2-Bromo-2-methyl-N-(4-nitro­phen­yl)propanamide

Abstract

The title compound, C₁₀H₁₁BrN₂O₃, exhibits a small twist between the amide residue and benzene ring [the C—N—C—C torsion angle = 12.7 (4)°]. The crystal structure is stabilized by weak N—H⋯O, C—H⋯Br and C—H⋯O inter­actions. These lead to supra­molecular layers in the bc plane.

Related literature

For initiators in ATRP (polymerization by atom transfer radical) processes, see: Matyjaszewski & Xia (2001 ▶); Pietrasik & Tsarevsky (2010 ▶). For graph-set notation of hydrogen-bond patterns, see: Etter (1990 ▶).

Experimental

Crystal data

• C₁₀H₁₁BrN₂O₃

• M _r = 287.11

• Monoclinic,

• a = 24.1245 (12) Å

• b = 5.8507 (3) Å

• c = 15.4723 (8) Å

• β = 91.837 (5)°

• V = 2182.72 (19) ų

• Z = 8

• Mo Kα radiation

• μ = 3.76 mm⁻¹

• T = 123 K

• 0.60 × 0.05 × 0.05 mm

Data collection

• Oxford Diffraction Xcalibur E diffractometer

• Absorption correction: analytical (CrysAlis PRO; Oxford Diffraction, 2009 ▶) T _min = 0.444, T _max = 1.000

• 5100 measured reflections

• 2633 independent reflections

• 2197 reflections with I > 2σ(I)

• R _int = 0.032

Refinement

• R[F ² > 2σ(F ²)] = 0.032

• wR(F ²) = 0.068

• S = 1.06

• 2633 reflections

• 151 parameters

• H atoms treated by a mixture of independent and constrained refinement

• Δρ_max = 0.55 e Å⁻³

• Δρ_min = −0.60 e Å⁻³

Data collection: CrysAlis CCD (Oxford Diffraction, 2009 ▶); cell refinement: CrysAlis CCD; data reduction: CrysAlis CCD; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997 ▶) and Mercury (Macrae et al., 2006 ▶); software used to prepare material for publication: SHELXL97.

Supplementary Material

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

Table 1. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C6—H6⋯O1	0.95	2.27	2.862 (3)	120
C7—H7⋯O1i	0.95	2.45	3.139 (3)	129
N1—H1n⋯O3ii	0.84 (3)	2.66 (3)	3.316 (3)	136 (2)
C10—H10⋯Br1iii	0.95	2.91	3.812 (2)	160

Symmetry codes: (i) ; (ii) ; (iii) .

supplementary crystallographic information

Comment

The title compound, (I), forms a part of a synthetic programme that the Polymer Research Group of Universidad del Valle is pursuing in order to obtain compounds that act as initiators of reactions in polymerization processes. Compound (I), Fig. 1, belongs to a series of polymeric ATRP (polymerization by atom transfer radical) initiators (Pietrasik & Tsarevsky, 2010); most initiators for ATRP processes are alkyl halides (Matyjaszewski & Xia, 2001). The C4—N1—C5—C6 torsion angle is 12.7 (4)°, indicating a small twist between the benzene ring and the amide. An intramolecular C—H···O interaction is observed (see Table 1).

In the crystal structure, weak C—H···O and N—H···O intermolecular interactions are detected (Table 1). In a first substructure (Fig. 2), molecules are linked by C7—H···O1ⁱ contacts (i: -x+1/2,-y-1/2,-z) which leads to the formation of dimers with graphs-set notation, R²₂(14) (Etter, 1990). In turn, N—H···O interactions link the dimers running along the c axis. The N1 atom acts as hydrogen bond donor to O3ⁱⁱ (ii: -x+1/2,+y-1/2,-z+1/2). In a second substructure, C10—H···Br (Table 1) interactions provide further links between the dimers. Overall, the crystal structure comprises layers in the bc plane (Fig. 3).

Experimental

The initial reagents were purchased from Aldrich Chemical Co. and were used as received. In a 100 mL round bottom flask 4-nitroaniline (3.258 mmol, 0.450 g), triethylamine (0.653 mmol, 0.066 g) were mixed, then a solution of 2-bromo isobuturyl bromide (0.704 g) in anhydrous THF (5 mL) was added drop wise, under an argon stream. The reaction was carried out in a dry bag overnight under magnetic stirring. The solid was filtered off and dichloromethane (20 mL) added to the organic phase which was washed with brine (40 mL) followed by water (10 mL). The solution was concentrated at low pressure affording colourless crystals and recrystalized from a solution of hexane and ethyl acetate (80:20). M. pt. 356 (1) K.

Refinement

The H-atoms were placed geometrically [C—H = 0.95 Å for aromatic & C—H = 0.98 Å for methyl], refined in the riding model approximation with U_iso(H) = 1.2–1.5U_eq(C). The N-bound H atom was refined freely.

Figures

Fig. 1.

An ORTEP-3 (Farrugia, 1997) plot of (I) with the atomic labelling scheme. Displacement ellipsoids are drawn at the 50% probability level. H atoms are shown as spheres of arbitrary radius.

Fig. 2.

Part of the crystal structure of (I), showing the formation of R22(10) and R44(18) rings, running along [110]. Symmetry code: (i) -x+1,-y+1,-z; (ii) -x+2,-y+2,-z.

Fig. 3.

Part of the crystal structure of (I), showing the formation of an infinite zig-zag chain of dimers along [001] direction. Symmetry code: (iii) x,-y+1/2+1,+z-1/2.

Crystal data

C10H11BrN2O3	F(000) = 1152
Mr = 287.11	Dx = 1.747 Mg m−3
Monoclinic, C2/c	Melting point: 385(1) K
Hall symbol: -C 2yc	Mo Kα radiation, λ = 0.71073 Å
a = 24.1245 (12) Å	Cell parameters from 2722 reflections
b = 5.8507 (3) Å	θ = 3.2–29.3°
c = 15.4723 (8) Å	µ = 3.76 mm−1
β = 91.837 (5)°	T = 123 K
V = 2182.72 (19) Å3	Fragment cut from needle, colourless
Z = 8	0.60 × 0.05 × 0.05 mm

Data collection

Oxford Diffraction Xcalibur E diffractometer	2633 independent reflections
Radiation source: fine-focus sealed tube	2197 reflections with I > 2σ(I)
graphite	Rint = 0.032
ω scans	θmax = 29.0°, θmin = 3.2°
Absorption correction: analytical (CrysAlis PRO; Oxford Diffraction, 2009)	h = −32→18
Tmin = 0.444, Tmax = 1.000	k = −6→7
5100 measured reflections	l = −19→21

Refinement

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)] = 0.032	Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.068	H atoms treated by a mixture of independent and constrained refinement
S = 1.06	w = 1/[σ2(Fo2) + (0.0213P)2] where P = (Fo2 + 2Fc2)/3
2633 reflections	(Δ/σ)max < 0.001
151 parameters	Δρmax = 0.55 e Å−3
0 restraints	Δρmin = −0.60 e Å−3

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 > 2sigma(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	0.418223 (9)	−0.36757 (5)	0.230618 (14)	0.01800 (9)
O1	0.33754 (6)	−0.2340 (4)	0.04409 (11)	0.0205 (4)
O2	0.09326 (6)	0.3711 (4)	0.06453 (11)	0.0219 (4)
O3	0.12126 (7)	0.6341 (3)	0.15486 (11)	0.0224 (4)
N1	0.34163 (8)	0.0629 (4)	0.13870 (13)	0.0177 (5)
N2	0.12933 (8)	0.4612 (4)	0.11152 (12)	0.0175 (5)
C1	0.44903 (10)	−0.3344 (5)	0.05532 (15)	0.0205 (6)
H1A	0.4520	−0.2507	0.0008	0.031*
H1B	0.4251	−0.4681	0.0461	0.031*
H1C	0.4860	−0.3844	0.0756	0.031*
C2	0.42421 (9)	−0.1793 (5)	0.12266 (14)	0.0156 (5)
C3	0.46064 (9)	0.0238 (5)	0.14342 (16)	0.0209 (6)
H3A	0.4986	−0.0283	0.1564	0.031*
H3B	0.4465	0.1044	0.1937	0.031*
H3C	0.4605	0.1275	0.0937	0.031*
C4	0.36323 (9)	−0.1220 (5)	0.09765 (14)	0.0143 (5)
C5	0.28757 (9)	0.1555 (5)	0.12844 (14)	0.0133 (5)
C6	0.24391 (9)	0.0415 (5)	0.08499 (14)	0.0156 (5)
H6	0.2497	−0.1040	0.0595	0.019*
C7	0.19187 (9)	0.1446 (5)	0.07971 (14)	0.0154 (5)
H7	0.1618	0.0700	0.0503	0.018*
C8	0.18422 (9)	0.3543 (5)	0.11722 (14)	0.0135 (5)
C9	0.22692 (9)	0.4702 (5)	0.16051 (14)	0.0158 (5)
H9	0.2208	0.6157	0.1857	0.019*
C10	0.27856 (9)	0.3680 (5)	0.16594 (14)	0.0150 (5)
H10	0.3083	0.4438	0.1957	0.018*
H1N	0.3624 (11)	0.132 (5)	0.1742 (17)	0.028 (8)*

Atomic displacement parameters (Ų)

	U11	U22	U33	U12	U13	U23
Br1	0.01677 (13)	0.01963 (16)	0.01755 (13)	0.00024 (10)	−0.00059 (9)	0.00090 (10)
O1	0.0181 (8)	0.0222 (12)	0.0211 (9)	0.0011 (8)	−0.0017 (7)	−0.0079 (8)
O2	0.0143 (8)	0.0292 (13)	0.0218 (9)	0.0013 (8)	−0.0029 (7)	0.0000 (8)
O3	0.0204 (9)	0.0223 (12)	0.0247 (9)	0.0072 (8)	0.0027 (7)	−0.0027 (9)
N1	0.0135 (10)	0.0205 (14)	0.0187 (11)	0.0023 (9)	−0.0038 (8)	−0.0075 (10)
N2	0.0183 (10)	0.0190 (14)	0.0152 (10)	0.0039 (9)	0.0026 (8)	0.0028 (9)
C1	0.0180 (12)	0.0222 (17)	0.0214 (12)	0.0066 (11)	0.0030 (10)	−0.0025 (11)
C2	0.0151 (11)	0.0158 (15)	0.0159 (11)	0.0025 (10)	0.0004 (9)	−0.0007 (10)
C3	0.0141 (11)	0.0220 (17)	0.0265 (13)	0.0001 (11)	0.0008 (10)	0.0007 (12)
C4	0.0166 (11)	0.0144 (14)	0.0122 (11)	−0.0001 (10)	0.0032 (9)	0.0011 (10)
C5	0.0127 (11)	0.0165 (15)	0.0109 (10)	−0.0002 (10)	0.0020 (8)	0.0010 (10)
C6	0.0176 (11)	0.0145 (15)	0.0148 (11)	0.0015 (10)	0.0005 (9)	−0.0023 (10)
C7	0.0121 (11)	0.0187 (16)	0.0152 (11)	−0.0004 (10)	−0.0013 (9)	0.0010 (10)
C8	0.0119 (11)	0.0170 (15)	0.0117 (11)	0.0030 (10)	0.0024 (8)	0.0034 (10)
C9	0.0200 (12)	0.0120 (14)	0.0155 (11)	0.0010 (10)	0.0030 (9)	−0.0018 (10)
C10	0.0143 (11)	0.0177 (15)	0.0130 (11)	−0.0018 (10)	−0.0001 (8)	−0.0016 (10)

Geometric parameters (Å, °)

Br1—C2	2.010 (2)	C3—H3A	0.9800
O1—C4	1.211 (3)	C3—H3B	0.9800
O2—N2	1.234 (3)	C3—H3C	0.9800
O3—N2	1.232 (3)	C5—C10	1.392 (4)
N1—C4	1.366 (3)	C5—C6	1.400 (3)
N1—C5	1.416 (3)	C6—C7	1.393 (3)
N1—H1N	0.84 (3)	C6—H6	0.9500
N2—C8	1.465 (3)	C7—C8	1.373 (4)
C1—C2	1.519 (3)	C7—H7	0.9500
C1—H1A	0.9800	C8—C9	1.387 (3)
C1—H1B	0.9800	C9—C10	1.382 (3)
C1—H1C	0.9800	C9—H9	0.9500
C2—C3	1.506 (4)	C10—H10	0.9500
C2—C4	1.546 (3)
C4—N1—C5	127.9 (2)	H3B—C3—H3C	109.5
C4—N1—H1N	117 (2)	O1—C4—N1	123.5 (2)
C5—N1—H1N	115 (2)	O1—C4—C2	121.0 (2)
O3—N2—O2	123.4 (2)	N1—C4—C2	115.4 (2)
O3—N2—C8	118.4 (2)	C10—C5—C6	120.1 (2)
O2—N2—C8	118.2 (2)	C10—C5—N1	116.8 (2)
C2—C1—H1A	109.5	C6—C5—N1	123.2 (2)
C2—C1—H1B	109.5	C7—C6—C5	119.0 (2)
H1A—C1—H1B	109.5	C7—C6—H6	120.5
C2—C1—H1C	109.5	C5—C6—H6	120.5
H1A—C1—H1C	109.5	C8—C7—C6	119.7 (2)
H1B—C1—H1C	109.5	C8—C7—H7	120.1
C3—C2—C1	112.2 (2)	C6—C7—H7	120.1
C3—C2—C4	115.2 (2)	C7—C8—C9	122.2 (2)
C1—C2—C4	110.53 (19)	C7—C8—N2	119.3 (2)
C3—C2—Br1	108.18 (15)	C9—C8—N2	118.5 (2)
C1—C2—Br1	106.45 (18)	C10—C9—C8	118.2 (2)
C4—C2—Br1	103.51 (14)	C10—C9—H9	120.9
C2—C3—H3A	109.5	C8—C9—H9	120.9
C2—C3—H3B	109.5	C9—C10—C5	120.9 (2)
H3A—C3—H3B	109.5	C9—C10—H10	119.6
C2—C3—H3C	109.5	C5—C10—H10	119.6
H3A—C3—H3C	109.5
C5—N1—C4—O1	0.7 (4)	C5—C6—C7—C8	−0.3 (3)
C5—N1—C4—C2	179.5 (2)	C6—C7—C8—C9	0.3 (4)
C3—C2—C4—O1	145.0 (2)	C6—C7—C8—N2	−179.9 (2)
C1—C2—C4—O1	16.6 (3)	O3—N2—C8—C7	170.6 (2)
Br1—C2—C4—O1	−97.1 (2)	O2—N2—C8—C7	−8.3 (3)
C3—C2—C4—N1	−33.9 (3)	O3—N2—C8—C9	−9.6 (3)
C1—C2—C4—N1	−162.3 (2)	O2—N2—C8—C9	171.6 (2)
Br1—C2—C4—N1	84.0 (2)	C7—C8—C9—C10	−0.4 (3)
C4—N1—C5—C10	−168.9 (2)	N2—C8—C9—C10	179.8 (2)
C4—N1—C5—C6	12.7 (4)	C8—C9—C10—C5	0.5 (3)
C10—C5—C6—C7	0.4 (3)	C6—C5—C10—C9	−0.5 (3)
N1—C5—C6—C7	178.7 (2)	N1—C5—C10—C9	−179.0 (2)

Hydrogen-bond geometry (Å, °)

D—H···A	D—H	H···A	D···A	D—H···A
C6—H6···O1	0.95	2.27	2.862 (3)	120
C7—H7···O1i	0.95	2.45	3.139 (3)	129
N1—H1n···O3ii	0.84 (3)	2.66 (3)	3.316 (3)	136 (2)
C10—H10···Br1iii	0.95	2.91	3.812 (2)	160

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