Photo-responsive chiral cyclic molecular switches based on stiff stilbene

Two novel photo-responsive chiral cyclic molecular switches constituted of stiff stilbene and binaphthyl moieties connected through alkyl chains of different length were fabricated. The cyclization synthetic strategy employed herein made it convenient to obtain the pure Z isomers rather than Z/E isomer mixtures. The detailed photo-switching behaviors of target compounds were studied by the UV-Vis absorption and circular dichroism spectra in dichloromethane. The twist angles of the binaphthyl of the switches were able to be reversibly modulated by Z/E isomerization of stiff stilbene unit under alternative UV light stimuli and influenced by the length of alkyl chain to some extent. (c) 2015 Elsevier Ltd. All rights reserved.