2,3,5,6-Tetra­fluoro-1,4-bis­({[(thio­phen-2-yl)methyl­idene]amino}­meth­yl)benzene

In the title compound, C₁₈H₁₂F₄N₂S₂, a bis-thio­phenyl Schiff base ligand with a perifluorinated aromatic core, the complete molecule is generated by crystallographic inversion symmetry. The thio­phene and tetra­fluorinated benzene rings are oriented at a dihedral angle of 77.38 (4)°. The crystal structure exhibits C—H...F hydrogen bonds, resulting in supra­molecular chains along the c-axis direction.

Key indicators

• Single-crystal X-ray study
• T = 296 K
• Mean [sigma](C-C) = 0.002 Å
• R factor = 0.030
• wR factor = 0.090
• Data-to-parameter ratio = 13.1

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT480_ALERT_4_C Long H...A H-Bond Reported H5     ..  F1      ..       2.56 Ang.
PLAT480_ALERT_4_C Long H...A H-Bond Reported H6B    ..  F1      ..       2.63 Ang.
PLAT911_ALERT_3_C Missing # FCF Refl Between THmin & STh/L=  0.595          8 Why ?
PLAT913_ALERT_3_C Missing # of Very Strong Reflections in FCF ....          1 Note

Alert level G
PLAT005_ALERT_5_G No _iucr_refine_instructions_details  in the CIF     Please Do !
PLAT066_ALERT_1_G Predicted and Reported Tmin&Tmax Range Identical          ? Check
PLAT909_ALERT_3_G Percentage of Observed Data at Theta(Max) still          84 %
PLAT910_ALERT_3_G Missing # of FCF Reflections Below Th(Min) .....          1 Why ?

   0 ALERT level A = Most likely a serious problem - resolve or explain
   0 ALERT level B = A potentially serious problem, consider carefully
   4 ALERT level C = Check. Ensure it is not caused by an omission or oversight
   4 ALERT level G = General information/check it is not something unexpected

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

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S1. Comment

In the past decade, thiophen-based bidentate Schiff base ligands have been utilized intensively to assemble various coordination compounds with intriguing structural features and potential applications (Hee & Soon, 2007; Fang et al., 2001). As part of our ongoing studies of the effect of fluorine substitution on crystal structures of coordination polymers (Chen et al., 2012), herein, we wish to report the crystal structure of the title compound, 2,3,5,6-tetrafluoro-1,4-bis(1-(1-thiophen-2-yl)methyleneaminomethyl)benzene, (I).

A perspective view of (I), including the atomic numbering scheme, is shown in Fig. 1. (I) crystallizes around a crystallographic centre with a half molecule in the asymmetric unit. Bond lengths and angles are within normal ranges. The terminal thiophenyl groups are coplanar, and they form a dihedral angle of 77.38 (4)° with the central tetrafluorinated benzene ring. Intermolecular C—H···F hydrogen-bonding interactions link the adjacent molecules to generate one-dimensional supramolecular chains along the c axis (see Fig. 2).

Related literature

For background information on thiophene-based Schiff base ligands, see: Hee & Soon (2007); Fang et al. (2001). For fluorine-functionalized complexes, see Chen et al. (2012). Zhang et al. (2011) describe the synthesis of the title compound.

S2. Experimental

Compound (I) was synthesized and purified according to the method described by Zhang et al. (2011) through a condensation of 2,3,5,6-tetrafluoro-1,4-benzenedimethanamine with thiophene-2-carboxaldehyde (yied 75%). ¹H NMR (CDCl₃): δ 2.71 (s, 4H, CH₂), 7.19 (s, 2H, CH), 7.58 (s, 2H, CH), 7.84 (s, 2H, CH), 8.02 (s, 2H, CH).

Colourless needle-like single crystals (m.p. 452.3—452.6 K) suitable for X-ray analysis were obtained by dissolving (I) (20.0 mg) in dichloromethane (6 ml) solution and then slowly evaporating the solvent at room temperature for a period of about one week.

S3. Refinement

All H atoms bound to carbon were assigned to calculated positions, with C—H = 0.97 Å (methylene) and 0.93 Å (aromatic and imine), and refined using a riding model, with U_iso(H)=1.2U_eq (C).

Computing details

Data collection: APEX2 (Bruker, 2007); cell refinement: APEX2 and SAINT (Bruker, 2007); data reduction: SAINT (Bruker, 2007); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008) and DIAMOND (Brandenburg, 2005); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

Figures

	Fig. 1. Molecular structure of the title compound with the atom-numbering scheme. Displacement ellipsoids are drawn at the 30% probability level. Hydrogen atoms are omitted for clarity.
	Fig. 2. View of the one-dimensional supramolecular chain structure constructed via intermolecular C—H···F hydrogen-bonding interactions (irrelative hydrogen atoms are omitted for clarity).

2,3,5,6-Tetrafluoro-1,4-bis({[(thiophen-2-yl)methylidene]amino}methyl)benzene

Crystal data

C18H12F4N2S2	F(000) = 404
Mr = 396.42	Dx = 1.497 Mg m^−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 5195 reflections
a = 15.500 (7) Å	θ = 2.6–31.7°
b = 4.865 (2) Å	µ = 0.35 mm^−1
c = 11.713 (6) Å	T = 296 K
β = 95.371 (9)°	Shape, colourless
V = 879.3 (7) Å^3	0.24 × 0.22 × 0.20 mm
Z = 2

Data collection

Bruker SMART APEX CCD diffractometer	1541 independent reflections
Radiation source: fine-focus sealed tube	1427 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.018
phi and ω scans	θmax = 25.0°, θmin = 2.6°
Absorption correction: multi-scan (SADABS; Sheldrick, 2003)	h = −18→17
Tmin = 0.921, Tmax = 0.934	k = −5→5
6136 measured reflections	l = −13→12

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.030	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.090	H-atom parameters constrained
S = 1.02	w = 1/[σ^2(Fo^2) + (0.0516P)^2 + 0.297P] where P = (Fo^2 + 2Fc^2)/3
1541 reflections	(Δ/σ)max = 0.001
118 parameters	Δρmax = 0.18 e Å^−3
0 restraints	Δρmin = −0.28 e Å^−3

Special details

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds 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 > 2sigma(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
C1	0.43101 (11)	0.7020 (4)	0.85018 (19)	0.0605 (5)
H1	0.4750	0.8166	0.8818	0.073*
C2	0.40375 (12)	0.6938 (4)	0.73736 (18)	0.0610 (5)
H2	0.4266	0.8036	0.6826	0.073*
C3	0.33673 (12)	0.5000 (4)	0.71153 (16)	0.0531 (4)
H3	0.3110	0.4671	0.6378	0.064*
C4	0.31367 (10)	0.3652 (3)	0.80758 (13)	0.0427 (4)
C5	0.24772 (9)	0.1542 (3)	0.81301 (13)	0.0428 (4)
H5	0.2214	0.0838	0.7446	0.051*
C6	0.15903 (10)	−0.1584 (3)	0.89660 (15)	0.0464 (4)
H6A	0.1831	−0.3231	0.9338	0.056*
H6B	0.1440	−0.2005	0.8162	0.056*
C7	0.07804 (9)	−0.0748 (3)	0.95097 (13)	0.0376 (3)
C8	0.05197 (9)	−0.2024 (3)	1.04813 (12)	0.0388 (3)
C9	0.02329 (9)	0.1316 (3)	0.90476 (12)	0.0388 (3)
F1	0.10088 (7)	−0.4083 (2)	1.09813 (8)	0.0566 (3)
F2	0.04382 (6)	0.2659 (2)	0.80981 (8)	0.0549 (3)
N1	0.22433 (8)	0.0614 (3)	0.90663 (12)	0.0445 (3)
S1	0.37524 (3)	0.47708 (10)	0.92848 (4)	0.05398 (19)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
C1	0.0407 (9)	0.0496 (10)	0.0913 (15)	−0.0038 (8)	0.0063 (9)	−0.0024 (10)
C2	0.0532 (10)	0.0521 (10)	0.0809 (14)	0.0022 (9)	0.0229 (9)	0.0114 (10)
C3	0.0513 (10)	0.0576 (11)	0.0517 (10)	0.0049 (8)	0.0108 (8)	0.0013 (8)
C4	0.0354 (7)	0.0451 (9)	0.0477 (9)	0.0048 (6)	0.0052 (6)	−0.0031 (7)
C5	0.0349 (7)	0.0481 (9)	0.0453 (9)	0.0027 (7)	0.0031 (6)	−0.0075 (7)
C6	0.0391 (8)	0.0437 (9)	0.0575 (10)	−0.0013 (7)	0.0107 (7)	−0.0063 (7)
C7	0.0327 (7)	0.0371 (8)	0.0427 (8)	−0.0012 (6)	0.0024 (6)	−0.0045 (6)
C8	0.0366 (7)	0.0355 (8)	0.0429 (8)	0.0042 (6)	−0.0033 (6)	0.0009 (6)
C9	0.0409 (8)	0.0389 (8)	0.0365 (8)	−0.0034 (6)	0.0030 (6)	0.0009 (6)
F1	0.0541 (6)	0.0549 (6)	0.0601 (6)	0.0183 (5)	0.0013 (5)	0.0136 (5)
F2	0.0608 (6)	0.0565 (6)	0.0492 (6)	0.0035 (5)	0.0144 (4)	0.0145 (5)
N1	0.0341 (7)	0.0488 (8)	0.0510 (8)	−0.0003 (6)	0.0056 (6)	−0.0053 (6)
S1	0.0457 (3)	0.0584 (3)	0.0562 (3)	−0.00403 (19)	−0.0039 (2)	−0.0020 (2)

Geometric parameters (Å, º)

C1—C2	1.350 (3)	C6—N1	1.469 (2)
C1—S1	1.713 (2)	C6—C7	1.515 (2)
C1—H1	0.9300	C6—H6A	0.9700
C2—C3	1.414 (3)	C6—H6B	0.9700
C2—H2	0.9300	C7—C8	1.389 (2)
C3—C4	1.378 (2)	C7—C9	1.391 (2)
C3—H3	0.9300	C8—F1	1.3555 (17)
C4—C5	1.454 (2)	C8—C9^i	1.380 (2)
C4—S1	1.7202 (17)	C9—F2	1.3531 (18)
C5—N1	1.270 (2)	C9—C8^i	1.380 (2)
C5—H5	0.9300
C2—C1—S1	112.19 (15)	N1—C6—H6A	109.4
C2—C1—H1	123.9	C7—C6—H6A	109.4
S1—C1—H1	123.9	N1—C6—H6B	109.4
C1—C2—C3	112.68 (17)	C7—C6—H6B	109.4
C1—C2—H2	123.7	H6A—C6—H6B	108.0
C3—C2—H2	123.7	C8—C7—C9	115.32 (13)
C4—C3—C2	112.58 (17)	C8—C7—C6	122.69 (14)
C4—C3—H3	123.7	C9—C7—C6	121.97 (14)
C2—C3—H3	123.7	F1—C8—C9^i	118.11 (13)
C3—C4—C5	127.50 (15)	F1—C8—C7	119.36 (13)
C3—C4—S1	110.81 (13)	C9^i—C8—C7	122.51 (14)
C5—C4—S1	121.70 (12)	F2—C9—C8^i	118.72 (13)
N1—C5—C4	123.20 (14)	F2—C9—C7	119.11 (13)
N1—C5—H5	118.4	C8^i—C9—C7	122.16 (14)
C4—C5—H5	118.4	C5—N1—C6	116.10 (14)
N1—C6—C7	111.25 (13)	C1—S1—C4	91.74 (10)
S1—C1—C2—C3	−0.6 (2)	C6—C7—C8—C9^i	−177.86 (14)
C1—C2—C3—C4	0.7 (2)	C8—C7—C9—F2	−179.81 (13)
C2—C3—C4—C5	−179.95 (15)	C6—C7—C9—F2	−1.4 (2)
C2—C3—C4—S1	−0.37 (19)	C8—C7—C9—C8^i	−0.5 (2)
C3—C4—C5—N1	−172.30 (16)	C6—C7—C9—C8^i	177.88 (14)
S1—C4—C5—N1	8.2 (2)	C4—C5—N1—C6	−177.93 (14)
N1—C6—C7—C8	−113.68 (16)	C7—C6—N1—C5	−120.34 (16)
N1—C6—C7—C9	68.1 (2)	C2—C1—S1—C4	0.36 (15)
C9—C7—C8—F1	179.22 (13)	C3—C4—S1—C1	0.02 (14)
C6—C7—C8—F1	0.8 (2)	C5—C4—S1—C1	179.62 (14)
C9—C7—C8—C9^i	0.5 (2)

Symmetry code: (i) −x, −y, −z+2.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
C6—H6A···F1	0.97	2.44	2.873 (3)	107
C5—H5···F1^ii	0.93	2.56	3.446 (2)	159
C6—H6B···F1^ii	0.97	2.63	3.542 (2)	156

Symmetry code: (ii) x, −y−1/2, z−1/2.