Photoswitching of Dextro/Levo Rotation with Axially Chiral Binaphthyls Linked to an Azobenzene
journal contributionposted on 07.08.2009 by Kazuto Takaishi, Masuki Kawamoto, Kazunori Tsubaki, Tatsuo Wada
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To examine the reversible photoisomerization and subsequent change of asymmetric field, we synthesized optically active 3,3′-disubstituted-1,1′-binaphthyls with an azobenzene moiety. Reflecting the structural change, the specific rotation and circular dichroism underwent significant variations. Under certain conditions, the positive−negative signals were reversible. Furthermore, the magnitude of these changes showed a 3,3′-substituent dependency. Dibenzyloxy or bis(diphenylmethyloxy) derivatives were better suited for sign interconversion of the optical properties. In contrast, the hydroxy group(s) lacked both optical signals and durability.