3,3,4,4,5,5-hexafluoro-1,2-bis(5-hydroxymethyl-2-methyl-3-thienyl) -cyclopent-1-ene

Article abstract of DOI:10.1107/S0108270104005815

The title compound, C₁₇H₁₄F₆O ₂S₂, a photochromic diarylethene, is one of the most promising materials for optical memories and other optoelectronic devices. The hexafluoro-cyclopentene group and the two thiophene rings are all planar, and the dihedral angles between the cyclopentene ring and the adjacent thiophene rings are 46.4 (1) and 49.5 (1)°.

Full text of DOI:10.1107/S0108270104005815

organic compounds
Acta Crystallographica Section C
Crystal Structure
Communications
parameters are given in Table 1. In the hexa¯uorocyclo-
pentene ring, the C1ÐC2 bond is clearly a double bond, being
signi®cantly shorter than the C1ÐC5 and C2ÐC3 single
bonds. The distance between the reactive C atoms C6 and C12
ISSN 0108-2701
Ê
is 3.596 (4) A; this distance is short enough theoretically for
the reaction to take place in the crystalline phase (Rama-
murthy & Venkatesan, 1987). The dihedral angles between the
hexa¯uorocyclopentene ring and the adjacent thiophene rings
3
,3,4,4,5,5-Hexafluoro-1,2-bis(5-
hydroxymethyl-2-methyl-3-thienyl)-
cyclopent-1-ene
ꢀ
are 46.4 (1) and 49.5 (1) , respectively. In addition, there exist
intermolecular hydrogen-bonding interactions between mol-
ecules. There are two independent hydrogen bonds (Table 2);
the O1ÐHÁ Á ÁO2 interaction connects two molecules into a
dimer, and the O2ÐHÁ Á ÁO1 interaction enables the dimers to
form two-dimensional layers parallel to the (100) plane.
b,a
b
b
Shou-Zhi Pu, *³ Fu-Shi Zhang, Ru-Ji Wang and Qiang
c
Liang
a
Institute of Organic Chemistry, Jiangxi Science and Technology Normal University,
b
Nanchang 330013, People's Republic of China, Department of Chemistry, Tsinghua
c
University, Beijing 100084, People's Republic of China, and Department of
Chemistry, Qingdao Normal College, Qingdao 266000, People's Republic of China
Correspondence e-mail: pushouzhi@tsinghua.org.cn
Received 8 September 2003
Accepted 11 March 2004
Online 9 April 2004
The title compound, C H F O S , a photochromic diaryl-
2 2
1
7
14
6
ethene, is one of the most promising materials for optical
memories and other optoelectronic devices. The hexa¯uoro-
cyclopentene group and the two thiophene rings are all planar,
and the dihedral angles between the cyclopentene ring and the
The molecule has approximate C symmetry (antiparallel
2
conformation) and can therefore undergo a photocyclization
reaction (Yamada et al., 2000). The photochromism is shown in
the scheme above. On irradiation with 254 nm UV light, the
colorless single crystal of (Ia) turned red immediately. When
observed under polarized light, the red color intensity
changed on rotation of the crystal. This phenomenon suggests
that the closed-ring isomers are packed regularly in the crystal.
When the red crystal was dissolved in ethanol, the solution
turned red; the absorption maximum was observed at 514 nm,
as it is for the closed-ring form, (Ib), shown in the scheme
above. Unfortunately, the single-crystal diffraction pattern of
ꢀ
adjacent thiophene rings are 46.4 (1) and 49.5 (1) .
Comment
Photochromic diarylethene derivatives have attracted much
attention as the most promising materials for optical memories
and other optoelectronic devices because of their good
thermal stability, high sensitivity and multiplexed recording
(Guo et al., 2003; Irie, 2000). A diarylethene with ®ve-
membered heterocyclic rings can have one of two possible
conformations, viz. with the two rings in mirror symmetry
(
parallel conformation) or in C2 symmetry (antiparallel
conformation; Irie & Mohri, 1988; Uchida et al., 1990).
According to the Woodward±Hoffmann rule, photoinduced
cyclization and cycloreversion reactions can proceed in a
conrotatory mode by alternate irradiation with UVand visible
light only from the antiparallel conformation (Woodward &
Hoffmann, 1970; Irie, 2000). In a previous paper, we have
reported the allomorphism of a diarylethene compound and
discussed its photochromic properties both in solution and in
the single-crystal phase (Pu et al., 2003). This compound is a
good example for validating the rule exactly. In the present
work, a novel photochromic diarylethene compound, (Ia), was
synthesized in high yield by a simple method. The structure of
this compound is presented here.
The molecular structure of (Ia) is shown in Fig. 1 and a
packing diagram is shown in Fig. 2. Selected geometric
Figure 1
The structure of (Ia), showing 35% probability displacement ellipsoids
and the atom-numbering scheme.
³ Correspondence address: Department of Chemistry, Tsinghua University,
Beijing 100084, People's Republic of China.
Acta Cryst. (2004). C60, o305±o307
DOI: 10.1107/S0108270104005815
# 2004 International Union of Crystallography o305

organic compounds
Crystal data
C
17
H
14
F
6
O
2
S
2
Mo Kꢂ radiation
Cell parameters from 6248
re¯ections
r
M = 428.40
Monoclinic, P2 =c
1
Ê
a = 13.5688 (10) A
ꢀ
ꢃ = 2.2±32.8
ꢄ = 0.36 mm
T = 296 (2) K
Ê
b = 7.5506 (6) A
� 1
Ê
c = 18.0929 (14) A
ꢀ
ꢁ
= 98.728 (2)
Prism, colorless
0.5 Â 0.3 Â 0.2 mm
Ê
3
V = 1832.2 (2) A
Z = 4
D
�
3
x
= 1.553 Mg m
Data collection
Bruker SMART APEX CCD
diffractometer
5308 independent re¯ections
4075 re¯ections with I > 2ꢅ(I)
!
scans
Absorption correction: multi-scan
SADABS; Bruker, 1997)
min = 0.79, Tmax = 0.93
4 143 measured re¯ections
Rint = 0.024
ꢀ
ꢃ
max = 30.0
(
T
h = � 19 ! 19
k = � 7 ! 10
l = � 25 ! 25
1
Re®nement
2
2
2
2
Re®nement on F
2
w = 1/[ꢅ (F ) + (0.001P)
o
2
R[F > 2ꢅ(F )] = 0.063
wR(F ) = 0.118
S = 1.05
+ 2.5P]
where P = (Fo + 2F )/3
2
2
2
c
(Á/ꢅ)max = 0.001
Ê
� 3
Áꢆmax = 0.75 e A
5
2
308 re¯ections
54 parameters
Áꢆmin = � 0.58 e AÊ
� 3
H atoms treated by a mixture of
independent and constrained
re®nement
Figure 2
A packing view along the a direction, showing the hydrogen bonding.
Table 1
Selected geometric parameters (A, ).
(
Ib) could not be obtained because it was very unstable under
Ê
ꢀ
the experimental conditions. The red color disappeared
rapidly upon irradiation with 450 nm light or daylight, and the
absorption spectrum of the solution containing the colorless
crystal is the same as that of the open-ring form (Ia).
S1ÐC6
S1ÐC9
F1ÐC3
1.718 (2)
1.727 (3)
1.343 (4)
O1ÐC10
C12ÐC13
C12ÐC17
1.424 (3)
1.367 (3)
1.497 (3)
C6ÐS1ÐC9
C2ÐC1ÐC13
C2ÐC1ÐC5
C13ÐC1ÐC5
F2ÐC3ÐF1
F2ÐC3ÐC2
92.73 (12)
130.4 (2)
111.15 (19)
118.43 (19)
105.9 (2)
F1ÐC3ÐC2
C2ÐC3ÐC4
C5ÐC4ÐC3
C1ÐC5ÐC4
C8ÐC9ÐC10
O1ÐC10ÐC9
111.6 (2)
105.3 (2)
105.3 (2)
105.29 (19)
128.5 (2)
113.12 (19)
Experimental
The novel diarylethene (Ia) was prepared by the reduction of
113.7 (2)
3,3,4,4,5,5-hexa¯uoro-1,2-bis(4-formyl-2-methyl-3-thienyl)cyclopent-
ene (BMFTP; Gilat et al., 1993; Pu et al., 2002) with lithium alumin-
ium hydride (see scheme below). A solution of BMFTP (0.8486 g,
Table 2
Hydrogen-bonding geometry (A, ).
2 mmol) in ether (20 ml) was added dropwise to a stirred solution of
LiAlH (0.1723 g, 4 mmol) in anhydrous ether (50 ml) at room
ꢀ
Ê
4
temperature, and stirring was continued for 1 h at room temperature.
Aqueous sodium potassium tartrate (30%, 5 ml) was then added. The
mixture was ®ltered after stirring for a few minutes and dried over
DÐHÁ Á ÁA
DÐH
HÁ Á ÁA
DÁ Á ÁA
DÐHÁ Á ÁA
i
O1ÐH1AÁ Á ÁO2
O2ÐH2AÁ Á ÁO1
0.78 (3)
0.79 (3)
2.00 (3)
1.96 (3)
2.738 (3)
2.748 (3)
159 (3)
173 (3)
ii
anhydrous MgSO
tography (silica gel, ethyl acetate/hexane 1:1) afforded (Ia) (0.8131 g,
5%) as colorless crystals. The structure of (Ia) was con®rmed by its
4
. The solvent was removed, and column chroma-
1
2
1
2
Symmetry codes: (i) 2 � x; 1 � y; 1 � z; (ii) x; � y; ‡ z.
9
1
melting point, NMR analysis and mass spectrometry (m.p. 398 K). H
NMR (500 MHz, CDCl ): ꢀ 2.06 (s, 6H), 2.99 (s, 4H), 4.72 (s, 2H), 6.99
s, 2H); MS m/z (M ): 428.
H atoms of the hydroxy groups were found in a difference Fourier
map and were re®ned individually. The other H atoms were placed at
idealized positions and treated as riding on their parent atoms, with
3
+
(
Ê
Ê
Ê
CÐH distances of 0.93 A for aryl, 0.96 A for methylene and 0.97 A
for methyl H atoms. The Uiso(H) values were set to 1.2Ueq of the
parent atoms for aryl and methylene H atoms, and at 1.5Ueq for
methyl atoms.
Data collection: SMART (Bruker, 1997); cell re®nement: SMART;
data reduction: SAINT (Bruker, 1997); program(s) used to solve
structure: SHELXTL (Bruker, 1997); program(s) used to re®ne
structure: SHELXTL; molecular graphics: SHELXTL; software used
to prepare material for publication: SHELXTL.
ꢁ
o306 Shou-Zhi Pu et al.
C
17
14
H F
6 2
O S
2
Acta Cryst. (2004). C60, o305±o307

organic compounds
This work has been supported by a State Key Fundamental
Research `Fundamental Research of Super-High Density and
Super-Fast Optical Storage' development project (grant No.
G199903305) and by Project of Fundamental Study funding of
Tsinghua University.
Gilat, S. L., Kawai, S. H. & Lehn, J.-M. (1993). J. Chem. Soc. Chem. Commun.
pp. 1439±1442.
Guo, H.-B., Zhang, F.-S., Wu, G.-S., Sun, F., Pu, S.-Z., Mai, X.-S. & Qi, G.-S.
(2003). Opt. Mater. 22, 269±274.
Irie, M. (2000). Chem. Rev. 100, 1685±1716.
Irie, M. & Mohri, M. (1988). J. Org. Chem. 53, 803±808.
Pu, S.-Z., Chan, S.-K., Wang, R.-J., Zhang, F.-S., Zhou, X.-H., Sun, F. & Yuan, P.
(
2002). Z. Kristallogr. New Cryst. Struct. 217, 415±416.
Pu, S.-Z., Zhang, F.-S., Sun, F., Wang, R.-J., Zhou, X.-H. & Chan, S.-K. (2003).
Tetrahedron Lett. 44, 1011±1015.
Ramamurthy, V. & Venkatesan, K. (1987). Chem. Rev. 87, 433±481.
Uchida, K., Nakayama, Y. & Irie, M. (1990). Bull. Chem. Soc. Jpn, 63, 1311±
Supplementary data for this paper are available from the IUCr electronic
archives (Reference: FR1446). Services for accessing these data are
described at the back of the journal.
1315.
Woodward, R. B. & Hoffmann, R. (1970). In The Conservation of Orbital
Symmetry. Weinheim: Verlag Chemie GmbH.
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Bruker (1997). SADABS, SMART and SHELXTL. Versions 5.10. Bruker
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ꢁ
Acta Cryst. (2004). C60, o305±o307
Shou-Zhi Pu et al.
17 14
C H F
6 2
O S
2
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