamic stereochemical properties are discussed. Introduction of nitro-acceptor and dimethylamine-donor substituents in a naphto [2,1-b]thiopyran-1’-ylidene-9H-thioxanthene helical shaped alkene resulted in a highly diastereoselective modulation of photostationary states with 70%-M or 90%-P helicity, respectively. The chiroptical switches offer attractive prospects as control elements for (supra)molecular functions and organization. This is demonstrated in dual mode photoswitching of luminescence and photoswitching between liquid crystalline phases.