Control of cycloreversion quantum yields of diarylethenes by introduction of substituants at the reactive carbons

Article abstract of DOI:10.1080/15421400590947072

Several diarylethene derivatives having various substituents at the reactive carbons were prepared and the quantum yields were measured. Although the cyclization quantum yields were scarcely affected by the introduction of substituents, the cycloreversion quantum yields varied depending on the substituents.

Full text of DOI:10.1080/15421400590947072

This article was downloaded by: [University of Arizona]
On: 05 May 2013, At: 12:54
Publisher: Taylor & Francis
Informa Ltd Registered in England and Wales Registered Number: 1072954
Registered office: Mortimer House, 37-41 Mortimer Street, London W1T 3JH,
UK
Molecular Crystals and Liquid
Crystals
Publication details, including instructions for
authors and subscription information:
http://www.tandfonline.com/loi/gmcl20
Control of Cycloreversion
Quantum Yields of
Diarylethenes by Introduction
of Substituents at the Reactive
Carbons
Kentaro Morimitsu a , Seiya Kobatake a & Masahiro
Irie a
a Department of Chemistry and Biochemistry,
Graduate School of Engineering, Kyushu University,
Higashi-ku, Fukuoka, Japan
Published online: 31 Aug 2006.
To cite this article: Kentaro Morimitsu , Seiya Kobatake & Masahiro Irie (2005):
Control of Cycloreversion Quantum Yields of Diarylethenes by Introduction of
Substituents at the Reactive Carbons, Molecular Crystals and Liquid Crystals, 431:1,
451-454
To link to this article: http://dx.doi.org/10.1080/15421400590947072
PLEASE SCROLL DOWN FOR ARTICLE
Full terms and conditions of use: http://www.tandfonline.com/page/terms-
and-conditions
This article may be used for research, teaching, and private study purposes.
Any substantial or systematic reproduction, redistribution, reselling, loan,
sub-licensing, systematic supply, or distribution in any form to anyone is
expressly forbidden.

The publisher does not give any warranty express or implied or make any
representation that the contents will be complete or accurate or up to
date. The accuracy of any instructions, formulae, and drug doses should be
independently verified with primary sources. The publisher shall not be liable
for any loss, actions, claims, proceedings, demand, or costs or damages
whatsoever or howsoever caused arising directly or indirectly in connection
with or arising out of the use of this material.

Mol. Cryst. Liq. Cryst., Vol. 431, pp. 151=[451]–154=[454], 2005
Copyright # Taylor & Francis Inc.
ISSN: 1542-1406 print=1563-5287 online
DOI: 10.1080/15421400590947072
Control of Cycloreversion Quantum Yields of
Diarylethenes by Introduction of Substituents at the
Reactive Carbons
Kentaro Morimitsu
Seiya Kobatake
Masahiro Irie
Department of Chemistry and Biochemistry, Graduate School of
Engineering, Kyushu University, Higashi-ku, Fukuoka, Japan
Several diarylethene derivatives having various substituents at the reactive car-
bons were prepared and the quantum yields were measured. Although the cycliza-
tion quantum yields were scarcely affected by the introduction of substituents, the
cycloreversion quantum yields varied depending on the substituents.
Keywords: diarylethene; photochromism; quantum yield; substituent effect
INTRODUCTION
Photochromic compounds undergo reversible isomerization between two
isomers having different absorption spectra upon irradiation with appro-
priate wavelength of light [1]. Among these photochromic compounds,
diarylethenes have attracted much attention because they undergo ther-
mally irreversible and fatigue-resistant photochromic reactions. Various
diarylethene derivatives have been synthesized so far in an attempt to
apply them to optoelectronic devices such as memories and switches [2].
Control of quantum yields is one of the most fundamental issues of
molecular design. In order to control the cycloreversion quantum
yields of diarylethenes we took a novel strategy to introduce various
The present work was partly supported by Grant-in-Aids for Scientific Research (S)
(No. 15105006), Scientific Research on Priority Areas (No. 15033252 and 12131211).
K. M. thanks to Research Fellowships of the Japan Society for the Promotion of Science
for Young Scientists.
Address correspondence to Masahiro Irie, Department of Chemistry and Biochemis-
try, Graduate School of Engineering, Kyushu University, Hakozaki 6-10-1, Higashi-ku,
Fukuoka 812-8581, Japan. E-mail: irie@cstf.kyushu-u.ac.jp
151=[451]

152=[452]
K. Morimitsu et al.
SCHEME 1 Chemical structure and photochromism of diarylethene
derivatives.
substituents at the reactive carbons [3]. Herein we report on photo-
chromic properties of several diarylethene derivatives having various
substituents at the reactive carbons as shown in Scheme 1.
RESULTS AND DISCUSSION
Photochromic Reaction
The synthesis of diarylethene derivatives was carried out according to
the general synthetic procedure [4]. Each diarylethene underwent
photochromism upon irradiation with appropriate wavelength of light
in hexane. Colorless solutions of the diarylethene derivatives turned
blue, purple, red, and orange, depending on the substituents at the

Control of Cycloreversion Quantum Yields of Diarylethenes
153=[453]
TABLE 1 Absorption Maxima of Closed-ring Isomers and
Quantum Yields in Hexane
max=nma
Ua!b
Ub!a
b
c
k
1
2
3
4
5
6
7
8
9
625
545
575
575
625
580
575
547
496
520
520
517
0.44
0.42
0.17
0.41
0.25
0.50
0.59
0.34
0.28
0.13
0.21
0.35
1.7 ꢁ 10ꢀ5
0.41
0.32
0.27
0.23
0.0062
0.013
0.030
0.59
0.55
0.58
10
11
12
0.35
aAbsorption maxima of the closed-ring isomers in the visible region.
bCyclization quantum yield.
cCycloreversion quantum yield.
reactive carbons. The absorption maxima of close-ring isomers are
summarized in Table 1.
Quantum Yield
The cyclization and cycloreversion quantum yields in hexane at room
temperature are shown in Table 1. The cyclization quantum yields are
close to the values of methyl derivatives 7a and 12a, and scarcely
affected by modification of substituents at the reactive carbons. Con-
versely, the cycloreversion quantum yields varied depending on the
substituents. Methoxy groups extremely suppressed the cyclorever-
sion reactivity to less than 10ꢀ4. However, cyano and p-conjugated
groups enhanced the reactivity. The substituent effect was inde-
pendent of the aryl groups, and similar tendency was observed for ben-
zothiophene derivatives. The cycloreversion quantum yields of 2b and
9b were obtained to be 0.41 and 0.59 which are 30 and 1.7 times larger
than those of 7b and 12b, respectively. We can control the cyclorever-
sion reactivity of the diarylethenes as much as 24000 times.
REFERENCES
[1] (a) Brown, G. H. (1971). Photochromism, Wiley-Interscience: New York.
(b) Du¨rr, H. & Bouas-Laurent, H. (1990). Photochromism: Molecules and Systems,
Elsevier: Amsterdam.
[2] (a) Irie, M. (2000). Chem. Rev., 100, 1685.

154=[454]
K. Morimitsu et al.
(b) Irie, M. & Uchida, K. (1998). Bull. Chem. Soc. Jpn., 71, 985.
[3] (a) Shibata, K., Kobatake, S., & Irie, M. (2001). Chem. Lett., 618.
(b) Morimitsu, K., Shibata, K., Kobatake, S., & Irie, M. (2002). J. Org. Chem., 67,
4574.
(c) Morimitsu, K., Shibata, K., Kobatake, S., & Irie, M. (2002). Chem. Lett., 572.
(d) Morimitsu, K., Kobatake, S., Nakamura, S., & Irie, M. (2003). Chem. Lett., 32,
858.
(e) Morimitsu, K., Kobatake, S., & Irie, M. (2004). Tetrahedron Lett., 45, 1155.
[4] (a) Irie, M., Lifka, T., Kobatake, S., & Kato, N. (2000). J. Am. Chem. Soc., 122, 4871.
(b) Irie, M., Sakemura, K., Okinaka, M., & Uchida, K. (1995). J. Org. Chem., 60,
8305.