Chemical control of the photochromic reactivity of diarylethene derivatives

Article abstract of DOI:10.1039/b506801k

Photochemically inactive diarylethene derivatives having a N-(O-hydroxyphenyl) group underwent photochromic reaction when they were esterified by the addition of acetic anhydride. The Royal Society of Chemistry 2005.

Full text of DOI:10.1039/b506801k

View Article Online / Journal Homepage / Table of Contents for this issue
COMMUNICATION
www.rsc.org/chemcomm | ChemComm
Chemical control of the photochromic reactivity of diarylethene
derivatives{
Masato Ohsumi, Tuyoshi Fukaminato and Masahiro Irie*
Received (in Cambridge, UK) 13th May 2005, Accepted 7th June 2005
First published as an Advance Article on the web 8th July 2005
DOI: 10.1039/b506801k
Photochemically inactive diarylethene derivatives having a
N-(O-hydroxyphenyl) group underwent photochromic reaction
when they were esterified by the addition of acetic anhydride.
Although photochromic performance of a certain type of
compounds has been remarkably improved,1–4 several problems
still remain for practical applications. A property that is strongly
desired but is still inadequate is gated photochromic reactivity.
Gated reactivity is the property whereby irradiation with any given
wavelength of light alone causes no color change, while a color
change is induced when another external stimulus, such as
additional photons of different wavelength,5,6 chemicals,7–10 or
heat,11 is present. Such threshold reactivity is indispensable for
application to display and memory technologies.
Several attempts to provide gated photochromic reactivity have
been reported.5–12 One of the chemical approaches is to use
protons to control the photochromic reactivity. The ring-opening
quantum yield of an indole fulgide derivative with a dimethyl-
amino substituent at the 5-position of the indole ring was found to
change by the addition of acid.7 Another approach is to use
intramolecular hydrogen bonds. When a diarylethene molecule is
interlocked by the hydrogen bonds, the molecule is photochemi-
cally inactive, while the molecule undergoes a photochromic
reaction when the bonds are unclasped by the addition of
hydrogen bond breaking agents, such as ethanol.10
Scheme 1
The absorption spectrum of 1a in cyclohexane solution at room
temperature is shown in Fig. 1a. 1a does not exhibit any
photochromic reaction in cyclohexane upon irradiation with
405 nm light, indicating that the photochromic reactivity is
strongly suppressed by the intramolecular proton transfer. The
formation of the intramolecular hydrogen bonding in the ground
state between the hydrogen atom in the phenol group and the
oxygen atom in the imide carbonyl group was confirmed by
1H NMR measurements as well as by molecular geometry
calculations (see ESI{). The hydrogen bonding induces quenching
of the excited state due to proton transfer.
We herein report on the design and synthesis of chemically
gated diarylethene derivatives having a N-(O-hydroxyphenyl)
group (Scheme 1). The excited states of the molecule are efficiently
quenched by the intramolecular proton transfer.13,14 Therefore,
they are not photochromic. On the other hand, when the hydroxyl
group is protected by esterification, the esterified diarylethenes are
expected to undergo typical photochromic reactions.
When acetic anhydride was added during irradiation with
405 nm light, the pale yellow color solution turned to pale red and
the color intensity increased with time (Fig. 1a; inset). The color
change is considered to be due to the esterification of the hydroxyl
group of 1a. In order to confirm the esterification, the colored
product was isolated by silica gel column chromatography and
1a was prepared from 2,3-bis(2,4,5-trimethyl-3-thienyl)maleic
anhydride15 by a conventional thermal imidization with o-amino-
phenol in toluene. The structure was identified by 1H NMR, mass
spectroscopy, and elemental analysis{ (synthetic procedures and
analysis data for 1 are described in the Electronic Supplementary
Information{). For all measurements, non-polar cyclohexane was
used as the solvent because the photocyclization reactions of the
diarylethene derivatives are suppressed in polar solvents due to the
contribution of twisted intramolecular charge transfer.16
1
HPLC. The colored product was identified as 2b by H NMR,
mass spectroscopy, and elemental analysis.{ 2b converted to 2a
upon irradiation with visible (l . 550 nm) light (synthetic
procedures and analysis data for 2 are described in the ESI{).
As expected, 2a exhibits a typical photochromic response in
cyclohexane solution. Fig. 1b shows the absorption spectral
changes of 2 in cyclohexane solution at room temperature. 2a
has a broad absorption band around 400 nm and the solution
color is pale yellow. Upon irradiation with 405 nm light, the pale
yellow color solution of 2a turns red (Fig. 1b; inset), and
absorption maxima were observed at 524 nm, and 375 nm. The
Department of Chemistry and Biochemistry, Graduate School of
Engineering, Kyushu University, Hakozaki 6-10-1, Higashi-ku, Fukuoka
812-8581, Japan. E-mail: irie@cstf.kyushu-u.ac.jp;
Fax: +81-92-642-3568; Tel: +81-92-642-3556
{ Electronic supplementary information (ESI) available: synthetic proce-
dures and analytical data. See http://dx.doi.org/10.1039/b506801k
This journal is ß The Royal Society of Chemistry 2005
Chem. Commun., 2005, 3921–3923 | 3921

View Article Online
the photochromic reactivity. The esterification and hydrolysis
reactions can be induced even in polymer matrices.14 It is worth
noting that the red color of 2b disappeared upon irradiation visible
light (.550 nm) even in the presence of hydrochloric acid. This
means that the intramolecular proton transfer does not suppress
the cycloreversion reaction.
Similar experiments were performed for 3 and 4 (synthetic
procedures and analysis data of compounds 3 and 4 are described
in ESI{). 3a did not exhibit any photochromic reaction on
photoirradiation. On the other hand, typical photochromic
behavior was observed for 4a. The optical and photochromic
properties for 3 and 4 are also summarized in Table 1.
In summary, we have demonstrated that the photochromic
reaction of diarylethene derivatives can be controlled by the
addition of acid. Such chemically gated systems can be applied to
display materials, memory media, as well as molecular logic gates.
This work was partly supported by Grant-In-Aid for
Fundamental Research Program (S) (No. 15105006) and also by
Grant-In-Aid for The 21st Century COE Program, ‘‘Functional
Innovation of Molecular Informatics’’ from the Ministry of
Education, Culture, Science, Sports and Technology of Japan.
Fig. 1 (a) Absorption spectral changes of 1 in cyclohexane solution;
(——) open-ring isomer (1a), (???????) after adding acetic anhydride, and
(- - -) after irradiating a solution of 1 containing acetic anhydride with
405 nm light. Inset: Photograph of the color change of 1 upon irradiation
with 405 nm light in the presence of acetic anhydride. (b) Absorption
spectral changes of 2 in cyclohexane solution; (- - -) open-ring isomer,
(???????) photostationary state under irradiation with 405 nm light, and
(——) closed-ring isomer. Inset: Photograph of the color change of 2
caused by photoirradiation.
Notes and references
1
{ Analytical Data for 1a: mp 224–225 uC; H NMR (400 MHz, CDCl3):
d 5 1.76 (s, 3H), 1.92 (s, 3H), 1.94 (s, 3H), 2.08 (s, 3H), 2.27 (s, 3H), 2.29 (s,
3H), 6.09 (s, 1H), 7.05–7.38 (m, 4H); HRMS (FAB+): m/z 5 437.1111 [M]+
(calcd. for C24H23NO3S2: 437.1119); Anal. calcd. for C24H23NO3S2: C,
65.88; H, 5.30; N, 3.20. Found: C, 66.08; H, 5.31; N, 3.15.
Analytical Data for 1b: 1H NMR (400 MHz, CDCl3): d 5 2.04 (s, 6H),
2.16 (s, 6H), 2.28 (s, 6H), 6.49 (s, 1H), 7.00–7.15 (m, 2H), 7.26–7.35 (m,
2H); HRMS (FAB+): m/z 5 437.1121 [M]+ (calcd. for C24H23NO3S2:
437.1119); Anal. calcd. for C24H23NO3S2: C, 65.88; H, 5.30; N, 3.20.
Found: C, 65.97; H, 5.33; N, 3.18.
color disappeared on irradiation with visible light (l . 550 nm)
and the absorption spectrum returned to that of 2a. The colored
product 2b was isolated with HPLC and the absorption spectrum
is shown in Fig. 1b. In the photostationary state in cyclohexane
under irradiation with 405 nm light, 75% of 2a converted to 2b.
1
Analytical Data for 2a: mp 156–157 uC; H NMR (400 MHz, CDCl3):
d 5 1.79 (s, 3H), 1.95 (s, 3H), 1.97 (s, 3H), 2.11 (s, 3H), 2.19 (s, 3H), 2.25 (s,
3H), 2.28 (s, 3H), 7.31–7.54 (m, 4H); HRMS (FAB+): m/z 5 479.1228 [M]+
(calcd. for C26H25NO4S2: 479.1225); Anal. calcd. for C26H25NO4S2: C,
65.11; H, 5.25; N, 2.92. Found: C, 65.07; H, 5.31; N, 2.96.
The quantum yield yields of the cyclization (WaAb
) and
cycloreversion (WbAa) reactions of 2 in cyclohexane were measured
by the standard procedure using furylfulgide as a reference.17 The
results are summarized in Table 1.
1
Analytical Data for 3a: mp 143–145 uC; H NMR (400 MHz, CDCl3):
d 5 1.99 (s, 3H), 2.11 (s, 3H), 2.13 (s, 3H), 2.25 (s, 3H), 5.59 (s, 1H), 7.11–
7.49 (m, 14H); HRMS (FAB+): m/z 5 561.1422 [M]+ (calcd. for
C34H27NO3S2: 561.1432); Anal. calcd. for C34H27NO3S2: C, 72.70; H,
4.84; N, 2.49. Found: C, 72.12; H, 4.91; N, 2.52.
2a returned to the photo-inactive state upon addition of
hydrochloric acid, indicating that 2a is hydrolyzed by the addition
of the acid. The esterification–hydrolysis processes can be repeated
many times. It is concluded that the photochromic reaction is
efficiently suppressed by the intramolecular proton transfer and
the protection of a hydroxyl group with an ester group provides
1
Analytical Data for 4a: mp 124–125 uC; H NMR (400 MHz, CDCl3):
d 5 1.99 (s, 3H), 2.11 (s, 3H), 2.12 (s, 3H), 2.21 (s, 3H), 2.25 (s, 3H), 7.33–
7.52 (m, 14H); HRMS (FAB+): m/z 5 603.1527 [M]+ (calcd. for
C36H29NO4S2: 603.1538); Anal. calcd. for C36H29NO4S2: C, 71.62; H,
4.84; N, 2.32. Found: C, 71.57; H, 5.14; N, 2.21.
Analytical Data for N-(3-hydroxyphenyl)-2,3-bis(2,4,5-trimethyl-3-thie-
nyl)maleimide (reference molecule): mp 109–110 uC; 1H NMR (400 MHz,
CDCl3): d 5 1.78 (s, 3H), 1.94 (s, 3H), 1.95 (s, 3H), 2.10 (s, 3H), 2.26
(s, 3H), 2.28 (s, 3H), 4.89 (s, 1H), 6.84 (dd, 1H, J 5 8.4 Hz, 2.4 Hz), 7.01–
7.02 (m, 1H), 7.09 (d, 1H, J 5 8 Hz), 7.35 (t, 1H, J 5 8 Hz); HRMS
(FAB+): m/z 5 437.1113 [M]+ (calcd. for C24H23NO3S2: 437.1119); Anal.
calcd. for C24H23NO3S2: C, 65.88; H, 5.30; N, 3.20. Found: C, 65.98; H,
5.32; N, 3.18.
Table 1 Absorption maxima and absorption coefficients of the open-
and closed-ring isomers of diarylethenes, and the photochromic
quantum yields in cyclohexane
l
max/nm
l
max/nm
(e/M21cm21
1a 324 (5700)
2a 306 (5200)
3a 408 (3500)
4a 395 (3800)
a
)
WaAb
(e/M21cm21
) WbAa
a
b
0
1b 385 (40000) 0.11 (533 nm)
533 (5800)
0.22 (405 nm) 2b 375 (30000) 0.18 (524 nm)
524 (4900)
3b 400 (36000) 0.044 (563 nm)
563 (8700)
0.30 (430 nm) 4b 391 (31000) 0.056 (557 nm)
557 (8800)
1 G. H. Brown, Photochromism, Wiley-Interscience, New York, 1971;
H. Du¨rr and H. Bouas-Laurent, Photochromism: Molecules and
Systems, Elsevier, Amsterdam, 1990; H. Bouas-Laurent and H. Du¨rr,
Pure Appl. Chem., 2001, 73, 639.
2 K. Uchida and M. Irie, Bull. Chem. Soc. Jpn., 1998, 71, 985; M. Irie,
Chem. Rev., 2000, 100, 1685; H. Tian and S. Yang, Chem. Soc. Rev.,
2004, 33, 85.
3 H. Hanazawa, R. Sumiya, Y. Horikawa and M. Irie, J. Chem. Soc.,
Chem. Commun., 1992, 206; M. Irie, T. Lifka, S. Kobatake and N. Kato,
J. Am. Chem. Soc., 2000, 122, 4871.
0
b
Photocyclization quantum yield. Photocycloreversion quantum
yield.
3922 | Chem. Commun., 2005, 3921–3923
This journal is ß The Royal Society of Chemistry 2005

View Article Online
4 M. Irie, S. Kobatake and M. Horichi, Science, 2001, 291, 1769; M. Irie,
T. Fukaminato, T. Sasaki, N. Tamai and T. Kawai, Nature, 2002, 420,
10 M. Irie, O. Miyatake, K. Uchida and T. Eriguchi, J. Am. Chem. Soc.,
1994, 116, 9894.
´
759; D. Dulic, S. J. van der Molen, T. Kudernac, H. T. Jonkman,
11 M. Irie, T. Eriguchi, T. Takata and K. Uchida, Tetrahedron, 1997, 53,
12263.
12 I. Willner, A. Doron and E. Katz, J. Phys. Org. Chem., 1998, 11,
546.
13 W. Klo¨pffer, Adv. Photochem., 1977, 10, 311.
14 N. C. Yang, H. W. Choi, J. K. Lee, J. Il Hwang and D. H. Shu, Chem.
Lett., 2002, 824.
15 M. Irie and M. Mohri, J. Org. Chem., 1988, 53, 803.
16 M. Irie and K. Sayo, J. Phys. Chem., 1992, 96, 7671; T. Yamaguchi,
K. Uchida and M. Irie, J. Am. Chem. Soc., 1997, 119, 6066.
17 Y. Yokoyama and Y. Kurita, J. Synth. Org. Chem. Jpn., 1991, 49, 364;
H. G. Heller and J. R. Langan, J. Chem. Soc., Perkin Trans. 2, 1981,
341.
J. J. D. de Jong, T. N. Bowden, J. van Esch, B. L. Feringa and B. J. van
Wees, Phys. Rev. Lett., 2003, 91, 207402; K. Matsuda and M. Irie,
J. Photochem. Photobiol. C, 2004, 5, 169; D. Sud, T. B. Norsten and
N. R. Branda, Angew. Chem., Int. Ed., 2005, 44, 1059.
5 M. Uchida and M. Irie, J. Am. Chem. Soc., 1993, 115, 6442.
6 M. Murakami, H. Miyasaka, T. Okada, S. Kobatake and M. Irie,
J. Am. Chem. Soc., 2004, 126, 14764.
7 F. Matsui, H. Taniguchi, Y. Yokoyama, K. Sugiyama and Y. Kurita,
Chem. Lett., 1994, 1869.
8 S. H. Kawai, S. L. Gilat and J.-M. Lehn, Eur. J. Org. Chem., 1999, 2359.
9 N. P. M. Huck and B. L. Feringa, J. Chem. Soc., Chem. Commun.,
1995, 1095.
This journal is ß The Royal Society of Chemistry 2005
Chem. Commun., 2005, 3921–3923 | 3923