2-Bromo-4-methyl­benzonitrile

Abstract

The title mol­ecule, C₈H₆BrN, is almost planar (r.m.s. deviation for the non-H atoms = 0.008 Å). In the crystal, weak π–π stacking inter­actions [centroid–centroid separations = 3.782 (2) and 3.919 (2) Å] generate [100] columns of mol­ecules.

Related literature

For the synthesis, see: Johnson & Sandborn (1941 ▶). 2-Bromo-4-methyl­benzonitrile derivatives are used as inter­mediates in the synthesis of phthalocyanine dyes. For applications of phthalocyanine dyes in photo redox reactions and photodynamic cancer therapy, see: Simon & Sirlin (1989 ▶); Simon et al. (1989 ▶).

Experimental

Crystal data

• C₈H₆BrN

• M _r = 196.05

• Triclinic,

• a = 7.5168 (11) Å

• b = 7.8383 (11) Å

• c = 7.9428 (11) Å

• α = 69.243 (7)°

• β = 64.375 (8)°

• γ = 87.567 (8)°

• V = 391.14 (10) ų

• Z = 2

• Mo Kα radiation

• μ = 5.17 mm⁻¹

• T = 296 K

• 0.41 × 0.28 × 0.19 mm

Data collection

• Bruker Kappa APEXII CCD diffractometer

• Absorption correction: multi-scan (SADABS; Bruker, 2007 ▶) T _min = 0.226, T _max = 0.440

• 8084 measured reflections

• 1921 independent reflections

• 1244 reflections with I > 2σ(I)

• R _int = 0.025

Refinement

• R[F ² > 2σ(F ²)] = 0.033

• wR(F ²) = 0.084

• S = 1.01

• 1921 reflections

• 92 parameters

• H-atom parameters constrained

• Δρ_max = 0.44 e Å⁻³

• Δρ_min = −0.49 e Å⁻³

Data collection: APEX2 (Bruker, 2007 ▶); cell refinement: SAINT (Bruker, 2007 ▶); data reduction: SAINT; 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 PLATON (Spek, 2009 ▶); software used to prepare material for publication: WinGX (Farrugia, 1999 ▶) and PLATON.

Supplementary Material

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

supplementary crystallographic information

Comment

Synthesis of 2-bromo-4-methylbenzonitrile derivatives are important compounds due to their use as intermediates in the synthesis of phthalocyanine dyes. The substituted phthalocyanine dyes have been used for photo redox reactions (Simon & Sirlin, 1989) and photodynamic cancer therapy (Simon et al.. 1989).

The title compound(I) is almost planar. The cyano plane (C4/C8/N1) is oriented at a dihedral angle of 79.7 (3)° with respect to aromatic ring (C1/C2/C3/C4/C5/C6). The dihedral angle between the plane containing the methyl carbon (C1/C2/C6/C7) and aromatic ring plane is 0.22 (0.18)°. No significant intermolecular or intramolecular hydrogen bonding interaction has been observed in the molecule.

Experimental

3-Bromo-4-amino toluene (10 g, 54 mmol) (Johnson & Sandborn, 1941) was dissolved in HCl (30 ml, 17%). The mixture was cooled to 273 K in an ice-salt mixture. Over 5 min, an aqueous solution (9 ml) of NaNO₂ (4.3 g) was added to the above mixture. The temperature was maintained at 273-278 K. A mixture of aqueous solution (6%) of Cu(I)cyanide and KCN (40%) was heated to 333 K and added to the above cold neutralized diazonium salt solution. After work up of reaction, colourless blocks of (I) were obtained by the slow evaporation of water.

Refinement

The H atoms were geometrically placed (C—H = 0.93–0.96Å) and refined as riding with U_iso(H) = 1.2U_eq(C) or 1.5U_eq(methyl C).

Figures

Fig. 1.

The molecular structure of (I) with 50% displacement ellipsoids.

Fig. 2.

Unit cell packing diagram.

Crystal data

C8H6BrN	Z = 2
Mr = 196.05	F(000) = 192
Triclinic, P1	Dx = 1.665 Mg m−3
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 7.5168 (11) Å	Cell parameters from 3073 reflections
b = 7.8383 (11) Å	θ = 2.2–21.2°
c = 7.9428 (11) Å	µ = 5.17 mm−1
α = 69.243 (7)°	T = 296 K
β = 64.375 (8)°	Block, colourless
γ = 87.567 (8)°	0.41 × 0.28 × 0.19 mm
V = 391.14 (10) Å3

Data collection

Bruker Kappa APEXII CCD diffractometer	1921 independent reflections
Radiation source: fine-focus sealed tube	1244 reflections with I > 2σ(I)
graphite	Rint = 0.025
φ and ω scans	θmax = 28.3°, θmin = 2.8°
Absorption correction: multi-scan (SADABS; Bruker, 2007)	h = −9→9
Tmin = 0.226, Tmax = 0.440	k = −10→10
8084 measured reflections	l = −10→10

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)] = 0.033	Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.084	H-atom parameters constrained
S = 1.01	w = 1/[σ2(Fo2) + (0.0326P)2 + 0.2649P] where P = (Fo2 + 2Fc2)/3
1921 reflections	(Δ/σ)max < 0.001
92 parameters	Δρmax = 0.44 e Å−3
0 restraints	Δρmin = −0.49 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	0.32613 (7)	0.89370 (4)	0.35907 (6)	0.07874 (19)
C1	0.2019 (4)	0.3498 (4)	0.7427 (4)	0.0525 (7)
C2	0.2395 (4)	0.5395 (4)	0.6606 (4)	0.0512 (7)
H2	0.2419	0.6033	0.7387	0.061*
C3	0.2732 (4)	0.6352 (4)	0.4660 (4)	0.0457 (6)
C4	0.2711 (4)	0.5439 (4)	0.3461 (4)	0.0445 (6)
C5	0.2349 (5)	0.3537 (4)	0.4270 (5)	0.0532 (7)
H5	0.2337	0.2899	0.3485	0.064*
C6	0.2008 (5)	0.2588 (4)	0.6222 (5)	0.0582 (8)
H6	0.1765	0.1310	0.6747	0.070*
C7	0.1639 (6)	0.2446 (5)	0.9569 (5)	0.0764 (10)
H7A	0.2191	0.3191	1.0006	0.115*
H7B	0.2253	0.1339	0.9654	0.115*
H7C	0.0231	0.2136	1.0415	0.115*
C8	0.3088 (5)	0.6413 (4)	0.1400 (5)	0.0540 (7)
N1	0.3389 (5)	0.7126 (4)	−0.0230 (5)	0.0771 (9)

Atomic displacement parameters (Ų)

	U11	U22	U33	U12	U13	U23
Br1	0.1226 (4)	0.0413 (2)	0.0893 (3)	0.01752 (18)	−0.0609 (3)	−0.02676 (18)
C1	0.0514 (18)	0.0578 (18)	0.0451 (17)	0.0061 (14)	−0.0231 (14)	−0.0136 (14)
C2	0.0571 (18)	0.0587 (18)	0.0515 (18)	0.0159 (14)	−0.0288 (15)	−0.0308 (15)
C3	0.0525 (17)	0.0403 (14)	0.0491 (17)	0.0096 (12)	−0.0251 (14)	−0.0193 (13)
C4	0.0449 (16)	0.0480 (16)	0.0410 (16)	0.0047 (12)	−0.0188 (13)	−0.0174 (13)
C5	0.0641 (19)	0.0478 (16)	0.0525 (18)	0.0029 (14)	−0.0249 (15)	−0.0249 (14)
C6	0.069 (2)	0.0437 (16)	0.056 (2)	0.0005 (14)	−0.0258 (16)	−0.0151 (15)
C7	0.086 (3)	0.085 (3)	0.050 (2)	0.007 (2)	−0.0321 (19)	−0.0132 (18)
C8	0.0586 (19)	0.0560 (18)	0.0478 (19)	−0.0003 (14)	−0.0225 (15)	−0.0205 (15)
N1	0.098 (2)	0.077 (2)	0.0512 (18)	−0.0056 (17)	−0.0332 (17)	−0.0171 (16)

Geometric parameters (Å, °)

Br1—C3	1.882 (3)	C4—C8	1.440 (4)
C1—C2	1.380 (4)	C5—C6	1.371 (4)
C1—C6	1.384 (4)	C5—H5	0.9300
C1—C7	1.503 (4)	C6—H6	0.9300
C2—C3	1.368 (4)	C7—H7A	0.9600
C2—H2	0.9300	C7—H7B	0.9600
C3—C4	1.384 (4)	C7—H7C	0.9600
C4—C5	1.383 (4)	C8—N1	1.133 (4)
C2—C1—C6	118.2 (3)	C6—C5—H5	119.9
C2—C1—C7	121.0 (3)	C4—C5—H5	119.9
C6—C1—C7	120.8 (3)	C5—C6—C1	121.2 (3)
C3—C2—C1	121.0 (3)	C5—C6—H6	119.4
C3—C2—H2	119.5	C1—C6—H6	119.4
C1—C2—H2	119.5	C1—C7—H7A	109.5
C2—C3—C4	120.8 (3)	C1—C7—H7B	109.5
C2—C3—Br1	119.6 (2)	H7A—C7—H7B	109.5
C4—C3—Br1	119.6 (2)	C1—C7—H7C	109.5
C5—C4—C3	118.6 (3)	H7A—C7—H7C	109.5
C5—C4—C8	119.6 (3)	H7B—C7—H7C	109.5
C3—C4—C8	121.8 (3)	N1—C8—C4	177.7 (3)
C6—C5—C4	120.3 (3)