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Acta Crystallogr Sect E Struct Rep Online. 2010 October 1; 66(Pt 10): o2594–o2595.
Published online 2010 September 18. doi:  10.1107/S1600536810035646
PMCID: PMC2983380

(E)-3-(4-Chloro­phen­yl)-3-[3-(4-chloro­phen­yl)-1H-pyrazol-1-yl]prop-2-enal

Abstract

In the title compound, C18H12Cl2N2O, the pyrazole ring is almost planar [r.m.s. deviation = 0.002 Å] while the two chloro­phenyl rings are twisted out from the plane of the pyrazole ring, making dihedral angles of 5.3 (1) and 65.34 (4)°. In the crystal, centrosymmetric R 2 2(24) dimers are formed about crystallographic inversion centres through a pair of C—H(...)Cl inter­actions. These dimers are further linked through a C—H(...)O hydrogen bond, forming a C(8) chain extending along the a axis. C—H(...)π inter­actions are also observed.

Related literature

For the pharmacological properties of pyrazoles and their derivatives, see: Baraldi et al. (1998 [triangle]); Bruno et al. (1990 [triangle]); Chen & Li (1998 [triangle]); Cottineau et al. (2002 [triangle]); Londershausen (1996 [triangle]); Mishra et al. (1998 [triangle]); Magedov et al. (2007 [triangle]); Rovnyak et al. (1982 [triangle]); Smith et al. (2001 [triangle]); Velaparthi et al. (2008 [triangle]); Wamhoff et al. (1993 [triangle]). For hybridization and electron delocalization around N atoms, see: Beddoes et al. (1986 [triangle]); Jin et al. (2004 [triangle]). For hydrogen bonding, see: Desiraju & Steiner (1999 [triangle]) and for hydrogen-bond motifs, see: Etter et al. (1990 [triangle]).

An external file that holds a picture, illustration, etc.
Object name is e-66-o2594-scheme1.jpg

Experimental

Crystal data

  • C18H12Cl2N2O
  • M r = 343.20
  • Triclinic, An external file that holds a picture, illustration, etc.
Object name is e-66-o2594-efi1.jpg
  • a = 9.4321 (6) Å
  • b = 9.6081 (5) Å
  • c = 9.9439 (7) Å
  • α = 90.533 (7)°
  • β = 116.924 (4)°
  • γ = 93.427 (6)°
  • V = 801.38 (9) Å3
  • Z = 2
  • Mo Kα radiation
  • μ = 0.41 mm−1
  • T = 293 K
  • 0.16 × 0.14 × 0.12 mm

Data collection

  • Bruker SMART APEX CCD area-detector diffractometer
  • Absorption correction: multi-scan (SADABS; Sheldrick, 2001 [triangle]) T min = 0.884, T max = 0.993
  • 8950 measured reflections
  • 3464 independent reflections
  • 2982 reflections with I > 2σ(I)
  • R int = 0.018

Refinement

  • R[F 2 > 2σ(F 2)] = 0.040
  • wR(F 2) = 0.116
  • S = 1.04
  • 3464 reflections
  • 211 parameters
  • H atoms treated by a mixture of independent and constrained refinement
  • Δρmax = 0.20 e Å−3
  • Δρmin = −0.24 e Å−3

Data collection: SMART (Bruker, 2001 [triangle]); cell refinement: SAINT (Bruker, 2001 [triangle]); data reduction: SAINT; program(s) used to solve structure: SHELXTL/PC (Sheldrick, 2008 [triangle]); program(s) used to refine structure: SHELXTL/PC; molecular graphics: PLATON (Spek, 2009 [triangle]); software used to prepare material for publication: SHELXTL/PC.

Table 1
Hydrogen-bond geometry (Å, °)

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536810035646/fb2206sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S1600536810035646/fb2206Isup2.hkl

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Acknowledgments

VS and SAB sincerely thank the Vice Chancellor and Management of Kalasalingam University, Anand Nagar, Krishnan Koil, for their support and encouragement. SA thanks the Vice-Chancellor of Anna University, Tirunelveli, for his support and encouragement.

supplementary crystallographic information

Comment

Pyrazole and its derivatives have been successfully tested for their fungicidal (Chen & Li, 1998), antihistaminic (Mishra et al., 1998), anti-inflammatory (Smith et al., 2001), antiarrhythmic and sedative (Bruno et al., 1990), hypoglycemic (Cottineau et al., 2002), antiviral (Baraldi et al., 1998) activities. Pyrazole derivates possess antimicrobial (Velaparthi et al.,2008), anticancer (Magedov et al., 2007) and anti-inflammatory (Rovnyak et al., 1982) properties. They can also be used as biodegradable agrochemicals (Wamhoff et al., 1993) as well as pesticides (Londershausen, 1996). Wide variety of biological effects of these molecules provoked interest for their crystal structure study and accordingly we have synthesized the title compound by multi-component reaction which conforms to principles of green chemistry. The crystal structure of the title compound is reported here.

The title molecule is shown in Fig. 1. The pyrazole ring is planar with the r.m.s. deviation equal to 0.002 Å. The sum of the bond angles at N1 of the pyrazole ring (359.7 (1)°) is in accordance with the sp2 hybridization of this atom (Beddoes et al., 1986). The C—N bond lengths in the pyrazole ring are 1.370 (2) [C5-N1] and 1.327 (2)Å [C3-N2] long. These distances are shorter than the pertinent single bond length (1.443 Å), however, they are longer than the double bond length (1.269 Å) (Jin et al., 2004). The values of these distances in the title structure indicate electron delocalization.

The two chlorophenyl rings are twisted out from the plane of the pyrazole ring with respective angles of 5.3 (1)° (C31//C36 ring) and 65.34 (4)° (C12//C17 ring). The propenal group assumes the extended conformation which is evidenced by the torsion angles of 173.3 (1)° [N1-C11-C1A-C2A] and 157.0 (2)° [C5-N1-C11-C1A]. The crystal structure is stabilized by intermolecular C—H···Cl, C—H···O and C—H···π-electron ring interactions (Tab. 1). The packing diagram of the title compound is shown in Fig. 2.

Each of two centrosymmetric R22(24) dimers (Etter et al., 1990) are formed around the crystallographic inversion centres through a pair of the respective C—H···Cl interactions (Figs. 3 and 4 referring to C13—H13···Cl2 and C36—H36···Cl1, respectively; Tab. 1). Though the latter H···Cl distances are somewhat longer by about 0.5Å than the accepted values for the C-H···Cl hydrogen bonding (Desiraju & Steiner, 1999) these dimers are an important motif in the present structure and therefore they are reported here.

These dimers are linked through a C—H···O bond making a chain C(8) motif (Etter et al., 1990) that extends along the a axis of the unit cell (Fig. 5). Further, one of these primary ring R22(24) motifs and the chain C(8) motif are combined to form a secondary ring R44(32) motif (Fig. 6). Also, the C—H···π-electron ring interactions are observed in the structure. The crystallographic inversions link the latter motifs into pairs, forming another ring motif.

Experimental

To a mixture of 1-(4-chlorophenyl)-1-ethanone N-[(E)-1-(4-chlorophenyl)ethylidene]hydrazone (0.003 mole) and 3 ml of dimethyl formamide kept in ice bath at 0°C, phosphorous oxycholride (0.024 mole) was added dropwise in 5 to 10 minutes. The reaction mixture was then irradiated under microwaves for 30 sec using a Biotage Microwave Synthesizer (frequency 2.45 GHz corresponding to the wavelength equal to 12.24 cm). The process of the reaction was monitored by thin layer chromatography using petroleum ether and ethyl acetate (4:1 v/v) as an eluent. The Rf value of the product was 0.62. After completion of the reaction, the reaction mixture was poured into crushed ice and extracted with dichloromethane. The organic layer was dried over anhydrous sodium sulfate. The title compound was separated by column chromatography: carrier: silica gel (60-120 mesh), eluent: petroleum ether and ethyl acetate mixture (98:2 v/v). The compound was crystallized from dichloromethane. Colourless crystals of a prismatic habitus with the average size of 0.5 × 0.5 × 0.2 cm were grown within a week.

Refinement

All the H atoms were observable in the difference electron density map. All the hydrogens except the one from the aldehyde group were situated into the idealized positions and refined by the riding model approximation. The used values for the constraints: d(C—H) = 0.93 Å. Uiso(H)= 1.2Ueq(C). The positional parameters of the aldehyde hydrogen were refined freely while Uiso(H)= 1.2Ueq(C).

Figures

Fig. 1.
The title molecule with the atom numbering scheme. The displacement ellipsoids are shown at the 50% probability level.
Fig. 2.
Packing diagram of the title structure viewed down the a axis. (Cl is shown in green, N in blue, O in red, C in black and H as a circle.)
Fig. 3.
Ring R22(24) motif involving the C13—H13···Cl2 interactions. These interactions are drawn as dashed lines. (Cl is shown in green, N in blue, O in red, C in black and H in violet.)
Fig. 4.
Ring R22(24) motif involving the C36—H36···Cl1 interactions. These interactions are drawn as dashed lines. (Cl is shown in green, N in blue, O in red, C in black and H in violet.)
Fig. 5.
Chain C(8) motif involving the C14—H14···O1 hydrogen bond. The hydrogen bonds are drawn as dashed lines. (Cl is shown in green, N in blue, O in red, C in black and H in violet.)
Fig. 6.
Secondary ring R44(32) motif formed by a combination of the ring R22(24) and the chain C(8) motifs. The C—H···O bonds and C—H···Cl interactions are drawn as dashed lines. (Cl is shown in ...

Crystal data

C18H12Cl2N2OZ = 2
Mr = 343.20F(000) = 352
Triclinic, P1Dx = 1.422 Mg m3
Hall symbol: -P 1Mo Kα radiation, λ = 0.71073 Å
a = 9.4321 (6) ÅCell parameters from 4879 reflections
b = 9.6081 (5) Åθ = 2.4–24.7°
c = 9.9439 (7) ŵ = 0.41 mm1
α = 90.533 (7)°T = 293 K
β = 116.924 (4)°Block, colourless
γ = 93.427 (6)°0.16 × 0.14 × 0.12 mm
V = 801.38 (9) Å3

Data collection

Bruker SMART APEX CCD area-detector diffractometer3464 independent reflections
Radiation source: fine-focus sealed tube2982 reflections with I > 2σ(I)
graphiteRint = 0.018
ω scansθmax = 27.0°, θmin = 2.1°
Absorption correction: multi-scan (SADABS; Sheldrick, 2001)h = −12→11
Tmin = 0.884, Tmax = 0.993k = −12→12
8950 measured reflectionsl = −12→12

Refinement

Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.040Hydrogen site location: difference Fourier map
wR(F2) = 0.116H atoms treated by a mixture of independent and constrained refinement
S = 1.04w = 1/[σ2(Fo2) + (0.064P)2 + 0.1138P] where P = (Fo2 + 2Fc2)/3
3464 reflections(Δ/σ)max < 0.001
211 parametersΔρmax = 0.20 e Å3
0 restraintsΔρmin = −0.24 e Å3

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 > 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)

xyzUiso*/Ueq
N10.32051 (15)0.14597 (14)0.94391 (16)0.0637 (3)
N20.33330 (15)0.11932 (14)0.81571 (16)0.0645 (3)
C30.23105 (17)0.01018 (15)0.74769 (19)0.0609 (4)
C40.1527 (2)−0.03430 (17)0.8341 (2)0.0703 (4)
H40.0765−0.10850.81090.084*
C50.2117 (2)0.05315 (17)0.9566 (2)0.0704 (4)
H50.18380.05101.03510.084*
C110.42212 (17)0.24992 (16)1.05026 (18)0.0616 (4)
C120.36968 (16)0.29488 (15)1.16169 (18)0.0588 (3)
C130.21605 (17)0.33822 (17)1.1154 (2)0.0656 (4)
H130.14690.34081.01290.079*
C140.16603 (17)0.37703 (17)1.2194 (2)0.0674 (4)
H140.06350.40531.18770.081*
C150.26958 (18)0.37363 (15)1.3718 (2)0.0617 (4)
C160.42360 (18)0.33354 (15)1.42098 (19)0.0625 (4)
H160.49310.33331.52350.075*
C170.47177 (16)0.29416 (15)1.31565 (18)0.0604 (4)
H170.57460.26651.34790.072*
C310.21217 (16)−0.04755 (15)0.60370 (19)0.0596 (4)
C320.2953 (2)0.01493 (17)0.5314 (2)0.0679 (4)
H320.35860.09710.57300.082*
C330.28550 (19)−0.04239 (17)0.4007 (2)0.0695 (4)
H330.34210.00020.35440.083*
C340.19066 (18)−0.16420 (17)0.33797 (18)0.0637 (4)
C350.10245 (17)−0.22597 (17)0.4035 (2)0.0670 (4)
H350.0357−0.30590.35900.080*
C360.11458 (17)−0.16782 (16)0.5355 (2)0.0651 (4)
H360.0561−0.20990.58030.078*
C1A0.55695 (18)0.29870 (18)1.0452 (2)0.0694 (4)
H1A0.58530.25530.97780.083*
C2A0.65832 (19)0.4138 (2)1.1383 (2)0.0739 (4)
O10.78899 (15)0.44765 (18)1.14726 (18)0.0993 (5)
Cl10.20652 (6)0.41935 (5)1.50378 (6)0.08373 (18)
Cl20.18660 (6)−0.24132 (5)0.17751 (5)0.08459 (18)
H2A0.612 (3)0.475 (2)1.198 (3)0.102*

Atomic displacement parameters (Å2)

U11U22U33U12U13U23
N10.0550 (7)0.0618 (7)0.0774 (8)0.0047 (6)0.0326 (6)0.0104 (6)
N20.0554 (7)0.0635 (7)0.0762 (8)0.0042 (6)0.0312 (6)0.0107 (6)
C30.0500 (7)0.0530 (7)0.0810 (10)0.0102 (6)0.0297 (7)0.0162 (7)
C40.0665 (9)0.0589 (8)0.0926 (12)0.0006 (7)0.0427 (9)0.0115 (8)
C50.0654 (9)0.0641 (9)0.0900 (11)0.0033 (7)0.0426 (9)0.0148 (8)
C110.0475 (7)0.0620 (8)0.0726 (9)0.0099 (6)0.0240 (7)0.0146 (7)
C120.0444 (7)0.0553 (7)0.0743 (9)0.0047 (6)0.0247 (6)0.0127 (7)
C130.0443 (7)0.0698 (9)0.0745 (9)0.0073 (6)0.0194 (7)0.0093 (7)
C140.0446 (7)0.0643 (9)0.0910 (11)0.0056 (6)0.0285 (8)0.0058 (8)
C150.0550 (8)0.0488 (7)0.0830 (10)−0.0070 (6)0.0341 (7)0.0005 (7)
C160.0532 (8)0.0544 (7)0.0722 (9)−0.0030 (6)0.0225 (7)0.0081 (7)
C170.0432 (7)0.0573 (8)0.0747 (9)0.0061 (6)0.0211 (6)0.0139 (7)
C310.0450 (7)0.0536 (7)0.0775 (9)0.0098 (6)0.0246 (7)0.0167 (7)
C320.0617 (9)0.0571 (8)0.0812 (10)−0.0050 (7)0.0300 (8)0.0110 (7)
C330.0612 (9)0.0686 (9)0.0755 (10)−0.0059 (7)0.0293 (8)0.0144 (8)
C340.0489 (7)0.0652 (8)0.0669 (9)0.0057 (6)0.0171 (6)0.0132 (7)
C350.0483 (7)0.0608 (8)0.0811 (10)−0.0025 (6)0.0205 (7)0.0100 (7)
C360.0477 (7)0.0605 (8)0.0856 (11)0.0009 (6)0.0290 (7)0.0138 (8)
C1A0.0498 (8)0.0802 (10)0.0790 (10)0.0084 (7)0.0292 (7)0.0104 (8)
C2A0.0507 (8)0.0877 (11)0.0792 (11)0.0029 (8)0.0260 (8)0.0168 (9)
O10.0524 (7)0.1234 (12)0.1192 (12)−0.0071 (7)0.0379 (7)0.0170 (9)
Cl10.0797 (3)0.0800 (3)0.1033 (4)−0.0142 (2)0.0546 (3)−0.0152 (2)
Cl20.0784 (3)0.0921 (3)0.0749 (3)−0.0089 (2)0.0293 (2)−0.0005 (2)

Geometric parameters (Å, °)

N1—N21.357 (2)C16—C171.375 (2)
N1—C51.370 (2)C16—H160.9300
N1—C111.408 (2)C17—H170.9300
N2—C31.327 (2)C31—C361.391 (2)
C3—C41.418 (2)C31—C321.398 (2)
C3—C311.460 (2)C32—C331.369 (2)
C4—C51.346 (3)C32—H320.9300
C4—H40.9300C33—C341.384 (2)
C5—H50.9300C33—H330.9300
C11—C1A1.351 (2)C34—C351.382 (2)
C11—C121.474 (2)C34—Cl21.7366 (18)
C12—C171.392 (2)C35—C361.375 (2)
C12—C131.399 (2)C35—H350.9300
C13—C141.374 (2)C36—H360.9300
C13—H130.9300C1A—C2A1.431 (3)
C14—C151.384 (2)C1A—H1A0.9300
C14—H140.9300C2A—O11.219 (2)
C15—C161.387 (2)C2A—H2A1.07 (2)
C15—Cl11.7313 (17)
N2—N1—C5111.32 (14)C17—C16—H16120.5
N2—N1—C11120.54 (13)C15—C16—H16120.5
C5—N1—C11127.88 (15)C16—C17—C12121.30 (13)
C3—N2—N1105.24 (13)C16—C17—H17119.3
N2—C3—C4110.62 (16)C12—C17—H17119.3
N2—C3—C31120.42 (14)C36—C31—C32117.70 (16)
C4—C3—C31128.96 (15)C36—C31—C3121.53 (14)
C5—C4—C3105.75 (15)C32—C31—C3120.75 (14)
C5—C4—H4127.1C33—C32—C31121.34 (15)
C3—C4—H4127.1C33—C32—H32119.3
C4—C5—N1107.06 (16)C31—C32—H32119.3
C4—C5—H5126.5C32—C33—C34119.49 (15)
N1—C5—H5126.5C32—C33—H33120.3
C1A—C11—N1119.59 (16)C34—C33—H33120.3
C1A—C11—C12125.45 (15)C35—C34—C33120.66 (16)
N1—C11—C12114.95 (13)C35—C34—Cl2120.04 (13)
C17—C12—C13118.47 (15)C33—C34—Cl2119.29 (13)
C17—C12—C11120.65 (13)C36—C35—C34119.15 (15)
C13—C12—C11120.88 (14)C36—C35—H35120.4
C14—C13—C12120.84 (15)C34—C35—H35120.4
C14—C13—H13119.6C35—C36—C31121.60 (15)
C12—C13—H13119.6C35—C36—H36119.2
C13—C14—C15119.37 (14)C31—C36—H36119.2
C13—C14—H14120.3C11—C1A—C2A123.32 (17)
C15—C14—H14120.3C11—C1A—H1A118.3
C14—C15—C16121.07 (15)C2A—C1A—H1A118.3
C14—C15—Cl1119.74 (12)O1—C2A—C1A123.47 (19)
C16—C15—Cl1119.20 (13)O1—C2A—H2A119.7 (13)
C17—C16—C15118.93 (15)C1A—C2A—H2A116.7 (13)
C5—N1—N2—C30.51 (16)C14—C15—C16—C17−1.3 (2)
C11—N1—N2—C3175.14 (12)Cl1—C15—C16—C17178.47 (11)
N1—N2—C3—C4−0.49 (16)C15—C16—C17—C120.5 (2)
N1—N2—C3—C31179.66 (12)C13—C12—C17—C160.7 (2)
N2—C3—C4—C50.30 (18)C11—C12—C17—C16−178.87 (13)
C31—C3—C4—C5−179.86 (14)N2—C3—C31—C36175.27 (13)
C3—C4—C5—N10.03 (18)C4—C3—C31—C36−4.6 (2)
N2—N1—C5—C4−0.34 (18)N2—C3—C31—C32−3.1 (2)
C11—N1—C5—C4−174.48 (14)C4—C3—C31—C32177.04 (15)
N2—N1—C11—C1A−16.7 (2)C36—C31—C32—C33−2.1 (2)
C5—N1—C11—C1A156.99 (16)C3—C31—C32—C33176.38 (14)
N2—N1—C11—C12164.21 (12)C31—C32—C33—C340.4 (2)
C5—N1—C11—C12−22.1 (2)C32—C33—C34—C351.9 (2)
C1A—C11—C12—C17−52.2 (2)C32—C33—C34—Cl2−176.72 (12)
N1—C11—C12—C17126.86 (15)C33—C34—C35—C36−2.4 (2)
C1A—C11—C12—C13128.27 (18)Cl2—C34—C35—C36176.17 (11)
N1—C11—C12—C13−52.66 (19)C34—C35—C36—C310.7 (2)
C17—C12—C13—C14−1.0 (2)C32—C31—C36—C351.5 (2)
C11—C12—C13—C14178.48 (14)C3—C31—C36—C35−176.91 (13)
C12—C13—C14—C150.3 (2)N1—C11—C1A—C2A173.32 (15)
C13—C14—C15—C160.9 (2)C12—C11—C1A—C2A−7.7 (3)
C13—C14—C15—Cl1−178.85 (12)C11—C1A—C2A—O1170.98 (18)

Hydrogen-bond geometry (Å, °)

Cg1 is the centroid of the C31–C36 ring.
D—H···AD—HH···AD···AD—H···A
C13—H13···Cl2i0.932.933.6447 (16)134
C14—H14···O1ii0.932.493.407 (2)167
C36—H36···Cl1iii0.932.903.6334 (16)137
C17—H17···Cg1iv0.932.683.4919 (18)147

Symmetry codes: (i) −x, −y, −z+1; (ii) x−1, y, z; (iii) −x, −y, −z+2; (iv) −x+1, −y, −z+2.

Footnotes

Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: FB2206).

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