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Acta Cryst. (2008). E64, o2186    [ doi:10.1107/S1600536808034119 ]

N-[4-(4-Nitrophenoxy)phenyl]propionamide

A. Nigar, Z. Akhter, M. Bolte, H. M. Siddiqi and R. Hussain

Abstract top

The title compound, C15H14N2O4, is an important intermediate for the synthesis of thermotropic liquid crystals. The dihedral angle between the two aromatic rings is 84.29 (4)°. An N-H...O hydrogen bond connects the molecules into chains running along the b axis. In addition, the crystal packing is stabilized by weak C-H...O hydrogen bonds.

Comment top

Liquid crystals are materials which exhibit phases where molecular order is intermediate between that of an ordered solid and a disordered liquid. They represent the combined properties of both the crystalline state (e.g. optical and electrical anisotropy) and the liquid state (e.g. molecular mobility and fluidity). The two major classes of liquid crystals are thermotropic and lyotropic, which can be distinguished by the mechanism that drive their self-organization. Background information on liquid crystals and their various applications were surveyed, for example, by Collings (1990), Bahadur (1992), and Collings & Hird (1997). One of the basic characteristics for the establishment of the mesophase is the ratio of rigid and flexible portions in the main structure (Cârlescu et al., 2005). Therefore such type of precursors can be used to study structure property relationship of the liquid crystalline materials.

The crystal structure of the compound reported here is an important intermediate for the synthesis of thermotropic liquid crystals (Akhter et al., 2007).

In the molecule of the title compound (Fig. 1), the bond lengths (Allen et al., 1995) and angles are within normal ranges.

The dihedral angle between the two aromatic rings is 84.29 (4)°. An N—H···O hydrogen bond connects the molecules to chains running along the b axis. In addition, the crystal packing is stabilized by weak C—H···O hydrogen bonds.

Related literature top

For background on liquid crystals, see: Bahadur (1992); Collings (1990); Collings & Hird (1997). For bond lengths and angles in organic compounds, see: Allen et al. (1995). For related literature, see: Akhter et al. (2007); Cârlescu et al. (2005).

Experimental top

A mixture of 5.046 g (50 mmol) 4-aminophenol, 6.91 g (50 mmol) anhydrous K2CO3 and 5.3 ml (50 mmol) 4-nitrofluorobenzene in 70 ml DMF was heated at 373 K for 18 h in an inert atmosphere. After cooling to room temperature, the reaction mixture was poured into 800 ml of water to yield a yellow solid. The product was filtered, dried and then re-crystallized from n-hexane (yield 86%). In a second step, propanoic acid and thionylchloride were refluxed in equimolar amounts for 30 min before evaporating excessive thionylchloride with a vacuum pump. The above prepared 4-[4-nitrophenoxy]aniline was then added to the propanoyl chloride solution in dry THF. 1 ml of triethylamine was also added for 1 g of 4-[4-nitrophenoxy]aniline and refluxed for 2 h under inert conditions. The reaction mixture was allowed to stand at room temperature overnight and filtered off the salt formed. The filterate was evaporated using a rotary evaporator, and the crude product obtained was re-crystallized from toluene (yield 76%, m.p. 416 K).

Refinement top

All H atoms could be located from difference Fourier maps. Except the amino H atom that was freely refined, all other H atoms were refined using a riding model with Uiso(H) = 1.2Ueq(C) and Uiso(H) = 1.5Ueq(Cmethyl) and distance restraints of C—H(aromatic) = 0.95 Å, C—H(methyl) = 0.98 Å and C—H(methylene) = 0.99 Å, respectively.

Computing details top

Data collection: X-AREA (Stoe & Cie, 2001); cell refinement: X-AREA (Stoe & Cie, 2001); data reduction: X-RED (Stoe & Cie, 2001); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: XP in SHELXTL-Plus (Sheldrick, 2008); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).

Figures top
[Figure 1] Fig. 1. The molecule of the title compound with atom labelling and displacement ellipsoids drawn at the 50% probability level. H atoms are given as spheres of arbitrary radius.
N-[4-(4-Nitrophenoxy)phenyl]propionamide top
Crystal data top
C15H14N2O4F(000) = 600
Mr = 286.28Dx = 1.394 Mg m−3
Monoclinic, P21/nMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ynCell parameters from 14480 reflections
a = 14.8597 (14) Åθ = 3.5–26.6°
b = 5.2400 (3) ŵ = 0.10 mm−1
c = 17.9034 (16) ÅT = 173 K
β = 101.875 (7)°Plate, yellow
V = 1364.21 (19) Å30.37 × 0.28 × 0.19 mm
Z = 4
Data collection top
Stoe IPDSII
diffractometer		2347 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tubeRint = 0.048
graphiteθmax = 26.4°, θmin = 3.5°
ω scansh = −18→18
16399 measured reflectionsk = −6→6
2788 independent reflectionsl = −22→22
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)] = 0.036H atoms treated by a mixture of independent and constrained refinement
wR(F2) = 0.096 w = 1/[σ2(Fo2) + (0.0525P)2 + 0.2968P]
where P = (Fo2 + 2Fc2)/3
S = 1.03(Δ/σ)max < 0.001
2788 reflectionsΔρmax = 0.28 e Å−3
195 parametersΔρmin = −0.19 e Å−3
0 restraintsExtinction correction: SHELXL97 (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: structure-invariant direct methodsExtinction coefficient: 0.0097 (15)
Crystal data top
C15H14N2O4V = 1364.21 (19) Å3
Mr = 286.28Z = 4
Monoclinic, P21/nMo Kα radiation
a = 14.8597 (14) ŵ = 0.10 mm−1
b = 5.2400 (3) ÅT = 173 K
c = 17.9034 (16) Å0.37 × 0.28 × 0.19 mm
β = 101.875 (7)°
Data collection top
Stoe IPDSII
diffractometer		2347 reflections with I > 2σ(I)
16399 measured reflectionsRint = 0.048
2788 independent reflectionsθmax = 26.4°
Refinement top
R[F2 > 2σ(F2)] = 0.036H atoms treated by a mixture of independent and constrained refinement
wR(F2) = 0.096Δρmax = 0.28 e Å−3
S = 1.03Δρmin = −0.19 e Å−3
2788 reflectionsAbsolute structure: ?
195 parametersFlack parameter: ?
0 restraintsRogers parameter: ?
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*/Ueq
N10.49215 (7)0.2717 (2)0.90078 (6)0.0246 (2)
H10.5157 (11)0.129 (3)0.9083 (9)0.033 (4)*
N2−0.13564 (7)0.9965 (2)0.86242 (7)0.0307 (3)
O10.52173 (6)0.69920 (16)0.90359 (6)0.0319 (2)
O20.10753 (6)0.21455 (17)0.82463 (6)0.0321 (2)
O3−0.12604 (8)1.1019 (2)0.92505 (7)0.0495 (3)
O4−0.19763 (7)1.0515 (2)0.80818 (6)0.0418 (3)
C10.54954 (8)0.4769 (2)0.91080 (7)0.0234 (3)
C20.65154 (9)0.4133 (2)0.93362 (8)0.0290 (3)
H2A0.67000.41150.99000.035*
H2B0.66200.24020.91490.035*
C30.71154 (9)0.6026 (3)0.90187 (9)0.0352 (3)
H3A0.77630.55400.91830.053*
H3B0.70230.77400.92090.053*
H3C0.69470.60190.84600.053*
C110.39403 (8)0.2759 (2)0.88371 (7)0.0226 (3)
C120.34820 (9)0.0773 (2)0.91224 (8)0.0291 (3)
H120.3826−0.04950.94370.035*
C130.25238 (9)0.0633 (2)0.89496 (8)0.0302 (3)
H130.2215−0.07140.91480.036*
C140.20289 (8)0.2483 (2)0.84859 (7)0.0250 (3)
C150.24723 (9)0.4488 (2)0.82019 (7)0.0270 (3)
H150.21240.57570.78900.032*
C160.34320 (9)0.4629 (2)0.83775 (7)0.0258 (3)
H160.37380.59940.81850.031*
C210.05086 (8)0.4152 (2)0.83521 (7)0.0251 (3)
C22−0.02514 (9)0.4618 (3)0.77680 (7)0.0309 (3)
H22−0.03470.36340.73130.037*
C23−0.08678 (9)0.6532 (3)0.78568 (7)0.0306 (3)
H23−0.13890.68750.74640.037*
C24−0.07090 (8)0.7935 (2)0.85284 (7)0.0255 (3)
C250.00430 (9)0.7460 (3)0.91150 (7)0.0302 (3)
H250.01340.84320.95720.036*
C260.06596 (9)0.5553 (3)0.90256 (7)0.0299 (3)
H260.11790.52090.94200.036*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
N10.0236 (5)0.0169 (5)0.0340 (6)0.0039 (4)0.0074 (4)0.0037 (4)
N20.0215 (5)0.0311 (6)0.0381 (6)−0.0002 (4)0.0029 (5)−0.0022 (5)
O10.0261 (5)0.0180 (4)0.0503 (6)0.0026 (4)0.0045 (4)0.0018 (4)
O20.0229 (5)0.0270 (5)0.0462 (6)−0.0025 (4)0.0065 (4)−0.0104 (4)
O30.0393 (6)0.0555 (7)0.0490 (7)0.0155 (5)−0.0018 (5)−0.0224 (6)
O40.0289 (5)0.0452 (6)0.0466 (6)0.0089 (4)−0.0032 (4)0.0036 (5)
C10.0237 (6)0.0209 (6)0.0264 (6)0.0024 (5)0.0068 (5)0.0025 (5)
C20.0255 (6)0.0230 (6)0.0387 (7)0.0032 (5)0.0070 (5)0.0058 (5)
C30.0265 (7)0.0322 (7)0.0493 (8)0.0022 (6)0.0133 (6)0.0065 (6)
C110.0240 (6)0.0196 (5)0.0253 (6)0.0015 (4)0.0078 (5)−0.0020 (4)
C120.0291 (7)0.0210 (6)0.0382 (7)0.0034 (5)0.0090 (5)0.0068 (5)
C130.0297 (7)0.0218 (6)0.0418 (7)−0.0017 (5)0.0136 (6)0.0038 (5)
C140.0222 (6)0.0234 (6)0.0303 (6)−0.0001 (5)0.0073 (5)−0.0063 (5)
C150.0269 (6)0.0237 (6)0.0292 (6)0.0023 (5)0.0030 (5)0.0030 (5)
C160.0262 (6)0.0231 (6)0.0283 (6)−0.0016 (5)0.0062 (5)0.0040 (5)
C210.0204 (6)0.0243 (6)0.0317 (7)−0.0026 (5)0.0082 (5)−0.0015 (5)
C220.0286 (7)0.0361 (7)0.0269 (6)−0.0046 (5)0.0033 (5)−0.0081 (5)
C230.0228 (6)0.0382 (7)0.0277 (7)−0.0020 (5)−0.0018 (5)−0.0015 (5)
C240.0188 (6)0.0273 (6)0.0306 (6)−0.0013 (5)0.0055 (5)−0.0002 (5)
C250.0260 (6)0.0372 (7)0.0260 (6)0.0020 (5)0.0018 (5)−0.0077 (6)
C260.0231 (6)0.0365 (7)0.0275 (7)0.0029 (5)−0.0007 (5)−0.0024 (5)
Geometric parameters (Å, °) top
N1—C11.3613 (16)C12—C131.3954 (19)
N1—C111.4270 (16)C12—H120.9500
N1—H10.825 (17)C13—C141.3849 (18)
N2—O41.2273 (15)C13—H130.9500
N2—O31.2314 (15)C14—C151.3910 (18)
N2—C241.4678 (16)C15—C161.3976 (18)
O1—C11.2339 (15)C15—H150.9500
O2—C211.3842 (15)C16—H160.9500
O2—C141.4047 (15)C21—C261.3899 (18)
C1—C21.5233 (17)C21—C221.3938 (18)
C2—C31.5201 (18)C22—C231.389 (2)
C2—H2A0.9900C22—H220.9500
C2—H2B0.9900C23—C241.3875 (18)
C3—H3A0.9800C23—H230.9500
C3—H3B0.9800C24—C251.3894 (18)
C3—H3C0.9800C25—C261.3871 (18)
C11—C121.3965 (17)C25—H250.9500
C11—C161.3972 (17)C26—H260.9500
C1—N1—C11126.93 (10)C14—C13—H13120.4
C1—N1—H1117.5 (11)C12—C13—H13120.4
C11—N1—H1115.4 (11)C13—C14—C15120.99 (11)
O4—N2—O3122.86 (12)C13—C14—O2118.22 (11)
O4—N2—C24118.75 (11)C15—C14—O2120.49 (11)
O3—N2—C24118.38 (11)C14—C15—C16119.71 (11)
C21—O2—C14117.81 (9)C14—C15—H15120.1
O1—C1—N1123.01 (11)C16—C15—H15120.1
O1—C1—C2121.87 (11)C11—C16—C15119.90 (11)
N1—C1—C2115.10 (10)C11—C16—H16120.0
C3—C2—C1112.62 (10)C15—C16—H16120.0
C3—C2—H2A109.1O2—C21—C26121.72 (11)
C1—C2—H2A109.1O2—C21—C22116.88 (11)
C3—C2—H2B109.1C26—C21—C22121.31 (12)
C1—C2—H2B109.1C23—C22—C21119.47 (12)
H2A—C2—H2B107.8C23—C22—H22120.3
C2—C3—H3A109.5C21—C22—H22120.3
C2—C3—H3B109.5C24—C23—C22118.89 (12)
H3A—C3—H3B109.5C24—C23—H23120.6
C2—C3—H3C109.5C22—C23—H23120.6
H3A—C3—H3C109.5C23—C24—C25121.81 (12)
H3B—C3—H3C109.5C23—C24—N2119.11 (11)
C12—C11—C16119.52 (11)C25—C24—N2119.08 (11)
C12—C11—N1117.63 (11)C26—C25—C24119.30 (12)
C16—C11—N1122.80 (11)C26—C25—H25120.4
C13—C12—C11120.68 (12)C24—C25—H25120.4
C13—C12—H12119.7C25—C26—C21119.22 (12)
C11—C12—H12119.7C25—C26—H26120.4
C14—C13—C12119.20 (11)C21—C26—H26120.4
C11—N1—C1—O1−2.4 (2)C14—C15—C16—C11−0.06 (19)
C11—N1—C1—C2176.22 (11)C14—O2—C21—C26−43.11 (17)
O1—C1—C2—C3−34.15 (18)C14—O2—C21—C22140.29 (12)
N1—C1—C2—C3147.24 (12)O2—C21—C22—C23177.11 (11)
C1—N1—C11—C12−148.08 (13)C26—C21—C22—C230.5 (2)
C1—N1—C11—C1634.49 (19)C21—C22—C23—C240.0 (2)
C16—C11—C12—C130.35 (19)C22—C23—C24—C25−0.6 (2)
N1—C11—C12—C13−177.16 (12)C22—C23—C24—N2179.81 (12)
C11—C12—C13—C140.4 (2)O4—N2—C24—C23−6.26 (18)
C12—C13—C14—C15−1.02 (19)O3—N2—C24—C23172.74 (13)
C12—C13—C14—O2172.67 (11)O4—N2—C24—C25174.14 (12)
C21—O2—C14—C13129.12 (12)O3—N2—C24—C25−6.86 (18)
C21—O2—C14—C15−57.16 (16)C23—C24—C25—C260.8 (2)
C13—C14—C15—C160.85 (19)N2—C24—C25—C26−179.65 (12)
O2—C14—C15—C16−172.70 (11)C24—C25—C26—C21−0.3 (2)
C12—C11—C16—C15−0.53 (18)O2—C21—C26—C25−176.78 (12)
N1—C11—C16—C15176.85 (11)C22—C21—C26—C25−0.3 (2)
Hydrogen-bond geometry (Å, °) top
D—H···AD—HH···AD···AD—H···A
N1—H1···O1i0.825 (17)2.255 (17)3.0306 (13)156.7 (15)
C25—H25···O3ii0.952.423.2082 (17)140
C23—H23···O4iii0.952.533.3400 (16)144
Symmetry codes: (i) x, y−1, z; (ii) −x, −y+2, −z+2; (iii) −x−1/2, y−1/2, −z+3/2.
Table 1
Hydrogen-bond geometry (Å, °) top
D—H···AD—HH···AD···AD—H···A
N1—H1···O1i0.825 (17)2.255 (17)3.0306 (13)156.7 (15)
C25—H25···O3ii0.952.423.2082 (17)140
C23—H23···O4iii0.952.533.3400 (16)144
Symmetry codes: (i) x, y−1, z; (ii) −x, −y+2, −z+2; (iii) −x−1/2, y−1/2, −z+3/2.
Acknowledgements top

The authors are grateful to the Department of Chemistry, Quaid-I-Azam University, Islamabad, Pakistan, the Institute for Inorganic Chemistry, University of Frankfurt, Germany, and NESCOM PO Box 2166, Islamabad, Pakistan, for providing laboratory and analytical facilities.

references
References top

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Stoe & Cie (2001). X-AREA and X-RED. Stoe & Cie, Darmstadt, Germany.