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

Samshuddin, S.; Narayana, B.; Yathirajan, H.S.; Safwan, A.P.; Tiekink, E.R.T.

doi:10.1107/S1600536810015795

organic compounds

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ISSN: 2056-9890

Volume 66| Part 6| June 2010| Pages o1279-o1280

https://doi.org/10.1107/S1600536810015795

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

S. Samshuddin,^a B. Narayana,^a H. S. Yathirajan,^b ‡ A. P. Safwan ^c and Edward R. T. Tiekink ^c ^*

^aDepartment of Studies in Chemistry, Mangalore University, Mangalagangotri 574 199, India, ^bDepartment of Studies in Chemistry, University of Mysore, Manasagangotri, Mysore 570 006, India, and ^cDepartment of Chemistry, University of Malaya, 50603 Kuala Lumpur, Malaysia
^*Correspondence e-mail: edward.tiekink@gmail.com

(Received 28 April 2010; accepted 29 April 2010; online 8 May 2010)

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

Experimental

Crystal data

C₂₁H₁₆Br₂N₂
M_r = 456.18
Orthorhombic, P 2₁ 2₁ 2₁
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 ) 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[F² > 2σ(F²)] = 0.027
wR(F²) = 0.052
S = 1.02
4201 reflections
226 parameters
H-atom parameters constrained
Δρ_max = 0.60 e Å⁻³
Δρ_min = −0.40 e Å⁻³
Absolute structure: Flack (1983 ), 1804 Friedel pairs
Flack parameter: 0.003 (7)

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C5—H5⋯N1ⁱ	0.95	2.58	3.374 (3)	141
C20—H20⋯Br1ⁱⁱ	0.95	2.92	3.768 (2)	148
Symmetry codes: (i) $[-x+1, y+{\script{1\over 2}}, -z+{\script{1\over 2}}]$ ; (ii) x, y-1, z.

Data collection: APEX2 (Bruker, 2008 ); cell refinement: SAINT (Bruker, 2008); data reduction: SAINT; program(s) used to solve structure: SIR97 (Altomare et al., 1999 ); 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 ).

Supporting information

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

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S1600536810015795/hb5428Isup2.hkl

checkCIF report

Comment top

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 φ₂ = 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.

Related literature top

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

Experimental top

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).

Structure description top

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

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

Computing details top

Data collection: APEX2 (Bruker, 2008); cell refinement: SAINT (Bruker, 2008); data reduction: SAINT (Bruker, 2008); program(s) used to solve structure: SIR97 (Altomare et al., 1999); 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 top

	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.

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

Crystal data top

C₂₁H₁₆Br₂N₂	F(000) = 904
M_r = 456.18	D_x = 1.652 Mg m⁻³
Orthorhombic, P2₁2₁2₁	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 2ac 2ab	Cell parameters from 4444 reflections
a = 10.5815 (3) Å	θ = 2.3–26.2°
b = 11.2119 (3) Å	µ = 4.43 mm⁻¹
c = 15.4569 (4) Å	T = 100 K
V = 1833.79 (9) Å³	Block, yellow
Z = 4	0.35 × 0.15 × 0.08 mm

Data collection top

Bruker SMART APEX diffractometer	4201 independent reflections
Radiation source: fine-focus sealed tube	3753 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.044
ω scans	θ_max = 27.5°, θ_min = 2.2°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	h = −13→13
T_min = 0.537, T_max = 0.746	k = −14→14
17504 measured reflections	l = −20→20

Refinement top

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)] = 0.027	H-atom parameters constrained
wR(F²) = 0.052	w = 1/[σ²(F_o²) + (0.0105P)²] where P = (F_o² + 2F_c²)/3
S = 1.02	(Δ/σ)_max < 0.001
4201 reflections	Δρ_max = 0.60 e Å⁻³
226 parameters	Δρ_min = −0.40 e Å⁻³
0 restraints	Absolute structure: Flack (1983), 1804 Friedel pairs
Primary atom site location: structure-invariant direct methods	Absolute structure parameter: 0.003 (7)

Crystal data top

C₂₁H₁₆Br₂N₂	V = 1833.79 (9) Å³
M_r = 456.18	Z = 4
Orthorhombic, P2₁2₁2₁	Mo Kα radiation
a = 10.5815 (3) Å	µ = 4.43 mm⁻¹
b = 11.2119 (3) Å	T = 100 K
c = 15.4569 (4) Å	0.35 × 0.15 × 0.08 mm

Data collection top

Bruker SMART APEX diffractometer	4201 independent reflections
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	3753 reflections with I > 2σ(I)
T_min = 0.537, T_max = 0.746	R_int = 0.044
17504 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.027	H-atom parameters constrained
wR(F²) = 0.052	Δρ_max = 0.60 e Å⁻³
S = 1.02	Δρ_min = −0.40 e Å⁻³
4201 reflections	Absolute structure: Flack (1983), 1804 Friedel pairs
226 parameters	Absolute structure parameter: 0.003 (7)
0 restraints

Special details top

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) top

	x	y	z	U_iso*/U_eq
Br1	0.45694 (3)	0.39983 (2)	−0.095975 (18)	0.03237 (9)
Br2	1.28094 (3)	−0.06644 (3)	0.379191 (19)	0.02784 (8)
N1	0.68637 (18)	−0.10495 (19)	0.19763 (12)	0.0155 (5)
N2	0.56377 (19)	−0.07418 (19)	0.18013 (13)	0.0175 (5)
C1	0.5321 (3)	0.0486 (2)	0.20739 (15)	0.0184 (5)
H1	0.4556	0.0479	0.2453	0.022*
C2	0.6507 (2)	0.0809 (3)	0.26139 (16)	0.0226 (6)
H2A	0.6878	0.1576	0.2422	0.027*
H2B	0.6304	0.0859	0.3238	0.027*
C3	0.7385 (2)	−0.0217 (2)	0.24286 (16)	0.0144 (6)
C4	0.5117 (2)	0.1321 (2)	0.13185 (17)	0.0165 (6)
C5	0.4266 (3)	0.2261 (2)	0.13916 (17)	0.0206 (6)
H5	0.3790	0.2351	0.1909	0.025*
C6	0.4100 (3)	0.3064 (2)	0.07249 (17)	0.0230 (6)
H6	0.3521	0.3707	0.0781	0.028*
C7	0.4791 (3)	0.2917 (2)	−0.00225 (17)	0.0208 (6)
C8	0.5631 (3)	0.1994 (2)	−0.01219 (16)	0.0213 (6)
H8	0.6087	0.1901	−0.0647	0.026*
C9	0.5803 (2)	0.1200 (2)	0.05566 (17)	0.0193 (6)
H9	0.6394	0.0567	0.0500	0.023*
C10	0.8685 (2)	−0.0309 (2)	0.27394 (16)	0.0141 (6)
C11	0.9485 (3)	−0.1218 (2)	0.24481 (16)	0.0179 (6)
H11	0.9182	−0.1784	0.2041	0.021*
C12	1.0714 (3)	−0.1300 (2)	0.27476 (17)	0.0199 (6)
H12	1.1256	−0.1914	0.2544	0.024*
C13	1.1146 (2)	−0.0478 (3)	0.33476 (17)	0.0190 (6)
C14	1.0378 (2)	0.0425 (2)	0.36482 (16)	0.0190 (5)
H14	1.0685	0.0981	0.4062	0.023*
C15	0.9159 (2)	0.0512 (2)	0.33413 (16)	0.0178 (6)
H15	0.8631	0.1140	0.3541	0.021*
C16	0.4888 (2)	−0.1457 (2)	0.12849 (16)	0.0168 (5)
C17	0.3627 (2)	−0.1161 (2)	0.11246 (16)	0.0195 (6)
H17	0.3271	−0.0468	0.1380	0.023*
C18	0.2893 (3)	−0.1876 (3)	0.05953 (17)	0.0223 (6)
H18	0.2036	−0.1666	0.0494	0.027*
C19	0.3379 (3)	−0.2884 (3)	0.02115 (17)	0.0222 (6)
H19	0.2869	−0.3362	−0.0157	0.027*
C20	0.4627 (3)	−0.3189 (2)	0.03732 (17)	0.0225 (6)
H20	0.4969	−0.3886	0.0113	0.027*
C21	0.5387 (3)	−0.2497 (2)	0.09078 (16)	0.0188 (5)
H21	0.6236	−0.2725	0.1018	0.023*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Br1	0.0559 (2)	0.01873 (14)	0.02246 (14)	0.00349 (14)	−0.01182 (14)	0.00164 (12)
Br2	0.01697 (13)	0.03195 (17)	0.03461 (17)	0.00011 (12)	−0.00644 (13)	0.00337 (14)
N1	0.0142 (11)	0.0171 (11)	0.0151 (10)	−0.0003 (9)	−0.0004 (8)	0.0027 (10)
N2	0.0142 (11)	0.0189 (12)	0.0193 (10)	0.0029 (10)	−0.0035 (9)	−0.0018 (9)
C1	0.0191 (14)	0.0189 (13)	0.0172 (13)	0.0012 (12)	0.0014 (11)	−0.0035 (11)
C2	0.0227 (14)	0.0244 (16)	0.0208 (13)	0.0058 (13)	−0.0072 (12)	−0.0030 (13)
C3	0.0172 (14)	0.0140 (13)	0.0121 (12)	−0.0011 (10)	0.0006 (10)	0.0028 (10)
C4	0.0134 (13)	0.0182 (13)	0.0179 (13)	−0.0005 (10)	−0.0044 (11)	−0.0022 (11)
C5	0.0194 (14)	0.0231 (14)	0.0195 (14)	0.0009 (11)	−0.0028 (11)	−0.0035 (12)
C6	0.0255 (16)	0.0166 (14)	0.0269 (16)	0.0043 (12)	−0.0055 (13)	−0.0047 (12)
C7	0.0284 (17)	0.0171 (14)	0.0170 (13)	−0.0012 (12)	−0.0115 (12)	−0.0024 (12)
C8	0.0264 (17)	0.0217 (15)	0.0159 (13)	−0.0010 (12)	−0.0008 (12)	−0.0018 (11)
C9	0.0176 (14)	0.0183 (15)	0.0219 (13)	0.0058 (11)	−0.0012 (11)	−0.0030 (12)
C10	0.0150 (14)	0.0137 (13)	0.0136 (12)	−0.0018 (10)	0.0004 (10)	0.0022 (10)
C11	0.0209 (15)	0.0173 (14)	0.0156 (12)	−0.0048 (12)	−0.0016 (12)	−0.0017 (10)
C12	0.0203 (15)	0.0163 (14)	0.0232 (14)	0.0003 (11)	0.0030 (12)	0.0011 (11)
C13	0.0124 (13)	0.0239 (15)	0.0205 (13)	−0.0005 (11)	−0.0010 (11)	0.0094 (12)
C14	0.0222 (14)	0.0176 (13)	0.0173 (13)	−0.0044 (11)	−0.0033 (12)	0.0025 (11)
C15	0.0210 (14)	0.0143 (13)	0.0180 (13)	0.0003 (11)	0.0037 (11)	0.0002 (11)
C16	0.0189 (13)	0.0188 (12)	0.0126 (12)	−0.0049 (10)	0.0008 (11)	0.0013 (11)
C17	0.0218 (14)	0.0186 (13)	0.0181 (14)	−0.0005 (11)	−0.0008 (12)	0.0025 (12)
C18	0.0187 (15)	0.0292 (16)	0.0190 (14)	−0.0032 (13)	−0.0030 (13)	0.0058 (12)
C19	0.0255 (16)	0.0243 (16)	0.0168 (14)	−0.0098 (13)	−0.0023 (12)	0.0001 (12)
C20	0.0249 (16)	0.0230 (14)	0.0196 (14)	−0.0061 (13)	0.0040 (13)	−0.0033 (11)
C21	0.0159 (14)	0.0221 (13)	0.0183 (13)	−0.0028 (11)	0.0021 (12)	0.0021 (12)

Geometric parameters (Å, º) top

Br1—C7	1.903 (3)	C9—H9	0.9500
Br2—C13	1.901 (2)	C10—C11	1.399 (4)
N1—C3	1.291 (3)	C10—C15	1.402 (4)
N1—N2	1.369 (3)	C11—C12	1.383 (4)
N2—C16	1.382 (3)	C11—H11	0.9500
N2—C1	1.478 (3)	C12—C13	1.385 (4)
C1—C4	1.512 (4)	C12—H12	0.9500
C1—C2	1.550 (4)	C13—C14	1.379 (4)
C1—H1	1.0000	C14—C15	1.377 (4)
C2—C3	1.506 (4)	C14—H14	0.9500
C2—H2A	0.9900	C15—H15	0.9500
C2—H2B	0.9900	C16—C17	1.397 (3)
C3—C10	1.461 (4)	C16—C21	1.407 (3)
C4—C9	1.390 (4)	C17—C18	1.383 (4)
C4—C5	1.391 (4)	C17—H17	0.9500
C5—C6	1.380 (4)	C18—C19	1.377 (4)
C5—H5	0.9500	C18—H18	0.9500
C6—C7	1.377 (4)	C19—C20	1.386 (4)
C6—H6	0.9500	C19—H19	0.9500
C7—C8	1.373 (4)	C20—C21	1.390 (4)
C8—C9	1.388 (4)	C20—H20	0.9500
C8—H8	0.9500	C21—H21	0.9500

C3—N1—N2	109.2 (2)	C11—C10—C15	118.4 (2)
N1—N2—C16	120.8 (2)	C11—C10—C3	121.0 (2)
N1—N2—C1	113.1 (2)	C15—C10—C3	120.6 (2)
C16—N2—C1	125.1 (2)	C12—C11—C10	120.6 (2)
N2—C1—C4	112.9 (2)	C12—C11—H11	119.7
N2—C1—C2	100.8 (2)	C10—C11—H11	119.7
C4—C1—C2	112.8 (2)	C11—C12—C13	119.3 (2)
N2—C1—H1	110.0	C11—C12—H12	120.3
C4—C1—H1	110.0	C13—C12—H12	120.3
C2—C1—H1	110.0	C14—C13—C12	121.3 (2)
C3—C2—C1	102.6 (2)	C14—C13—Br2	120.3 (2)
C3—C2—H2A	111.2	C12—C13—Br2	118.3 (2)
C1—C2—H2A	111.2	C15—C14—C13	119.2 (2)
C3—C2—H2B	111.2	C15—C14—H14	120.4
C1—C2—H2B	111.2	C13—C14—H14	120.4
H2A—C2—H2B	109.2	C14—C15—C10	121.1 (2)
N1—C3—C10	122.0 (2)	C14—C15—H15	119.4
N1—C3—C2	113.1 (2)	C10—C15—H15	119.4
C10—C3—C2	124.9 (2)	N2—C16—C17	120.9 (2)
C9—C4—C5	118.8 (2)	N2—C16—C21	120.3 (2)
C9—C4—C1	121.3 (2)	C17—C16—C21	118.8 (2)
C5—C4—C1	119.9 (2)	C18—C17—C16	120.3 (3)
C6—C5—C4	121.0 (2)	C18—C17—H17	119.9
C6—C5—H5	119.5	C16—C17—H17	119.9
C4—C5—H5	119.5	C19—C18—C17	121.4 (3)
C7—C6—C5	118.8 (2)	C19—C18—H18	119.3
C7—C6—H6	120.6	C17—C18—H18	119.3
C5—C6—H6	120.6	C18—C19—C20	118.7 (3)
C8—C7—C6	121.8 (2)	C18—C19—H19	120.6
C8—C7—Br1	118.3 (2)	C20—C19—H19	120.6
C6—C7—Br1	119.8 (2)	C19—C20—C21	121.4 (3)
C7—C8—C9	118.9 (2)	C19—C20—H20	119.3
C7—C8—H8	120.5	C21—C20—H20	119.3
C9—C8—H8	120.5	C20—C21—C16	119.5 (3)
C8—C9—C4	120.6 (2)	C20—C21—H21	120.3
C8—C9—H9	119.7	C16—C21—H21	120.3
C4—C9—H9	119.7

C3—N1—N2—C16	176.5 (2)	N1—C3—C10—C11	10.1 (4)
C3—N1—N2—C1	7.3 (3)	C2—C3—C10—C11	−171.9 (2)
N1—N2—C1—C4	110.1 (2)	N1—C3—C10—C15	−169.7 (2)
C16—N2—C1—C4	−58.6 (3)	C2—C3—C10—C15	8.4 (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—C3	9.2 (2)	C10—C11—C12—C13	0.6 (4)
C4—C1—C2—C3	−111.5 (2)	C11—C12—C13—C14	−0.4 (4)
N2—N1—C3—C10	178.0 (2)	C11—C12—C13—Br2	176.76 (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—C10	175.7 (2)	C13—C14—C15—C10	0.8 (4)
N2—C1—C4—C9	−34.0 (3)	C11—C10—C15—C14	−0.7 (4)
C2—C1—C4—C9	79.5 (3)	C3—C10—C15—C14	179.1 (2)
N2—C1—C4—C5	148.6 (2)	N1—N2—C16—C17	178.2 (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—C6	177.3 (2)	C1—N2—C16—C21	165.9 (2)
C4—C5—C6—C7	0.4 (4)	N2—C16—C17—C18	179.0 (2)
C5—C6—C7—C8	0.2 (4)	C21—C16—C17—C18	−0.8 (4)
C5—C6—C7—Br1	179.2 (2)	C16—C17—C18—C19	−0.3 (4)
C6—C7—C8—C9	−1.1 (4)	C17—C18—C19—C20	0.9 (4)
Br1—C7—C8—C9	179.9 (2)	C18—C19—C20—C21	−0.3 (4)
C7—C8—C9—C4	1.3 (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—C20	1.4 (4)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C5—H5···N1ⁱ	0.95	2.58	3.374 (3)	141
C20—H20···Br1ⁱⁱ	0.95	2.92	3.768 (2)	148

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

Experimental details

Crystal data
Chemical formula	C₂₁H₁₆Br₂N₂
M_r	456.18
Crystal system, space group	Orthorhombic, P2₁2₁2₁
Temperature (K)	100
a, b, c (Å)	10.5815 (3), 11.2119 (3), 15.4569 (4)
V (Å³)	1833.79 (9)
Z	4
Radiation type	Mo Kα
µ (mm⁻¹)	4.43
Crystal size (mm)	0.35 × 0.15 × 0.08

Data collection
Diffractometer	Bruker SMART APEX diffractometer
Absorption correction	Multi-scan (SADABS; Sheldrick, 1996)
T_min, T_max	0.537, 0.746
No. of measured, independent and observed [I > 2σ(I)] reflections	17504, 4201, 3753
R_int	0.044
(sin θ/λ)_max (Å⁻¹)	0.650

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.027, 0.052, 1.02
No. of reflections	4201
No. of parameters	226
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.60, −0.40
Absolute structure	Flack (1983), 1804 Friedel pairs
Absolute structure parameter	0.003 (7)

Computer programs: APEX2 (Bruker, 2008), SAINT (Bruker, 2008), SIR97 (Altomare et al., 1999), SHELXL97 (Sheldrick, 2008), ORTEP-3 (Farrugia, 1997) and DIAMOND (Brandenburg, 2006), publCIF (Westrip, 2010).

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C5—H5···N1ⁱ	0.95	2.58	3.374 (3)	141
C20—H20···Br1ⁱⁱ	0.95	2.92	3.768 (2)	148

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

Footnotes

‡Additional correspondence author, e-mail: yathirajan@hotmail.com.

Acknowledgements

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

References

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