Packing effects in 4,4'-bis(4-hydroxy­butyl)-2,2'-bi­pyridine and 4,4'-bis(4-bromo­butyl)-2,2'-bi­pyridine

Structure analyses of 4,4'-bis(4-hydroxy­butyl)-2,2'-bi­pyridine, C₁₈H₂₄N₂O₂, (I), and 4,4'-bis(4-bromo­butyl)-2,2'-bi­pyridine, C₁₈H₂₂Br₂N₂, (II), reveal intermolecular hydrogen bonding in both compounds. For (I), O-H...N intermolecular hydrogen bonding leads to the formation of an infinite two-dimensional polymer, and [pi] stacking interactions are also observed. For (II), C-H...N intermolecular hydrogen bonding leads to the formation of a zigzag polymer. The two compounds crystallize in different crystal systems, but both mol­ecules possess C_i symmetry, with one half mol­ecule in the asymmetric unit.

S1. Comment

Compounds containing 2,2'-bipyridine (bpy), substituted at the 4,4'-positions with alkyl chains of different lengths, are interesting precursors for functionalization with thiols, carboxylic acids, disulfides or other anchoring groups. Compounds with such terminating groups have displayed the potential to form a self-assembled monolayer on metallic or semiconducting surfaces (Bain, Troughton et al., 1989; Haga et al., 2000; Bain, Biebuyck & Whitesides, 1989; Vogelson et al., 2003). Interestingly, alkyl-substituted bpy at the 4,4'-positions has been used as a covalent link in porphyrin–RuO₂ clusters and the influence of the linking alkyl chain length on the photoinduced intramolecular electron transfer in such clusters has also been studied (Resch & Fox, 1991). Derivatives of [Ru(bpy)₃]²⁺ with different alkyl substituents (e.g. tert-butyl and dinonyl) on the bipyridyl ligands have been prepared and, due to their enhanced solubility, processed for the construction of electroluminescent devices (Rudmann et al., 2002).

4,4'-Alkyl-substituted 2,2'-bpy-based compounds have also been used to synthesize macrocyclic compounds (Chambron & Sauvage, 1986, 1987). Owing to the chelating nature of bpy, metal complexes with alkyl-substituted bipyridine have been prepared and their behaviour as versatile solvatochromic probes that form metalloaggregates in water-rich media has been investigated (Gameiro et al., 2001). Ruthenium(II) complexes of 2,2'-bpy derivatives, [Ru(bpy)₃]²⁺ [Rbpy is 4,4'-bis(alkylaminocarbonyl)-2,2'-bipyridine, where the alkyl is propyl, hexyl or adamantyl], have been synthesized and the kinetics of the photo-induced electron transfer (ET) reaction between these complexes and methyl viologen (MV²⁺) has been investigated (Hamada et al., 2003). Compounds derived from the alkylation of 4,4'-dimethyl-2,2'-bpy have also been screened for fungicidal activity against nine plant diseases (Kelly Basetti et al., 1995).

The different synthetic strategies to prepare the 4,4'-substituted derivatives of 2,2'-bpy have been critically discussed and evaluated by Newkome et al. (2004). Our interest in alkyl-substituted bpy stems from the possibility of preparing prototype molecules with appropriate end-groups that could form self-assembled monolayers when brought into contact with substrates such as gold, ITO, platinum or silver. We report here the crystal structure analyses of the important precursors 4,4'-bis(hydroxybutyl)-2,2'-bipyridine, (I), and 4,4'-bis(bromobutyl)-2,2'-bipyridine, (II), which will lead us to the final prototype compounds.

The centrosymmetric molecular structure of (I) is shown in Fig. 1. The bond distances and angles are normal, and the bipyridine moiety is planar. Atoms C5, C2, C2A and C5A are collinear, and the N1—C2—C2A—C3A torsion angle is equal to −0.84 (16)° [symmetry code: (a) −x, 1 − y, −z].

Analysis of the crystal packing diagram (Fig. 2) reveals interesting features at the supramolecular level. Intermolecular hydrogen bonding occurs between the lone pair on the N atoms of the bipyridine group and the H atom of the hydroxy group [O1—H1···N1ⁱ = 1.91 (2) Å; for details and symmetry code see Table 1]. As a result, the diol molecules lie one behind each other, as in a tandem arrangement, giving rise to well ordered double-stranded chains forming a two-dimensional polymeric sheet structure parallel to (10–1). These chains are aligned parallel to one another in the ac plane. Another notable feature of the crystal structure is that the diol molecules lying in different planes are interconnected through π–π contacts established between the bipyridine moieties, with an interplanar distance of 3.296 (1) Å and a centroid–centroid offset (or ring slippage) of about 1.25 Å (Fig. 2).

Halogenation (Chambron & Sauvage, 1987) of (I) yielded an interesting precursor in the form of the corresponding dibromide, 4,4'-bis(bromobutyl)-2,2'-bipyridine, (II). The molecular structure of (II) is depicted in Fig. 3. Again the molecule is centrosymmetric and the bond distances and angles are normal. The four C atoms of the bipyridine moiety, C5, C2, C2A and C5A, are collinear, and the N1—C2—C2A—N3A torsion angle is 1.1 (4)° [symmetry code: (a) 2 − x, 1 − y, 2 − z].

Part of the crystal structure of (II) is illustrated in Fig. 4. It can be seen that a zigzag polymeric chain is formed as a result of intermolecular hydrogen bonding between the lone pair on the N atom of the aromatic rings and the H atoms of the C atom attached to the bromo group in the alkyl chain (Table 2). The inherent fashion of hydrogen bonding in this molecule makes it nearly impossible to establish π–π interactions, as was observed in the case of the diol (I).

The dibromo derivative can, very efficiently, be complexed with different types of metal ions upon rotation of the pyridine ring in order to obtain a cis conformation of the heteroaromatic rings. Furthermore, both the free ligand and the corresponding metal complex can undergo a very facile substitution of the bromo group with thioacetate (Gryko et al., 1999, 2000; Zheng et al., 1999). Such thioacetate functionalized molecules are extremely good candidates for immobilization on the surface of metals such as gold, silver and copper. The nanostructures thus created on such metallic surfaces can be characterized by a series of analytical techniques, for instance, scanning tunelling microscopy (STM), atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS), to elicit a great deal of information concerning the arrangement and packing of molecules on the surface, as well as their electrical and optical behaviour.

S2. Experimental

Compound (I) was synthesized from 4,4'-dimethyl-2,2'-bipyridine in accordance with the protocol described by Chambron & Sauvage (1987). Suitable crystals of (I) were obtained as colourless rods by slow concentration of a solution in chloroform. Halogenation of (I) (Chambron & Sauvage, 1987) yielded the corresponding dibromide, (II). Crystals were grown from a solution in chloroform. ¹H NMR and elemental analyses for (I) and (II) have been reported previously (Chambron & Sauvage, 1987). For (I): dC (400 MHz, CD3OD, p.p.m.): 157.2, 154.9, 150.07, 125.5, 123.03, 62.58, 36.09, 33.12, 27.77; ESI–MS (MeOH): m/z 301 ([M+H]+, 100%). For (II): dC (400 MHz, CDCl3, p.p.m.): 155.10, 153.01, 148.74, 124.39, 121.94, 34.73, 33.33, 32.26, 28.83; ESI–MS (CHCl3/MeOH): m/z 427 ([M+H]+, 100%).

S3. Refinement

For (I), H atoms were located in difference Fourier maps and refined isotropically [C—H = 0.944 (16)–1.025 (18) Å]. For (II), H atoms were included in calculated positions and treated as riding atoms [C—H = 0.95–0.99 Å, with U_iso(H) = 1.2U_eq(C)].

Computing details

For both compounds, data collection: X-AREA (Stoe & Cie, 2004); cell refinement: X-AREA; data reduction: X-RED32 (Stoe & Cie, 2004); program(s) used to solve structure: SHELXS97 (Sheldrick, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: PLATON (Spek, 2003); software used to prepare material for publication: SHELXL97.

Figures

	Fig. 1. The molecular structure of (I), with displacement ellipsoids at the 50% probability level. [Symmetry operation: (A) −x, 1 − y, −z.]
	Fig. 2. The crystal structure of (I), showing the formation of double-stranded hydrogen-bonded (dashed lines) two-dimensional sheets parallel to (10–1).
	Fig. 3. The molecular structure of (II), with displacement ellipsoids at the 50% probability level. [Symmetry operation: (A) 2 − x, 1 − y, 2 − z.]
	Fig. 4. Part of the crystal structure of (II), showing the formation of the hydrogen-bonded (dashed lines) C—H···N zigzag polymer chain. [Symmetry code: (i) 3/2 − x, 1/2 + y, z.]

(I) 4,4'-bis(4-hydroxybutyl)-2,2'-bipyridine

Crystal data

C18H24N2O2	F(000) = 648
Mr = 300.39	Dx = 1.221 Mg m^−3
Monoclinic, C2/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -C 2yc	Cell parameters from 4949 reflections
a = 22.878 (3) Å	θ = 2.0–29.5°
b = 4.7657 (5) Å	µ = 0.08 mm^−1
c = 16.789 (2) Å	T = 173 K
β = 116.759 (9)°	Rod, colourless
V = 1634.5 (4) Å^3	0.50 × 0.17 × 0.10 mm
Z = 4

Data collection

STOE IPDS diffractometer	1733 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.048
Graphite monochromator	θmax = 29.2°, θmin = 2.0°
Detector resolution: 0.81Å pixels mm^-1	h = −30→30
ϕ oscillation scans	k = −6→6
11138 measured reflections	l = −23→22
2210 independent 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)] = 0.041	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.118	All H-atom parameters refined
S = 1.05	w = 1/[σ^2(Fo^2) + (0.0673P)^2 + 0.3603P] where P = (Fo^2 + 2Fc^2)/3
2210 reflections	(Δ/σ)max < 0.001
148 parameters	Δρmax = 0.32 e Å^−3
0 restraints	Δρmin = −0.16 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.

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
O1	0.38863 (5)	−0.1556 (2)	0.23801 (7)	0.0430 (3)
H1	0.4194 (9)	−0.068 (4)	0.2911 (13)	0.062 (5)*
N1	−0.02394 (4)	0.3477 (2)	−0.10911 (6)	0.0245 (2)
C2	0.01218 (5)	0.3912 (2)	−0.02070 (6)	0.0206 (2)
C3	0.06885 (5)	0.2382 (2)	0.02965 (7)	0.0228 (2)
H3	0.0927 (7)	0.264 (3)	0.0928 (9)	0.029 (3)*
C4	0.09052 (5)	0.0360 (2)	−0.01106 (7)	0.0242 (2)
C5	0.05314 (5)	−0.0074 (2)	−0.10196 (7)	0.0280 (2)
H5	0.0644 (8)	−0.144 (3)	−0.1336 (10)	0.040 (4)*
C6	−0.00341 (5)	0.1495 (3)	−0.14721 (7)	0.0287 (3)
H6	−0.0312 (7)	0.124 (3)	−0.2102 (10)	0.033 (4)*
C7	0.15147 (5)	−0.1321 (2)	0.04344 (8)	0.0297 (3)
H7A	0.1565 (9)	−0.269 (4)	0.0056 (12)	0.049 (5)*
H7B	0.1457 (8)	−0.220 (4)	0.0922 (11)	0.045 (4)*
C8	0.21374 (5)	0.0427 (3)	0.08786 (8)	0.0312 (3)
H8A	0.2202 (9)	0.150 (4)	0.0396 (12)	0.054 (5)*
H8B	0.2073 (8)	0.189 (4)	0.1239 (11)	0.048 (4)*
C9	0.27345 (6)	−0.1367 (3)	0.14334 (9)	0.0326 (3)
H9A	0.2672 (9)	−0.243 (4)	0.1900 (12)	0.057 (5)*
H9B	0.2785 (9)	−0.278 (4)	0.1036 (12)	0.057 (5)*
C10	0.33580 (6)	0.0300 (3)	0.19055 (9)	0.0386 (3)
H10A	0.3435 (9)	0.138 (4)	0.1449 (13)	0.060 (5)*
H10B	0.3327 (9)	0.161 (4)	0.2366 (12)	0.050 (5)*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O1	0.0292 (5)	0.0427 (6)	0.0383 (5)	0.0083 (4)	−0.0014 (4)	−0.0077 (4)
N1	0.0226 (4)	0.0284 (5)	0.0210 (4)	−0.0009 (3)	0.0085 (3)	−0.0008 (3)
C2	0.0185 (4)	0.0220 (5)	0.0215 (4)	−0.0032 (4)	0.0092 (4)	−0.0004 (4)
C3	0.0193 (4)	0.0237 (5)	0.0229 (4)	−0.0024 (4)	0.0074 (4)	−0.0011 (4)
C4	0.0201 (5)	0.0221 (5)	0.0310 (5)	−0.0026 (4)	0.0118 (4)	−0.0006 (4)
C5	0.0289 (5)	0.0279 (6)	0.0306 (5)	−0.0015 (4)	0.0165 (4)	−0.0045 (4)
C6	0.0283 (5)	0.0347 (6)	0.0227 (5)	−0.0010 (4)	0.0113 (4)	−0.0040 (4)
C7	0.0228 (5)	0.0245 (5)	0.0387 (6)	0.0013 (4)	0.0110 (4)	−0.0007 (5)
C8	0.0233 (5)	0.0273 (6)	0.0374 (6)	−0.0002 (4)	0.0085 (4)	0.0011 (5)
C9	0.0251 (5)	0.0301 (6)	0.0369 (6)	0.0020 (4)	0.0090 (5)	0.0006 (5)
C10	0.0254 (6)	0.0349 (7)	0.0404 (7)	0.0008 (5)	0.0015 (5)	−0.0011 (5)

Geometric parameters (Å, º)

O1—C10	1.4181 (15)	C6—H6	0.965 (15)
O1—H1	0.95 (2)	C7—C8	1.5242 (16)
N1—C6	1.3387 (14)	C7—H7A	0.953 (18)
N1—C2	1.3509 (12)	C7—H7B	0.978 (17)
C2—C3	1.3931 (14)	C8—C9	1.5227 (16)
C2—C2^i	1.4890 (19)	C8—H8A	1.025 (18)
C3—C4	1.3951 (15)	C8—H8B	0.978 (18)
C3—H3	0.957 (13)	C9—C10	1.5085 (17)
C4—C5	1.3885 (16)	C9—H9A	0.997 (19)
C4—C7	1.5081 (15)	C9—H9B	0.99 (2)
C5—C6	1.3876 (16)	C10—H10A	1.00 (2)
C5—H5	0.944 (16)	C10—H10B	1.020 (17)
C10—O1—H1	109.8 (12)	C8—C7—H7B	105.8 (10)
C6—N1—C2	117.43 (9)	H7A—C7—H7B	111.7 (14)
N1—C2—C3	121.88 (9)	C9—C8—C7	112.08 (10)
N1—C2—C2^i	116.58 (11)	C9—C8—H8A	110.8 (10)
C3—C2—C2^i	121.54 (11)	C7—C8—H8A	108.8 (10)
C2—C3—C4	120.22 (9)	C9—C8—H8B	111.5 (10)
C2—C3—H3	121.0 (8)	C7—C8—H8B	108.9 (10)
C4—C3—H3	118.7 (8)	H8A—C8—H8B	104.4 (13)
C5—C4—C3	117.54 (10)	C10—C9—C8	113.66 (10)
C5—C4—C7	122.10 (10)	C10—C9—H9A	107.0 (11)
C3—C4—C7	120.34 (10)	C8—C9—H9A	111.1 (11)
C6—C5—C4	118.86 (10)	C10—C9—H9B	110.0 (11)
C6—C5—H5	119.1 (9)	C8—C9—H9B	108.4 (11)
C4—C5—H5	122.1 (9)	H9A—C9—H9B	106.5 (16)
N1—C6—C5	124.05 (10)	O1—C10—C9	109.38 (11)
N1—C6—H6	114.4 (9)	O1—C10—H10A	110.5 (11)
C5—C6—H6	121.6 (9)	C9—C10—H10A	108.6 (11)
C4—C7—C8	114.31 (9)	O1—C10—H10B	106.7 (10)
C4—C7—H7A	108.4 (11)	C9—C10—H10B	110.4 (10)
C8—C7—H7A	109.4 (10)	H10A—C10—H10B	111.3 (14)
C4—C7—H7B	107.3 (10)
C6—N1—C2—C3	0.25 (14)	C2—N1—C6—C5	−1.62 (16)
C6—N1—C2—C2^i	−178.87 (11)	C4—C5—C6—N1	1.68 (17)
N1—C2—C3—C4	1.03 (15)	C5—C4—C7—C8	119.31 (12)
C2^i—C2—C3—C4	−179.90 (11)	C3—C4—C7—C8	−62.34 (14)
C2—C3—C4—C5	−0.95 (15)	C4—C7—C8—C9	178.92 (10)
C2—C3—C4—C7	−179.37 (9)	C7—C8—C9—C10	−178.35 (11)
C3—C4—C5—C6	−0.31 (16)	C8—C9—C10—O1	−178.28 (11)
C7—C4—C5—C6	178.08 (10)

Symmetry code: (i) −x, −y+1, −z.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O1—H1···N1^ii	0.95 (2)	1.91 (2)	2.8495 (14)	172.5 (18)

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

(II) 4,4'-bis(4-bromobutyl)-2,2'-bipyridine

Crystal data

C18H22Br2N2	F(000) = 856
Mr = 426.20	Dx = 1.609 Mg m^−3
Orthorhombic, Pbca	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ac 2ab	Cell parameters from 4377 reflections
a = 8.3566 (12) Å	θ = 1.4–25.6°
b = 14.246 (2) Å	µ = 4.61 mm^−1
c = 14.779 (2) Å	T = 173 K
V = 1759.4 (4) Å^3	Plate, colourless
Z = 4	0.30 × 0.20 × 0.10 mm

Data collection

STOE IPDS-II diffractometer	1560 independent reflections
Radiation source: fine-focus sealed tube	1064 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.055
rotation method scans	θmax = 25.1°, θmin = 2.9°
Absorption correction: refdelF DELrefABS in PLATON (Spek, 2003)	h = −9→9
Tmin = 0.267, Tmax = 0.631	k = −16→16
7834 measured reflections	l = −17→14

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)] = 0.037	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.091	H-atom parameters constrained
S = 0.96	w = 1/[σ^2(Fo^2) + (0.0503P)^2] where P = (Fo^2 + 2Fc^2)/3
1560 reflections	(Δ/σ)max < 0.001
100 parameters	Δρmax = 0.41 e Å^−3
0 restraints	Δρmin = −0.65 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.

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	0.03706 (4)	0.74683 (3)	0.37863 (3)	0.04190 (17)
N1	1.0144 (3)	0.4109 (2)	0.41392 (19)	0.0277 (6)
C2	0.9514 (3)	0.4823 (2)	0.4614 (2)	0.0240 (7)
C3	0.8025 (4)	0.5208 (2)	0.4414 (2)	0.0273 (7)
H8	0.7620	0.5709	0.4772	0.033*
C4	0.7129 (4)	0.4866 (2)	0.3699 (2)	0.0283 (8)
C5	0.7792 (4)	0.4121 (2)	0.3209 (2)	0.0276 (8)
H5	0.7228	0.3856	0.2713	0.033*
C6	0.9255 (4)	0.3780 (2)	0.3449 (3)	0.0301 (8)
H3	0.9677	0.3274	0.3105	0.036*
C7	0.5509 (4)	0.5241 (3)	0.3431 (3)	0.0347 (8)
H2A	0.4730	0.4719	0.3466	0.042*
H2B	0.5565	0.5441	0.2791	0.042*
C8	0.4859 (4)	0.6056 (2)	0.3985 (3)	0.0323 (8)
H11A	0.5599	0.6597	0.3938	0.039*
H11B	0.4791	0.5871	0.4629	0.039*
C9	0.3199 (4)	0.6346 (2)	0.3646 (3)	0.0316 (8)
H7A	0.3287	0.6586	0.3020	0.038*
H7B	0.2490	0.5789	0.3637	0.038*
C10	0.2476 (4)	0.7085 (2)	0.4235 (3)	0.0299 (8)
H10A	0.3193	0.7638	0.4254	0.036*
H10B	0.2368	0.6841	0.4860	0.036*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Br1	0.0373 (2)	0.0474 (3)	0.0410 (3)	0.01093 (17)	0.00046 (15)	0.00705 (19)
N1	0.0270 (14)	0.0269 (15)	0.0292 (15)	−0.0002 (12)	0.0002 (12)	−0.0009 (13)
C2	0.0243 (16)	0.0223 (16)	0.0253 (18)	−0.0026 (12)	0.0024 (12)	0.0012 (14)
C3	0.0291 (16)	0.0243 (16)	0.028 (2)	−0.0022 (14)	−0.0003 (14)	−0.0044 (15)
C4	0.0271 (17)	0.0263 (17)	0.031 (2)	−0.0036 (13)	0.0006 (13)	0.0041 (16)
C5	0.0288 (17)	0.0288 (18)	0.0253 (19)	−0.0049 (14)	−0.0022 (13)	−0.0028 (15)
C6	0.0329 (17)	0.0301 (18)	0.0272 (19)	−0.0041 (14)	0.0055 (15)	−0.0032 (15)
C7	0.0311 (18)	0.0364 (19)	0.037 (2)	0.0023 (15)	−0.0053 (15)	−0.0061 (18)
C8	0.0298 (18)	0.0325 (19)	0.035 (2)	0.0016 (15)	−0.0047 (15)	−0.0009 (16)
C9	0.0280 (16)	0.0338 (18)	0.033 (2)	0.0034 (14)	−0.0013 (15)	−0.0047 (17)
C10	0.0261 (15)	0.0276 (18)	0.036 (2)	0.0021 (15)	−0.0038 (15)	0.0043 (16)

Geometric parameters (Å, º)

Br1—C10	1.958 (3)	C7—C8	1.521 (5)
N1—C2	1.344 (4)	C7—H2A	0.9900
N1—C6	1.346 (5)	C7—H2B	0.9900
C2—C3	1.392 (4)	C8—C9	1.531 (5)
C2—C2^i	1.488 (6)	C8—H11A	0.9900
C3—C4	1.383 (5)	C8—H11B	0.9900
C3—H8	0.9500	C9—C10	1.494 (5)
C4—C5	1.400 (5)	C9—H7A	0.9900
C4—C7	1.508 (4)	C9—H7B	0.9900
C5—C6	1.363 (5)	C10—H10A	0.9900
C5—H5	0.9500	C10—H10B	0.9900
C6—H3	0.9500
C2—N1—C6	116.3 (3)	C8—C7—H2B	108.1
N1—C2—C3	122.5 (3)	H2A—C7—H2B	107.3
N1—C2—C2^i	116.3 (3)	C7—C8—C9	110.7 (3)
C3—C2—C2^i	121.2 (4)	C7—C8—H11A	109.5
C4—C3—C2	120.5 (3)	C9—C8—H11A	109.5
C4—C3—H8	119.8	C7—C8—H11B	109.5
C2—C3—H8	119.8	C9—C8—H11B	109.5
C3—C4—C5	116.6 (3)	H11A—C8—H11B	108.1
C3—C4—C7	124.2 (3)	C10—C9—C8	111.5 (3)
C5—C4—C7	119.2 (3)	C10—C9—H7A	109.3
C6—C5—C4	119.4 (3)	C8—C9—H7A	109.3
C6—C5—H5	120.3	C10—C9—H7B	109.3
C4—C5—H5	120.3	C8—C9—H7B	109.3
N1—C6—C5	124.7 (3)	H7A—C9—H7B	108.0
N1—C6—H3	117.7	C9—C10—Br1	111.2 (2)
C5—C6—H3	117.7	C9—C10—H10A	109.4
C4—C7—C8	116.7 (3)	Br1—C10—H10A	109.4
C4—C7—H2A	108.1	C9—C10—H10B	109.4
C8—C7—H2A	108.1	Br1—C10—H10B	109.4
C4—C7—H2B	108.1	H10A—C10—H10B	108.0
C6—N1—C2—C3	0.2 (5)	C2—N1—C6—C5	0.1 (5)
C6—N1—C2—C2^i	179.1 (3)	C4—C5—C6—N1	0.0 (5)
N1—C2—C3—C4	−0.6 (5)	C3—C4—C7—C8	1.0 (5)
C2^i—C2—C3—C4	−179.5 (4)	C5—C4—C7—C8	−179.5 (3)
C2—C3—C4—C5	0.7 (5)	C4—C7—C8—C9	−178.9 (3)
C2—C3—C4—C7	−179.8 (3)	C7—C8—C9—C10	174.7 (3)
C3—C4—C5—C6	−0.4 (5)	C8—C9—C10—Br1	178.9 (2)
C7—C4—C5—C6	−179.9 (3)

Symmetry code: (i) −x+2, −y+1, −z+1.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
C10—H10A···N1^ii	0.99	2.52	3.506 (4)	173

Symmetry code: (ii) −x+3/2, y+1/2, z.