2-[2-(4-Bromo­phen­yl)hydrazinyl­idene]-1,3-diphenyl­propane-1,3-dione

Bustos, C.; Alvarez-Thon, L.; Cárcamo, J.-G.; Garland, M.T.; Sánchez, C.

doi:10.1107/S1600536811017557

organic compounds

CRYSTALLOGRAPHIC
COMMUNICATIONS

ISSN: 2056-9890

Volume 67| Part 6| June 2011| Page o1426

doi:10.1107/S1600536811017557

Open

access

2-[2-(4-Bromophenyl)hydrazinylidene]-1,3-diphenylpropane-1,3-dione

Carlos Bustos,^a Luis Alvarez-Thon,^b ^* Juan-Guillermo Cárcamo,^c Maria Teresa Garland ^d and Christian Sánchez ^a

^aInstituto de Ciencias Químicas, Universidad Austral de Chile, Avda. Los Robles s/n, Campus Isla Teja, Casilla 567, Valdivia, Chile, ^bDepartamento de Ciencias Físicas, Universidad Andres Bello, Avda. República 220, Santiago de Chile, Chile, ^cInstituto de Ciencias Moleculares y Microbiología, Universidad Austral de Chile, Avda. Los Robles s/n, Campus Isla Teja, Casilla 567, Valdivia, Chile, and ^dLaboratorio de Cristalografía, Departamento de Física, Facultad de Ciencias Físicas y Matemáticas, Universidad de Chile, Santiago de Chile, Chile
^*Correspondence e-mail: lalvarez@unab.cl

(Received 5 May 2011; accepted 10 May 2011; online 14 May 2011)

The conformation of the title molecule, C₂₁H₁₅BrN₂O₂, is stabilized by a weak intramolecular C—H⋯N hydrogen bond and a strong resonance-assisted N—H⋯O intramolecular hydrogen bond. In the crystal, the molecules are linked by weak intermolecular C—H⋯O interactions, forming zigzag chains along the b axis.

Related literature

For resonance-assisted hydrogen bonds and related structures, see: Bertolasi et al. (1994 ). For details of the synthesis, see: Bustos et al. (2007 , 2009 ); Yao (1964 ).

Experimental

Crystal data

C₂₁H₁₅BrN₂O₂
M_r = 407.25
Monoclinic, P 2₁ /n
a = 12.0273 (9) Å
b = 10.2977 (8) Å
c = 14.2626 (11) Å
β = 96.452 (1)°
V = 1755.3 (2) Å³
Z = 4
Mo Kα radiation
μ = 2.36 mm⁻¹
T = 150 K
0.44 × 0.41 × 0.12 mm

Data collection

Bruker D8 Discover diffractometer with SMART CCD area detector
Absorption correction: multi-scan (SADABS; Bruker, 2000 ) T_min = 0.368, T_max = 0.753
13742 measured reflections
3575 independent reflections
3107 reflections with I > 2σ(I)
R_int = 0.021

Refinement

R[F² > 2σ(F²)] = 0.030
wR(F²) = 0.079
S = 1.06
3575 reflections
235 parameters
H-atom parameters constrained
Δρ_max = 0.67 e Å⁻³
Δρ_min = −0.17 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N2—H21⋯O2	0.88	1.90	2.592 (2)	135
C8—H8⋯N1	0.95	2.60	3.060 (3)	110
C17—H17⋯O2ⁱ	0.95	2.46	3.382 (3)	162
Symmetry code: (i) $[-x-{\script{1\over 2}}, y-{\script{1\over 2}}, -z+{\script{1\over 2}}]$ .

Data collection: SMART (Bruker, 2001 ); cell refinement: SAINT (Bruker, 2000); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: XP in SHELXTL-PC (Sheldrick, 2008); software used to prepare material for publication: PLATON (Spek, 2009 ) and Mercury (Macrae et al., 2006 ).

Supporting information

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536811017557/pv2416sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536811017557/pv2416Isup2.hkl

Supporting information file. DOI: 10.1107/S1600536811017557/pv2416Isup3.cml

checkCIF report

Comment top

In recent years, much attention has been devoted to structural studies on heterodienic systems forming strong intramolecular hydrogen bonds, N—H···O, assisted by resonance (RAHB, Resonance Assisted Hydrogen Bond) which, inter alia, could have potential technological applications as bistate molecular switches (Bertolasi et al., 1994; Bustos et al., 2007). On the other hand, it is well known that the phenyl diazonium salts are capable of coupling with a series of β-diketonate anions to give β-diketohidrazones that contain the N—H···O core (Yao, 1964; Bustos et al., 2007; Bustos et al., 2009). Using this reaction (Yao, 1964) we have prepared the title compound and, in this report, we present its crystal and molecular structure determined by X-ray diffraction method.

The molecular structure of the title compound exhibits a strong intramolecular hydrogen bond (N2–H21···O2) and a weak intramolecular hydrogen bond (C8–H8···N1) (Fig. 1 and Tab. 1). The molecules are linked by weak intermolecular C17–H17···O2ⁱ interactions forming zigzag chains along the b axis (Fig. 2).

Related literature top

For resonance-assisted hydrogen bonds and related structures, see: Bertolasi et al. (1994). For details of the synthesis, see: Bustos et al. (2007, 2009); Yao (1964).

Experimental top

In a 500 ml flask, 1,3-diphenylpropane-1,3-dione (2.24 g, 0.01 mole) was dissolved in an ethanol solution (100 ml) containing of sodium hydroxide (0.4 g, 0.01 mole) and of sodium acetate (3.65 g, 0.045 mole). The resulting β-diketonate solution was diluted with water to a final volume of about 220 ml, stirred and cooled at 268 K. In another 50 ml beaker a diazonium ion solution was prepared by adding 4-bromoaniline (97%) (1.77 g, 0.01 mole) in 8 ml of hydrochloric acid (5 mol/L), cooling at 268 K, and adding a saturated aqueous solution containing sodium nitrite (0.69 g, 0.01 mole). The diazonium salt solution was then added dropwise, with vigorous stirring, into the β-diketonate solution. During the addition a yellow solid precipitate of the title compound was formed which was filtered by suction and washed with an abundant quantity of water (Yield: 96% of crude product). Single crystals suitable for X-ray studies were obtained by recrystallization from a concentrated solution of the compound in ethanol.

Computing details top

Data collection: SMART (Bruker, 2001); cell refinement: SAINT (Bruker, 2000); data reduction: SAINT (Bruker, 2000); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: XP in SHELXTL-PC (Sheldrick, 2008); software used to prepare material for publication: PLATON (Spek, 2009) and Mercury (Macrae et al., 2006).

Figures top

	Fig. 1. A view of the title compound with the atom numbering scheme. Displacement ellipsoids are drawn at the 50% probability level. The strong intramolecular hydrogen bond (N2–H21···O2) is depicted with dashed lines.
	Fig. 2. A partial view of the unit cell along the c-axis, showing the formation of zigzag chains of molecules along the b axis.

2-[2-(4-Bromophenyl)hydrazinylidene]-1,3-diphenylpropane-1,3-dione top

Crystal data top

C₂₁H₁₅BrN₂O₂	F(000) = 824
M_r = 407.25	D_x = 1.541 Mg m⁻³
Monoclinic, P2₁/n	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2yn	Cell parameters from 999 reflections
a = 12.0273 (9) Å	θ = 2.1–26.4°
b = 10.2977 (8) Å	µ = 2.36 mm⁻¹
c = 14.2626 (11) Å	T = 150 K
β = 96.452 (1)°	Polyhedron, yellow
V = 1755.3 (2) Å³	0.44 × 0.41 × 0.12 mm
Z = 4

Data collection top

Bruker D8 Discover diffractometer with SMART CCD area detector	3575 independent reflections
Radiation source: fine-focus sealed tube	3107 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.021
ϕ and ω scans	θ_max = 26.4°, θ_min = 2.1°
Absorption correction: multi-scan (SADABS; Bruker, 2000)	h = −14→15
T_min = 0.368, T_max = 0.753	k = −12→12
13742 measured reflections	l = −17→17

Refinement top

Refinement on F²	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F² > 2σ(F²)] = 0.030	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.079	H-atom parameters constrained
S = 1.06	w = 1/[σ²(F_o²) + (0.0456P)² + 0.6227P] where P = (F_o² + 2F_c²)/3
3575 reflections	(Δ/σ)_max = 0.002
235 parameters	Δρ_max = 0.67 e Å⁻³
0 restraints	Δρ_min = −0.17 e Å⁻³

Crystal data top

C₂₁H₁₅BrN₂O₂	V = 1755.3 (2) Å³
M_r = 407.25	Z = 4
Monoclinic, P2₁/n	Mo Kα radiation
a = 12.0273 (9) Å	µ = 2.36 mm⁻¹
b = 10.2977 (8) Å	T = 150 K
c = 14.2626 (11) Å	0.44 × 0.41 × 0.12 mm
β = 96.452 (1)°

Data collection top

Bruker D8 Discover diffractometer with SMART CCD area detector	3575 independent reflections
Absorption correction: multi-scan (SADABS; Bruker, 2000)	3107 reflections with I > 2σ(I)
T_min = 0.368, T_max = 0.753	R_int = 0.021
13742 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.030	0 restraints
wR(F²) = 0.079	H-atom parameters constrained
S = 1.06	Δρ_max = 0.67 e Å⁻³
3575 reflections	Δρ_min = −0.17 e Å⁻³
235 parameters

Special details top

Geometry. Bond distances, angles etc. have been calculated using the rounded fractional coordinates. All su's are estimated from the variances of the (full) variance-covariance matrix. The cell e.s.d.'s are taken into account in the estimation of distances, angles and torsion angles

Refinement. Refinement on F² for ALL reflections except those flagged by the user for potential systematic errors. Weighted R-factors wR and all goodnesses of fit S are based on F², conventional R-factors R are based on F, with F set to zero for negative F². The observed criterion of F² > σ(F²) is used only for calculating -R-factor-obs 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	0.23271 (2)	1.04855 (2)	0.59316 (1)	0.0359 (1)
O1	0.13462 (11)	0.13416 (13)	0.33354 (11)	0.0333 (4)
O2	−0.09408 (11)	0.40741 (15)	0.32404 (10)	0.0329 (4)
N1	0.13907 (13)	0.45872 (14)	0.37523 (11)	0.0244 (5)
N2	0.07047 (14)	0.55054 (14)	0.39738 (12)	0.0259 (5)
C1	0.11110 (16)	0.66570 (18)	0.44103 (13)	0.0244 (5)
C2	0.03445 (16)	0.74538 (19)	0.47975 (14)	0.0275 (6)
C3	0.07041 (16)	0.85857 (19)	0.52624 (14)	0.0283 (6)
C4	0.18176 (17)	0.89302 (18)	0.53100 (13)	0.0272 (6)
C5	0.25851 (16)	0.81515 (19)	0.49182 (14)	0.0294 (6)
C6	0.22285 (16)	0.70074 (19)	0.44637 (13)	0.0280 (6)
C7	0.29704 (16)	0.25718 (18)	0.31885 (13)	0.0255 (5)
C8	0.34273 (16)	0.3676 (2)	0.28233 (14)	0.0294 (6)
C9	0.45584 (17)	0.3718 (2)	0.27136 (16)	0.0358 (7)
C10	0.52336 (18)	0.2658 (2)	0.29719 (16)	0.0402 (7)
C11	0.47871 (18)	0.1550 (2)	0.33354 (16)	0.0370 (7)
C12	0.36607 (17)	0.1503 (2)	0.34456 (14)	0.0304 (6)
C13	−0.05567 (15)	0.24899 (18)	0.21378 (13)	0.0241 (5)
C14	0.00727 (16)	0.23913 (18)	0.13846 (14)	0.0277 (6)
C15	−0.03124 (18)	0.1653 (2)	0.05974 (14)	0.0332 (6)
C16	−0.13105 (19)	0.0989 (2)	0.05795 (16)	0.0369 (7)
C17	−0.19298 (18)	0.1058 (2)	0.13385 (17)	0.0373 (7)
C18	−0.15682 (16)	0.1820 (2)	0.21102 (15)	0.0306 (6)
C19	0.17494 (16)	0.24228 (18)	0.32685 (13)	0.0250 (6)
C20	0.09791 (15)	0.35573 (18)	0.32905 (13)	0.0245 (5)
C21	−0.02208 (15)	0.33948 (18)	0.29325 (13)	0.0251 (5)
H2	−0.04240	0.72210	0.47430	0.0330*
H3	0.01900	0.91180	0.55450	0.0340*
H5	0.33500	0.83990	0.49600	0.0350*
H6	0.27470	0.64690	0.41910	0.0340*
H8	0.29640	0.44040	0.26480	0.0350*
H9	0.48690	0.44720	0.24620	0.0430*
H10	0.60090	0.26910	0.28990	0.0480*
H11	0.52540	0.08250	0.35080	0.0440*
H12	0.33530	0.07460	0.36960	0.0360*
H14	0.07700	0.28290	0.14060	0.0330*
H15	0.01100	0.16070	0.00740	0.0400*
H16	−0.15730	0.04810	0.00440	0.0440*
H17	−0.26070	0.05800	0.13290	0.0450*
H18	−0.20080	0.18880	0.26210	0.0370*
H21	−0.00220	0.53940	0.38450	0.0310*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Br1	0.0364 (1)	0.0287 (1)	0.0424 (1)	−0.0006 (1)	0.0032 (1)	−0.0091 (1)
O1	0.0286 (7)	0.0262 (7)	0.0452 (8)	0.0008 (6)	0.0049 (6)	0.0005 (6)
O2	0.0243 (7)	0.0386 (8)	0.0362 (8)	0.0060 (6)	0.0050 (6)	−0.0053 (7)
N1	0.0248 (8)	0.0254 (8)	0.0234 (8)	0.0059 (6)	0.0041 (6)	0.0006 (6)
N2	0.0227 (8)	0.0264 (8)	0.0285 (8)	0.0039 (6)	0.0027 (7)	−0.0031 (6)
C1	0.0285 (10)	0.0237 (9)	0.0207 (8)	0.0033 (7)	0.0019 (7)	0.0018 (7)
C2	0.0249 (10)	0.0280 (10)	0.0302 (10)	0.0026 (7)	0.0053 (8)	0.0007 (8)
C3	0.0301 (10)	0.0260 (9)	0.0297 (10)	0.0063 (8)	0.0076 (8)	−0.0003 (8)
C4	0.0334 (11)	0.0233 (9)	0.0250 (9)	0.0013 (8)	0.0038 (8)	−0.0012 (8)
C5	0.0240 (10)	0.0312 (10)	0.0332 (10)	0.0012 (8)	0.0036 (8)	0.0003 (8)
C6	0.0267 (10)	0.0284 (10)	0.0293 (10)	0.0067 (8)	0.0056 (8)	−0.0007 (8)
C7	0.0247 (9)	0.0277 (10)	0.0233 (9)	0.0026 (7)	−0.0001 (7)	−0.0049 (7)
C8	0.0270 (10)	0.0314 (10)	0.0297 (10)	0.0023 (8)	0.0027 (8)	−0.0021 (8)
C9	0.0290 (11)	0.0394 (12)	0.0396 (12)	−0.0045 (9)	0.0060 (9)	−0.0046 (9)
C10	0.0235 (10)	0.0536 (14)	0.0435 (13)	0.0021 (10)	0.0038 (9)	−0.0133 (11)
C11	0.0292 (11)	0.0385 (12)	0.0416 (12)	0.0121 (9)	−0.0034 (9)	−0.0095 (10)
C12	0.0293 (10)	0.0299 (10)	0.0308 (10)	0.0052 (8)	−0.0013 (8)	−0.0056 (8)
C13	0.0202 (9)	0.0232 (9)	0.0284 (9)	0.0030 (7)	0.0008 (7)	0.0041 (7)
C14	0.0227 (9)	0.0289 (10)	0.0314 (10)	−0.0029 (8)	0.0030 (8)	0.0013 (8)
C15	0.0368 (11)	0.0349 (11)	0.0279 (10)	0.0005 (9)	0.0035 (8)	−0.0016 (8)
C16	0.0394 (12)	0.0319 (11)	0.0363 (11)	−0.0022 (9)	−0.0096 (10)	−0.0028 (9)
C17	0.0260 (10)	0.0335 (11)	0.0502 (13)	−0.0074 (8)	−0.0051 (9)	0.0049 (10)
C18	0.0236 (9)	0.0324 (11)	0.0359 (11)	−0.0002 (8)	0.0040 (8)	0.0074 (9)
C19	0.0255 (10)	0.0250 (10)	0.0241 (9)	0.0021 (7)	0.0005 (7)	−0.0017 (7)
C20	0.0238 (9)	0.0256 (9)	0.0239 (9)	0.0033 (7)	0.0025 (7)	−0.0002 (7)
C21	0.0240 (9)	0.0239 (9)	0.0277 (9)	0.0024 (7)	0.0049 (7)	0.0035 (8)

Geometric parameters (Å, º) top

Br1—C4	1.8985 (19)	C13—C21	1.488 (3)
O1—C19	1.222 (2)	C14—C15	1.392 (3)
O2—C21	1.232 (2)	C15—C16	1.379 (3)
N1—N2	1.317 (2)	C16—C17	1.383 (3)
N1—C20	1.315 (2)	C17—C18	1.382 (3)
N2—C1	1.402 (2)	C19—C20	1.494 (3)
N2—H21	0.8800	C20—C21	1.485 (3)
C1—C6	1.385 (3)	C2—H2	0.9500
C1—C2	1.394 (3)	C3—H3	0.9500
C2—C3	1.386 (3)	C5—H5	0.9500
C3—C4	1.380 (3)	C6—H6	0.9500
C4—C5	1.387 (3)	C8—H8	0.9500
C5—C6	1.389 (3)	C9—H9	0.9500
C7—C8	1.389 (3)	C10—H10	0.9500
C7—C19	1.494 (3)	C11—H11	0.9500
C7—C12	1.402 (3)	C12—H12	0.9500
C8—C9	1.387 (3)	C14—H14	0.9500
C9—C10	1.385 (3)	C15—H15	0.9500
C10—C11	1.386 (3)	C16—H16	0.9500
C11—C12	1.382 (3)	C17—H17	0.9500
C13—C14	1.386 (3)	C18—H18	0.9500
C13—C18	1.395 (3)

Br1···C17ⁱ	3.700 (2)	C4···H18ⁱⁱⁱ	3.0500
Br1···C18ⁱ	3.433 (2)	C5···H14^viii	2.9000
Br1···C13ⁱ	3.5778 (19)	C6···H16^vi	3.0100
Br1···H11ⁱⁱ	3.2300	C6···H14^viii	2.9500
Br1···H18ⁱⁱⁱ	3.2500	C14···H6^iv	2.9900
O1···C13	2.945 (2)	C14···H5^iv	3.0300
O1···C14	3.209 (2)	C15···H6^iv	3.0700
O1···C8^iv	3.231 (2)	C19···H14	2.8100
O1···C9^iv	3.218 (3)	C20···H14	2.7700
O1···C3ⁱⁱⁱ	3.346 (2)	C20···H8	2.7900
O2···N1	2.866 (2)	C20···H2ⁱⁱⁱ	3.0600
O2···C2ⁱⁱⁱ	3.220 (2)	C21···H21	2.4300
O2···C17^v	3.382 (3)	H2···H21	2.3600
O2···N2	2.592 (2)	H2···C20ⁱⁱⁱ	3.0600
O1···H8^iv	2.6300	H3···O1ⁱⁱⁱ	2.6200
O1···H12	2.4900	H3···C3^vii	2.7900
O1···H3ⁱⁱⁱ	2.6200	H3···H3^vii	2.4000
O1···H9^iv	2.6000	H5···C14^viii	3.0300
O2···H18	2.6900	H5···H14^viii	2.3900
O2···H17^v	2.4600	H6···N1	2.5600
O2···H21	1.9000	H6···C14^viii	2.9900
N1···O2	2.866 (2)	H6···C15^viii	3.0700
N1···C8	3.060 (3)	H6···H14^viii	2.4900
N2···O2	2.592 (2)	H6···H16^vi	2.4400
N1···H8	2.6000	H8···N1	2.6000
N1···H16^vi	2.9000	H8···C20	2.7900
N1···H6	2.5600	H8···O1^viii	2.6300
C2···O2ⁱⁱⁱ	3.220 (2)	H9···O1^viii	2.6000
C2···C20ⁱⁱⁱ	3.469 (3)	H10···H18^xi	2.6000
C2···C21ⁱⁱⁱ	3.373 (3)	H11···Br1ⁱⁱ	3.2300
C3···O1ⁱⁱⁱ	3.346 (2)	H12···O1	2.4900
C3···C3^vii	3.410 (3)	H14···C19	2.8100
C3···C21ⁱⁱⁱ	3.386 (3)	H14···C20	2.7700
C8···O1^viii	3.231 (2)	H14···C5^iv	2.9000
C8···N1	3.060 (3)	H14···C6^iv	2.9500
C9···O1^viii	3.218 (3)	H14···H5^iv	2.3900
C13···O1	2.945 (2)	H14···H6^iv	2.4900
C13···Br1^ix	3.5778 (19)	H16···N1^xii	2.9000
C14···C19	3.173 (3)	H16···C6^xii	3.0100
C14···O1	3.209 (2)	H16···H6^xii	2.4400
C17···O2^x	3.382 (3)	H17···O2^x	2.4600
C17···Br1^ix	3.700 (2)	H18···O2	2.6900
C18···Br1^ix	3.433 (2)	H18···H10^xiii	2.6000
C19···C14	3.173 (3)	H18···Br1ⁱⁱⁱ	3.2500
C20···C2ⁱⁱⁱ	3.469 (3)	H18···C4ⁱⁱⁱ	3.0500
C21···C2ⁱⁱⁱ	3.373 (3)	H21···O2	1.9000
C21···C3ⁱⁱⁱ	3.386 (3)	H21···C21	2.4300
C3···H3^vii	2.7900	H21···H2	2.3600

N2—N1—C20	119.24 (16)	C19—C20—C21	119.06 (16)
N1—N2—C1	121.18 (16)	N1—C20—C19	116.22 (16)
N1—N2—H21	119.00	C13—C21—C20	120.18 (16)
C1—N2—H21	119.00	O2—C21—C13	119.06 (16)
N2—C1—C2	117.45 (17)	O2—C21—C20	120.55 (17)
N2—C1—C6	122.17 (17)	C1—C2—H2	120.00
C2—C1—C6	120.38 (17)	C3—C2—H2	120.00
C1—C2—C3	120.00 (18)	C2—C3—H3	120.00
C2—C3—C4	119.26 (18)	C4—C3—H3	120.00
C3—C4—C5	121.19 (18)	C4—C5—H5	120.00
Br1—C4—C3	120.03 (15)	C6—C5—H5	120.00
Br1—C4—C5	118.78 (15)	C1—C6—H6	120.00
C4—C5—C6	119.59 (18)	C5—C6—H6	120.00
C1—C6—C5	119.56 (18)	C7—C8—H8	120.00
C12—C7—C19	117.24 (17)	C9—C8—H8	120.00
C8—C7—C12	119.53 (18)	C8—C9—H9	120.00
C8—C7—C19	123.12 (17)	C10—C9—H9	120.00
C7—C8—C9	120.13 (19)	C9—C10—H10	120.00
C8—C9—C10	119.89 (19)	C11—C10—H10	120.00
C9—C10—C11	120.5 (2)	C10—C11—H11	120.00
C10—C11—C12	119.8 (2)	C12—C11—H11	120.00
C7—C12—C11	120.12 (19)	C7—C12—H12	120.00
C14—C13—C21	120.75 (17)	C11—C12—H12	120.00
C14—C13—C18	119.50 (18)	C13—C14—H14	120.00
C18—C13—C21	119.50 (17)	C15—C14—H14	120.00
C13—C14—C15	120.28 (18)	C14—C15—H15	120.00
C14—C15—C16	119.73 (19)	C16—C15—H15	120.00
C15—C16—C17	120.3 (2)	C15—C16—H16	120.00
C16—C17—C18	120.3 (2)	C17—C16—H16	120.00
C13—C18—C17	119.92 (19)	C16—C17—H17	120.00
O1—C19—C20	117.28 (17)	C18—C17—H17	120.00
O1—C19—C7	120.11 (17)	C13—C18—H18	120.00
C7—C19—C20	122.60 (16)	C17—C18—H18	120.00
N1—C20—C21	124.02 (17)

C20—N1—N2—C1	−175.78 (17)	C8—C9—C10—C11	0.3 (3)
N2—N1—C20—C21	4.7 (3)	C9—C10—C11—C12	−0.3 (3)
N2—N1—C20—C19	−165.54 (16)	C10—C11—C12—C7	0.2 (3)
N1—N2—C1—C6	13.0 (3)	C18—C13—C14—C15	1.4 (3)
N1—N2—C1—C2	−166.92 (17)	C21—C13—C18—C17	174.85 (18)
N2—C1—C6—C5	−179.01 (18)	C14—C13—C21—O2	135.6 (2)
C2—C1—C6—C5	0.9 (3)	C14—C13—C21—C20	−39.1 (3)
N2—C1—C2—C3	178.10 (18)	C18—C13—C21—O2	−38.7 (3)
C6—C1—C2—C3	−1.8 (3)	C18—C13—C21—C20	146.63 (18)
C1—C2—C3—C4	2.0 (3)	C21—C13—C14—C15	−172.87 (18)
C2—C3—C4—C5	−1.3 (3)	C14—C13—C18—C17	0.5 (3)
C2—C3—C4—Br1	179.34 (15)	C13—C14—C15—C16	−1.8 (3)
C3—C4—C5—C6	0.4 (3)	C14—C15—C16—C17	0.2 (3)
Br1—C4—C5—C6	179.76 (14)	C15—C16—C17—C18	1.7 (3)
C4—C5—C6—C1	−0.2 (3)	C16—C17—C18—C13	−2.1 (3)
C19—C7—C8—C9	−175.90 (19)	O1—C19—C20—N1	141.39 (18)
C8—C7—C12—C11	0.0 (3)	C7—C19—C20—C21	151.86 (17)
C8—C7—C19—O1	159.27 (19)	O1—C19—C20—C21	−29.4 (3)
C8—C7—C19—C20	−22.0 (3)	C7—C19—C20—N1	−37.4 (3)
C19—C7—C12—C11	176.17 (18)	N1—C20—C21—O2	−17.5 (3)
C12—C7—C8—C9	0.1 (3)	N1—C20—C21—C13	157.07 (18)
C12—C7—C19—C20	161.96 (18)	C19—C20—C21—O2	152.44 (18)
C12—C7—C19—O1	−16.8 (3)	C19—C20—C21—C13	−33.0 (3)
C7—C8—C9—C10	−0.2 (3)

Symmetry codes: (i) x+1/2, −y+3/2, z+1/2; (ii) −x+1, −y+1, −z+1; (iii) −x, −y+1, −z+1; (iv) −x+1/2, y−1/2, −z+1/2; (v) −x−1/2, y+1/2, −z+1/2; (vi) x+1/2, −y+1/2, z+1/2; (vii) −x, −y+2, −z+1; (viii) −x+1/2, y+1/2, −z+1/2; (ix) x−1/2, −y+3/2, z−1/2; (x) −x−1/2, y−1/2, −z+1/2; (xi) x+1, y, z; (xii) x−1/2, −y+1/2, z−1/2; (xiii) x−1, y, z.

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N2—H21···O2	0.88	1.90	2.592 (2)	135
C8—H8···N1	0.95	2.60	3.060 (3)	110
C17—H17···O2^x	0.95	2.46	3.382 (3)	162

Symmetry code: (x) −x−1/2, y−1/2, −z+1/2.

Experimental details

Crystal data
Chemical formula	C₂₁H₁₅BrN₂O₂
M_r	407.25
Crystal system, space group	Monoclinic, P2₁/n
Temperature (K)	150
a, b, c (Å)	12.0273 (9), 10.2977 (8), 14.2626 (11)
β (°)	96.452 (1)
V (Å³)	1755.3 (2)
Z	4
Radiation type	Mo Kα
µ (mm⁻¹)	2.36
Crystal size (mm)	0.44 × 0.41 × 0.12

Data collection
Diffractometer	Bruker D8 Discover diffractometer with SMART CCD area detector
Absorption correction	Multi-scan (SADABS; Bruker, 2000)
T_min, T_max	0.368, 0.753
No. of measured, independent and observed [I > 2σ(I)] reflections	13742, 3575, 3107
R_int	0.021
(sin θ/λ)_max (Å⁻¹)	0.625

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.030, 0.079, 1.06
No. of reflections	3575
No. of parameters	235
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.67, −0.17

Computer programs: SMART (Bruker, 2001), SAINT (Bruker, 2000), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), XP in SHELXTL-PC (Sheldrick, 2008), PLATON (Spek, 2009) and Mercury (Macrae et al., 2006).

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N2—H21···O2	0.88	1.90	2.592 (2)	135
C8—H8···N1	0.95	2.60	3.060 (3)	110
C17—H17···O2ⁱ	0.95	2.46	3.382 (3)	162

Symmetry code: (i) −x−1/2, y−1/2, −z+1/2.

Acknowledgements

The authors thank the Fondo Nacional de Desarrollo Científico y Tecnológico (FONDECYT; grant Nos. 11100446 and 1080269) and the Universidad Andrés Bello (grant No. DI-06–10-R) for financial assistance.

References

Bertolasi, V., Gilli, P., Ferretti, V. & Gilli, G. (1994). Acta Cryst. B50, 617–625. CSD CrossRef CAS Web of Science IUCr Journals Google Scholar
Bruker (2000). SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA. Google Scholar
Bruker (2001). SMART. Bruker AXS Inc., Madison, Wisconsin, USA. Google Scholar
Bustos, C., Sánchez, C., Martínez, R., Ugarte, R., Schott, E., Carey, D. M. L., Garland, M. T. & Espinoza, L. (2007). Dyes Pigm. 74, 615–621. Web of Science CSD CrossRef CAS Google Scholar
Bustos, C., Schott, E., Ríos, M., Sánchez, C. & Cárcamo, J. G. (2009). J. Chil. Chem. Soc. 54, 267–268. CrossRef CAS Google Scholar
Macrae, C. F., Edgington, P. R., McCabe, P., Pidcock, E., Shields, G. P., Taylor, R., Towler, M. & van de Streek, J. (2006). J. Appl. Cryst. 39, 453–457. Web of Science CrossRef CAS IUCr Journals Google Scholar
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar
Spek, A. L. (2009). Acta Cryst. D65, 148–155. Web of Science CrossRef CAS IUCr Journals Google Scholar
Yao, H. C. (1964). J. Org. Chem. 29, 2959–2962. CrossRef CAS Web of Science Google Scholar