1. Photoresponsive chiral dopant
nematic
liquid crystal
Photoresponsive chiral dopant
cholesteric +

2. Example of molecular devices by photoswitching
Introduction
Example of molecular devices by photoswitching
Photoswitching of the reflection color
Light-driven molecular machines UV
Vis. UV
Vis.
Y. Li, A. Urban, Q. Li, J. Am. Chem. Soc. 2012, 134, 9573.
R. Thomas, Y. Yoshida, T. Akasaka, N. Tamaoki, Chem. Eur. J., 2012, 18,

3. Control of helical sense and strength by binaphthyl
Introduction
Control of helical sense and strength by binaphthyl
Proni, G.;Spada, G. P.; Lustenberger, P.; Welti, R.; Diederich, F. J. Org. Chem.2000, 65, 5522−5527.

4. Conformation of binaphthyl derivatives
Introduction
Conformation of binaphthyl derivatives

5. Purpose
Change and control of twisting direction, degree of dihedral angle in the binaphthyl ring by photoswitching
Molecular design

6. Change of absorption and CD spectra
Result-Photocromism
Change of absorption and CD spectra
(R)-D1 in n-heptane
Substraction of the CD spectra
Absorption and CD spectra changes were observed.

7. Host LCs and Standard LC Left-handed screw sense
Experiment
Host LCs and Standard LC
Host LCs
Standard LC
(COC)
Left-handed screw sense
The chiral nematic LC induced by adding (R)-1 –(R)-5 and (S)-1 as a chiral dopnat to PCH or 5CB showed a finger-printed texture in the polarized optical microscope.

8. Reversible photswitching of helical inversion(1)
Result- helical inversion
Reversible photswitching of helical inversion(1)
Reversible photoswitching of helical inversion was observed along with the photoisomerization
→Dihedral angle of binaphthyl rings are controlled

9. Reversible photswitching of helical inversion(2)
Result- helical inversion
Reversible photswitching of helical inversion(2)
Helical inversion was obsreved only in the (R)-D1.

10. Helical Twisting Power of D1-D5 and the reversibility
Result- HTP and reversibility
Helical Twisting Power of D1-D5 and the reversibility
(Positive and negative signs represent a right-handed and a left-handed screw sense)
Change of Helical Twisting Power was observed along with photoisomerization.
→Strength of chiral nematic LC was controlled

11. Conclusion Conclusion
・The photoresponsive chiral diarylethene derivatives were synthesized and used as chiral
dopants to induce th chiral nematic LCs.
・The chiral nematic LCs that included (R)-D1 and (S)-D1 showed a reversible helical inversion in
the screw sense.
・ (R)-D1 and (S)-D1 are the first chiral dopnats to induce a helical inversion in a chiral nemtaic
LC via the photoisomerization between open and closed forms of the diarylethene moiety.