Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536807028395/wn2153sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S1600536807028395/wn2153Isup2.hkl |
CCDC reference: 654946
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.
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.
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 C8═N2 bond length is 1.270 (3) Å, indicative of a C═N 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).
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.
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. |
C14H8F4N2O2 | F(000) = 632 |
Mr = 312.22 | Dx = 1.544 Mg m−3 |
Monoclinic, P21/c | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -P 2ybc | Cell parameters from 2406 reflections |
a = 12.863 (3) Å | θ = 2.3–25.3° |
b = 12.549 (2) Å | µ = 0.14 mm−1 |
c = 8.3211 (16) Å | T = 298 K |
β = 90.10 (1)° | Block, colourless |
V = 1343.1 (4) Å3 | 0.38 × 0.31 × 0.18 mm |
Z = 4 |
Bruker APEX area-detector diffractometer | 2406 independent reflections |
Radiation source: fine-focus sealed tube | 1526 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.087 |
φ and ω scans | θmax = 25.3°, θmin = 2.3° |
Absorption correction: multi-scan (SADABS; Sheldrick, 1996) | h = −15→14 |
Tmin = 0.948, Tmax = 0.975 | k = −15→15 |
8038 measured reflections | l = −10→9 |
Refinement on F2 | Secondary atom site location: difference Fourier map |
Least-squares matrix: full | Hydrogen site location: inferred from neighbouring sites |
R[F2 > 2σ(F2)] = 0.049 | H-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 reflections | Δρmax = 0.31 e Å−3 |
210 parameters | Δρmin = −0.34 e Å−3 |
96 restraints | Extinction correction: SHELXL97 (Sheldrick, 1997), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
Primary atom site location: structure-invariant direct methods | Extinction coefficient: 0.006 (3) |
C14H8F4N2O2 | V = 1343.1 (4) Å3 |
Mr = 312.22 | Z = 4 |
Monoclinic, P21/c | Mo Kα radiation |
a = 12.863 (3) Å | µ = 0.14 mm−1 |
b = 12.549 (2) Å | T = 298 K |
c = 8.3211 (16) Å | 0.38 × 0.31 × 0.18 mm |
β = 90.10 (1)° |
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 = 0.975 | Rint = 0.087 |
8038 measured reflections |
R[F2 > 2σ(F2)] = 0.049 | 96 restraints |
wR(F2) = 0.155 | H-atom parameters constrained |
S = 1.00 | Δρmax = 0.31 e Å−3 |
2406 reflections | Δρmin = −0.34 e Å−3 |
210 parameters |
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. |
x | y | z | Uiso*/Ueq | Occ. (<1) | |
F1 | 0.19004 (12) | 0.98237 (12) | −0.08870 (18) | 0.0833 (5) | |
F2 | 0.59865 (15) | 0.96853 (16) | 0.3082 (3) | 0.1065 (8) | 0.888 (4) |
F3 | 0.50517 (18) | 0.8671 (3) | 0.4495 (2) | 0.1311 (11) | 0.888 (4) |
F4 | 0.5854 (2) | 0.8061 (2) | 0.2409 (4) | 0.1325 (11) | 0.888 (4) |
N2 | 0.24083 (14) | 0.77557 (14) | −0.0569 (2) | 0.0564 (5) | |
N1 | 0.1229 (2) | 0.30915 (18) | −0.0163 (3) | 0.0858 (7) | |
O2 | 0.0583 (2) | 0.24421 (15) | −0.0567 (3) | 0.1127 (8) | |
O1 | 0.1894 (2) | 0.28961 (18) | 0.0814 (4) | 0.1400 (11) | |
C8 | 0.22886 (17) | 0.68459 (18) | 0.0073 (3) | 0.0560 (6) | |
H8 | 0.2590 | 0.6716 | 0.1069 | 0.067* | |
C6 | 0.29922 (16) | 0.85362 (17) | 0.0263 (2) | 0.0520 (6) | |
C14 | 0.17518 (18) | 0.49656 (18) | −0.0107 (3) | 0.0579 (6) | |
H14 | 0.2178 | 0.4809 | 0.0764 | 0.069* | |
C7 | 0.38544 (17) | 0.83251 (18) | 0.1211 (3) | 0.0557 (6) | |
H7 | 0.4077 | 0.7625 | 0.1341 | 0.067* | |
C5 | 0.27186 (19) | 0.95961 (18) | 0.0080 (3) | 0.0598 (6) | |
C13 | 0.11706 (18) | 0.41783 (17) | −0.0826 (3) | 0.0595 (6) | |
C2 | 0.43918 (18) | 0.91442 (19) | 0.1972 (3) | 0.0606 (6) | |
C9 | 0.16923 (16) | 0.59942 (17) | −0.0702 (2) | 0.0510 (6) | |
C11 | 0.04589 (19) | 0.53895 (19) | −0.2696 (3) | 0.0639 (6) | |
H11 | 0.0028 | 0.5537 | −0.3565 | 0.077* | |
C12 | 0.05175 (19) | 0.43717 (19) | −0.2105 (3) | 0.0641 (6) | |
H12 | 0.0126 | 0.3825 | −0.2557 | 0.077* | |
C3 | 0.4067 (2) | 1.0184 (2) | 0.1792 (3) | 0.0710 (7) | |
H3 | 0.4421 | 1.0730 | 0.2312 | 0.085* | |
C1 | 0.53030 (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) |
C10 | 0.10359 (16) | 0.61967 (18) | −0.2007 (2) | 0.0571 (6) | |
H10 | 0.0988 | 0.6885 | −0.2417 | 0.069* | |
C4 | 0.3218 (2) | 1.04161 (19) | 0.0841 (3) | 0.0727 (7) | |
H4 | 0.2990 | 1.1115 | 0.0719 | 0.087* |
U11 | U22 | U33 | U12 | U13 | U23 | |
F1 | 0.0829 (11) | 0.0742 (10) | 0.0930 (10) | 0.0090 (7) | −0.0250 (8) | 0.0103 (7) |
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) |
N2 | 0.0582 (12) | 0.0519 (11) | 0.0590 (11) | −0.0046 (9) | −0.0073 (9) | −0.0036 (9) |
N1 | 0.0954 (18) | 0.0547 (14) | 0.1074 (18) | 0.0008 (13) | −0.0218 (15) | −0.0023 (12) |
O2 | 0.146 (2) | 0.0564 (12) | 0.1361 (19) | −0.0302 (13) | −0.0375 (16) | 0.0007 (11) |
O1 | 0.149 (2) | 0.0699 (14) | 0.201 (3) | −0.0046 (14) | −0.087 (2) | 0.0301 (15) |
C8 | 0.0571 (13) | 0.0566 (14) | 0.0544 (13) | −0.0035 (11) | −0.0078 (10) | −0.0025 (10) |
C6 | 0.0537 (13) | 0.0506 (13) | 0.0518 (12) | −0.0084 (10) | −0.0010 (10) | −0.0002 (10) |
C14 | 0.0574 (14) | 0.0555 (14) | 0.0607 (13) | 0.0021 (11) | −0.0121 (11) | −0.0035 (11) |
C7 | 0.0568 (14) | 0.0504 (13) | 0.0598 (13) | −0.0035 (10) | −0.0040 (11) | −0.0001 (10) |
C5 | 0.0587 (14) | 0.0585 (15) | 0.0623 (13) | 0.0015 (11) | −0.0075 (11) | 0.0033 (11) |
C13 | 0.0611 (14) | 0.0440 (13) | 0.0733 (15) | −0.0002 (11) | −0.0051 (12) | −0.0033 (11) |
C2 | 0.0615 (14) | 0.0598 (15) | 0.0605 (13) | −0.0123 (12) | −0.0051 (11) | −0.0012 (11) |
C9 | 0.0493 (12) | 0.0505 (13) | 0.0532 (12) | −0.0028 (10) | −0.0030 (9) | −0.0047 (10) |
C11 | 0.0617 (15) | 0.0664 (16) | 0.0634 (14) | −0.0064 (12) | −0.0172 (11) | −0.0024 (12) |
C12 | 0.0639 (15) | 0.0569 (14) | 0.0715 (15) | −0.0093 (12) | −0.0088 (12) | −0.0113 (12) |
C3 | 0.0803 (18) | 0.0568 (15) | 0.0758 (16) | −0.0196 (13) | −0.0098 (14) | −0.0060 (12) |
C1 | 0.0770 (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) |
C10 | 0.0580 (14) | 0.0556 (14) | 0.0579 (13) | −0.0042 (11) | −0.0051 (11) | 0.0017 (10) |
C4 | 0.0902 (19) | 0.0472 (14) | 0.0806 (17) | −0.0046 (13) | −0.0061 (15) | 0.0025 (12) |
F1—C5 | 1.355 (3) | C7—H7 | 0.9300 |
F2—C1 | 1.3377 (10) | C5—C4 | 1.368 (3) |
F3—C1 | 1.3381 (10) | C13—C12 | 1.378 (3) |
F4—C1 | 1.3380 (10) | C2—C3 | 1.378 (4) |
N2—C8 | 1.270 (3) | C2—C1 | 1.472 (3) |
N2—C6 | 1.415 (3) | C9—C10 | 1.399 (3) |
N1—O1 | 1.205 (3) | C11—C12 | 1.371 (3) |
N1—O2 | 1.212 (3) | C11—C10 | 1.380 (3) |
N1—C13 | 1.473 (3) | C11—H11 | 0.9300 |
C8—C9 | 1.465 (3) | C12—H12 | 0.9300 |
C8—H8 | 0.9300 | C3—C4 | 1.380 (4) |
C6—C5 | 1.384 (3) | C3—H3 | 0.9300 |
C6—C7 | 1.387 (3) | C1—F2' | 1.3395 (11) |
C14—C13 | 1.376 (3) | C1—F4' | 1.3398 (11) |
C14—C9 | 1.385 (3) | C1—F3' | 1.3399 (11) |
C14—H14 | 0.9300 | C10—H10 | 0.9300 |
C7—C2 | 1.391 (3) | C4—H4 | 0.9300 |
C8—N2—C6 | 118.75 (19) | C11—C12—H12 | 120.8 |
O1—N1—O2 | 122.5 (3) | C13—C12—H12 | 120.8 |
O1—N1—C13 | 118.5 (2) | C2—C3—C4 | 120.2 (2) |
O2—N1—C13 | 118.9 (2) | C2—C3—H3 | 119.9 |
N2—C8—C9 | 122.3 (2) | C4—C3—H3 | 119.9 |
N2—C8—H8 | 118.8 | F2—C1—F4 | 104.9 (2) |
C9—C8—H8 | 118.8 | F2—C1—F3 | 104.06 (17) |
C5—C6—C7 | 116.7 (2) | F4—C1—F3 | 107.6 (2) |
C5—C6—N2 | 118.4 (2) | F2—C1—F2' | 39.6 (7) |
C7—C6—N2 | 124.8 (2) | F4—C1—F2' | 120.1 (9) |
C13—C14—C9 | 119.0 (2) | F3—C1—F2' | 64.7 (7) |
C13—C14—H14 | 120.5 | F2—C1—F4' | 69.8 (8) |
C9—C14—H14 | 120.5 | F4—C1—F4' | 39.0 (8) |
C6—C7—C2 | 121.0 (2) | F3—C1—F4' | 132.1 (10) |
C6—C7—H7 | 119.5 | F2'—C1—F4' | 99.8 (8) |
C2—C7—H7 | 119.5 | F2—C1—F3' | 131.1 (8) |
F1—C5—C4 | 118.7 (2) | F4—C1—F3' | 63.7 (9) |
F1—C5—C6 | 117.7 (2) | F3—C1—F3' | 47.4 (8) |
C4—C5—C6 | 123.5 (2) | F2'—C1—F3' | 102.0 (8) |
C14—C13—C12 | 122.7 (2) | F4'—C1—F3' | 99.6 (8) |
C14—C13—N1 | 118.3 (2) | F2—C1—C2 | 113.42 (19) |
C12—C13—N1 | 118.9 (2) | F4—C1—C2 | 113.36 (18) |
C3—C2—C7 | 120.0 (2) | F3—C1—C2 | 112.74 (19) |
C3—C2—C1 | 120.8 (2) | F2'—C1—C2 | 124.4 (9) |
C7—C2—C1 | 119.3 (2) | F4'—C1—C2 | 112.9 (9) |
C14—C9—C10 | 118.70 (19) | F3'—C1—C2 | 114.6 (9) |
C14—C9—C8 | 119.6 (2) | C11—C10—C9 | 120.9 (2) |
C10—C9—C8 | 121.7 (2) | C11—C10—H10 | 119.6 |
C12—C11—C10 | 120.4 (2) | C9—C10—H10 | 119.6 |
C12—C11—H11 | 119.8 | C5—C4—C3 | 118.6 (2) |
C10—C11—H11 | 119.8 | C5—C4—H4 | 120.7 |
C11—C12—C13 | 118.3 (2) | C3—C4—H4 | 120.7 |
C6—N2—C8—C9 | 179.72 (18) | C14—C13—C12—C11 | 1.0 (4) |
C8—N2—C6—C5 | −147.5 (2) | N1—C13—C12—C11 | 179.1 (2) |
C8—N2—C6—C7 | 35.2 (3) | C7—C2—C3—C4 | −0.9 (4) |
C5—C6—C7—C2 | 1.8 (3) | C1—C2—C3—C4 | 179.3 (2) |
N2—C6—C7—C2 | 179.17 (19) | C3—C2—C1—F2 | −26.3 (3) |
C7—C6—C5—F1 | 177.73 (19) | C7—C2—C1—F2 | 153.9 (2) |
N2—C6—C5—F1 | 0.2 (3) | C3—C2—C1—F4 | −145.8 (3) |
C7—C6—C5—C4 | −3.4 (3) | C7—C2—C1—F4 | 34.4 (3) |
N2—C6—C5—C4 | 179.1 (2) | C3—C2—C1—F3 | 91.7 (3) |
C9—C14—C13—C12 | −0.9 (4) | C7—C2—C1—F3 | −88.2 (3) |
C9—C14—C13—N1 | −179.0 (2) | C3—C2—C1—F2' | 17.6 (10) |
O1—N1—C13—C14 | −11.1 (4) | C7—C2—C1—F2' | −162.2 (10) |
O2—N1—C13—C14 | 165.8 (2) | C3—C2—C1—F4' | −103.2 (10) |
O1—N1—C13—C12 | 170.7 (3) | C7—C2—C1—F4' | 77.0 (10) |
O2—N1—C13—C12 | −12.4 (4) | C3—C2—C1—F3' | 143.7 (10) |
C6—C7—C2—C3 | 0.2 (3) | C7—C2—C1—F3' | −36.1 (11) |
C6—C7—C2—C1 | 179.99 (18) | C12—C11—C10—C9 | 0.2 (3) |
C13—C14—C9—C10 | 0.5 (3) | C14—C9—C10—C11 | −0.1 (3) |
C13—C14—C9—C8 | 178.6 (2) | C8—C9—C10—C11 | −178.3 (2) |
N2—C8—C9—C14 | 167.7 (2) | F1—C5—C4—C3 | −178.4 (2) |
N2—C8—C9—C10 | −14.2 (3) | C6—C5—C4—C3 | 2.7 (4) |
C10—C11—C12—C13 | −0.6 (3) | C2—C3—C4—C5 | −0.5 (4) |
Experimental details
Crystal data | |
Chemical formula | C14H8F4N2O2 |
Mr | 312.22 |
Crystal system, space group | Monoclinic, P21/c |
Temperature (K) | 298 |
a, b, c (Å) | 12.863 (3), 12.549 (2), 8.3211 (16) |
β (°) | 90.10 (1) |
V (Å3) | 1343.1 (4) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 0.14 |
Crystal size (mm) | 0.38 × 0.31 × 0.18 |
Data collection | |
Diffractometer | Bruker APEX area-detector |
Absorption correction | Multi-scan (SADABS; Sheldrick, 1996) |
Tmin, Tmax | 0.948, 0.975 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 8038, 2406, 1526 |
Rint | 0.087 |
(sin θ/λ)max (Å−1) | 0.601 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.049, 0.155, 1.00 |
No. of reflections | 2406 |
No. of parameters | 210 |
No. of restraints | 96 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.31, −0.34 |
Computer programs: SMART (Bruker,1998), SAINT (Bruker, 1999), SAINT, SHELXS97 (Sheldrick, 1997), SHELXL97 (Sheldrick, 1997), SHELXTL (Bruker, 1998), SHELXTL.
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 C8═N2 bond length is 1.270 (3) Å, indicative of a C═N 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.