Masahiro Irie

Photochromism

- Fundamentals and Applications -

Department of Chemistry and Biochemistry Kyushu University, Fukuoka, Japan

Photon

Energy

Information

Photosynthesis

Photoresponsiveness

Vision

Phototaxis

Phototropism

Photochromism

A Bhν

hν’ Photoreceptor : Rhodopsin (Chlamydomonas)BacteriorhodopsinPhytochromeSodaliteMineral :

Natural

Artificial

Dyes : Spirobenzopyran, Azobenzene・・・

Matel-oxide GlassChalcogenide Glass

XX

Y Y

514 nm

366 nm

300 350 400 450 500 550 600

λ / nm

Abs

orba

nce

0.4

0.3

0.2

0.1

I I I I I I

II

II

N

H3C CH3

O NO2

RN

H3C CH3

NO2

OR

NNN

N

H3C

OO

CH3

CH3

O

OO

OCH3

OO

CH3

CH3H3C CH3H3C

SS

CH3

S

CH3

S

-+

CH3CH3

H3C

F2

F2F2F2F2

F2

OO

1867 M. Fritsche

hν, O2

∆

OCl

Cl

1899 W. Marckwald

ClCl

Cl

Cl

O

Cl

hν+ Cl

∆

(G. Scheibe et al. J. Phys. Chem. 66, 2449 (1962))

Brief History of Photochromism

N OMe

Me Me

N OMe

(J. Chem. Soc., 4522 (1952))

Me Me

1952 E. Fischer, Y. Hirsberg

hν

∆

Self-developing, Dry Photographic Systems

High-speed Printing Materials

Chemical Computer

Camouflage Fabrics

N C R (Spiropyran)R C A (Indigos)American Cyanamid (Spiropyrans, MetalDithizonates)

EG & G (Triarylmethane Leuco Derivatives)Fuji Film (Spiropyrans)

Lack of fatigue resistant characteristics

1970 ~ 1980 Dark Ages

(photo-degradation)

"Photochromism" G. Brown Ed.

N O

N

Me

Me Me

N O

N

Me

Me Me

O

O

Me

Me

MeMe

O

O

Me

OOMe

Fatigue Resistant Spironaphthoxazine

O

O

hν

Me

Thermally Irreversible Compounds

Me

Me Me

1980 ~ Present Renaissance

hν

hν'

∆

NN

N NAzobenzene

hν

hν', ∆

N

H3C CH3

O NO2R

N

H3C CH3

R

NO2

-O

Spirobenzopyran

+hν

hν', ∆

OO

Naphthopyran

hν

hν', ∆

Name Reaction

S S

O O

S

OS

OThioindigo

hν

hν', ∆

Anthracene Dimerhν

hν', ∆

NCCN

NO2

CN

CN

NO2

hν

hν', ∆

Dihydroazulene

Name Reaction

CH3

H3CS S H3C

CH3

S S

Diarylethene

hν'

hν

F2F2 F2

F2F2

F2

H3C

OO

CH3

CH3

O

O O

OCH3

OO

CH3

CH3H3C CH3 H3C

H3Chν'

Furyl Fulgide

hν

O

O O

R

O

O O

R

Naphthacene quinone

hν

hν'

S

O

S

CH3OH3CCH3

CH3

Stilbene Derivative

hν

hν'

Requirements for Photonics Devices

1. Thermal stability of both isomers

2. Fatigue resistant character: repeatable cycle number > 104

3. High sensitivity:quantum yield > 0.5

4. Rapid response

5. Reactivity in the solid state

A Bhν

hν’

A New Class of Photochromic CompoundsThermally Irreversible and Fatigue Resistant

Diarylethenes

R1R2

YR3 R6X R4

R5

R1R2

YR3 R6X R4

R5HH HH

H

H

,

,,:

,,:

,

O O O OO N

CH2CN

SR1

R2

YR3 R3X R1

R2

Me

Me

Me MeS N Me

Me

S OEt NMe

Me

MeO

Me

Me

NC S

F2F2

F2

,

・Both isomers are thermally stable

long term stability :

short term stability : 150 °C

・Low fatigue

repeatable cycle number ： 105

・High sensitivityquantum yield ： 0.1 -1.0

・Rapid response< 10-11 sec

・Reactivity in the crystalline phase

・Sensitivity at visible region

forward reaction ： 488 nmbackward reaction ： 780 nm

470,000 years at 30 °C

R2 R5

R3 R6

X Y

R1

R4

hν

hν' R4

R1

YXR6R3

R5R2

Molecular Design of Diarylethenes

Thermal Stability

Fatigue Resistant Character

Response Time

Molecular Orbital Calculation

• Thermal reaction - - - disrotatory mode

A B C D A

B C

D

• Photochemical reaction - - - conrotatory mode

A B C D

A

B

C

D

Conrotatory Mode - - - Photochemical Reaction Process

OO

O O

A ( 50,46 )A ( 48,48 )B ( 49,47 )B ( 43,41 )

A ( 42,42 )

A ( 12,42 )

A ( 12,42 )

B ( 43,41 )

A ( 44,40 )

A ( 48,48 )A ( 50,46 )

B ( 49,47 )

A ( 50,46 )

A ( 48,48 )

A ( 42,42 )

Molecular Design PrincipleThermal Irreversibility

“ When the compound has aryl groups with low aromatic stabilization energy, both isomers of the diarylethene are thermally stable.”

Stable Unstable

OOS S N N

>>> >

φs = 0.001 (φB→A = 1)

A B1 - φsφs

φB→AP

After 103 cyclesAfter 103 cycles

[A] ～ 0.37 [A]0

φs = 0.0001 (φB→A = 1)

After 104 cycles

[A] ～ 0.37 [A]0

S

CH3

H3C S

S

CH3

H3C S

H3C CH3

H3C CH3S

CH3

H3C S

S

CH3

H3C S

> 100,000 > 10,000 ~ 2,000

~ 200 ~ 80

Crystalline Systems

F2

F2

F2

F2

F2

F2

F2 F2

F2 F2

F2 F2

Molecular Design PrincipleFatigue Resistant Character

UV

Vis.

Dichroism

SSH3C

CH3

CH3S

CH3

CH3 SH3C CH3 CH3

F2F2F2

F2F2F2

J. Am. Chem. Soc. 121, 2380 (1999)

SS

CH3

CH3S

CH3

CH3 SO2N NO2 O2N NO2

F2

F2

F2F2

F2F2

J. Am. Chem. Soc. 121, 8450 (1999)

F2F2 F2

SS EtEt

2a

F2F2 F2

SS MeMeF

F

FF

F FF

F

FF

1a

F2F2 F2

SS EtEt

2b

F2F2 F2

SS Me

MeFF

FF

F FF

F

FF

1b

UV

Vis.

UV

Vis.

Photochem. Photobio. Sci. ２,1088 (2003)Chem. Rec. 4, 23 (2004)

Nano-layered Structure

SSH3C

CH3

CH3S

CH3

CH3SH3C CH3 CH3

F2

F2F2

F2F2

F2

X-ray Crystallographic Analysis

1a 1b

J. Am. Chem. Soc. 122, 1589 (2000)

Bull. Chem. Soc. Jpn. 73, 2179 (2000)

4.0 4.5 5.0 5.53.53.02.5Distance between the reacting carbon atoms / A

Φ

0

0.2

0.4

0.6

0.8

1.0

S SR

R

F2F2

F2

Me or H H or Me

R' R'

S SMe

Me

F2F2

F2

R R

S SMe

Me

F2F2

F2

R1 R1

R2R2

Chem. Commun. 2804 (2002)J. Phys. Chem. A. 106, 209 (2002)

SS

CH3

H3CS

CH3

H3C S

F2

F2 F2F2F2

F2

H3C CH3 H3C CH3

Surface Morphology Changes of Single Crystal 1

Science, 291, 1769 (2001)

UV

Vis.

(100)

R6XR3

XR4

R1R2 R5

(R,R) (S,S)

R3X R6

XR1

R4R5R2hν

hν', ∆

+R6

XR3X R4

R1R2 R5

Absolute Asymmetric Photosynthesis

Ang. Chem. 42, 1636 (2003)

Tetrahedron Lett. 42, 7291 (2001)

J. Am. Chem. Soc. 122, 9631 (2000)