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Acta Crystallogr Sect E Struct Rep Online. 2010 June 1; 66(Pt 6): o1279–o1280.
Published online 2010 May 8. doi:  10.1107/S1600536810015795
PMCID: PMC2979444

3,5-Bis(4-bromo­phen­yl)-1-phenyl-4,5-dihydro-1H-pyrazole

Abstract

In the title compound, C21H16Br2N2, the central pyrazole ring adopts an flattened envelope conformation, with the stereogenic C atom in the flap position. The deviations from planarity for this ring are relatively minor (r.m.s. deviation = 0.045 Å) and the dihedral angles formed with the N- and Cimine-bound benzene rings are 7.73 (13) and 11.00 (13)°, respectively. By contrast, the benzene ring bound at the chiral C atom is almost orthogonal to the rest of the mol­ecule; the dihedral angle formed between this ring and the pyrazole ring is 79.53 (13)°. In the crystal, the packing is stabilized by C—H(...)N and C—H(...)Br inter­actions.

Related literature

For the pharmacological activity of pyrazoline derivatives, see: Hes et al. (1978 [triangle]); Amir et al. (2008 [triangle]); Sarojini et al. (2010 [triangle]). For related structures, see: Fun et al. (2010 [triangle]); Yathirajan et al. (2007 [triangle]). For the structure of the parent compound, 1,3,5-triphenyl-2-pyrazoline, see: Foces-Foces et al. (2001 [triangle]). For conformational analysis, see: Cremer & Pople (1975 [triangle]).

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Object name is e-66-o1279-scheme1.jpg

Experimental

Crystal data

  • C21H16Br2N2
  • M r = 456.18
  • Orthorhombic, An external file that holds a picture, illustration, etc.
Object name is e-66-o1279-efi1.jpg
  • a = 10.5815 (3) Å
  • b = 11.2119 (3) Å
  • c = 15.4569 (4) Å
  • V = 1833.79 (9) Å3
  • Z = 4
  • Mo Kα radiation
  • μ = 4.43 mm−1
  • T = 100 K
  • 0.35 × 0.15 × 0.08 mm

Data collection

  • Bruker SMART APEX diffractometer
  • Absorption correction: multi-scan (SADABS; Sheldrick, 1996 [triangle]) T min = 0.537, T max = 0.746
  • 17504 measured reflections
  • 4201 independent reflections
  • 3753 reflections with I > 2σ(I)
  • R int = 0.044

Refinement

  • R[F 2 > 2σ(F 2)] = 0.027
  • wR(F 2) = 0.052
  • S = 1.02
  • 4201 reflections
  • 226 parameters
  • H-atom parameters constrained
  • Δρmax = 0.60 e Å−3
  • Δρmin = −0.40 e Å−3
  • Absolute structure: Flack (1983 [triangle]), 1804 Friedel pairs
  • Flack parameter: 0.003 (7)

Data collection: APEX2 (Bruker, 2008 [triangle]); cell refinement: SAINT (Bruker, 2008 [triangle]); data reduction: SAINT; program(s) used to solve structure: SIR97 (Altomare et al., 1999 [triangle]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 [triangle]); molecular graphics: ORTEP-3 (Farrugia, 1997 [triangle]) and DIAMOND (Brandenburg, 2006 [triangle]); software used to prepare material for publication: publCIF (Westrip, 2010 [triangle]).

Table 1
Hydrogen-bond geometry (Å, °)

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536810015795/hb5428sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S1600536810015795/hb5428Isup2.hkl

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

Acknowledgments

SS thanks Mangalore University and the UGC SAP for financial assistance for the purchase of chemicals. HSY thanks the University of Mysore for the sanction of sabbatical leave

supplementary crystallographic information

Comment

Derivatives of pyrazoline possess a range of pharmacological activities, having, for example, anti-tumour, anti-microbial, and anti-tubercular activities (Hes et al., 1978; Amir et al., 2008). Further, some of these compounds also have anti-inflammatory, anti-diabetic, anaesthetic, analgesic and DPPH scavenging properties (Sarojini et al., 2010). In continuation of previous structural studies of pyrazoline derivatives (Fun et al., 2010, Yathirajan et al., 2007), the title compound, (I), was synthesised and its crystal structure determined.

The structure analysis of (I) shows the C1 centre to have an S configuration, Fig. 1. The conformation of the central pyrazole ring is an envelope on the C1 atom as defined by the ring-puckering parameters of q2 = 0.101 (3) Å and [var phi]2 = 251.7 (14) ° (Cremer & Pople, 1975). That being stated, the maximum deviations from the five atoms of the ring are 0.052 (2) and -0.064 (3) Å for the N2 and C1 atoms, respectively; the r.m.s. deviation = 0.0450 Å. The N2- and C3-bound benzene rings are approximately co-planar with the central ring as seen in the dihedral angles formed between their respective least-squares planes and that through the pyrazole ring of 7.73 (13) and 11.00 (13) °; the dihedral angle between these benzene rings is 4.32 (12) °. By contrast, the C1-bound benzene ring is almost orthogonal to the remaining molecule with a dihedral angle of 79.53 (13) ° formed between it and the pyrazole ring. To a first approximation, the overall conformation in (I) resembles that in the analogous 1,3,5-triphenyl-2-pyrazoline "parent" compound although the deviations from planarity are slightly greater in the literature structure (Foces-Foces et al., 2001). Further, the N1–N2 [1.369 (3) Å] and N1═C3 [1.291 (3) Å] bond distances in (I) are comparable to the equivalent distances in 1,3,5-triphenyl-2-pyrazoline of 1.387 (5) and 1.285 (7) Å, respectively.

The molecules are consolidated into a 3-D network by C–H···N and C—H···Br contacts, Fig. 2 and Table 1.

Experimental

A mixture of (2E)-1,3-bis(4-bromophenyl)prop-2-en-1-one (3.66 g, 0.01 mol) and phenyl hydrazine (1.08 g, 0.01 mol) in glacial acetic acid (50 ml) was refluxed for 6 h. The reaction mixture was cooled and poured into ice-cold water (50 ml). The precipitate was collected by filtration and purified by recrystallization from ethanol. Yellow blocks of (I) were grown from toluene by slow evaporation; the yield was 86%, m.pt. 481 K. Analytical data (%): Found (Calc'd): C 55.21 (55.29); H 3.48 (3.54); N 6.10 (6.14).

Refinement

Carbon-bound H-atoms were placed in calculated positions (C—H 0.95 to 1.00 Å) and were included in the refinement in the riding model approximation, with Uiso(H) set to 1.2 to 1.5Ueq(C).

Figures

Fig. 1.
The molecular structure of (I) showing displacement ellipsoids at the 50% probability level.
Fig. 2.
A view in projection down the a axis of the crystal packing in (I) mediated by C–H···N and C–H···Br contacts, shown as orange and purple dashed lines, respectively.

Crystal data

C21H16Br2N2F(000) = 904
Mr = 456.18Dx = 1.652 Mg m3
Orthorhombic, P212121Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 2ac 2abCell parameters from 4444 reflections
a = 10.5815 (3) Åθ = 2.3–26.2°
b = 11.2119 (3) ŵ = 4.43 mm1
c = 15.4569 (4) ÅT = 100 K
V = 1833.79 (9) Å3Block, yellow
Z = 40.35 × 0.15 × 0.08 mm

Data collection

Bruker SMART APEX diffractometer4201 independent reflections
Radiation source: fine-focus sealed tube3753 reflections with I > 2σ(I)
graphiteRint = 0.044
ω scansθmax = 27.5°, θmin = 2.2°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)h = −13→13
Tmin = 0.537, Tmax = 0.746k = −14→14
17504 measured reflectionsl = −20→20

Refinement

Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.027H-atom parameters constrained
wR(F2) = 0.052w = 1/[σ2(Fo2) + (0.0105P)2] where P = (Fo2 + 2Fc2)/3
S = 1.02(Δ/σ)max < 0.001
4201 reflectionsΔρmax = 0.60 e Å3
226 parametersΔρmin = −0.40 e Å3
0 restraintsAbsolute structure: Flack (1983), 1804 Friedel pairs
Primary atom site location: structure-invariant direct methodsFlack parameter: 0.003 (7)

Special details

Geometry. All s.u.'s (except the s.u. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell s.u.'s are taken into account individually in the estimation of s.u.'s in distances, angles and torsion angles; correlations between s.u.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell s.u.'s is used for estimating s.u.'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 > 2σ(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
Br10.45694 (3)0.39983 (2)−0.095975 (18)0.03237 (9)
Br21.28094 (3)−0.06644 (3)0.379191 (19)0.02784 (8)
N10.68637 (18)−0.10495 (19)0.19763 (12)0.0155 (5)
N20.56377 (19)−0.07418 (19)0.18013 (13)0.0175 (5)
C10.5321 (3)0.0486 (2)0.20739 (15)0.0184 (5)
H10.45560.04790.24530.022*
C20.6507 (2)0.0809 (3)0.26139 (16)0.0226 (6)
H2A0.68780.15760.24220.027*
H2B0.63040.08590.32380.027*
C30.7385 (2)−0.0217 (2)0.24286 (16)0.0144 (6)
C40.5117 (2)0.1321 (2)0.13185 (17)0.0165 (6)
C50.4266 (3)0.2261 (2)0.13916 (17)0.0206 (6)
H50.37900.23510.19090.025*
C60.4100 (3)0.3064 (2)0.07249 (17)0.0230 (6)
H60.35210.37070.07810.028*
C70.4791 (3)0.2917 (2)−0.00225 (17)0.0208 (6)
C80.5631 (3)0.1994 (2)−0.01219 (16)0.0213 (6)
H80.60870.1901−0.06470.026*
C90.5803 (2)0.1200 (2)0.05566 (17)0.0193 (6)
H90.63940.05670.05000.023*
C100.8685 (2)−0.0309 (2)0.27394 (16)0.0141 (6)
C110.9485 (3)−0.1218 (2)0.24481 (16)0.0179 (6)
H110.9182−0.17840.20410.021*
C121.0714 (3)−0.1300 (2)0.27476 (17)0.0199 (6)
H121.1256−0.19140.25440.024*
C131.1146 (2)−0.0478 (3)0.33476 (17)0.0190 (6)
C141.0378 (2)0.0425 (2)0.36482 (16)0.0190 (5)
H141.06850.09810.40620.023*
C150.9159 (2)0.0512 (2)0.33413 (16)0.0178 (6)
H150.86310.11400.35410.021*
C160.4888 (2)−0.1457 (2)0.12849 (16)0.0168 (5)
C170.3627 (2)−0.1161 (2)0.11246 (16)0.0195 (6)
H170.3271−0.04680.13800.023*
C180.2893 (3)−0.1876 (3)0.05953 (17)0.0223 (6)
H180.2036−0.16660.04940.027*
C190.3379 (3)−0.2884 (3)0.02115 (17)0.0222 (6)
H190.2869−0.3362−0.01570.027*
C200.4627 (3)−0.3189 (2)0.03732 (17)0.0225 (6)
H200.4969−0.38860.01130.027*
C210.5387 (3)−0.2497 (2)0.09078 (16)0.0188 (5)
H210.6236−0.27250.10180.023*

Atomic displacement parameters (Å2)

U11U22U33U12U13U23
Br10.0559 (2)0.01873 (14)0.02246 (14)0.00349 (14)−0.01182 (14)0.00164 (12)
Br20.01697 (13)0.03195 (17)0.03461 (17)0.00011 (12)−0.00644 (13)0.00337 (14)
N10.0142 (11)0.0171 (11)0.0151 (10)−0.0003 (9)−0.0004 (8)0.0027 (10)
N20.0142 (11)0.0189 (12)0.0193 (10)0.0029 (10)−0.0035 (9)−0.0018 (9)
C10.0191 (14)0.0189 (13)0.0172 (13)0.0012 (12)0.0014 (11)−0.0035 (11)
C20.0227 (14)0.0244 (16)0.0208 (13)0.0058 (13)−0.0072 (12)−0.0030 (13)
C30.0172 (14)0.0140 (13)0.0121 (12)−0.0011 (10)0.0006 (10)0.0028 (10)
C40.0134 (13)0.0182 (13)0.0179 (13)−0.0005 (10)−0.0044 (11)−0.0022 (11)
C50.0194 (14)0.0231 (14)0.0195 (14)0.0009 (11)−0.0028 (11)−0.0035 (12)
C60.0255 (16)0.0166 (14)0.0269 (16)0.0043 (12)−0.0055 (13)−0.0047 (12)
C70.0284 (17)0.0171 (14)0.0170 (13)−0.0012 (12)−0.0115 (12)−0.0024 (12)
C80.0264 (17)0.0217 (15)0.0159 (13)−0.0010 (12)−0.0008 (12)−0.0018 (11)
C90.0176 (14)0.0183 (15)0.0219 (13)0.0058 (11)−0.0012 (11)−0.0030 (12)
C100.0150 (14)0.0137 (13)0.0136 (12)−0.0018 (10)0.0004 (10)0.0022 (10)
C110.0209 (15)0.0173 (14)0.0156 (12)−0.0048 (12)−0.0016 (12)−0.0017 (10)
C120.0203 (15)0.0163 (14)0.0232 (14)0.0003 (11)0.0030 (12)0.0011 (11)
C130.0124 (13)0.0239 (15)0.0205 (13)−0.0005 (11)−0.0010 (11)0.0094 (12)
C140.0222 (14)0.0176 (13)0.0173 (13)−0.0044 (11)−0.0033 (12)0.0025 (11)
C150.0210 (14)0.0143 (13)0.0180 (13)0.0003 (11)0.0037 (11)0.0002 (11)
C160.0189 (13)0.0188 (12)0.0126 (12)−0.0049 (10)0.0008 (11)0.0013 (11)
C170.0218 (14)0.0186 (13)0.0181 (14)−0.0005 (11)−0.0008 (12)0.0025 (12)
C180.0187 (15)0.0292 (16)0.0190 (14)−0.0032 (13)−0.0030 (13)0.0058 (12)
C190.0255 (16)0.0243 (16)0.0168 (14)−0.0098 (13)−0.0023 (12)0.0001 (12)
C200.0249 (16)0.0230 (14)0.0196 (14)−0.0061 (13)0.0040 (13)−0.0033 (11)
C210.0159 (14)0.0221 (13)0.0183 (13)−0.0028 (11)0.0021 (12)0.0021 (12)

Geometric parameters (Å, °)

Br1—C71.903 (3)C9—H90.9500
Br2—C131.901 (2)C10—C111.399 (4)
N1—C31.291 (3)C10—C151.402 (4)
N1—N21.369 (3)C11—C121.383 (4)
N2—C161.382 (3)C11—H110.9500
N2—C11.478 (3)C12—C131.385 (4)
C1—C41.512 (4)C12—H120.9500
C1—C21.550 (4)C13—C141.379 (4)
C1—H11.0000C14—C151.377 (4)
C2—C31.506 (4)C14—H140.9500
C2—H2A0.9900C15—H150.9500
C2—H2B0.9900C16—C171.397 (3)
C3—C101.461 (4)C16—C211.407 (3)
C4—C91.390 (4)C17—C181.383 (4)
C4—C51.391 (4)C17—H170.9500
C5—C61.380 (4)C18—C191.377 (4)
C5—H50.9500C18—H180.9500
C6—C71.377 (4)C19—C201.386 (4)
C6—H60.9500C19—H190.9500
C7—C81.373 (4)C20—C211.390 (4)
C8—C91.388 (4)C20—H200.9500
C8—H80.9500C21—H210.9500
C3—N1—N2109.2 (2)C11—C10—C15118.4 (2)
N1—N2—C16120.8 (2)C11—C10—C3121.0 (2)
N1—N2—C1113.1 (2)C15—C10—C3120.6 (2)
C16—N2—C1125.1 (2)C12—C11—C10120.6 (2)
N2—C1—C4112.9 (2)C12—C11—H11119.7
N2—C1—C2100.8 (2)C10—C11—H11119.7
C4—C1—C2112.8 (2)C11—C12—C13119.3 (2)
N2—C1—H1110.0C11—C12—H12120.3
C4—C1—H1110.0C13—C12—H12120.3
C2—C1—H1110.0C14—C13—C12121.3 (2)
C3—C2—C1102.6 (2)C14—C13—Br2120.3 (2)
C3—C2—H2A111.2C12—C13—Br2118.3 (2)
C1—C2—H2A111.2C15—C14—C13119.2 (2)
C3—C2—H2B111.2C15—C14—H14120.4
C1—C2—H2B111.2C13—C14—H14120.4
H2A—C2—H2B109.2C14—C15—C10121.1 (2)
N1—C3—C10122.0 (2)C14—C15—H15119.4
N1—C3—C2113.1 (2)C10—C15—H15119.4
C10—C3—C2124.9 (2)N2—C16—C17120.9 (2)
C9—C4—C5118.8 (2)N2—C16—C21120.3 (2)
C9—C4—C1121.3 (2)C17—C16—C21118.8 (2)
C5—C4—C1119.9 (2)C18—C17—C16120.3 (3)
C6—C5—C4121.0 (2)C18—C17—H17119.9
C6—C5—H5119.5C16—C17—H17119.9
C4—C5—H5119.5C19—C18—C17121.4 (3)
C7—C6—C5118.8 (2)C19—C18—H18119.3
C7—C6—H6120.6C17—C18—H18119.3
C5—C6—H6120.6C18—C19—C20118.7 (3)
C8—C7—C6121.8 (2)C18—C19—H19120.6
C8—C7—Br1118.3 (2)C20—C19—H19120.6
C6—C7—Br1119.8 (2)C19—C20—C21121.4 (3)
C7—C8—C9118.9 (2)C19—C20—H20119.3
C7—C8—H8120.5C21—C20—H20119.3
C9—C8—H8120.5C20—C21—C16119.5 (3)
C8—C9—C4120.6 (2)C20—C21—H21120.3
C8—C9—H9119.7C16—C21—H21120.3
C4—C9—H9119.7
C3—N1—N2—C16176.5 (2)N1—C3—C10—C1110.1 (4)
C3—N1—N2—C17.3 (3)C2—C3—C10—C11−171.9 (2)
N1—N2—C1—C4110.1 (2)N1—C3—C10—C15−169.7 (2)
C16—N2—C1—C4−58.6 (3)C2—C3—C10—C158.4 (4)
N1—N2—C1—C2−10.5 (3)C15—C10—C11—C12−0.1 (4)
C16—N2—C1—C2−179.1 (2)C3—C10—C11—C12−179.8 (2)
N2—C1—C2—C39.2 (2)C10—C11—C12—C130.6 (4)
C4—C1—C2—C3−111.5 (2)C11—C12—C13—C14−0.4 (4)
N2—N1—C3—C10178.0 (2)C11—C12—C13—Br2176.76 (19)
N2—N1—C3—C2−0.3 (3)C12—C13—C14—C15−0.3 (4)
C1—C2—C3—N1−6.1 (3)Br2—C13—C14—C15−177.42 (19)
C1—C2—C3—C10175.7 (2)C13—C14—C15—C100.8 (4)
N2—C1—C4—C9−34.0 (3)C11—C10—C15—C14−0.7 (4)
C2—C1—C4—C979.5 (3)C3—C10—C15—C14179.1 (2)
N2—C1—C4—C5148.6 (2)N1—N2—C16—C17178.2 (2)
C2—C1—C4—C5−98.0 (3)C1—N2—C16—C17−13.9 (4)
C9—C4—C5—C6−0.2 (4)N1—N2—C16—C21−1.9 (3)
C1—C4—C5—C6177.3 (2)C1—N2—C16—C21165.9 (2)
C4—C5—C6—C70.4 (4)N2—C16—C17—C18179.0 (2)
C5—C6—C7—C80.2 (4)C21—C16—C17—C18−0.8 (4)
C5—C6—C7—Br1179.2 (2)C16—C17—C18—C19−0.3 (4)
C6—C7—C8—C9−1.1 (4)C17—C18—C19—C200.9 (4)
Br1—C7—C8—C9179.9 (2)C18—C19—C20—C21−0.3 (4)
C7—C8—C9—C41.3 (4)C19—C20—C21—C16−0.8 (4)
C5—C4—C9—C8−0.6 (4)N2—C16—C21—C20−178.4 (2)
C1—C4—C9—C8−178.1 (2)C17—C16—C21—C201.4 (4)

Hydrogen-bond geometry (Å, °)

D—H···AD—HH···AD···AD—H···A
C5—H5···N1i0.952.583.374 (3)141
C20—H20···Br1ii0.952.923.768 (2)148

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

Footnotes

Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: HB5428).

References

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