Br...O contacts and [pi]-[pi] stacking dominate the packing in methyl 4-bromo-3,5-di­meth­oxy­benzoate

The title compound, C₁₀H₁₁BrO₄, a useful precursor to pharmaceutically active isocoumarin and isochroman derivatives, crystallizes with two unique mol­ecules in the asymmetric unit. A [pi]-[pi] stacking inter­action links the planar mol­ecules in the asymmetric unit. Additional [pi]-[pi] contacts stack pairs of mol­ecules along the c axis. A feature of the crystal packing is the presence of a number of short Br...O contacts. A particularly unusual arrangement involves the formation of dimers, with pairs of Br...O contacts imposing a close Br...Br inter­action and generating five-membered rings within an eight-membered ring formed by two Br...O contacts. Only two comparable arrangements have been reported previously. The Br...O contacts combine with weak C-H...O hydrogen bonds to form corrugated sheets of mol­ecules approximately parallel to (001). These sheets are stacked along the c axis by [pi]-[pi] inter­actions to generate a three-dimensional network.

S1. Comment

Aromatic esters with 3,5-dihydroxy/dimethoxy substitution are very important precursors towards the synthesis of many naturally occurring isocoumarins, dihydroisocoumarins and isochromans. Thus, hibiuripyranone, a potent cytotoxic dihydroisocoumarin isolated from the marine sponge Mycale adhaerens, has a bromo substituent at the isocoumarin C-7 position (Uchida et al., 1998). Other examples include angelicoin A, isolated from Pleurospermum angelicoides, which has a 3-methylbut-2-enyl substituent at the 7-position (Shibano et al., 2006), achylisocoumarins I–III, from Achyls triphylla, with geranyl 7-substituents, and the antimalarial 7-alkyl/6,8-dihydroxy-3-pentyl-3,4-dihydroisocoumarins (Kongsaeree et al., 2003), produced from Geotrichum sp., with alkyl/alkenyl substitution at C-7, respectively. Methyl 4-bromo-3,5-dimethoxybenzoate, (I), is the key synthetic precursor for the synthesis of these isocoumarins. The Br atom at C-4 can be replaced by the required alkyl or aryl substituents by lithiation followed by coupling. In addition, the title ester has also been used in the Suzuki–Miyaura vinylation of electron-rich sterically hindered ortho,ortho'-substituted aryl halides with potassium vinyltrifluoroborate (Brooker et al., 2010).

Compounds in which a Br atom is flanked by two methoxy groups on a benzene ring are unusual, with only two discrete structures (Toyota et al., 2009; Caira et al., 2007) reported to date in the Cambridge Structural Database [CSD, Version 5.34 (November 2012) plus two updates; Allen, 2002]. Interest in these compounds was clearly sparked by the fact that they are closely related to brodimoprim [systematic name: 5-(4-bromo-3,5-dimethoxybenzyl)pyrimidine-2,4-diamine], which functions as a broad-spectrum antibacterial agent to treat upper respiratory tract infections (Toyota et al., 2009; Caira et al., 2007). Compounds with both methylcarboxylate and bromo substituents in a 1,4-configuration on a benzene ring are also rare, with only 15 occurrences in the CSD, including the archetypal methyl 4-bromobenzoate (Bolte & Wissler, 2006), but the majority have multiple bromo substituents on the aromatic ring (Li, 2011a,b,c,d). No structures were found with a single methoxy group at the 3-position.

Ester (I) was prepared, in high yield, by reaction of 4-bromo-3,5-dihydroxybenzoic acid with dimethyl sulfate in dry acetone, using anhydrous potassium carbonate as a mild base (see reaction scheme). Dimethyl sulfate not only methylates the free hydroxyl groups but also forms the ester simultaneously.

Compound (I) crystallizes with two unique but closely similar molecules, A and B, in the asymmetric unit of the orthorhombic unit cell (Fig. 1). The two molecules overlay, with an r.m.s. deviation of 0.0676 Å, with slight differences apparent in the orientation of the methoxy and carboxylate substituents on the benzene ring. Bond distances (Allen et al., 1987) and angles in (I) are normal and similar to those found in similar structures, such as methyl 4-bromobenzoate (Bolte & Wissler, 2006), methyl 4-bromo-3-hydroxybenzoate (Huang et al., 2011) and 5-(4-bromo-3,5-dimethoxybenzyl)pyrimidine-2,4-diamine (Caira et al., 2007). Both molecules are almost planar, with r.m.s. deviations of 0.0343 Å for molecule A and 0.0821 Å for molecule B from the best-fit planes through all non-H atoms of the two molecules. In the asymmetric unit, the planes of the two molecules are inclined to one another at an angle of only 1.22 (3)°, commensurate with a π–π stacking interaction between them.

In the crystal structure, C31B–H31A···O11B hydrogen bonds (Table 1) supplement the π–π contacts between adjacent A and B molecules in the asymmetric unit. The centroid-to-centroid distance, CgA···CgB, is 3.567 (3) Å (CgA and CgB are the centroids of the C1A–C6A and C1B–C6B benzene rings, respectively). An additional CgA···CgBⁱⁱⁱ [symmetry code: (iii) x, y, z - 1] π–π interaction at a distance of 3.572 (3) Å stacks A/B pairs of molecules along the c axis (Fig. 2).

Each A molecule forms a dimer with an adjacent B molecule through a short O5B···Br4Aⁱ contact [3.171 (3) Å; symmetry code: (i) x - 1/2, y, z - 1/2], augmented by a weak C51B—H51E···O3Aⁱ hydrogen bond (Table 1). Short intermolecular Br···O contacts are also formed between two adjacent B molecules. The Br4B···O3B^iv and O3···Br4B^iv contacts [3.320 (3) Å; symmetry code: (iv) -x + 1, -y + 1, z] form dimers and this configuration also imposes a short Br4B···Br4B^iv interaction [3.5394 (8) Å]. An overview of the Br···O and related contacts observed in the packing of these molecules is shown in Fig. 4.

Short Br···O contacts have been reported for several decades (Hassel & Romming, 1962; Leser & Rabinovich, 1978; Ramasubbu et al., 1986; Kruszynski, 2007). However, the arrangement adopted in (I) by adjacent B molecules, with the Br···O/Br···Br contacts generating five-membered rings within the eight-membered ring formed by the two Br···O contacts, is most unusual. The CSD reveals only two previous structures with a similar pattern of Br···O and Br···Br contacts (search limits: only organic; R ≤ 0.1; Br···O 2.8–3.5 Å and Br···Br 3.0–4.0 Å). These were 6,7-dibromo-4a-hydroxy-3,8-dihydroxymethyl-10a-methoxy-1,4,4a,10a-tetrahydrodibenzo[b,e][1,4]dioxin-1-one hemihydrate (CSD refcode FAHSUD; Xu et al., 2004), with Br···O and Br···Br contacts of 3.487 and 3.510 Å, respectively, and 5-(4-bromo-3,5-dimethoxybenzyl)pyrimidine-2,4-diamine 2-propanol solvate (XIBGOF; Caira et al., 2007), where the Br···O and Br···Br contacts were 3.473 and 3.597 Å, respectively. The latter compound quite closely resembles the structure of (I), but in neither instance was this unusual aspect of the crystal packing explored, or even mentioned, in the original reports (Fig. 4).

Br···O contacts, with the Br and O atoms each bound to a separate benzene ring, are very common, with 977 discrete contacts revealed in a CSD search for contacts with an intermolecular Br···O distance in the range 2.8–3.8 Å. The mean of these distances is 3.5 (2) Å. Limiting a similar search to contacts involving methoxybenzene derivatives, as are found in (I), reduces the number of discrete contacts to 246, still with a mean Br···O distance of 3.5 (2) Å. A histogram of these data (Fig. 5) compares the lengths of intermolecular Br···O contacts observed for compounds with Br- and methoxy-substituted benzene rings, within this range. Clearly, the Br···O contacts observed in the structure of (I) [3.171 (3) and 3.320 (3) Å] are among the shortest, and arguably strongest, of such contacts.

The Br···O and Br···Br contacts shown in Fig. 3 combine with an additional C51B—H51F···O11Bⁱⁱ hydrogen bond (Table 1) to link the molecules of (I) into corrugated sheets approximately parallel to (001) (Fig. 5a). These sheets are interconnected by the π–π stacking interactions and additional C—H···O contacts, detailed above, to generate a three-dimensional network with the layers stacked along the c axis (Fig. 5b).

Related literature

For related literature, see: Allen (2002); Allen et al. (1987); Bolte & Wissler (2006); Brooker et al. (2010); Caira et al. (2007); Hassel & Romming (1962); Huang et al. (2011); Kongsaeree et al. (2003); Kruszynski (2007); Leser & Rabinovich (1978); Li (2011a, 2011b, 2011c, 2011d); Ramasubbu et al. (1986); Shibano et al. (2006); Toyota et al. (2009); Uchida et al. (1998); Xu et al. (2004).

S2. Experimental

4-Bromo-3,5-dihydroxybenzoic acid (2.0 g, 0.008 mol) was refluxed with dimethyl sulfate (2.1 g, 0.017 mol) in dry acetone for 12 h, using anhydrous potassium carbonate (2.3 g, 0.017 mol) as a mild base. The reaction mixture was filtered when hot and the filter cake washed with hot dry acetone. The combined filtrate and washings were rotary-evaporated to leave a solid, which recrystallized from ethanol as colourless needles (yield 90%, m.p. 399 K). Spectroscopic analysis: IR (neat, ν, cm^-1): 1732 (ester C═O). 1601, 1588 (C═C); ¹H NMR (Frequency?, CDCl₃, δ, p.p.m.): 3.94 (1H, s, –OMe– ester), 3.96 (6H, s, –OMe), 7.27 (2H, Ar—H); ¹³C NMR (Frequency?, CDCl₃, δ, p.p.m.): 55.1 (–OMe ester), 56.6 (2-OMe), 166.4 (C═O, ester), 130.0 (ipso-C), 105.4 (ortho-C), 157 (meta-C), 106 (para-C). Analysis, calculated for C₁₀H₁₁BrO₄: C 43.66; H 4.03%; found: C 43.69; H 4.07%. MS m/z: (M⁺) 273.98, 275.98.

S3. Refinement

All C-bound H atoms were refined using a riding model, with C—H = 0.95 Å and U_iso(H) = 1.2U_eq(C) for aromatic H, and C—H = 0.98 Å and U_iso(H) = 1.5U_eq(C) for methyl H. The crystal studied was found to be twinned and refinement converged with a 0.619 (9):0.381 (9) domain ratio. Comparison of F_o and F_c clearly indicated that the 040 reflection was impeded by the beam-stop and it was removed from the final refinement.

Computing details

Data collection: APEX2 (Bruker, 2011); cell refinement: APEX2 and SAINT (Bruker, 2011); data reduction: SAINT (Bruker, 2011); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008) and TITAN (Hunter & Simpson, 1999); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008) and TITAN (Hunter & Simpson, 1999); molecular graphics: Mercury (Macrae et al., 2008); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008), enCIFer (Allen et al., 2004), PLATON (Spek, 2009) and publCIF (Westrip 2010).

Figures

	Fig. 1. The asymmetric unit of (I), showing the atom numbering for unique molecules A and B. Displacement ellipsoids are drawn at the 50% probability level.
	Fig. 2. Alternating A and B molecules of (I) stacked by π–π contacts along c. π–π contacts are shown as dashed lines (green in the electronic version of the paper), with the dark and light spheres (red and green, respectively) representing the centroids of the benzene rings of adjacent pairs of A and B molecules. C—H···O hydrogen bonds are shown as dashed lines (turquoise). [Symmetry code: (iii) x, y, z - 1.]
	Fig. 3. Br···O and associated contacts, shown as dashed lines, formed by adjacent molecules of (I). [Symmetry codes: (i) x - 1/2, y, z - 1/2; (iv) -x + 1, -y + 1, z.]
	Fig. 4. A histogram (Macrae et al., 2008) comparing the lengths of intermolecular Br···O contacts within the range 2.8–3.8 Å in compounds with Br- and methoxy-substituted benzene rings.
	Fig. 5. Views of the crystal packing of (I). (a) Corrugated sheets that run approximately parallel to the (001) plane. (b) A view along the c axis. A representative π–π contact is shown in this view as a dashed line between benzene-ring centroids, represented by spheres (red in the electronic version of the paper). Hydrogen bonds and other close contacts are also drawn as dashed lines.

Methyl 4-bromo-3,5-dimethoxybenzoate

Crystal data

C10H11BrO4	F(000) = 4416
Mr = 275.10	Dx = 1.729 Mg m^−3
Orthorhombic, Fdd2	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: F 2 -2d	Cell parameters from 4838 reflections
a = 19.1372 (11) Å	θ = 2.2–24.8°
b = 63.972 (4) Å	µ = 3.88 mm^−1
c = 6.9053 (5) Å	T = 91 K
V = 8453.8 (9) Å^3	Square block, colourless
Z = 32	0.43 × 0.41 × 0.26 mm

Data collection

Bruker APEXII CCD area-detector diffractometer	3417 independent reflections
Radiation source: fine-focus sealed tube	3185 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.058
ω scans	θmax = 25.7°, θmin = 3.3°
Absorption correction: multi-scan (SADABS; Bruker, 2011)	h = −22→22
Tmin = 0.430, Tmax = 0.745	k = −76→76
21112 measured reflections	l = −6→8

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)] = 0.026	H-atom parameters constrained
wR(F^2) = 0.058	w = 1/[σ^2(Fo^2) + (0.0275P)^2] where P = (Fo^2 + 2Fc^2)/3
S = 1.05	(Δ/σ)max = 0.002
3417 reflections	Δρmax = 0.29 e Å^−3
278 parameters	Δρmin = −0.30 e Å^−3
1 restraint	Absolute structure: Flack (1983), 1267 Friedel pairs
Primary atom site location: structure-invariant direct methods	Absolute structure parameter: 0.381 (9)

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
C12A	0.35488 (17)	0.56017 (6)	0.6674 (7)	0.0312 (10)
H12A	0.3433	0.5665	0.7927	0.047*
H12B	0.3275	0.5474	0.6497	0.047*
H12C	0.3439	0.5701	0.5634	0.047*
O12A	0.42872 (12)	0.55515 (4)	0.6622 (4)	0.0262 (6)
O11A	0.45218 (12)	0.58925 (4)	0.6988 (4)	0.0278 (7)
C11A	0.47156 (18)	0.57149 (6)	0.6832 (6)	0.0211 (9)
C1A	0.54628 (16)	0.56484 (6)	0.6831 (6)	0.0178 (8)
C2A	0.59641 (19)	0.58030 (6)	0.7110 (6)	0.0208 (9)
H2A	0.5828	0.5944	0.7312	0.025*
C3A	0.66644 (18)	0.57480 (6)	0.7091 (5)	0.0188 (8)
O3A	0.72009 (12)	0.58865 (4)	0.7338 (4)	0.0234 (7)
C31A	0.7013 (2)	0.60998 (6)	0.7697 (6)	0.0270 (10)
H31A	0.6745	0.6154	0.6596	0.041*
H31B	0.7437	0.6184	0.7868	0.041*
H31C	0.6727	0.6108	0.8873	0.041*
C4A	0.68552 (17)	0.55409 (5)	0.6780 (6)	0.0181 (8)
Br4A	0.780605 (17)	0.546595 (6)	0.66805 (6)	0.02276 (11)
C5A	0.63504 (17)	0.53835 (5)	0.6520 (6)	0.0193 (8)
O5A	0.65872 (11)	0.51857 (4)	0.6229 (4)	0.0212 (6)
C51A	0.60746 (18)	0.50252 (5)	0.6031 (7)	0.0304 (10)
H51A	0.5811	0.5012	0.7241	0.046*
H51B	0.6306	0.4892	0.5742	0.046*
H51C	0.5755	0.5061	0.4974	0.046*
C6A	0.56460 (17)	0.54390 (5)	0.6537 (6)	0.0181 (8)
H6A	0.5295	0.5336	0.6352	0.022*
C12B	0.77837 (18)	0.60938 (6)	0.2646 (7)	0.0267 (10)
H12D	0.7637	0.6216	0.1889	0.040*
H12E	0.8257	0.6052	0.2259	0.040*
H12F	0.7781	0.6129	0.4027	0.040*
O12B	0.73057 (11)	0.59224 (4)	0.2297 (4)	0.0201 (6)
O11B	0.64222 (12)	0.61377 (4)	0.3050 (4)	0.0226 (6)
C11B	0.66292 (18)	0.59686 (6)	0.2571 (5)	0.0169 (8)
C1B	0.61587 (17)	0.57883 (5)	0.2152 (5)	0.0152 (8)
C2B	0.64165 (17)	0.55900 (5)	0.1819 (6)	0.0160 (8)
H2B	0.6906	0.5566	0.1807	0.019*
C3B	0.59487 (17)	0.54254 (5)	0.1498 (6)	0.0146 (8)
O3B	0.61363 (11)	0.52223 (3)	0.1209 (4)	0.0210 (6)
C31B	0.68670 (16)	0.51720 (5)	0.1253 (7)	0.0211 (9)
H31D	0.7114	0.5255	0.0279	0.032*
H31E	0.6930	0.5023	0.0970	0.032*
H31F	0.7056	0.5203	0.2539	0.032*
C4B	0.52356 (16)	0.54672 (5)	0.1501 (6)	0.0157 (8)
Br4B	0.459311 (17)	0.524840 (5)	0.11229 (6)	0.02100 (10)
C5B	0.49829 (17)	0.56692 (5)	0.1789 (6)	0.0137 (7)
O5B	0.42754 (11)	0.56947 (3)	0.1733 (4)	0.0198 (6)
C51B	0.40127 (18)	0.59013 (5)	0.1876 (7)	0.0242 (9)
H51D	0.4155	0.5962	0.3118	0.036*
H51E	0.3502	0.5899	0.1796	0.036*
H51F	0.4200	0.5986	0.0814	0.036*
C6B	0.54529 (17)	0.58293 (5)	0.2136 (5)	0.0157 (8)
H6B	0.5289	0.5967	0.2364	0.019*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
C12A	0.0132 (17)	0.032 (2)	0.048 (3)	0.0019 (15)	−0.002 (2)	0.002 (2)
O12A	0.0160 (12)	0.0253 (14)	0.0372 (18)	0.0000 (10)	−0.0003 (14)	0.0014 (15)
O11A	0.0223 (14)	0.0279 (16)	0.0330 (18)	0.0062 (11)	0.0011 (13)	0.0021 (14)
C11A	0.0206 (18)	0.028 (2)	0.015 (2)	−0.0024 (16)	0.0007 (17)	0.0018 (18)
C1A	0.0155 (17)	0.022 (2)	0.016 (2)	0.0028 (14)	−0.0001 (17)	0.0069 (17)
C2A	0.026 (2)	0.0176 (19)	0.019 (2)	0.0017 (16)	−0.0009 (17)	0.0020 (17)
C3A	0.0217 (18)	0.0189 (19)	0.016 (2)	−0.0036 (15)	−0.0013 (16)	0.0021 (17)
O3A	0.0213 (13)	0.0179 (13)	0.0311 (19)	−0.0019 (11)	−0.0019 (12)	−0.0032 (13)
C31A	0.033 (2)	0.019 (2)	0.029 (3)	−0.0036 (17)	−0.0078 (19)	0.0004 (19)
C4A	0.0144 (16)	0.0230 (19)	0.017 (2)	0.0002 (14)	0.0042 (16)	0.0011 (18)
Br4A	0.01556 (17)	0.02133 (19)	0.0314 (2)	−0.00069 (14)	0.00145 (17)	−0.00032 (19)
C5A	0.0240 (19)	0.0189 (18)	0.015 (2)	−0.0013 (15)	0.0031 (18)	−0.0028 (18)
O5A	0.0188 (13)	0.0165 (13)	0.0283 (17)	−0.0001 (9)	0.0025 (13)	−0.0035 (13)
C51A	0.033 (2)	0.0137 (19)	0.045 (3)	−0.0037 (16)	0.003 (2)	−0.003 (2)
C6A	0.0188 (17)	0.0211 (19)	0.014 (2)	−0.0051 (15)	0.0002 (17)	−0.0012 (18)
C12B	0.0165 (19)	0.020 (2)	0.043 (3)	−0.0076 (15)	0.0003 (18)	−0.008 (2)
O12B	0.0134 (13)	0.0156 (13)	0.0314 (18)	−0.0040 (10)	−0.0027 (11)	−0.0035 (12)
O11B	0.0197 (13)	0.0141 (13)	0.0339 (18)	−0.0009 (10)	−0.0032 (12)	−0.0029 (12)
C11B	0.0176 (18)	0.0171 (19)	0.016 (2)	−0.0021 (15)	−0.0036 (15)	0.0019 (17)
C1B	0.0164 (18)	0.0140 (18)	0.015 (2)	−0.0030 (14)	−0.0038 (15)	0.0011 (16)
C2B	0.0154 (17)	0.0169 (18)	0.016 (2)	−0.0028 (14)	0.0004 (17)	0.0046 (17)
C3B	0.0186 (16)	0.0102 (17)	0.015 (2)	0.0001 (13)	0.0010 (17)	0.0020 (17)
O3B	0.0171 (12)	0.0134 (13)	0.0325 (17)	0.0008 (10)	0.0014 (14)	0.0011 (13)
C31B	0.0154 (18)	0.0169 (18)	0.031 (3)	0.0038 (14)	0.0019 (19)	0.000 (2)
C4B	0.0176 (16)	0.0151 (17)	0.015 (2)	−0.0052 (13)	−0.0006 (16)	0.0028 (16)
Br4B	0.01688 (17)	0.01156 (16)	0.0346 (2)	−0.00300 (14)	−0.00119 (17)	−0.00051 (18)
C5B	0.0162 (16)	0.0122 (17)	0.0129 (19)	−0.0004 (13)	0.0004 (16)	0.0029 (16)
O5B	0.0108 (11)	0.0122 (12)	0.0363 (17)	−0.0001 (9)	−0.0022 (13)	−0.0002 (13)
C51B	0.0149 (17)	0.0180 (19)	0.040 (3)	0.0035 (14)	−0.0054 (18)	0.001 (2)
C6B	0.0201 (18)	0.0091 (17)	0.018 (2)	0.0014 (13)	0.0013 (16)	0.0009 (15)

Geometric parameters (Å, º)

C12A—O12A	1.449 (4)	C12B—H12D	0.9800
C12A—H12A	0.9800	C12B—H12E	0.9800
C12A—H12B	0.9800	C12B—H12F	0.9800
C12A—H12C	0.9800	O12B—C11B	1.341 (4)
O12A—C11A	1.336 (4)	O11B—C11B	1.198 (4)
O11A—C11A	1.200 (4)	C11B—C1B	1.492 (5)
C11A—C1A	1.492 (4)	C1B—C6B	1.376 (4)
C1A—C2A	1.391 (5)	C1B—C2B	1.380 (4)
C1A—C6A	1.400 (5)	C2B—C3B	1.400 (4)
C2A—C3A	1.386 (5)	C2B—H2B	0.9500
C2A—H2A	0.9500	C3B—O3B	1.362 (4)
C3A—O3A	1.367 (4)	C3B—C4B	1.391 (4)
C3A—C4A	1.391 (5)	O3B—C31B	1.435 (4)
O3A—C31A	1.433 (4)	O3B—Br4B^ii	3.320 (2)
C31A—H31A	0.9800	C31B—H31D	0.9800
C31A—H31B	0.9800	C31B—H31E	0.9800
C31A—H31C	0.9800	C31B—H31F	0.9800
C4A—C5A	1.407 (5)	C4B—C5B	1.394 (5)
C4A—Br4A	1.883 (3)	C4B—Br4B	1.881 (3)
Br4A—O5B^i	3.170 (2)	Br4B—Br4B^ii	3.5392 (7)
C5A—O5A	1.359 (4)	C5B—O5B	1.364 (4)
C5A—C6A	1.394 (4)	C5B—C6B	1.384 (5)
O5A—C51A	1.427 (4)	O5B—C51B	1.418 (4)
C51A—H51A	0.9800	C51B—H51D	0.9800
C51A—H51B	0.9800	C51B—H51E	0.9800
C51A—H51C	0.9800	C51B—H51F	0.9800
C6A—H6A	0.9500	C6B—H6B	0.9500
C12B—O12B	1.448 (4)
O12A—C12A—H12A	109.5	O12B—C12B—H12E	109.5
O12A—C12A—H12B	109.5	H12D—C12B—H12E	109.5
H12A—C12A—H12B	109.5	O12B—C12B—H12F	109.5
O12A—C12A—H12C	109.5	H12D—C12B—H12F	109.5
H12A—C12A—H12C	109.5	H12E—C12B—H12F	109.5
H12B—C12A—H12C	109.5	C11B—O12B—C12B	114.8 (3)
C11A—O12A—C12A	115.0 (3)	O11B—C11B—O12B	123.8 (3)
O11A—C11A—O12A	124.1 (3)	O11B—C11B—C1B	123.5 (3)
O11A—C11A—C1A	124.5 (3)	O12B—C11B—C1B	112.6 (3)
O12A—C11A—C1A	111.4 (3)	C6B—C1B—C2B	121.7 (3)
C2A—C1A—C6A	121.8 (3)	C6B—C1B—C11B	116.5 (3)
C2A—C1A—C11A	117.3 (3)	C2B—C1B—C11B	121.8 (3)
C6A—C1A—C11A	120.9 (3)	C1B—C2B—C3B	119.3 (3)
C3A—C2A—C1A	119.0 (3)	C1B—C2B—H2B	120.4
C3A—C2A—H2A	120.5	C3B—C2B—H2B	120.4
C1A—C2A—H2A	120.5	O3B—C3B—C4B	116.2 (3)
O3A—C3A—C2A	124.1 (3)	O3B—C3B—C2B	124.9 (3)
O3A—C3A—C4A	116.1 (3)	C4B—C3B—C2B	118.9 (3)
C2A—C3A—C4A	119.8 (3)	C3B—O3B—C31B	117.9 (2)
C3A—O3A—C31A	116.7 (3)	C3B—O3B—Br4B^ii	139.18 (18)
O3A—C31A—H31A	109.5	C31B—O3B—Br4B^ii	101.92 (17)
O3A—C31A—H31B	109.5	O3B—C31B—H31D	109.5
H31A—C31A—H31B	109.5	O3B—C31B—H31E	109.5
O3A—C31A—H31C	109.5	H31D—C31B—H31E	109.5
H31A—C31A—H31C	109.5	O3B—C31B—H31F	109.5
H31B—C31A—H31C	109.5	H31D—C31B—H31F	109.5
C3A—C4A—C5A	121.4 (3)	H31E—C31B—H31F	109.5
C3A—C4A—Br4A	120.1 (3)	C3B—C4B—C5B	121.3 (3)
C5A—C4A—Br4A	118.5 (3)	C3B—C4B—Br4B	119.9 (3)
C4A—Br4A—O5B^i	137.67 (12)	C5B—C4B—Br4B	118.9 (2)
O5A—C5A—C6A	124.1 (3)	C4B—Br4B—Br4B^ii	112.37 (10)
O5A—C5A—C4A	117.1 (3)	O5B—C5B—C6B	124.2 (3)
C6A—C5A—C4A	118.8 (3)	O5B—C5B—C4B	116.8 (3)
C5A—O5A—C51A	117.1 (3)	C6B—C5B—C4B	119.0 (3)
O5A—C51A—H51A	109.5	C5B—O5B—C51B	117.5 (3)
O5A—C51A—H51B	109.5	O5B—C51B—H51D	109.5
H51A—C51A—H51B	109.5	O5B—C51B—H51E	109.5
O5A—C51A—H51C	109.5	H51D—C51B—H51E	109.5
H51A—C51A—H51C	109.5	O5B—C51B—H51F	109.5
H51B—C51A—H51C	109.5	H51D—C51B—H51F	109.5
C5A—C6A—C1A	119.2 (3)	H51E—C51B—H51F	109.5
C5A—C6A—H6A	120.4	C1B—C6B—C5B	119.9 (3)
C1A—C6A—H6A	120.4	C1B—C6B—H6B	120.1
O12B—C12B—H12D	109.5	C5B—C6B—H6B	120.1

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

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
C31A—H31A···O11B	0.98	2.53	3.411 (5)	150
C51B—H51E···O3A^iii	0.98	2.52	3.483 (4)	168
C51B—H51F···O11B^iv	0.98	2.47	3.093 (4)	121

Symmetry codes: (iii) x−1/2, y, z−1/2; (iv) x−1/4, −y+5/4, z−1/4.