3,6-Dibromo-9-(3-pyridylmeth­yl)-9H-carbazole

The title compound, C₁₈H₁₂Br₂N₂, was synthesized by N-alkyl­ation of 3-(chloro­meth­yl)pyridine with 3,6-dibromo-9H-carbazole. The carbazole ring system is essentially planar, with a mean deviation of 0.0138 Å, and forms a dihedral angle of 96.7 (8)° with the plane of the pyridine ring. In the crystal structure, π–π inter­actions and weak C—H...Br inter­actions are observed.

Key indicators

• Single-crystal X-ray study
• T = 294 K
• Mean [sigma](C-C)= 0.005 Å
• R factor = 0.034
• wR factor = 0.078
• Data-to-parameter ratio = 16.0

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S1. Comment

Carbazole derivatives substituted by N-alkylation possess valuable pharmaceutical properties (Buu-Hoï & Royer, 1950; Harfenist & Joyner, 1983; Caulfield et al., 2002; Harper et al., 2002). The title compound 3,6-dibromo-9-(3-pyridylmethyl)-9H-carbazole, (I) (Fig. 1), was synthesized by N-alkylation of 3-(Chloromethyl)pyridine with 3,6-dibromo-9H-carbazole.

The carbazole ring is essentially planar, with mean deviations of 0.0138 Å. These values are consistent with those previously reported (Huang et al., 2005; Duan, Han et al., 2005 or Duan, Huang et al., 2005). The dihedral angle formed between the carbazole ring and the plane of the pyridine ring is 96.7 (su?)°. C—Br distances are in the range 1.905 (3) to 1.907 (3) Å and are consistent with literature values (Allen et al., 1987). In the crystal structure, π–π interactions are observed; the shortest, 3.519 Å, is between the N1, C?–C12 and C7–C12 rings of molecules related by (1 − x, −y, 2 − z). In addition, there are C—H···Br interactions, as shown in Fig. 2 and detailed in Table 1.

S2. Experimental

The title compound was prepared according to the procedure of Duan, Han et al. (2005) or Duan, Huang et al. (2005). A solution of potassium hydroxide (7.0 g) in dimethylformamide (50 ml) was stirred at room temperature for 20 min. 3,6-Dibromo-carbazole (6.5 g, 20 mmol), prepared according to Smith et al. (1992), was added and the mixture stirred for a further 40 min. A solution of 3-(chloromethyl)pyridine (3.825 g, 30 mmol) in dimethylformamide (50 ml) was added dropwise with stirring. The resulting mixture was then stirred at room temperature for 10 h and poured into water (500 ml), yielding a white precipitate. The solid product (I) was collected by filtration, washed with cold water and recrystallized from EtOH (yield: 7.11 g (85.5%); m.p. 488 K). Compound (I) (40 mg) was dissolved in a mixture of chloroform (5 ml) and ethanol (5 ml) and the solution was kept at room temperature for 18 d. Slow evaporation of the solution yielded colourless crystals suitable for X-ray analysis.

S3. Refinement

All H atoms were placed in calculated positions and refined using a riding model, with C—H = 0.93 (aromatic) and 0.97 (methylene) Å, and with U_iso(H) = 1.2U_eq(C).

Computing details

Data collection: SMART (Bruker, 1997); cell refinement: SAINT (Bruker, 1997); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SHELXTL (Bruker, 1997); software used to prepare material for publication: SHELXTL.

Figures

	Fig. 1. Displacement ellipsoid (30%) plot of (I).
	Fig. 2. Packing diagram of (I), viewed along [001]. Dashed lines indicate C—H···Br interactions.

3,6-Dibromo-9-(3-pyridylmethyl)-9H-carbazole

Crystal data

C18H12Br2N2	F(000) = 816
Mr = 416.12	Dx = 1.769 Mg m^−3
Monoclinic, P21/c	Melting point: 488 K
Hall symbol: -p 2ybc	Mo Kα radiation, λ = 0.71073 Å
a = 10.469 (3) Å	Cell parameters from 2796 reflections
b = 16.405 (5) Å	θ = 2.5–26.4°
c = 9.866 (3) Å	µ = 5.19 mm^−1
β = 112.761 (4)°	T = 294 K
V = 1562.6 (8) Å^3	Rod, colourless
Z = 4	0.26 × 0.22 × 0.14 mm

Data collection

Bruker SMART CCD area-detector diffractometer	3194 independent reflections
Radiation source: fine-focus sealed tube	2238 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.046
ϕ and ω scans	θmax = 26.5°, θmin = 2.1°
Absorption correction: multi-scan (SADABS; Bruker, 1997)	h = −12→13
Tmin = 0.258, Tmax = 0.484	k = −16→20
8670 measured reflections	l = −10→12

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F^2 > 2σ(F^2)] = 0.034	H-atom parameters constrained
wR(F^2) = 0.078	w = 1/[σ^2(Fo^2) + (0.0276P)^2 + 0.8633P] where P = (Fo^2 + 2Fc^2)/3
S = 1.00	(Δ/σ)max = 0.001
3194 reflections	Δρmax = 0.48 e Å^−3
200 parameters	Δρmin = −0.52 e Å^−3
0 restraints	Extinction correction: SHELXL97, Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.0233 (8)

Special details

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'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 > σ(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	−0.00354 (4)	0.11991 (3)	0.40210 (4)	0.06161 (17)
Br2	0.80862 (4)	−0.09086 (2)	0.85957 (5)	0.06183 (17)
N1	0.4620 (2)	0.16487 (15)	0.9894 (3)	0.0355 (6)
N2	0.6579 (3)	0.39737 (19)	1.0202 (4)	0.0605 (9)
C1	0.3459 (3)	0.16398 (18)	0.8594 (3)	0.0314 (7)
C2	0.2245 (3)	0.20913 (19)	0.8188 (4)	0.0409 (8)
H2	0.2124	0.2477	0.8819	0.049*
C3	0.1226 (3)	0.1950 (2)	0.6824 (4)	0.0426 (8)
H3	0.0401	0.2241	0.6525	0.051*
C4	0.1423 (3)	0.1373 (2)	0.5888 (3)	0.0383 (8)
C5	0.2617 (3)	0.09198 (19)	0.6256 (3)	0.0353 (7)
H5	0.2729	0.0539	0.5613	0.042*
C6	0.3652 (3)	0.10598 (17)	0.7640 (3)	0.0307 (7)
C7	0.5001 (3)	0.07045 (17)	0.8407 (3)	0.0305 (7)
C8	0.5739 (3)	0.01016 (18)	0.8028 (3)	0.0352 (7)
H8	0.5382	−0.0156	0.7117	0.042*
C9	0.7025 (3)	−0.00941 (19)	0.9068 (4)	0.0393 (8)
C10	0.7577 (3)	0.0265 (2)	1.0449 (4)	0.0438 (8)
H10	0.8439	0.0101	1.1123	0.053*
C11	0.6855 (3)	0.0861 (2)	1.0820 (4)	0.0428 (8)
H11	0.7221	0.1112	1.1736	0.051*
C12	0.5557 (3)	0.10815 (18)	0.9788 (3)	0.0332 (7)
C13	0.4866 (3)	0.2169 (2)	1.1169 (3)	0.0415 (8)
H13A	0.5190	0.1837	1.2051	0.050*
H13B	0.4001	0.2422	1.1085	0.050*
C14	0.5693 (4)	0.3393 (2)	1.0215 (4)	0.0482 (9)
H14	0.4848	0.3370	0.9416	0.058*
C15	0.5922 (3)	0.28248 (19)	1.1308 (3)	0.0356 (7)
C16	0.7160 (3)	0.2878 (2)	1.2504 (4)	0.0480 (9)
H16	0.7358	0.2516	1.3284	0.058*
C17	0.8103 (4)	0.3470 (2)	1.2535 (4)	0.0573 (10)
H17	0.8943	0.3516	1.3335	0.069*
C18	0.7776 (4)	0.3992 (2)	1.1358 (5)	0.0590 (10)
H18	0.8429	0.4379	1.1371	0.071*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Br1	0.0346 (2)	0.0907 (3)	0.0459 (2)	0.00194 (19)	0.00059 (15)	−0.0041 (2)
Br2	0.0535 (3)	0.0609 (3)	0.0743 (3)	0.02057 (19)	0.0283 (2)	−0.0020 (2)
N1	0.0361 (14)	0.0378 (15)	0.0310 (14)	0.0023 (12)	0.0112 (11)	−0.0048 (11)
N2	0.065 (2)	0.060 (2)	0.058 (2)	−0.0096 (17)	0.0262 (18)	0.0038 (16)
C1	0.0302 (15)	0.0313 (16)	0.0338 (16)	−0.0012 (13)	0.0137 (13)	−0.0008 (13)
C2	0.0435 (19)	0.0385 (19)	0.044 (2)	0.0040 (15)	0.0206 (16)	−0.0037 (15)
C3	0.0310 (17)	0.047 (2)	0.048 (2)	0.0062 (15)	0.0128 (15)	0.0071 (16)
C4	0.0305 (16)	0.046 (2)	0.0331 (17)	−0.0059 (15)	0.0063 (13)	0.0015 (14)
C5	0.0330 (16)	0.0377 (17)	0.0343 (17)	−0.0020 (14)	0.0120 (13)	−0.0023 (13)
C6	0.0292 (15)	0.0318 (17)	0.0322 (16)	−0.0006 (12)	0.0129 (13)	0.0024 (13)
C7	0.0291 (15)	0.0298 (17)	0.0329 (16)	−0.0020 (13)	0.0122 (13)	0.0016 (13)
C8	0.0373 (17)	0.0355 (18)	0.0347 (17)	−0.0002 (14)	0.0161 (14)	−0.0003 (13)
C9	0.0359 (17)	0.0379 (18)	0.049 (2)	0.0048 (14)	0.0224 (16)	0.0026 (15)
C10	0.0321 (17)	0.047 (2)	0.046 (2)	0.0054 (15)	0.0074 (15)	0.0050 (16)
C11	0.0379 (18)	0.051 (2)	0.0327 (17)	0.0030 (16)	0.0067 (14)	−0.0022 (15)
C12	0.0346 (16)	0.0315 (17)	0.0333 (17)	−0.0008 (13)	0.0128 (13)	0.0002 (13)
C13	0.0502 (19)	0.046 (2)	0.0307 (17)	−0.0016 (16)	0.0187 (15)	−0.0077 (14)
C14	0.051 (2)	0.056 (2)	0.0341 (19)	−0.0037 (18)	0.0128 (16)	−0.0026 (17)
C15	0.0388 (17)	0.0418 (18)	0.0290 (16)	0.0038 (15)	0.0161 (14)	−0.0096 (14)
C16	0.046 (2)	0.050 (2)	0.040 (2)	0.0093 (17)	0.0080 (16)	−0.0032 (16)
C17	0.0337 (19)	0.062 (3)	0.064 (3)	0.0006 (18)	0.0062 (17)	−0.017 (2)
C18	0.056 (2)	0.055 (2)	0.075 (3)	−0.0084 (19)	0.035 (2)	−0.011 (2)

Geometric parameters (Å, º)

Br1—C4	1.905 (3)	C8—C9	1.378 (4)
Br2—C9	1.907 (3)	C8—H8	0.9300
N1—C1	1.384 (4)	C9—C10	1.388 (5)
N1—C12	1.385 (4)	C10—C11	1.369 (4)
N1—C13	1.459 (4)	C10—H10	0.9300
N2—C18	1.329 (5)	C11—C12	1.395 (4)
N2—C14	1.333 (4)	C11—H11	0.9300
C1—C2	1.389 (4)	C13—C15	1.510 (4)
C1—C6	1.407 (4)	C13—H13A	0.9700
C2—C3	1.375 (4)	C13—H13B	0.9700
C2—H2	0.9300	C14—C15	1.375 (5)
C3—C4	1.392 (5)	C14—H14	0.9300
C3—H3	0.9300	C15—C16	1.377 (4)
C4—C5	1.376 (4)	C16—C17	1.377 (5)
C5—C6	1.395 (4)	C16—H16	0.9300
C5—H5	0.9300	C17—C18	1.375 (6)
C6—C7	1.443 (4)	C17—H17	0.9300
C7—C8	1.393 (4)	C18—H18	0.9300
C7—C12	1.401 (4)
C1—N1—C12	108.5 (2)	C11—C10—C9	120.2 (3)
C1—N1—C13	127.2 (3)	C11—C10—H10	119.9
C12—N1—C13	124.3 (2)	C9—C10—H10	119.9
C18—N2—C14	115.8 (3)	C10—C11—C12	118.2 (3)
N1—C1—C2	129.7 (3)	C10—C11—H11	120.9
N1—C1—C6	109.0 (2)	C12—C11—H11	120.9
C2—C1—C6	121.3 (3)	N1—C12—C11	129.6 (3)
C3—C2—C1	117.9 (3)	N1—C12—C7	109.3 (3)
C3—C2—H2	121.0	C11—C12—C7	121.1 (3)
C1—C2—H2	121.0	N1—C13—C15	111.9 (3)
C2—C3—C4	120.4 (3)	N1—C13—H13A	109.2
C2—C3—H3	119.8	C15—C13—H13A	109.2
C4—C3—H3	119.8	N1—C13—H13B	109.2
C5—C4—C3	123.0 (3)	C15—C13—H13B	109.2
C5—C4—Br1	118.7 (2)	H13A—C13—H13B	107.9
C3—C4—Br1	118.3 (2)	N2—C14—C15	125.6 (3)
C4—C5—C6	116.8 (3)	N2—C14—H14	117.2
C4—C5—H5	121.6	C15—C14—H14	117.2
C6—C5—H5	121.6	C14—C15—C16	116.7 (3)
C5—C6—C1	120.5 (3)	C14—C15—C13	120.9 (3)
C5—C6—C7	132.8 (3)	C16—C15—C13	122.4 (3)
C1—C6—C7	106.7 (2)	C17—C16—C15	119.5 (3)
C8—C7—C12	120.7 (3)	C17—C16—H16	120.2
C8—C7—C6	132.7 (3)	C15—C16—H16	120.2
C12—C7—C6	106.6 (3)	C18—C17—C16	118.6 (3)
C9—C8—C7	116.6 (3)	C18—C17—H17	120.7
C9—C8—H8	121.7	C16—C17—H17	120.7
C7—C8—H8	121.7	N2—C18—C17	123.7 (4)
C8—C9—C10	123.2 (3)	N2—C18—H18	118.1
C8—C9—Br2	118.3 (2)	C17—C18—H18	118.1
C10—C9—Br2	118.5 (2)
C12—N1—C1—C2	179.2 (3)	C8—C9—C10—C11	−1.8 (5)
C13—N1—C1—C2	−2.0 (5)	Br2—C9—C10—C11	179.0 (2)
C12—N1—C1—C6	−0.1 (3)	C9—C10—C11—C12	1.0 (5)
C13—N1—C1—C6	178.8 (3)	C1—N1—C12—C11	−178.7 (3)
N1—C1—C2—C3	−178.6 (3)	C13—N1—C12—C11	2.4 (5)
C6—C1—C2—C3	0.6 (5)	C1—N1—C12—C7	0.3 (3)
C1—C2—C3—C4	−0.3 (5)	C13—N1—C12—C7	−178.6 (3)
C2—C3—C4—C5	−0.1 (5)	C10—C11—C12—N1	178.9 (3)
C2—C3—C4—Br1	179.4 (2)	C10—C11—C12—C7	0.0 (5)
C3—C4—C5—C6	0.2 (5)	C8—C7—C12—N1	−179.5 (3)
Br1—C4—C5—C6	−179.3 (2)	C6—C7—C12—N1	−0.3 (3)
C4—C5—C6—C1	0.0 (4)	C8—C7—C12—C11	−0.4 (5)
C4—C5—C6—C7	178.8 (3)	C6—C7—C12—C11	178.8 (3)
N1—C1—C6—C5	178.9 (3)	C1—N1—C13—C15	−107.0 (3)
C2—C1—C6—C5	−0.4 (4)	C12—N1—C13—C15	71.7 (4)
N1—C1—C6—C7	−0.1 (3)	C18—N2—C14—C15	−0.1 (5)
C2—C1—C6—C7	−179.5 (3)	N2—C14—C15—C16	1.7 (5)
C5—C6—C7—C8	0.4 (6)	N2—C14—C15—C13	−177.1 (3)
C1—C6—C7—C8	179.3 (3)	N1—C13—C15—C14	60.6 (4)
C5—C6—C7—C12	−178.6 (3)	N1—C13—C15—C16	−118.1 (3)
C1—C6—C7—C12	0.3 (3)	C14—C15—C16—C17	−1.4 (5)
C12—C7—C8—C9	−0.3 (4)	C13—C15—C16—C17	177.3 (3)
C6—C7—C8—C9	−179.2 (3)	C15—C16—C17—C18	−0.3 (5)
C7—C8—C9—C10	1.4 (5)	C14—N2—C18—C17	−1.8 (6)
C7—C8—C9—Br2	−179.4 (2)	C16—C17—C18—N2	2.1 (6)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
C11—H11···Br1^i	0.93	2.89	3.595 (3)	134

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