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In the title Schiff base, C14H8F4N2O, the dihedral angle between the two rings is 20.92 (4)°. The mol­ecular components are stabilized via π–π stacking inter­actions between adjacent benzene rings of the Schiff base units; the centroid-to-centroid distance is 3.834 (3) Å. The F atoms of the trifluoro­methyl group are disordered over two sites in a ratio of ca 0.9:0.1.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536807028395/wn2153sup1.cif
Contains datablocks I, global

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S1600536807028395/wn2153Isup2.hkl
Contains datablock I

CCDC reference: 654946

Key indicators

  • Single-crystal X-ray study
  • T = 298 K
  • Mean [sigma](C-C) = 0.003 Å
  • Disorder in main residue
  • R factor = 0.049
  • wR factor = 0.155
  • Data-to-parameter ratio = 11.5

checkCIF/PLATON results

No syntax errors found



Alert level B PLAT031_ALERT_4_B Refined Extinction Parameter within Range ...... 2.00 Sigma PLAT242_ALERT_2_B Check Low Ueq as Compared to Neighbors for C1 PLAT432_ALERT_2_B Short Inter X...Y Contact C4 .. F4' .. 2.82 Ang.
Alert level C PLAT066_ALERT_1_C Predicted and Reported Transmissions Identical . ? PLAT152_ALERT_1_C Supplied and Calc Volume s.u. Inconsistent ..... ? PLAT242_ALERT_2_C Check Low Ueq as Compared to Neighbors for N1 PLAT301_ALERT_3_C Main Residue Disorder ......................... 12.00 Perc. PLAT779_ALERT_2_C Suspect or Irrelevant (Bond) Angle in CIF ...... 39.60 Deg. F2 -C1 -F2' 1.555 1.555 1.555 PLAT779_ALERT_2_C Suspect or Irrelevant (Bond) Angle in CIF ...... 39.00 Deg. F4 -C1 -F4' 1.555 1.555 1.555
Alert level G PLAT860_ALERT_3_G Note: Number of Least-Squares Restraints ....... 96
0 ALERT level A = In general: serious problem 3 ALERT level B = Potentially serious problem 6 ALERT level C = Check and explain 1 ALERT level G = General alerts; check 2 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 0 ALERT type 5 Informative message, check

Comment top

Schiff base ligands have significant importance in chemistry, especially in the development of Schiff base complexes (Johnson et al., 1996; Alizadeh et al., 1999; Wang & Zheng, 2007). Schiff bases that have solvent-dependent UV/vis spectra (solvatochromicity) can be suitable NLO (nonlinear optically active) materials (Alemi & Shaabani, 2000). They are also useful in the asymmetric oxidation of methyl phenyl sulfide and are enantioselective (Kim & Shim, 1999). In this paper, we report the synthesis and crystal structure of the title compound.

In the molecular structure of the title compound (Fig. 1), the C8N2 bond length is 1.270 (3) Å, indicative of a CN double bond. The C—F, C—O and C—C distances are unremarkable. The F atoms of the trifluoromethyl group were found to be disordered over two positions, the two components being rotated by about 30°.

Tha packing is governed by π···π stacking interactions. The centroid-centroid distance between adjacent benzene rings (at x, y, z and x, 1/2 - y, 1/2 + z) is 3.834 (3) Å, indicating a normal π···π contact.

Related literature top

For related literature, see: Alemi & Shaabani (2000); Alizadeh et al. (1999); Johnson et al. (1996); Kim & Shin (1999); Wang & Zheng (2007).

Experimental top

Under nitrogen, a mixture of 3-nitrobenzaldehyde (1.51 g,10 mmol), Na2SO4 (3.0 g) and 5-fluoro-2-trifluoromethybenezenamine (1.79 g, 10 mmol) in absolute ethanol (20 ml) was refluxed for about 12 h to yield a yellow precipitate. The product was collected by vacuum filtration and washed with ethanol. The crude solid was redissolved in CH2Cl2 (100 ml) and washed with water (2 x 15 ml) and brine (8 ml). After drying over Na2SO4, the solvent was removed under vacuum, and a yellow solid was isolated in 92% yield (3.1 g). Colourless single crystals of the Schiff base suitable for X-ray analysis were grown from CH2Cl2 and absolute ethanol (4:1) by slow evaporation of the solvents at room temperature over a period of about one week.

Refinement top

All H atoms were placed in calculated positions [Csp2—H = 0.93 Å] and refined using a riding model, with Uiso(H) = 1.2Ueq(C). The site occupancy factors of atoms F2, F3, F4 and F2', F3' F4' refined to 0.888 (4) and 0.112 (4), respectively.

Structure description top

Schiff base ligands have significant importance in chemistry, especially in the development of Schiff base complexes (Johnson et al., 1996; Alizadeh et al., 1999; Wang & Zheng, 2007). Schiff bases that have solvent-dependent UV/vis spectra (solvatochromicity) can be suitable NLO (nonlinear optically active) materials (Alemi & Shaabani, 2000). They are also useful in the asymmetric oxidation of methyl phenyl sulfide and are enantioselective (Kim & Shim, 1999). In this paper, we report the synthesis and crystal structure of the title compound.

In the molecular structure of the title compound (Fig. 1), the C8N2 bond length is 1.270 (3) Å, indicative of a CN double bond. The C—F, C—O and C—C distances are unremarkable. The F atoms of the trifluoromethyl group were found to be disordered over two positions, the two components being rotated by about 30°.

Tha packing is governed by π···π stacking interactions. The centroid-centroid distance between adjacent benzene rings (at x, y, z and x, 1/2 - y, 1/2 + z) is 3.834 (3) Å, indicating a normal π···π contact.

For related literature, see: Alemi & Shaabani (2000); Alizadeh et al. (1999); Johnson et al. (1996); Kim & Shin (1999); Wang & Zheng (2007).

Computing details top

Data collection: SMART (Bruker,1998); cell refinement: SAINT (Bruker, 1999); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SHELXTL (Bruker, 1998); software used to prepare material for publication: SHELXTL.

Figures top
[Figure 1] Fig. 1. The molecular structure of the title compound, showing the atomic numbering scheme. Displacement ellipsoids are drawn at the 30% probability level. Both disorder components are shown.
2-Fluoro-N-(3-Nitrobenzylidene)-5-(trifluoromethyl)aniline top
Crystal data top
C14H8F4N2O2F(000) = 632
Mr = 312.22Dx = 1.544 Mg m3
Monoclinic, P21/cMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybcCell parameters from 2406 reflections
a = 12.863 (3) Åθ = 2.3–25.3°
b = 12.549 (2) ŵ = 0.14 mm1
c = 8.3211 (16) ÅT = 298 K
β = 90.10 (1)°Block, colourless
V = 1343.1 (4) Å30.38 × 0.31 × 0.18 mm
Z = 4
Data collection top
Bruker APEX area-detector
diffractometer
2406 independent reflections
Radiation source: fine-focus sealed tube1526 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.087
φ and ω scansθmax = 25.3°, θmin = 2.3°
Absorption correction: multi-scan
(SADABS; Sheldrick, 1996)
h = 1514
Tmin = 0.948, Tmax = 0.975k = 1515
8038 measured reflectionsl = 109
Refinement top
Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.049H-atom parameters constrained
wR(F2) = 0.155 w = 1/[σ2(Fo2) + (0.089P)2]
where P = (Fo2 + 2Fc2)/3
S = 1.00(Δ/σ)max < 0.001
2406 reflectionsΔρmax = 0.31 e Å3
210 parametersΔρmin = 0.34 e Å3
96 restraintsExtinction correction: SHELXL97 (Sheldrick, 1997), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: structure-invariant direct methodsExtinction coefficient: 0.006 (3)
Crystal data top
C14H8F4N2O2V = 1343.1 (4) Å3
Mr = 312.22Z = 4
Monoclinic, P21/cMo Kα radiation
a = 12.863 (3) ŵ = 0.14 mm1
b = 12.549 (2) ÅT = 298 K
c = 8.3211 (16) Å0.38 × 0.31 × 0.18 mm
β = 90.10 (1)°
Data collection top
Bruker APEX area-detector
diffractometer
2406 independent reflections
Absorption correction: multi-scan
(SADABS; Sheldrick, 1996)
1526 reflections with I > 2σ(I)
Tmin = 0.948, Tmax = 0.975Rint = 0.087
8038 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.04996 restraints
wR(F2) = 0.155H-atom parameters constrained
S = 1.00Δρmax = 0.31 e Å3
2406 reflectionsΔρmin = 0.34 e Å3
210 parameters
Special details top

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 (Å2) top
xyzUiso*/UeqOcc. (<1)
F10.19004 (12)0.98237 (12)0.08870 (18)0.0833 (5)
F20.59865 (15)0.96853 (16)0.3082 (3)0.1065 (8)0.888 (4)
F30.50517 (18)0.8671 (3)0.4495 (2)0.1311 (11)0.888 (4)
F40.5854 (2)0.8061 (2)0.2409 (4)0.1325 (11)0.888 (4)
N20.24083 (14)0.77557 (14)0.0569 (2)0.0564 (5)
N10.1229 (2)0.30915 (18)0.0163 (3)0.0858 (7)
O20.0583 (2)0.24421 (15)0.0567 (3)0.1127 (8)
O10.1894 (2)0.28961 (18)0.0814 (4)0.1400 (11)
C80.22886 (17)0.68459 (18)0.0073 (3)0.0560 (6)
H80.25900.67160.10690.067*
C60.29922 (16)0.85362 (17)0.0263 (2)0.0520 (6)
C140.17518 (18)0.49656 (18)0.0107 (3)0.0579 (6)
H140.21780.48090.07640.069*
C70.38544 (17)0.83251 (18)0.1211 (3)0.0557 (6)
H70.40770.76250.13410.067*
C50.27186 (19)0.95961 (18)0.0080 (3)0.0598 (6)
C130.11706 (18)0.41783 (17)0.0826 (3)0.0595 (6)
C20.43918 (18)0.91442 (19)0.1972 (3)0.0606 (6)
C90.16923 (16)0.59942 (17)0.0702 (2)0.0510 (6)
C110.04589 (19)0.53895 (19)0.2696 (3)0.0639 (6)
H110.00280.55370.35650.077*
C120.05175 (19)0.43717 (19)0.2105 (3)0.0641 (6)
H120.01260.38250.25570.077*
C30.4067 (2)1.0184 (2)0.1792 (3)0.0710 (7)
H30.44211.07300.23120.085*
C10.53030 (17)0.88854 (16)0.2968 (2)0.0805 (8)
F2'0.5717 (13)0.9541 (12)0.4066 (16)0.1065 (8)0.112 (4)
F3'0.5223 (16)0.7972 (9)0.379 (2)0.1311 (11)0.112 (4)
F4'0.6153 (9)0.8669 (16)0.210 (2)0.1325 (11)0.112 (4)
C100.10359 (16)0.61967 (18)0.2007 (2)0.0571 (6)
H100.09880.68850.24170.069*
C40.3218 (2)1.04161 (19)0.0841 (3)0.0727 (7)
H40.29901.11150.07190.087*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
F10.0829 (11)0.0742 (10)0.0930 (10)0.0090 (7)0.0250 (8)0.0103 (7)
F20.0812 (14)0.1240 (17)0.1144 (18)0.0439 (11)0.0324 (12)0.0193 (13)
F30.1160 (16)0.198 (3)0.0790 (14)0.0485 (18)0.0326 (12)0.0497 (15)
F40.1058 (17)0.113 (2)0.178 (2)0.0311 (15)0.0713 (16)0.0253 (18)
N20.0582 (12)0.0519 (11)0.0590 (11)0.0046 (9)0.0073 (9)0.0036 (9)
N10.0954 (18)0.0547 (14)0.1074 (18)0.0008 (13)0.0218 (15)0.0023 (12)
O20.146 (2)0.0564 (12)0.1361 (19)0.0302 (13)0.0375 (16)0.0007 (11)
O10.149 (2)0.0699 (14)0.201 (3)0.0046 (14)0.087 (2)0.0301 (15)
C80.0571 (13)0.0566 (14)0.0544 (13)0.0035 (11)0.0078 (10)0.0025 (10)
C60.0537 (13)0.0506 (13)0.0518 (12)0.0084 (10)0.0010 (10)0.0002 (10)
C140.0574 (14)0.0555 (14)0.0607 (13)0.0021 (11)0.0121 (11)0.0035 (11)
C70.0568 (14)0.0504 (13)0.0598 (13)0.0035 (10)0.0040 (11)0.0001 (10)
C50.0587 (14)0.0585 (15)0.0623 (13)0.0015 (11)0.0075 (11)0.0033 (11)
C130.0611 (14)0.0440 (13)0.0733 (15)0.0002 (11)0.0051 (12)0.0033 (11)
C20.0615 (14)0.0598 (15)0.0605 (13)0.0123 (12)0.0051 (11)0.0012 (11)
C90.0493 (12)0.0505 (13)0.0532 (12)0.0028 (10)0.0030 (9)0.0047 (10)
C110.0617 (15)0.0664 (16)0.0634 (14)0.0064 (12)0.0172 (11)0.0024 (12)
C120.0639 (15)0.0569 (14)0.0715 (15)0.0093 (12)0.0088 (12)0.0113 (12)
C30.0803 (18)0.0568 (15)0.0758 (16)0.0196 (13)0.0098 (14)0.0060 (12)
C10.0770 (18)0.0820 (19)0.0824 (19)0.0195 (16)0.0213 (14)0.0061 (15)
F2'0.0812 (14)0.1240 (17)0.1144 (18)0.0439 (11)0.0324 (12)0.0193 (13)
F3'0.1160 (16)0.198 (3)0.0790 (14)0.0485 (18)0.0326 (12)0.0497 (15)
F4'0.1058 (17)0.113 (2)0.178 (2)0.0311 (15)0.0713 (16)0.0253 (18)
C100.0580 (14)0.0556 (14)0.0579 (13)0.0042 (11)0.0051 (11)0.0017 (10)
C40.0902 (19)0.0472 (14)0.0806 (17)0.0046 (13)0.0061 (15)0.0025 (12)
Geometric parameters (Å, º) top
F1—C51.355 (3)C7—H70.9300
F2—C11.3377 (10)C5—C41.368 (3)
F3—C11.3381 (10)C13—C121.378 (3)
F4—C11.3380 (10)C2—C31.378 (4)
N2—C81.270 (3)C2—C11.472 (3)
N2—C61.415 (3)C9—C101.399 (3)
N1—O11.205 (3)C11—C121.371 (3)
N1—O21.212 (3)C11—C101.380 (3)
N1—C131.473 (3)C11—H110.9300
C8—C91.465 (3)C12—H120.9300
C8—H80.9300C3—C41.380 (4)
C6—C51.384 (3)C3—H30.9300
C6—C71.387 (3)C1—F2'1.3395 (11)
C14—C131.376 (3)C1—F4'1.3398 (11)
C14—C91.385 (3)C1—F3'1.3399 (11)
C14—H140.9300C10—H100.9300
C7—C21.391 (3)C4—H40.9300
C8—N2—C6118.75 (19)C11—C12—H12120.8
O1—N1—O2122.5 (3)C13—C12—H12120.8
O1—N1—C13118.5 (2)C2—C3—C4120.2 (2)
O2—N1—C13118.9 (2)C2—C3—H3119.9
N2—C8—C9122.3 (2)C4—C3—H3119.9
N2—C8—H8118.8F2—C1—F4104.9 (2)
C9—C8—H8118.8F2—C1—F3104.06 (17)
C5—C6—C7116.7 (2)F4—C1—F3107.6 (2)
C5—C6—N2118.4 (2)F2—C1—F2'39.6 (7)
C7—C6—N2124.8 (2)F4—C1—F2'120.1 (9)
C13—C14—C9119.0 (2)F3—C1—F2'64.7 (7)
C13—C14—H14120.5F2—C1—F4'69.8 (8)
C9—C14—H14120.5F4—C1—F4'39.0 (8)
C6—C7—C2121.0 (2)F3—C1—F4'132.1 (10)
C6—C7—H7119.5F2'—C1—F4'99.8 (8)
C2—C7—H7119.5F2—C1—F3'131.1 (8)
F1—C5—C4118.7 (2)F4—C1—F3'63.7 (9)
F1—C5—C6117.7 (2)F3—C1—F3'47.4 (8)
C4—C5—C6123.5 (2)F2'—C1—F3'102.0 (8)
C14—C13—C12122.7 (2)F4'—C1—F3'99.6 (8)
C14—C13—N1118.3 (2)F2—C1—C2113.42 (19)
C12—C13—N1118.9 (2)F4—C1—C2113.36 (18)
C3—C2—C7120.0 (2)F3—C1—C2112.74 (19)
C3—C2—C1120.8 (2)F2'—C1—C2124.4 (9)
C7—C2—C1119.3 (2)F4'—C1—C2112.9 (9)
C14—C9—C10118.70 (19)F3'—C1—C2114.6 (9)
C14—C9—C8119.6 (2)C11—C10—C9120.9 (2)
C10—C9—C8121.7 (2)C11—C10—H10119.6
C12—C11—C10120.4 (2)C9—C10—H10119.6
C12—C11—H11119.8C5—C4—C3118.6 (2)
C10—C11—H11119.8C5—C4—H4120.7
C11—C12—C13118.3 (2)C3—C4—H4120.7
C6—N2—C8—C9179.72 (18)C14—C13—C12—C111.0 (4)
C8—N2—C6—C5147.5 (2)N1—C13—C12—C11179.1 (2)
C8—N2—C6—C735.2 (3)C7—C2—C3—C40.9 (4)
C5—C6—C7—C21.8 (3)C1—C2—C3—C4179.3 (2)
N2—C6—C7—C2179.17 (19)C3—C2—C1—F226.3 (3)
C7—C6—C5—F1177.73 (19)C7—C2—C1—F2153.9 (2)
N2—C6—C5—F10.2 (3)C3—C2—C1—F4145.8 (3)
C7—C6—C5—C43.4 (3)C7—C2—C1—F434.4 (3)
N2—C6—C5—C4179.1 (2)C3—C2—C1—F391.7 (3)
C9—C14—C13—C120.9 (4)C7—C2—C1—F388.2 (3)
C9—C14—C13—N1179.0 (2)C3—C2—C1—F2'17.6 (10)
O1—N1—C13—C1411.1 (4)C7—C2—C1—F2'162.2 (10)
O2—N1—C13—C14165.8 (2)C3—C2—C1—F4'103.2 (10)
O1—N1—C13—C12170.7 (3)C7—C2—C1—F4'77.0 (10)
O2—N1—C13—C1212.4 (4)C3—C2—C1—F3'143.7 (10)
C6—C7—C2—C30.2 (3)C7—C2—C1—F3'36.1 (11)
C6—C7—C2—C1179.99 (18)C12—C11—C10—C90.2 (3)
C13—C14—C9—C100.5 (3)C14—C9—C10—C110.1 (3)
C13—C14—C9—C8178.6 (2)C8—C9—C10—C11178.3 (2)
N2—C8—C9—C14167.7 (2)F1—C5—C4—C3178.4 (2)
N2—C8—C9—C1014.2 (3)C6—C5—C4—C32.7 (4)
C10—C11—C12—C130.6 (3)C2—C3—C4—C50.5 (4)

Experimental details

Crystal data
Chemical formulaC14H8F4N2O2
Mr312.22
Crystal system, space groupMonoclinic, P21/c
Temperature (K)298
a, b, c (Å)12.863 (3), 12.549 (2), 8.3211 (16)
β (°) 90.10 (1)
V3)1343.1 (4)
Z4
Radiation typeMo Kα
µ (mm1)0.14
Crystal size (mm)0.38 × 0.31 × 0.18
Data collection
DiffractometerBruker APEX area-detector
Absorption correctionMulti-scan
(SADABS; Sheldrick, 1996)
Tmin, Tmax0.948, 0.975
No. of measured, independent and
observed [I > 2σ(I)] reflections
8038, 2406, 1526
Rint0.087
(sin θ/λ)max1)0.601
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.049, 0.155, 1.00
No. of reflections2406
No. of parameters210
No. of restraints96
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.31, 0.34

Computer programs: SMART (Bruker,1998), SAINT (Bruker, 1999), SAINT, SHELXS97 (Sheldrick, 1997), SHELXL97 (Sheldrick, 1997), SHELXTL (Bruker, 1998), SHELXTL.

 

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