3-(4-Bromo­phen­yl)-1-phenyl-1H-pyrazole-4-carbaldehyde

In the title compound, C₁₆H₁₁BrN₂O, the phenyl and chloro­benzene rings are twisted out of the mean plane of the pyrazole ring, forming dihedral angles of 13.70 (10) and 36.48 (10)°, respectively. The carbaldehyde group is also twisted out of the pyrazole plane [the C—C—C—O torsion angle is 7.9 (3)°]. A helical supra­molecular chain along the b axis and mediated by C—H...O inter­actions is the most prominent feature of the crystal packing.

Key indicators

• Single-crystal X-ray study
• T = 100 K
• Mean [sigma](C-C) = 0.003 Å
• R factor = 0.025
• wR factor = 0.069
• Data-to-parameter ratio = 14.3

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT029_ALERT_3_C _diffrn_measured_fraction_theta_full Low .......      0.972
PLAT431_ALERT_2_C Short Inter HL..A Contact  Br1    ..  O1      ..       3.17 Ang.
PLAT911_ALERT_3_C Missing # FCF Refl Between THmin & STh/L=  0.600         10
PLAT912_ALERT_4_C Missing # of FCF Reflections Above STh/L=  0.600         64
PLAT913_ALERT_3_C Missing # of Very Strong Reflections in FCF ....          4

Alert level G
PLAT005_ALERT_5_G No _iucr_refine_instructions_details in CIF ....          ?
PLAT128_ALERT_4_G Alternate Setting of Space-group P21/c   .......      P21/n

   0 ALERT level A = Most likely a serious problem - resolve or explain
   0 ALERT level B = A potentially serious problem, consider carefully
   5 ALERT level C = Check. Ensure it is not caused by an omission or oversight
   2 ALERT level G = General information/check it is not something unexpected

   0 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   1 ALERT type 2 Indicator that the structure model may be wrong or deficient
   3 ALERT type 3 Indicator that the structure quality may be low
   2 ALERT type 4 Improvement, methodology, query or suggestion
   1 ALERT type 5 Informative message, check

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S1. Comment

A broad spectrum of biological activities [anti-bacterial, anti-depressant, anti-convulsive, anti-hypertensive, anti-oxidant anti-viral and anti-tumour] have been noted for pyrazoles and their derivatives (Kaushik et al., 2010; Ali et al., 2007; Krishnamurthy et al., 2004). In continuation of structural studies in this area (Asiri et al., 2011), the title compound, (I), was investigated.

The dihedral angles formed between the central pyrazole ring [r.m.s. deviation = 0.003 Å] and the N– and C-bound benzene rings of 13.70 (10) and 36.48 (10) °, respectively, indicate significant twists in the molecule of (I), Fig. 1. Similarly, the carbaldehyde group is twisted out of the plane of the five-membered ring as seen in the value of the C13—C14—C16—O1 torsion angle of 7.9 (3) °. The relative disposition of the benzene rings preclude close intermolecular association with the imine-N2 atom which, indeed, forms a close intramolecular C2—H···N2 contact, Table 1.

The crystal packing features C—H···O interactions involving a bifurcated carbonyl-O1 atom, Table 1. These result in the formation of a helical supramolecular chain along the b axis, Fig. 2.

Related literature

For background details and biological applications of pyrazoles, see: Kaushik et al. (2010); Ali et al. (2007); Krishnamurthy et al. (2004). For a related structure, see: Asiri et al. (2011).

S2. Experimental

Phosphoryl chloride (5.6 ml) was added drop wise to cold N,N-dimethylformamide (22.5 ml) under continuous stirring at 273–278 K for about 30 min. 4-Bromoacetophenone phenylhydrazone (5 g, 17 mmol) was added to the above reaction mixture. The resulting mixture was further stirred at 333 K for 6 h. and cooled to room temperature. The crude product was poured into crushed ice which resulted in a white precipitate. The resultant solid was filtered, dried and purified by column chromatography using chloroform. Recrystallization was by slow evaporation of chloroform solution of (I) which yielded colourless prisms. M.pt. 413–415 K. Yield: 56%.

S3. Refinement

Carbon-bound H-atoms were placed in calculated positions [C—H 0.95 Å, U_iso(H) = 1.2U_eq(C)] and were included in the refinement in the riding model approximation.

Computing details

Data collection: CrysAlis PRO (Agilent, 2010); cell refinement: CrysAlis PRO (Agilent, 2010); data reduction: CrysAlis PRO (Agilent, 2010); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 (Farrugia, 1997) and DIAMOND (Brandenburg, 2006); software used to prepare material for publication: publCIF (Westrip, 2010).

Figures

	Fig. 1. The molecular structures of (I) showing displacement ellipsoids at the 70% probability level.
	Fig. 2. Helical supramolecular chain in (I) mediated by C—H···O (orange dashed lines) interactions.

3-(4-Bromophenyl)-1-phenyl-1H-pyrazole-4-carbaldehyde

Crystal data

C16H11BrN2O	F(000) = 656
Mr = 327.18	Dx = 1.655 Mg m^−3
Monoclinic, P21/n	Cu Kα radiation, λ = 1.54184 Å
Hall symbol: -P 2yn	Cell parameters from 3680 reflections
a = 17.7233 (4) Å	θ = 2.7–74.1°
b = 3.8630 (1) Å	µ = 4.23 mm^−1
c = 20.4224 (5) Å	T = 100 K
β = 110.137 (3)°	Prism, colourless
V = 1312.75 (6) Å^3	0.25 × 0.20 × 0.15 mm
Z = 4

Data collection

Agilent SuperNova Dual diffractometer with an Atlas detector	2593 independent reflections
Radiation source: SuperNova (Cu) X-ray Source	2542 reflections with I > 2σ(I)
Mirror monochromator	Rint = 0.012
Detector resolution: 10.4041 pixels mm^-1	θmax = 74.3°, θmin = 2.9°
ω scans	h = −21→21
Absorption correction: multi-scan (CrysAlis PRO; Agilent, 2010)	k = −4→4
Tmin = 0.418, Tmax = 0.569	l = −19→25
4619 measured reflections

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.025	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.069	H-atom parameters constrained
S = 1.02	w = 1/[σ^2(Fo^2) + (0.0432P)^2 + 1.2934P] where P = (Fo^2 + 2Fc^2)/3
2593 reflections	(Δ/σ)max = 0.004
181 parameters	Δρmax = 0.39 e Å^−3
0 restraints	Δρmin = −0.66 e Å^−3

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 (Ų)

	x	y	z	Uiso*/Ueq
Br1	0.979494 (11)	0.14952 (5)	1.111751 (9)	0.01554 (9)
O1	0.66107 (9)	0.4209 (4)	0.71084 (7)	0.0183 (3)
N1	0.54596 (9)	0.8378 (4)	0.84419 (8)	0.0106 (3)
N2	0.60504 (9)	0.7642 (4)	0.90629 (8)	0.0114 (3)
C1	0.47250 (10)	0.9916 (5)	0.84392 (9)	0.0112 (3)
C2	0.45581 (11)	0.9963 (5)	0.90561 (10)	0.0146 (4)
H2	0.4929	0.9008	0.9471	0.018*
C3	0.38437 (12)	1.1422 (5)	0.90583 (11)	0.0170 (4)
H3	0.3729	1.1496	0.9480	0.020*
C4	0.32952 (12)	1.2773 (5)	0.84520 (11)	0.0169 (4)
H4	0.2805	1.3744	0.8456	0.020*
C5	0.34673 (11)	1.2698 (5)	0.78370 (10)	0.0165 (4)
H5	0.3092	1.3617	0.7421	0.020*
C6	0.41865 (12)	1.1284 (5)	0.78272 (10)	0.0148 (4)
H6	0.4307	1.1255	0.7408	0.018*
C7	0.73867 (11)	0.5078 (5)	0.94282 (9)	0.0112 (4)
C8	0.73831 (12)	0.3647 (5)	1.00557 (10)	0.0128 (4)
H8	0.6888	0.3396	1.0135	0.015*
C9	0.80911 (12)	0.2589 (5)	1.05641 (9)	0.0141 (4)
H9	0.8085	0.1639	1.0991	0.017*
C10	0.88090 (11)	0.2942 (5)	1.04391 (10)	0.0135 (4)
C11	0.88296 (11)	0.4357 (5)	0.98216 (10)	0.0146 (4)
H11	0.9326	0.4580	0.9744	0.018*
C12	0.81210 (11)	0.5442 (5)	0.93190 (9)	0.0133 (4)
H12	0.8133	0.6440	0.8898	0.016*
C13	0.56590 (11)	0.7418 (5)	0.78887 (9)	0.0117 (3)
H13	0.5340	0.7694	0.7411	0.014*
C14	0.64162 (11)	0.5954 (5)	0.81478 (10)	0.0115 (4)
C15	0.66323 (11)	0.6177 (5)	0.88888 (9)	0.0105 (4)
C16	0.68436 (11)	0.4243 (5)	0.77447 (10)	0.0135 (4)
H16	0.7332	0.3085	0.7991	0.016*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Br1	0.01392 (13)	0.01863 (13)	0.01135 (12)	0.00306 (7)	0.00088 (9)	0.00292 (7)
O1	0.0176 (7)	0.0277 (7)	0.0116 (6)	−0.0046 (6)	0.0076 (5)	−0.0054 (6)
N1	0.0085 (7)	0.0138 (8)	0.0094 (7)	0.0002 (6)	0.0029 (6)	−0.0001 (5)
N2	0.0103 (7)	0.0144 (7)	0.0089 (7)	0.0004 (6)	0.0024 (6)	0.0000 (6)
C1	0.0089 (8)	0.0110 (9)	0.0143 (8)	−0.0015 (7)	0.0048 (7)	−0.0025 (7)
C2	0.0142 (9)	0.0164 (9)	0.0134 (8)	0.0000 (7)	0.0051 (7)	−0.0003 (7)
C3	0.0168 (10)	0.0180 (10)	0.0195 (10)	−0.0001 (7)	0.0103 (8)	−0.0031 (7)
C4	0.0130 (9)	0.0141 (9)	0.0246 (10)	−0.0002 (8)	0.0076 (8)	−0.0026 (8)
C5	0.0113 (9)	0.0161 (9)	0.0192 (9)	0.0009 (8)	0.0014 (7)	0.0006 (8)
C6	0.0139 (9)	0.0172 (10)	0.0136 (9)	−0.0002 (7)	0.0051 (8)	0.0002 (7)
C7	0.0107 (8)	0.0111 (9)	0.0113 (8)	0.0002 (7)	0.0032 (7)	−0.0014 (7)
C8	0.0131 (9)	0.0150 (9)	0.0127 (9)	−0.0004 (7)	0.0075 (7)	−0.0008 (7)
C9	0.0190 (9)	0.0149 (9)	0.0097 (8)	0.0004 (8)	0.0067 (7)	0.0011 (7)
C10	0.0129 (9)	0.0141 (9)	0.0110 (8)	0.0007 (7)	0.0010 (7)	−0.0009 (7)
C11	0.0106 (9)	0.0200 (9)	0.0138 (9)	−0.0019 (7)	0.0049 (7)	0.0012 (8)
C12	0.0135 (9)	0.0167 (9)	0.0108 (8)	−0.0006 (7)	0.0053 (7)	0.0018 (7)
C13	0.0123 (8)	0.0145 (9)	0.0082 (8)	−0.0018 (7)	0.0034 (7)	−0.0014 (7)
C14	0.0119 (8)	0.0132 (8)	0.0103 (8)	−0.0016 (7)	0.0051 (7)	−0.0010 (7)
C15	0.0114 (9)	0.0117 (8)	0.0094 (9)	−0.0026 (6)	0.0048 (7)	−0.0009 (6)
C16	0.0118 (8)	0.0168 (9)	0.0134 (9)	−0.0020 (7)	0.0064 (7)	−0.0031 (7)

Geometric parameters (Å, º)

Br1—C10	1.9023 (19)	C7—C8	1.398 (3)
O1—C16	1.220 (2)	C7—C12	1.401 (2)
N1—C13	1.347 (2)	C7—C15	1.472 (3)
N1—N2	1.368 (2)	C8—C9	1.387 (3)
N1—C1	1.429 (2)	C8—H8	0.9500
N2—C15	1.328 (2)	C9—C10	1.388 (3)
C1—C6	1.390 (3)	C9—H9	0.9500
C1—C2	1.390 (3)	C10—C11	1.386 (3)
C2—C3	1.387 (3)	C11—C12	1.385 (3)
C2—H2	0.9500	C11—H11	0.9500
C3—C4	1.386 (3)	C12—H12	0.9500
C3—H3	0.9500	C13—C14	1.383 (3)
C4—C5	1.391 (3)	C13—H13	0.9500
C4—H4	0.9500	C14—C15	1.430 (2)
C5—C6	1.393 (3)	C14—C16	1.455 (3)
C5—H5	0.9500	C16—H16	0.9500
C6—H6	0.9500
C13—N1—N2	112.47 (15)	C9—C8—H8	119.5
C13—N1—C1	127.81 (16)	C7—C8—H8	119.5
N2—N1—C1	119.70 (15)	C8—C9—C10	118.95 (17)
C15—N2—N1	104.93 (14)	C8—C9—H9	120.5
C6—C1—C2	121.05 (17)	C10—C9—H9	120.5
C6—C1—N1	120.28 (16)	C11—C10—C9	121.26 (17)
C2—C1—N1	118.67 (17)	C11—C10—Br1	118.24 (14)
C3—C2—C1	119.17 (18)	C9—C10—Br1	120.50 (14)
C3—C2—H2	120.4	C12—C11—C10	119.49 (17)
C1—C2—H2	120.4	C12—C11—H11	120.3
C2—C3—C4	120.68 (18)	C10—C11—H11	120.3
C2—C3—H3	119.7	C11—C12—C7	120.44 (17)
C4—C3—H3	119.7	C11—C12—H12	119.8
C3—C4—C5	119.61 (18)	C7—C12—H12	119.8
C3—C4—H4	120.2	N1—C13—C14	106.98 (16)
C5—C4—H4	120.2	N1—C13—H13	126.5
C4—C5—C6	120.48 (19)	C14—C13—H13	126.5
C4—C5—H5	119.8	C13—C14—C15	104.56 (16)
C6—C5—H5	119.8	C13—C14—C16	126.51 (17)
C1—C6—C5	118.99 (18)	C15—C14—C16	128.61 (17)
C1—C6—H6	120.5	N2—C15—C14	111.05 (16)
C5—C6—H6	120.5	N2—C15—C7	120.77 (16)
C8—C7—C12	118.90 (17)	C14—C15—C7	128.17 (16)
C8—C7—C15	120.71 (16)	O1—C16—C14	123.78 (18)
C12—C7—C15	120.40 (16)	O1—C16—H16	118.1
C9—C8—C7	120.97 (17)	C14—C16—H16	118.1
C13—N1—N2—C15	−0.1 (2)	Br1—C10—C11—C12	−179.81 (15)
C1—N1—N2—C15	178.39 (16)	C10—C11—C12—C7	−0.8 (3)
C13—N1—C1—C6	−14.2 (3)	C8—C7—C12—C11	0.9 (3)
N2—N1—C1—C6	167.59 (17)	C15—C7—C12—C11	−178.95 (18)
C13—N1—C1—C2	164.85 (18)	N2—N1—C13—C14	0.3 (2)
N2—N1—C1—C2	−13.4 (3)	C1—N1—C13—C14	−178.04 (17)
C6—C1—C2—C3	−0.4 (3)	N1—C13—C14—C15	−0.3 (2)
N1—C1—C2—C3	−179.44 (17)	N1—C13—C14—C16	173.58 (18)
C1—C2—C3—C4	1.0 (3)	N1—N2—C15—C14	−0.1 (2)
C2—C3—C4—C5	−0.7 (3)	N1—N2—C15—C7	178.76 (16)
C3—C4—C5—C6	−0.1 (3)	C13—C14—C15—N2	0.3 (2)
C2—C1—C6—C5	−0.4 (3)	C16—C14—C15—N2	−173.44 (19)
N1—C1—C6—C5	178.59 (18)	C13—C14—C15—C7	−178.49 (18)
C4—C5—C6—C1	0.7 (3)	C16—C14—C15—C7	7.8 (3)
C12—C7—C8—C9	−0.2 (3)	C8—C7—C15—N2	37.3 (3)
C15—C7—C8—C9	179.64 (17)	C12—C7—C15—N2	−142.86 (19)
C7—C8—C9—C10	−0.6 (3)	C8—C7—C15—C14	−143.99 (19)
C8—C9—C10—C11	0.7 (3)	C12—C7—C15—C14	35.8 (3)
C8—C9—C10—Br1	−179.51 (15)	C13—C14—C16—O1	7.9 (3)
C9—C10—C11—C12	0.0 (3)	C15—C14—C16—O1	−179.63 (19)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
C12—H12···O1^i	0.95	2.49	3.435 (2)	171
C16—H16···O1^ii	0.95	2.46	3.288 (3)	145

Symmetry codes: (i) −x+3/2, y+1/2, −z+3/2; (ii) −x+3/2, y−1/2, −z+3/2.