Secondary interactions in the iso­morphous compounds 2,6-bis­(chloro­methyl)­pyridinium chloride and 2,6-bis­(bromo­methyl)­pyridinium bromide

The title compounds, C₇H₈Cl₂N⁺·Cl⁻ and C₇H₈Br₂N⁺·Br⁻, are isomorphous. In the crystal packing, layers parallel to the ac plane are formed by a classical N⁺—H...X⁻ hydrogen bond (X = halogen) and two X...X contacts. A third X...X contact links the layers, and a fourth, which is however very long, completes a ladder-like motif of halogen atoms. Hydro­gen bonds of the form C—H...X play at best a subordinate role in the packing.

S1. Comment

We are interested in secondary interactions (hydrogen bonds and halogen-halogen contacts) in halides of simple halogenated derivatives of anilines (Gray & Jones, 2002, and references therein) and pyridines [halopyridines (Freytag & Jones, 2001, and references therein) and halomethylpyridines (Jones & Vancea, 2003, and references therein)]. Here, we report the structures of the isomorphous pair of compounds 2,6-bis(chloromethyl)pyridinium chloride, (I), and 2,6-bis(bromomethyl)pyridinium bromide, (II). It is common for such pairs to be isomorphous, e.g. 4-chloropyridinium chloride and its bromine analogue (Freytag et al., 1999). Please approve Coeditor change to `isomorphous' - these two compounds have the same space group (P 21/m) and similar unit cell and abc. \sch

The asymmetric units of (I) and (II) are shown in Figs. 1 and 2, respectively. Bond lengths and angles may be regarded as normal, e.g. the widened angles at the ring N atom (Tables 1 and 3). The rings are essentially planar [r.m.s. deviations 0.006 Å for (I) and (II)], with the substituent C atoms lying slightly outside the plane [in (I), C7 − 0.105 (3) and C8 0.065 (2) Å; in (II), C7 − 0.102 (4) and C8 0.063 (3) Å]. The C—X vectors (X = halogen) of the halomethyl groups extend almost perpendicularly from, and to opposite sides of, the ring (for torsion angles see Tables 1 and 3).

Both compounds form the expected classical hydrogen bond from the N⁺—H group to the halide ion (Tables 2 and 4). Non-classical hydrogen contacts of the form C—H···X are observed, but are all either long (uncorrected H···X > 2.9 Å) and/or markedly non-linear. Three independent halogen-halogen contacts in each structure provide more striking examples of secondary interactions (Table 5). The contact to the anion is in each case the shortest (because it is charge-assisted) and essentially linear, as would be expected from the concept of a small positive region in the extension of the C—Cl vector. The other two contacts, between cations, may be classified as type I (C—X···X angles approximately equal) and type II (one C—X···X angle ca 90°, the other ca 180°) according to the classification of Pedireddi et al. (1994).

The net effect of the classical hydrogen bond and the two shorter halogen-halogen interactions is to connect the residues, via the glide-plane operators, to form layers parallel to the ac plane at b ≈ 1/4, 3/4; one such layer is shown in Fig. 3. The third and longest halogen-halogen interaction then links the layers, in the process forming halogen parallelograms (Fig. 4), with angles 117.54 (1) and 62.46 (1)° for (I), and 117.39 (1) and 62.61 (1)° for (II). It is noteworthy that the parallelograms are themselves linked into ladder-like tapes via further halogen-halogen contacts [3.8840 (6) Å for (I) and 3.9610 (4) Å for (II); symmetry code: (iii) Please define], which are much longer than the sum of the van der Waals radii but may still be structurally significant.

S2. Experimental

Compound (I) was obtained as a hygroscopic white solid by bubbling HCl gas through a solution of the corresponding pyridine (0.352 g, 2 mmol) in dichloromethane (10 ml), and was recrystallized from dichloromethane-petroleum ether (Ratio?). Compound (II) was obtained in an analogous fashion, but is insoluble in dichloromethane and was recrystallized from ethanol-diisopropyl ether (Ratio?).

S3. Refinement

Crystals of compound (I) cracked badly at 133 K, presumably because of a phase transition, and were therefore measured at the slightly higher temperature of 173 K. The NH H atoms were refined freely. Other H atoms were introduced at geometrically calculated positions and refined using a riding model, with fixed C—H distances of 0.95 (sp² C—H) or 0.99 Å (methylene H), and with U_iso(H) = 1.2U_eq(C). From the coeditor: Please check and approve minor changes above, e.g. I think the C—H methylene should be 0.99 Å.

Computing details

For both compounds, data collection: SMART (Bruker, 1998); cell refinement: SAINT (Bruker, 1998); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: XP (Siemens, 1994); software used to prepare material for publication: SHELXL97.

Figures

	Fig. 1. The asymmetric unit of (I) in the crystal. Displacement ellipsoids are drawn at the 50% probability level and H atoms are shown as small spheres of arbitrary radii. The classical hydrogen bond is indicated as a broken line.
	Fig. 2. The asymmetric unit of (II) in the crystal. Displacement ellipsoids are drawn at the 50% probability level and H atoms are shown as small spheres of arbitrary radii. The classical hydrogen bond is indicated as a broken line.
	Fig. 3. A packing diagram for (I), viewed approximately parallel to the b axis, showing one layer at b ≈ 1/4. Hydrogen bonds and Cl···Cl interactions are indicated by dashed lines. H atoms not involved in hydrogen bonding have been omitted.
	Fig. 4. A packing diagram for (I) as a projection parallel to the c axis. Cl···Cl interactions are indicated by dashed lines. Note that the chlorine parallelograms (e.g. at the left-hand cell margin), which are not an artefact of projection, can themselves be linked via Cl atoms (see text).

(I) 2,6-Bis(chloromethyl)pyridinium chloride

Crystal data

C7H8Cl2N^+·Cl^−	F(000) = 432
Mr = 212.49	Dx = 1.594 Mg m^−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
a = 7.2167 (6) Å	Cell parameters from 4471 reflections
b = 14.6054 (14) Å	θ = 2.8–30.5°
c = 8.4990 (8) Å	µ = 0.97 mm^−1
β = 98.716 (5)°	T = 173 K
V = 885.47 (14) Å^3	Tapering prism, colourless
Z = 4	0.38 × 0.07 × 0.07 mm

Data collection

Bruker SMART1000 CCD area-detector diffractometer	2590 independent reflections
Radiation source: fine-focus sealed tube	1991 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.038
Detector resolution: 8.192 pixels mm^-1	θmax = 30.0°, θmin = 2.8°
ω and ϕ scans	h = −10→10
Absorption correction: multi-scan (SADABS; Bruker, 1998)	k = −20→20
Tmin = 0.722, Tmax = 0.942	l = −11→11
13915 measured reflections

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.031	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.081	H atoms treated by a mixture of independent and constrained refinement
S = 0.99	w = 1/[σ^2(Fo^2) + (0.0463P)^2] where P = (Fo^2 + 2Fc^2)/3
2590 reflections	(Δ/σ)max < 0.001
104 parameters	Δρmax = 0.53 e Å^−3
0 restraints	Δρmin = −0.29 e Å^−3

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.

Non-bonded contacts:

3.3085 (0.0006) Cl2 - Cl3_$6 3.5695 (0.0006) Cl1 - Cl2_$4 3.5886 (0.0006) Cl1 - Cl2_$7

173.02 (0.06) C8 - Cl2 - Cl3_$6 77.01 (0.05) C7 - Cl1 - Cl2_$4 88.82 (0.05) Cl1 - Cl2_$4 - C8_$4 147.05 (0.05) C7 - Cl1 - Cl2_$7 71.80 (0.05) Cl1 - Cl2_$7 - C8_$7

Operators for generating equivalent atoms:

$4 x + 1, −y + 1/2, z + 1/2 $6 x, −y + 1/2, z − 1/2 $7 − x + 1, y − 1/2, −z + 1/2

============================================================================

Least-squares planes (x,y,z in crystal coordinates) and deviations from them (* indicates atom used to define plane)

2.6721 (0.0042) x + 3.5977 (0.0089) y − 8.0013 (0.0019) z = 1.1375 (0.0040)

* 0.0064 (0.0010) N * −0.0083 (0.0010) C2 * 0.0017 (0.0011) C3 * 0.0067 (0.0011) C4 * −0.0088 (0.0011) C5 * 0.0023 (0.0010) C6 − 0.1048 (0.0025) C7 0.0654 (0.0024) C8

Rms deviation of fitted atoms = 0.0063

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
N	0.56926 (17)	0.23902 (9)	0.15461 (15)	0.0183 (3)
H1	0.485 (3)	0.1934 (14)	0.107 (2)	0.041 (6)*
C2	0.7501 (2)	0.21805 (10)	0.20742 (17)	0.0188 (3)
C3	0.8691 (2)	0.28601 (11)	0.27647 (18)	0.0218 (3)
H3	0.9973	0.2728	0.3129	0.026*
C4	0.7997 (2)	0.37340 (11)	0.29194 (19)	0.0236 (3)
H4	0.8807	0.4206	0.3384	0.028*
C5	0.6120 (2)	0.39223 (11)	0.23966 (19)	0.0230 (3)
H5	0.5632	0.4517	0.2524	0.028*
C6	0.4969 (2)	0.32349 (10)	0.16893 (18)	0.0190 (3)
C7	0.8076 (2)	0.12001 (10)	0.19459 (19)	0.0224 (3)
H7A	0.9341	0.1164	0.1635	0.027*
H7B	0.7182	0.0878	0.1132	0.027*
C8	0.2964 (2)	0.33641 (11)	0.09990 (19)	0.0212 (3)
H8A	0.2397	0.3851	0.1583	0.025*
H8B	0.2258	0.2789	0.1084	0.025*
Cl1	0.80786 (6)	0.06835 (3)	0.38661 (5)	0.03091 (12)
Cl2	0.28672 (5)	0.36806 (3)	−0.10576 (5)	0.02486 (11)
Cl3	0.27679 (5)	0.10048 (3)	0.00754 (5)	0.02386 (11)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
N	0.0191 (6)	0.0179 (6)	0.0177 (6)	−0.0012 (5)	0.0015 (5)	0.0001 (5)
C2	0.0193 (7)	0.0187 (7)	0.0185 (7)	−0.0002 (6)	0.0034 (6)	0.0027 (6)
C3	0.0195 (7)	0.0242 (8)	0.0206 (7)	−0.0032 (6)	0.0000 (6)	0.0020 (6)
C4	0.0266 (8)	0.0208 (7)	0.0228 (8)	−0.0068 (6)	0.0016 (6)	−0.0012 (6)
C5	0.0288 (8)	0.0174 (7)	0.0227 (8)	0.0003 (6)	0.0041 (6)	−0.0004 (6)
C6	0.0213 (7)	0.0186 (7)	0.0175 (7)	0.0005 (6)	0.0048 (6)	0.0014 (6)
C7	0.0246 (8)	0.0209 (8)	0.0208 (8)	0.0019 (6)	0.0009 (6)	0.0005 (6)
C8	0.0212 (7)	0.0218 (8)	0.0210 (7)	0.0016 (6)	0.0043 (6)	0.0013 (6)
Cl1	0.0371 (2)	0.0250 (2)	0.0298 (2)	−0.00067 (17)	0.00245 (17)	0.00843 (17)
Cl2	0.02277 (19)	0.0280 (2)	0.0229 (2)	0.00133 (14)	0.00055 (14)	0.00234 (16)
Cl3	0.02468 (19)	0.02143 (19)	0.0244 (2)	−0.00253 (14)	0.00027 (14)	−0.00251 (15)

Geometric parameters (Å, º)

N—C2	1.3493 (19)	C5—C6	1.381 (2)
N—C6	1.3524 (19)	C5—H5	0.9500
N—H1	0.95 (2)	C6—C8	1.489 (2)
C2—C3	1.384 (2)	C7—Cl1	1.7977 (16)
C2—C7	1.499 (2)	C7—H7A	0.9900
C3—C4	1.385 (2)	C7—H7B	0.9900
C3—H3	0.9500	C8—Cl2	1.7991 (16)
C4—C5	1.388 (2)	C8—H8A	0.9900
C4—H4	0.9500	C8—H8B	0.9900
C2—N—C6	122.99 (13)	N—C6—C5	119.17 (14)
C2—N—H1	120.6 (12)	N—C6—C8	116.47 (14)
C6—N—H1	116.4 (12)	C5—C6—C8	124.31 (14)
N—C2—C3	119.02 (14)	C2—C7—Cl1	107.28 (11)
N—C2—C7	117.18 (13)	C2—C7—H7A	110.3
C3—C2—C7	123.72 (14)	Cl1—C7—H7A	110.3
C2—C3—C4	119.42 (14)	C2—C7—H7B	110.3
C2—C3—H3	120.3	Cl1—C7—H7B	110.3
C4—C3—H3	120.3	H7A—C7—H7B	108.5
C3—C4—C5	120.14 (14)	C6—C8—Cl2	107.92 (10)
C3—C4—H4	119.9	C6—C8—H8A	110.1
C5—C4—H4	119.9	Cl2—C8—H8A	110.1
C6—C5—C4	119.25 (14)	C6—C8—H8B	110.1
C6—C5—H5	120.4	Cl2—C8—H8B	110.1
C4—C5—H5	120.4	H8A—C8—H8B	108.4
C6—N—C2—C3	−1.4 (2)	C2—N—C6—C8	178.06 (13)
C6—N—C2—C7	175.56 (14)	C4—C5—C6—N	1.1 (2)
N—C2—C3—C4	0.9 (2)	C4—C5—C6—C8	−176.38 (15)
C7—C2—C3—C4	−175.84 (15)	N—C2—C7—Cl1	−98.77 (14)
C2—C3—C4—C5	0.5 (2)	C3—C2—C7—Cl1	78.07 (17)
C3—C4—C5—C6	−1.5 (2)	N—C6—C8—Cl2	−87.88 (14)
C2—N—C6—C5	0.4 (2)	C5—C6—C8—Cl2	89.62 (16)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N—H1···Cl3	0.95 (2)	2.10 (2)	3.0516 (13)	174.4 (17)
C7—H7A···Cl3^i	0.99	2.99	3.9632 (17)	169
C7—H7B···Cl3^ii	0.99	2.94	3.6572 (16)	130
C8—H8A···Cl3^iii	0.99	2.95	3.6085 (16)	125
C8—H8B···Cl3	0.99	2.79	3.5322 (17)	133
C3—H3···Cl2^iv	0.95	2.94	3.7727 (16)	147
C7—H7A···Cl2^iv	0.99	2.98	3.6178 (16)	123
C8—H8A···Cl1^v	0.99	2.72	3.4758 (17)	134

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

(II) 2,6-Bis(bromomethyl)pyridinium bromide

Crystal data

C7H8Br2N^+·Br^−	F(000) = 648
Mr = 345.87	Dx = 2.377 Mg m^−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
a = 7.4633 (6) Å	Cell parameters from 4337 reflections
b = 15.0136 (12) Å	θ = 2.7–30.5°
c = 8.7377 (6) Å	µ = 12.46 mm^−1
β = 99.146 (4)°	T = 133 K
V = 966.62 (13) Å^3	Plate, colourless
Z = 4	0.26 × 0.18 × 0.04 mm

Data collection

Bruker SMART1000 CCD area-detector diffractometer	2825 independent reflections
Radiation source: fine-focus sealed tube	2503 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.043
Detector resolution: 8.192 pixels mm^-1	θmax = 30.0°, θmin = 2.7°
ω and ϕ scans	h = −10→10
Absorption correction: multi-scan (SADABS; Bruker, 1998)	k = −20→21
Tmin = 0.282, Tmax = 0.608	l = −12→12
17828 measured reflections

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.022	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.057	H atoms treated by a mixture of independent and constrained refinement
S = 1.02	w = 1/[σ^2(Fo^2) + (0.0299P)^2 + 0.6042P] where P = (Fo^2 + 2Fc^2)/3
2825 reflections	(Δ/σ)max = 0.001
104 parameters	Δρmax = 0.61 e Å^−3
0 restraints	Δρmin = −0.68 e Å^−3

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.

Non-bonded distances etc.:

3.3549 (0.0004) Br2 - Br3_$6 3.7482 (0.0004) Br1 - Br2_$4 3.6959 (0.0004) Br1 - Br2_$7

174.19 (0.06) C8 - Br2 - Br3_$6 75.06 (0.07) C7 - Br1 - Br2_$4 89.16 (0.06) Br1 - Br2_$4 - C8_$4 149.72 (0.06) C7 - Br1 - Br2_$7 71.68 (0.06) Br1 - Br2_$7 - C8_$7

Operators for generating equivalent atoms:

$4 x + 1, −y + 1/2, z + 1/2 $6 x, −y + 1/2, z − 1/2 $7 − x + 1, y − 1/2, −z + 1/2 =============================================================================

Least-squares planes (x,y,z in crystal coordinates) and deviations from them (* indicates atom used to define plane)

2.6113 (0.0060) x + 3.9687 (0.0129) y − 8.2389 (0.0026) z = 1.1544 (0.0058)

* 0.0050 (0.0014) N * −0.0096 (0.0014) C2 * 0.0055 (0.0015) C3 * 0.0031 (0.0016) C4 * −0.0078 (0.0015) C5 * 0.0039 (0.0014) C6 − 0.1016 (0.0035) C7 0.0626 (0.0033) C8

Rms deviation of fitted atoms = 0.0062

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
N	0.5718 (2)	0.24097 (11)	0.1566 (2)	0.0133 (3)
H1	0.497 (4)	0.1995 (17)	0.115 (3)	0.018 (6)*
C2	0.7484 (3)	0.22112 (13)	0.2048 (2)	0.0144 (4)
C3	0.8637 (3)	0.28755 (14)	0.2715 (2)	0.0164 (4)
H3	0.9889	0.2755	0.3039	0.020*
C4	0.7947 (3)	0.37227 (14)	0.2907 (3)	0.0181 (4)
H4	0.8728	0.4182	0.3369	0.022*
C5	0.6115 (3)	0.38974 (14)	0.2424 (3)	0.0170 (4)
H5	0.5634	0.4472	0.2567	0.020*
C6	0.4995 (3)	0.32244 (13)	0.1730 (2)	0.0135 (4)
C7	0.8049 (3)	0.12665 (13)	0.1883 (3)	0.0170 (4)
H7A	0.9283	0.1243	0.1605	0.020*
H7B	0.7200	0.0966	0.1058	0.020*
C8	0.3043 (3)	0.33418 (14)	0.1097 (2)	0.0154 (4)
H8A	0.2508	0.3814	0.1675	0.019*
H8B	0.2374	0.2780	0.1192	0.019*
Br1	0.80166 (3)	0.067970 (15)	0.38717 (3)	0.02218 (7)
Br2	0.28757 (3)	0.367763 (14)	−0.10939 (2)	0.01665 (6)
Br3	0.27054 (3)	0.096247 (13)	0.00963 (2)	0.01639 (6)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
N	0.0145 (8)	0.0118 (7)	0.0135 (8)	−0.0012 (6)	0.0012 (6)	−0.0008 (6)
C2	0.0142 (9)	0.0160 (9)	0.0129 (10)	0.0013 (7)	0.0019 (7)	0.0010 (7)
C3	0.0139 (9)	0.0197 (9)	0.0151 (10)	−0.0010 (8)	0.0006 (7)	0.0013 (7)
C4	0.0208 (11)	0.0163 (9)	0.0161 (10)	−0.0044 (8)	0.0001 (8)	−0.0015 (7)
C5	0.0212 (11)	0.0138 (9)	0.0159 (10)	−0.0001 (8)	0.0024 (8)	−0.0013 (7)
C6	0.0151 (9)	0.0155 (9)	0.0102 (9)	0.0009 (7)	0.0031 (7)	0.0008 (6)
C7	0.0177 (10)	0.0156 (9)	0.0169 (11)	0.0015 (8)	0.0004 (8)	0.0004 (7)
C8	0.0152 (10)	0.0176 (9)	0.0136 (10)	0.0022 (7)	0.0030 (7)	0.0007 (7)
Br1	0.02415 (13)	0.01936 (11)	0.02259 (13)	−0.00011 (8)	0.00233 (9)	0.00582 (8)
Br2	0.01485 (11)	0.01887 (11)	0.01567 (11)	0.00107 (7)	0.00069 (8)	0.00073 (7)
Br3	0.01741 (11)	0.01539 (10)	0.01555 (11)	−0.00171 (7)	0.00009 (7)	−0.00152 (7)

Geometric parameters (Å, º)

N—C2	1.351 (3)	C5—C6	1.388 (3)
N—C6	1.354 (3)	C5—H5	0.9500
N—H1	0.88 (3)	C6—C8	1.484 (3)
C2—C3	1.384 (3)	C7—Br1	1.952 (2)
C2—C7	1.493 (3)	C7—H7A	0.9900
C3—C4	1.392 (3)	C7—H7B	0.9900
C3—H3	0.9500	C8—Br2	1.964 (2)
C4—C5	1.390 (3)	C8—H8A	0.9900
C4—H4	0.9500	C8—H8B	0.9900
C2—N—C6	123.49 (18)	N—C6—C5	118.77 (19)
C2—N—H1	120.0 (17)	N—C6—C8	116.88 (18)
C6—N—H1	116.5 (17)	C5—C6—C8	124.31 (18)
N—C2—C3	118.85 (19)	C2—C7—Br1	107.43 (15)
N—C2—C7	117.10 (18)	C2—C7—H7A	110.2
C3—C2—C7	123.99 (19)	Br1—C7—H7A	110.2
C2—C3—C4	119.5 (2)	C2—C7—H7B	110.2
C2—C3—H3	120.3	Br1—C7—H7B	110.2
C4—C3—H3	120.3	H7A—C7—H7B	108.5
C5—C4—C3	120.03 (19)	C6—C8—Br2	107.47 (14)
C5—C4—H4	120.0	C6—C8—H8A	110.2
C3—C4—H4	120.0	Br2—C8—H8A	110.2
C6—C5—C4	119.36 (19)	C6—C8—H8B	110.2
C6—C5—H5	120.3	Br2—C8—H8B	110.2
C4—C5—H5	120.3	H8A—C8—H8B	108.5
C6—N—C2—C3	−1.5 (3)	C2—N—C6—C8	178.21 (18)
C6—N—C2—C7	175.88 (19)	C4—C5—C6—N	1.0 (3)
N—C2—C3—C4	1.5 (3)	C4—C5—C6—C8	−176.8 (2)
C7—C2—C3—C4	−175.7 (2)	N—C2—C7—Br1	−96.15 (19)
C2—C3—C4—C5	−0.3 (3)	C3—C2—C7—Br1	81.1 (2)
C3—C4—C5—C6	−1.0 (3)	N—C6—C8—Br2	−87.12 (19)
C2—N—C6—C5	0.3 (3)	C5—C6—C8—Br2	90.7 (2)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N—H1···Br3	0.88 (3)	2.37 (3)	3.2417 (17)	174 (2)
C7—H7A···Br3^i	0.99	3.08	4.056 (2)	167
C7—H7B···Br3^ii	0.99	3.07	3.768 (2)	129
C8—H8A···Br3^iii	0.99	2.99	3.694 (2)	129
C8—H8B···Br3	0.99	2.92	3.677 (2)	134
C3—H3···Br2^iv	0.95	3.10	3.935 (2)	147
C7—H7A···Br2^iv	0.99	3.09	3.753 (2)	126
C8—H8A···Br1^v	0.99	2.86	3.599 (2)	132

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