How is helical inversion? introduction How is helical inversion? H.Hayasaka, et al. J. Am. Chem. Soc. 2012, 134, 3758−3765

Structures which induce helical inversion introduction Structures which induce helical inversion Type1:Intrinsic chirality Type2:dinamic conformation change R. Elelkema, et al. J. Am. Chem. Soc. 2006, 128, 14397-14407 H.Hayasaka, et al. J. Am. Chem. Soc. 2012, 134, 3758−3765

purpose Design strategy based on the chiral conflict and equilibrium shifting between multiple chiral moieties in a singl molecule and control helical inversion Molecular design

Absorbance and CD spectra of (S,R,S)-1a Result - photoisomerzaion Absorbance and CD spectra of (S,R,S)-1a 10μm in hexane Absorption and CD spectra changes were observed.

Measurement of cholesteric liquid crystal handedness Result – helical inversion Measurement of cholesteric liquid crystal handedness Reversible photoswitching of helical inversion was observed along with the photoisomerization

Helical inversion and measurement of HTP Result – HTP Helical inversion and measurement of HTP (Positive and negative signs represent a right-handed and a left-handed screw sense)

Mechanism of helical inversion Discussion Mechanism of helical inversion

Conclusions Conclusion ・ A series of azoarene compounds containing axially chiral moieties with different chiral configureation was synthesized. ・ The chiral confict and equilibrium shifting between opposite chiral configuration in these compounds was used to promote the handedness inversion. ・ Handedness was found in different LC hosts and the HTPs for both stated were moderate to high.