1,2-Bis[5-(2,2-dicyano­vinyl)-2-ethyl-3-thien­yl]-3,3,4,4,5,5-hexa­fluoro­cyclo­pent-1-ene, a new photochromic diaryl­ethene compound

The title compound, C₂₅H₁₄N₄F₆S₂, is a new symmetric photo­chromic diaryl­ethene which can potentially be applied in optoelectronic devices, such as optical memories, photo switches, and color displays. In the crystalline phase, this mol­ecule, which has crystallographic twofold rotation symmetry, adopts an anti­parallel conformation that can undergo effective photocyclization reactions by a conrotatory mechanism. The distance between the two reactive C atoms is 3.642 (7) Å. The dihedral angle between the central cyclo­pentene ring and each thio­phene ring is 48.0 (2)°. The colourless crystals turn green when exposed to UV radiation and the process is reversible when exposed to visible light of appropriate wavelength.

Key indicators

• Single-crystal X-ray study
• T = 295 K
• Mean [sigma](C-C) = 0.007 Å
• Disorder in main residue
• R factor = 0.049
• wR factor = 0.118
• Data-to-parameter ratio = 12.0

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT242_ALERT_2_C Check Low       Ueq as Compared to Neighbors for         C2
PLAT242_ALERT_2_C Check Low       Ueq as Compared to Neighbors for         C3
PLAT301_ALERT_3_C Main Residue  Disorder .........................       8.00 Perc.
PLAT340_ALERT_3_C Low Bond Precision on C-C bonds (x 1000) Ang ...          7
PLAT371_ALERT_2_C Long   C(sp2)-C(sp1) Bond  C9     -   C10    ...       1.42 Ang.
PLAT371_ALERT_2_C Long   C(sp2)-C(sp1) Bond  C9     -   C11    ...       1.43 Ang.
PLAT601_ALERT_2_C Structure Contains Solvent Accessible VOIDS of .      33.00 A   3  

Alert level G
REFLT03_ALERT_4_G  WARNING: Large fraction of Friedel related reflns may
                     be needed to determine absolute structure
           From the CIF: _diffrn_reflns_theta_max           25.00
           From the CIF: _reflns_number_total               2178
           Count of symmetry unique reflns         1453
           Completeness (_total/calc)            149.90%
           TEST3: Check Friedels for noncentro structure
           Estimate of Friedel pairs measured       725
           Fraction of Friedel pairs measured     0.499
           Are heavy atom types Z>Si present        yes

   0 ALERT level A = In general: serious problem
   0 ALERT level B = Potentially serious problem
   7 ALERT level C = Check and explain
   1 ALERT level G = General alerts; check

   0 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   5 ALERT type 2 Indicator that the structure model may be wrong or deficient
   2 ALERT type 3 Indicator that the structure quality may be low
   1 ALERT type 4 Improvement, methodology, query or suggestion

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Computing details

Data collection: XSCANS (Bruker, 1997); cell refinement: XSCANS; data reduction: XSCANS; program(s) used to solve structure: SHELXTL (Bruker, 1997); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL.

1,2-Bis[2-ethyl-5-(2,2-dicyanovinyl)-3-thienyl]-3,3,4,4,5,5- hexafluorocyclopent-1-ene

Crystal data

C25H14F6N4S2	Dx = 1.474 Mg m^−3
Mr = 548.52	Melting point = 438–439 K
Hexagonal, P6522	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 65 2 (0 0 1)	Cell parameters from 60 reflections
a = 8.4786 (7) Å	θ = 2.1–12.5°
c = 59.562 (9) Å	µ = 0.28 mm^−1
V = 3708.0 (7) Å^3	T = 295 K
Z = 6	Prism, colorless
F(000) = 1668	0.4 × 0.4 × 0.3 mm

Data collection

Bruker P4 diffractometer	Rint = 0.064
Radiation source: fine-focus sealed tube	θmax = 25.0°, θmin = 2.1°
Graphite monochromator	h = −1→10
ω scans	k = −10→1
5982 measured reflections	l = −1→70
2178 independent reflections	3 standard reflections every 97 reflections
1542 reflections with I > 2σ(I)	intensity decay: none

Refinement

Refinement on F^2	Hydrogen site location: inferred from neighbouring sites
Least-squares matrix: full	H-atom parameters constrained
R[F^2 > 2σ(F^2)] = 0.049	w = 1/[σ^2(Fo^2) + (0.001P)^2 + 4P] where P = (Fo^2 + 2Fc^2)/3
wR(F^2) = 0.118	(Δ/σ)max < 0.001
S = 1.07	Δρmax = 0.18 e Å^−3
2178 reflections	Δρmin = −0.19 e Å^−3
182 parameters	Extinction correction: SHELXL97, Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
8 restraints	Extinction coefficient: 0.0026 (4)
Primary atom site location: structure-invariant direct methods	Absolute structure: Flack (1983), 725 Friedel pairs
Secondary atom site location: difference Fourier map	Absolute structure parameter: −0.1 (2)

Special details

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes.

Refinement. Refinement of F² against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F², conventional R-factors R are based on F, with F set to zero for negative F². The threshold expression of F² > σ(F²) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F² are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq	Occ. (<1)
S1	0.26456 (17)	0.89681 (18)	0.047760 (17)	0.0597 (3)
F1	−0.3429 (5)	0.8414 (5)	0.03203 (7)	0.1328 (15)
F2	−0.2048 (4)	1.1270 (5)	0.03419 (5)	0.0975 (11)
F3	−0.2791 (12)	1.2140 (9)	0.00028 (12)	0.098 (2)	0.50
F4	−0.5026 (8)	0.9387 (12)	−0.0011 (2)	0.108 (5)	0.50
N1	0.5825 (8)	0.9564 (9)	0.08672 (7)	0.1044 (18)
N2	0.5654 (7)	1.3708 (8)	0.12714 (7)	0.1051 (18)
C1	−0.0729 (6)	0.9949 (6)	0.01132 (6)	0.0537 (11)
C2	−0.2419 (6)	0.9917 (7)	0.02001 (6)	0.0594 (12)
C3	−0.3236 (10)	1.0384 (13)	−0.00060 (13)	0.071 (4)	0.50
C4	0.1219 (6)	0.8666 (6)	0.02578 (6)	0.0506 (10)
C5	0.0531 (6)	0.9835 (6)	0.02725 (6)	0.0531 (11)
C6	0.1145 (6)	1.0923 (7)	0.04690 (6)	0.0605 (12)
H6A	0.0780	1.1755	0.0508	0.073*
C7	0.2322 (6)	1.0639 (6)	0.05971 (6)	0.0564 (11)
C8	0.3161 (7)	1.1642 (7)	0.07950 (6)	0.0660 (13)
H8A	0.2789	1.2457	0.0839	0.079*
C9	0.4417 (7)	1.1588 (7)	0.09285 (6)	0.0668 (14)
C10	0.5197 (8)	1.0470 (9)	0.08924 (8)	0.0765 (16)
C11	0.5087 (8)	1.2767 (8)	0.11186 (7)	0.0781 (16)
C12	0.0810 (7)	0.7238 (7)	0.00836 (6)	0.0608 (12)
H12A	0.1599	0.7808	−0.0045	0.073*
H12B	−0.0436	0.6753	0.0033	0.073*
C13	0.1052 (8)	0.5664 (7)	0.01630 (7)	0.0806 (16)
H13A	0.0748	0.4802	0.0043	0.121*
H13B	0.0266	0.5077	0.0289	0.121*
H13C	0.2295	0.6120	0.0207	0.121*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
S1	0.0610 (8)	0.0678 (8)	0.0521 (5)	0.0336 (7)	−0.0045 (5)	0.0000 (5)
F1	0.089 (3)	0.114 (3)	0.209 (4)	0.061 (2)	0.070 (3)	0.079 (3)
F2	0.089 (2)	0.129 (3)	0.0980 (19)	0.072 (2)	−0.0159 (17)	−0.049 (2)
F3	0.130 (7)	0.104 (6)	0.095 (4)	0.086 (5)	−0.008 (5)	−0.009 (5)
F4	0.050 (4)	0.170 (16)	0.096 (5)	0.049 (7)	0.015 (5)	0.030 (12)
N1	0.106 (4)	0.154 (6)	0.074 (3)	0.080 (4)	−0.010 (3)	−0.007 (3)
N2	0.118 (4)	0.105 (4)	0.064 (2)	0.034 (4)	−0.019 (3)	−0.012 (3)
C1	0.053 (3)	0.062 (3)	0.0503 (19)	0.032 (2)	−0.0027 (19)	−0.009 (2)
C2	0.064 (3)	0.067 (3)	0.052 (2)	0.036 (3)	0.002 (2)	−0.004 (2)
C3	0.052 (6)	0.091 (15)	0.079 (5)	0.042 (8)	−0.010 (7)	−0.014 (7)
C4	0.048 (2)	0.058 (3)	0.0447 (19)	0.026 (2)	0.0032 (18)	0.0013 (18)
C5	0.056 (3)	0.063 (3)	0.0417 (19)	0.031 (2)	−0.0024 (18)	−0.0012 (19)
C6	0.070 (3)	0.069 (3)	0.048 (2)	0.038 (3)	−0.001 (2)	−0.006 (2)
C7	0.062 (3)	0.063 (3)	0.0424 (19)	0.030 (2)	−0.0029 (19)	−0.0038 (19)
C8	0.080 (4)	0.065 (3)	0.047 (2)	0.031 (3)	−0.007 (2)	−0.001 (2)
C9	0.070 (3)	0.072 (4)	0.042 (2)	0.023 (3)	−0.002 (2)	0.003 (2)
C10	0.072 (4)	0.101 (5)	0.053 (3)	0.040 (4)	−0.006 (2)	0.003 (3)
C11	0.080 (4)	0.085 (4)	0.047 (2)	0.025 (3)	−0.007 (2)	0.002 (3)
C12	0.065 (3)	0.066 (3)	0.054 (2)	0.035 (3)	0.001 (2)	−0.006 (2)
C13	0.106 (5)	0.067 (4)	0.072 (3)	0.045 (4)	0.010 (3)	−0.001 (3)

Geometric parameters (Å, º)

S1—C4	1.713 (4)	C4—C12	1.497 (6)
S1—C7	1.725 (5)	C5—C6	1.418 (5)
F1—C2	1.334 (5)	C6—C7	1.370 (6)
F2—C2	1.329 (5)	C6—H6A	0.930
F3—C3	1.341 (9)	C7—C8	1.419 (6)
F4—C3	1.317 (8)	C8—C9	1.348 (6)
F4—F3^i	1.338 (11)	C8—H8A	0.930
N1—C10	1.143 (7)	C9—C10	1.417 (8)
N2—C11	1.146 (6)	C9—C11	1.427 (6)
C1—C1^i	1.351 (7)	C12—C13	1.524 (6)
C1—C5	1.468 (5)	C12—H12A	0.970
C1—C2	1.511 (6)	C12—H12B	0.970
C2—C3^i	1.476 (8)	C13—H13A	0.960
C2—C3	1.555 (8)	C13—H13B	0.960
C3—C2^i	1.476 (8)	C13—H13C	0.960
C4—C5	1.381 (6)
C4—S1—C7	92.7 (2)	C7—C6—H6A	123.0
C1^i—C1—C5	130.4 (2)	C5—C6—H6A	123.0
C1^i—C1—C2	110.05 (19)	C6—C7—C8	123.2 (4)
C5—C1—C2	119.5 (3)	C6—C7—S1	110.1 (3)
F2—C2—F1	104.2 (4)	C8—C7—S1	126.6 (4)
F2—C2—C3^i	119.5 (5)	C9—C8—C7	129.6 (5)
F1—C2—C3^i	101.4 (5)	C9—C8—H8A	115.2
F2—C2—C1	112.9 (4)	C7—C8—H8A	115.2
F1—C2—C1	110.6 (4)	C8—C9—C10	125.0 (4)
C3^i—C2—C1	107.5 (4)	C8—C9—C11	119.3 (5)
F2—C2—C3	103.0 (4)	C10—C9—C11	115.7 (5)
F1—C2—C3	120.8 (5)	N1—C10—C9	178.8 (6)
C1—C2—C3	105.3 (4)	N2—C11—C9	178.7 (7)
F4—C3—F3	107.9 (8)	C4—C12—C13	114.5 (4)
F4—C3—C2^i	113.6 (8)	C4—C12—H12A	108.6
F3—C3—C2^i	109.9 (7)	C13—C12—H12A	108.6
F4—C3—C2	111.8 (8)	C4—C12—H12B	108.6
F3—C3—C2	109.7 (6)	C13—C12—H12B	108.6
C2^i—C3—C2	103.9 (5)	H12A—C12—H12B	107.6
C5—C4—C12	127.9 (4)	C12—C13—H13A	109.5
C5—C4—S1	111.4 (3)	C12—C13—H13B	109.5
C12—C4—S1	120.7 (3)	H13A—C13—H13B	109.5
C4—C5—C6	111.7 (4)	C12—C13—H13C	109.5
C4—C5—C1	126.1 (4)	H13A—C13—H13C	109.5
C6—C5—C1	122.2 (4)	H13B—C13—H13C	109.5
C7—C6—C5	114.1 (4)
C1^i—C1—C2—F2	−122.1 (5)	C1—C2—C3—F4^i	−173.1 (9)
C5—C1—C2—F2	59.1 (5)	F2—C2—C3—F4	−101.7 (8)
C1^i—C1—C2—F1	121.6 (5)	F1—C2—C3—F4	13.8 (10)
C5—C1—C2—F1	−57.1 (6)	C3^i—C2—C3—F4	40.8 (9)
C1^i—C1—C2—C3^i	11.8 (8)	C1—C2—C3—F4	139.8 (7)
C5—C1—C2—C3^i	−167.0 (5)	F2—C2—C3—F3	18.0 (7)
C1^i—C1—C2—C3	−10.4 (7)	F1—C2—C3—F3	133.5 (6)
C5—C1—C2—C3	170.8 (5)	C3^i—C2—C3—F3	160.5 (13)
F4^i—F4—C3—C3^i	161 (3)	C1—C2—C3—F3	−100.5 (7)
F3^i—F4—C3—C3^i	−7.4 (16)	F2—C2—C3—C2^i	135.4 (5)
C3^i—F4—C3—F4^i	−161 (3)	F1—C2—C3—C2^i	−109.1 (7)
F3^i—F4—C3—F4^i	−169 (2)	C3^i—C2—C3—C2^i	−82.1 (10)
F4^i—F4—C3—F3	−7.2 (19)	C1—C2—C3—C2^i	16.9 (6)
C3^i—F4—C3—F3	−169 (2)	F2—C2—C3—F3^i	−137.5 (4)
F3^i—F4—C3—F3	−175.9 (6)	F1—C2—C3—F3^i	−22.0 (6)
F4^i—F4—C3—C2^i	−129.3 (18)	C3^i—C2—C3—F3^i	5.0 (8)
C3^i—F4—C3—C2^i	69.4 (16)	C1—C2—C3—F3^i	104.0 (4)
F3^i—F4—C3—C2^i	62.0 (10)	C7—S1—C4—C5	1.0 (3)
F4^i—F4—C3—C2	113.6 (17)	C7—S1—C4—C12	−177.3 (4)
C3^i—F4—C3—C2	−47.7 (15)	C12—C4—C5—C6	176.2 (4)
F3^i—F4—C3—C2	−55.2 (10)	S1—C4—C5—C6	−1.9 (5)
F4^i—F4—C3—F3^i	169 (2)	C12—C4—C5—C1	−1.8 (7)
C3^i—F4—C3—F3^i	7.4 (16)	S1—C4—C5—C1	180.0 (3)
F4^i—F3—C3—C3^i	−26 (5)	C1^i—C1—C5—C4	−48.1 (9)
C3^i—F3—C3—F4^i	26 (5)	C2—C1—C5—C4	130.4 (5)
F4^i—F3—C3—F4	5.4 (15)	C1^i—C1—C5—C6	134.0 (6)
C3^i—F3—C3—F4	32 (5)	C2—C1—C5—C6	−47.5 (6)
F4^i—F3—C3—C2^i	129.7 (10)	C4—C5—C6—C7	2.2 (6)
C3^i—F3—C3—C2^i	156 (5)	C1—C5—C6—C7	−179.7 (4)
F4^i—F3—C3—C2	−116.7 (11)	C5—C6—C7—C8	177.1 (4)
C3^i—F3—C3—C2	−90 (5)	C5—C6—C7—S1	−1.4 (5)
F4^i—F3—C3—F3^i	−0.9 (12)	C4—S1—C7—C6	0.2 (4)
C3^i—F3—C3—F3^i	25 (4)	C4—S1—C7—C8	−178.2 (4)
F2—C2—C3—C3^i	−142.5 (10)	C6—C7—C8—C9	−175.5 (5)
F1—C2—C3—C3^i	−27.0 (11)	S1—C7—C8—C9	2.7 (8)
C1—C2—C3—C3^i	99.0 (9)	C7—C8—C9—C10	0.9 (9)
F2—C2—C3—F4^i	−54.6 (11)	C7—C8—C9—C11	178.9 (5)
F1—C2—C3—F4^i	61.0 (12)	C5—C4—C12—C13	−153.8 (5)
C3^i—C2—C3—F4^i	87.9 (13)	S1—C4—C12—C13	24.3 (6)

Symmetry code: (i) x−y+1, −y+2, −z.