2,2',6,6'-Tetrachloro-4,4'-propane-2,2-diyldiphenol, 2,2',6-tribromo-4,4'-propane-2,2-diyldiphenol and 2,2',6,6'-tetrabromo-4,4'-propane-2,2-diyldiphenol

Three flame retardants with very similar molecular structures showing three different packing patterns have been studied. The crystal structure of 2,2',6,6'-tetrachloro-4,4'-propane-2,2-diyldiphenol, C₁₅H₁₂Cl₄O₂, can be described as a packing of sheets. The packing shows a very short intermolecular Cl...Cl contact distance of 3.094 (2) Å between pairs of mol­ecules inside each sheet. The crystal structure of 2,2',6-tribromo-4,4'-propane-2,2-diyldiphenol, C₁₅H₁₃Br₃O₂, can be described as a packing of doubly stranded helical square tubes. These square helices are interconnected through Br...Br contacts between different helices. Finally, a previously known structure, 2,2',6,6'-tetrabromo-4,4'-propane-2,2-diyldiphenol [Simonov, Cheban, Rotaru & Bels'skii (1986). Kristallografiya, 31, 397-399], C₁₅H₁₂Br₄O₂, which is the most commonly used flame retardant and which has twofold rotational symmetry, has been refined in the correct absolute configuration. The structure shows large differences from the chloro analogue with regard to packing, van der Waals distances and hydrogen-bond distances.

S1. Comment

In recent years, several reports have indicated that the widespread use of flame retardants is responsible for the bioaccumulation of these compounds in nature. The decomposition of flame retardants in the natural environment and the products obtained from these is a long-running project in our department. The goal is a better understanding of the reactivity of these compounds in the environment.

The different substances observed in decomposition experiments that mimic realistic circumstances in the natural environment indicate large differences among the decomposition products, depending on the halogen substitution pattern and on whether the reactant is in aqueous solution or in the solid state.

The title compounds are members of a class collectively named `halogenated bisphenols', which are used as reactive flame retardants. This means that they are not only mixed together with a prefabricated plastic material but also take part in the polymerization process, where they are covalently bound into the polymer. The salient feature of reactive flame retardants is thus that they migrate less easily to the environment, due to this covalent bonding to the polymer. The corresponding additive flame retardants, which are simply mixed into a pre-produced polymer, migrate more easily (Kuryla & Papa, 1979).

The three title compounds, 2,2',6,6'-tetrachloro-4,4'-propane-2,2-diyldiphenol, (I), 2,2',6,-tribromo-4,4'-propane-2,2-diyldiphenol, (II) and 2,2',6,6'-tetrabromo-4,4'-propane-2,2-diyldiphenol, (III), are three common flame retardants with pseudo-isomorphous molecular structures (Figs. 1–3), but exhibiting very different crystal structures. \sch

The first two of the title compounds, (I) and (II), represent previously unknown structures, while the third, (III), has been reported previously by Simonov et al. (1986). Diffraction data have been remeasured for (III), and we have changed the absolute configuration of the molecule and also the space group, from P4₁2₁2 (92) to P4₃2₁2 (96), as these two constitute an enantiomorphic space-group pair. Some anomalous bond distances found with the refinement in P4₁2₁2 (92) are shown to be absent when refining the structure model with the correct absolute configuration in P4₃2₁2 (96).

The crystal structure of (I) is built up by a packing of sheets of hydrogen-bonded molecules, further stabilized by a very short intermolecular Cl···Cl contact: Cl1···Cl1ⁱ = 3.094 (2) Å [symmetry code: (i) 1 - x, -y, -z]. This is shorter than is observed in most of the well determined (R ≤ 10%) and non-disordered similar structures in the Cambridge Structural Database (CSD; Allen & Kennard, 1993), for instance, triphenylchloromethane (Dunand & Gerdil, 1982), where the shortest intermolecular Cl···Cl distance is 3.210 Å, which is itself considered to be very short (Desiraju, 1989). A similarly short intermolecular inter-halogen distance does not occur in the bromo analogue, (III).

The shortest intermolecular O···O contact distance in (I), O1···O2ⁱⁱ 2.723 (3) Å [symmetry code: (ii) x, y - 1, z], is also shorter than the corresponding shortest intermolecular O···O contact distance in (III) [O···O 3.11 (1) Å], thus indicating stronger hydrogen bonding between the molecules of (I) along the b axis.

Regarding the close similarity of the molecular structures, a reasonable conjecture would be that the tetrachlorobisphenol in (I) should have a rather similar structure to the brominated analogue in (III). The present investigation shows that this is not the case at all, neither concerning space group nor packing of the molecules. Further investigations will be carried out to elucidate the physical background to the close Cl···Cl contact in (I), whether it is a consequence or a reason for the packing of (I).

The hydrogen-bonding scheme in (I) cannot be deduced with certainty, since at least two schemes are possible (Fig. 4). The conformations of the four hydroxyl groups are restricted by the space-group symmetry. One can speculate on other hydrogen-bond schemes which break the space-group symmetry, e.g. with the four hydroxyl groups pointing to each other in a circular pattern, or a disordered hydrogen-bond scheme. This possible violation of the space-group symmetry by the H atoms cannot be detected in the diffraction data.

The second compound, (II), differs from the most commonly used flame retardant, (III), only by the lack of one Br atom, yet it crystallizes in a totally different structure. The crystal structure of (II) can be described as a packing of square helices running along the c axis. Each helix is built of two strands of hydrogen-bonded molecules of (II), further stabilized by interactions between the halogens and the aromatic ring systems. Three molecules of each strand in the helices are shown in Fig. 5. The two strands fit together to make up a square-type double helix in the ab plane. The shortest Br···Br distances (3.71–4.21 Å) correspond to intermolecular Br···Br contacts between different helices.

In contrast with the plausible hydrogen-bonding pattern of (II), no appreciable hydrogen bonding can be deduced from the packing of (III). Here, the molecules preferentially pack in long chains, with interactions between the aromatic rings and the aliphatic central part of the molecule, to give the packing pattern shown in Fig. 6, which is completely different from (II). The rather long intermolecular O···O contacts in (III) (>= 3.1 Å) may contribute to a minor stabilization of the structure of (III). The reported position for atom H1 involved in the possible hydrogen bond is that derived from the least-squares calculations. A geometrically computed position for H1 (0.2458, 0.2955, 0.0487) gives a linear link to the plausible acceptor O1ⁱⁱⁱ [symmetry code: (iii) y, x, -z]. Atom H1 and the symmetry-related H1 cannot both be linearly directed to the corresponding acceptor, but there is a possibility of a hydrogen positional disorder around atom O1, giving some slight stabilization due to intermolecular hydrogen bonds in (III).

Compound (II) exhibits much shorter intermolecular O···O distances compared with (III), so the contribution from hydrogen bonds to the stabilization of the structure is probably much larger for (II) than for (III). Similar Br···Br contact distances exist in both (II) and (III). In (II), the intermolecular Br···Br distances are >3.71 Å; in (III), these distances are >3.93 Å. This also indicates slightly stronger intermolecular bonding involving the Br···Br contacts for (II) compared with (III).

Both rings of (I) are planar, to within 0.013 Å for C4—C9 and 0.010 Å for C10—C15. Atom Cl1 involved in the very short intermolecular Cl···Cl contact is within 0.007 (5) Å of the plane defined by the C atoms in the aromatic ring. Atom O1 of the C4—C9 ring has the largest deviation from the ring plane. This can be interpreted as originating from effects by the short intermolecular O1···O2ⁱⁱ contact. The substituents of the second ring deviate more from the ring plane: deviations are 0.103 (5) for Cl4, 0.037 (5) for O2 and 0.098 (6) Å for Cl3. The angle between the two ring planes is 64.0 (1)° and this is smaller than corresponding interplanar angles of most of the similar structures from the CSD. There are seven structures with the 4,4'-dihydroxy-diphenyl-dimethyl-methane skeleton available in the CSD. One of them exhibits an interplanar angle of 64°, but the others have interplanar angles in the range 72–96°. The compound with the smallest angle, 2,2',6,6'-tetranitro-4,4'-isopropylidenediphenol (CSD refcode BIDJED; Wang et al., 1982) is also heavily affected by intermolecular bonding effects, similar to those present in (I). Smaller interplanar angles shown by similar compounds from the CSD are only present when either heavily steric interactions occur or a direct covalent bond restricts the conformation of the different rings.

Both rings of (II) are planar, to within 0.007 Å for C4—C9 and 0.02 Å for C10—C15. The ring with two Br substituents is more puckered than that with only one Br substituent. Most conspicuous are the deviations from the ring plane of the two hydroxyl O atoms: 0.108 (7) for O1 and 0.019 (7) Å for O2. These deviations can be described as a function of steric interaction. Atom O2 is pushed away by the close contact from Br1 and stays approximately in the ring plane, while atom O1 is pushed out of the ring plane, as it is situated in between two close Br substituents (Br2 and Br3). It is rather strange that the angular distortion found for O2 is also present for O1; the difference is mostly the out-of-plane deviation of O1. Both ring planes are defined solely by the C atoms in each ring. The angle between the two ring planes is 81.8 (2)°.

The ring of (III) is planar to within 0.011 Å (C3—C8). The two atoms deviating most from this plane are Br1 [0.022 (1) Å] and Br2 [0.118 (10) Å]. In this compound, the angular distortion of atom O1 with respect to the ring is much less than the corresponding distortions in the dibromo-substituted ring of (II). The ring plane is defined solely by the C atoms in the ring. The angle between the ring plane and the plane of the symmetry-related ring is 80.2 (2)°

Related literature

For related literature, see: Allen & Kennard (1993); Desiraju (1989); Dunand & Gerdil (1982); Flack (1983); Kuryla & Papa (1979); Sheldrick (1997); Simonov et al. (1986); Wang et al. (1982).

S2. Experimental

All compounds were re-crystallized from ethanol at ambient temperature. Original source?

S3. Refinement

For (I), the H atoms were placed geometrically. The hydroxyl groups were allowed to rotate freely around the C—O bond, using the AFIX83 instruction in SHELXL97 (Sheldrick, 1997). The hydroxyl H atoms converged to a position that could be interpreted as a favourable conformation for the formation of a hydrogen-bonded chain of molecules. For (II), the spacegroup was determined from reflection conditions, indicating the unique space group Fdd2 (43). The Flack parameter (Flack, 1983) was refined as a scale factor of this model and of the inverted model. The refined value of the Flack parameter in this model was 0.49 (2); thus, a merging of Friedel-related reflections was done for the final model. The total number of 2936 reflections gave 1559 unique reflections plus 1377 Friedel-related equivalents. The merging of reflection data improved wR2 and R1 without affecting s.u.s by more than approximately 10%. All coordinates and derived distances etc. were equal to within 1 s.u. of the corresponding quantities. The highest residual electron-density peak (1.50 e Å^-3) was located at (0.0814, 0.0417, 0.4149), 1.16 Å from H8, and should not be interpreted as an additional atom. Compound (II) is a strong absorber of Mo Kα radiation. Thus a possible cause for the residual peak is an imperfect absorption correction. The applied absorption correction decreased the internal R value from 0.25 to 0.06, but the remaining absorption effects could be an explanation of the positive ghost peak. However, the residual peak can also be interpreted as a ripple in the residual density map. For (III), the high internal R value is, to a large extent, dependent on the weak scattering from the crystal. Thus R_int is dominated by a large fraction of weak reflections. Of 1625 unique reflections in total, only 539 fulfil the criterion I ≥ 3σ(I). The internal R value calculated from these 539 reflections is 0.0634; the corresponding wR2 = 0.0464 and R1 = 0.0419, thus indicating insignificant differences to the refinement with all reflections present. The applied absorption correction did not affect the internal R value as much, but wR2 and R1 were significantly lowered, as expected. The total number of reflections (1625) was composed of 990 unique reflections and 635 Friedel equivalents. The Friedel equivalents were not averaged, as the four Br atoms of each molecule give a considerable contribution to anomalous dispersion effects and no signs of twinning were detectable. The present model was refined in P4₃2₁2 (96), instead of the inverse spacegroup P4₁2₁2 (92) previously used by Simonov et al. (1986). The Flack parameter clearly indicates that P4₃2₁2 (96) is the correct space group. This change of absolute configuration eliminates some of the anomalous bonding distances previously reported by Simonov et al. (1986). For all three compounds, C—H distances were constrained to 0.93–0.96 Å, O—H distances to 0.82 Å and U_iso(H) to 1.2 or 1.5 times U_eq of the parent atom. Query.

Computing details

Data collection: DIF4 (Stoe, 1988) for (I); EXPOSE (Stoe, 1997) for (II), (III). Cell refinement: DIF4 for (I); CELL (Stoe, 1997) for (II), (III). Data reduction: REDU4 (Stoe, 1988) for (I); INTEGRATE (Stoe, 1997) for (II), (III). For all compounds, program(s) used to solve structure: SHELXS97 (Sheldrick, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: DIAMOND (Bergerhoff, 1996).

Figures

	Fig. 1. The molecular structure of (I) showing 50% probability displacement ellipsoids. H atoms are shown with an arbitrary radius.
	Fig. 2. The molecular structure of (II) showing 50% probability displacement ellipsoids. H atoms are shown with an arbitrary radius.
	Fig. 3. The molecular structure of (III) showing 50% probability displacement ellipsoids. H atoms are shown with an arbitrary radius.
	Fig. 4. A stereoview of the square pattern of the O atoms from four molecules of (I), illustrating the possibilities for hydrogen bonding. The H-atom positions shown were optimized from the geometrically calculated positions.
	Fig. 5. A stereoview of the three molecules of (II) in each strand of the two-stranded helix.
	Fig. 6. A stereoview of one of the chains of (III), dominated by hydrophobic interactions.

(I) 3,5,3',5'-Tetrachloro-4,4'-dihydroxy-diphenyl-dimethl-methane

Crystal data

C15H12Cl4O2	F(000) = 1488
Mr = 366.05	Dx = 1.550 Mg m^−3
Orthorhombic, Pbcn	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2n 2ab	Cell parameters from 56 reflections
a = 25.675 (9) Å	θ = 7.5–10.7°
b = 11.602 (3) Å	µ = 0.75 mm^−1
c = 10.530 (4) Å	T = 293 K
V = 3136.6 (17) Å^3	Prism, light yellow
Z = 8	0.23 × 0.16 × 0.13 mm

Data collection

Stoe AED2 diffractometer	1267 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.061
Graphite monochromator	θmax = 25.0°, θmin = 1.6°
θ/2θ scans	h = −1→30
Absorption correction: numerical (X-RED; Stoe, 1997)	k = −1→13
Tmin = 0.843, Tmax = 0.906	l = −1→12
3572 measured reflections	4 standard reflections every 90 min
2771 independent reflections	intensity decay: <1%

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)] = 0.054	H-atom parameters constrained
wR(F^2) = 0.075	w = 1/[σ^2(Fo^2) + (0.01P)^2] where P = (Fo^2 + 2Fc^2)/3
S = 1.07	(Δ/σ)max = 0.001
2771 reflections	Δρmax = 0.28 e Å^−3
191 parameters	Δρmin = −0.32 e Å^−3
0 restraints	Extinction correction: SHELXL97 (Sheldrick, 1997), Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.00102 (11)

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
Cl1	0.53872 (4)	−0.02927 (10)	0.10785 (10)	0.0478 (3)
Cl2	0.63226 (4)	−0.27957 (9)	0.47048 (12)	0.0512 (3)
Cl3	0.50709 (4)	0.35165 (10)	0.44769 (13)	0.0644 (4)
Cl4	0.65296 (4)	0.54535 (10)	0.15129 (12)	0.0560 (4)
O1	0.55563 (9)	−0.23293 (19)	0.2637 (3)	0.0468 (9)
H1	0.5623	−0.2884	0.3091	0.070*
O2	0.55271 (10)	0.5328 (2)	0.2787 (3)	0.0530 (9)
H2	0.5247	0.5242	0.3150	0.080*
C1	0.68558 (14)	0.1512 (4)	0.3862 (4)	0.0319 (11)
C2	0.73417 (14)	0.1468 (4)	0.3003 (4)	0.0536 (14)
H2A	0.7538	0.0784	0.3188	0.080*
H2B	0.7554	0.2134	0.3158	0.080*
H2C	0.7236	0.1458	0.2129	0.080*
C3	0.70328 (15)	0.1513 (4)	0.5260 (4)	0.0498 (13)
H3A	0.7239	0.0839	0.5423	0.075*
H3B	0.6733	0.1510	0.5804	0.075*
H3C	0.7237	0.2190	0.5424	0.075*
C4	0.65264 (14)	0.0458 (3)	0.3535 (4)	0.0269 (9)
C5	0.65745 (14)	−0.0588 (3)	0.4160 (4)	0.0315 (11)
H5	0.6822	−0.0663	0.4798	0.038*
C6	0.62650 (14)	−0.1521 (3)	0.3860 (4)	0.0305 (10)
C7	0.58851 (14)	−0.1448 (3)	0.2918 (4)	0.0324 (11)
C8	0.58480 (13)	−0.0415 (3)	0.2275 (3)	0.0291 (10)
C9	0.61605 (13)	0.0506 (3)	0.2552 (4)	0.0311 (10)
H9	0.6129	0.1178	0.2077	0.037*
C10	0.65273 (15)	0.2592 (3)	0.3609 (4)	0.0273 (10)
C11	0.66843 (14)	0.3491 (3)	0.2842 (4)	0.0348 (11)
H11	0.7018	0.3491	0.2498	0.042*
C12	0.63489 (16)	0.4391 (3)	0.2581 (4)	0.0351 (10)
C13	0.58500 (16)	0.4435 (3)	0.3084 (4)	0.0383 (12)
C14	0.57022 (14)	0.3537 (4)	0.3886 (4)	0.0384 (12)
C15	0.60333 (15)	0.2652 (3)	0.4148 (4)	0.0336 (11)
H15	0.5927	0.2073	0.4700	0.040*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Cl1	0.0507 (7)	0.0459 (6)	0.0469 (7)	0.0012 (6)	−0.0230 (6)	0.0019 (7)
Cl2	0.0589 (7)	0.0346 (6)	0.0601 (8)	−0.0002 (6)	−0.0110 (7)	0.0171 (7)
Cl3	0.0478 (7)	0.0542 (7)	0.0913 (11)	0.0121 (7)	0.0256 (8)	0.0075 (9)
Cl4	0.0557 (7)	0.0460 (7)	0.0662 (8)	−0.0114 (7)	−0.0090 (7)	0.0228 (7)
O1	0.0474 (17)	0.0246 (14)	0.068 (2)	−0.0036 (15)	−0.0077 (19)	0.0030 (18)
O2	0.0372 (17)	0.0332 (15)	0.089 (3)	0.0030 (16)	−0.0101 (18)	0.001 (2)
C1	0.032 (2)	0.029 (2)	0.034 (3)	0.002 (2)	−0.004 (2)	0.000 (3)
C2	0.036 (3)	0.044 (3)	0.081 (4)	0.002 (3)	0.007 (3)	0.004 (3)
C3	0.053 (3)	0.039 (3)	0.058 (3)	−0.010 (3)	−0.023 (3)	−0.002 (3)
C4	0.027 (2)	0.024 (2)	0.029 (2)	0.005 (2)	0.003 (2)	0.000 (2)
C5	0.028 (2)	0.037 (3)	0.029 (3)	0.006 (2)	−0.009 (2)	0.004 (2)
C6	0.034 (2)	0.026 (2)	0.032 (3)	0.003 (2)	−0.003 (2)	0.008 (2)
C7	0.033 (2)	0.025 (2)	0.040 (3)	−0.001 (2)	−0.002 (2)	−0.006 (2)
C8	0.033 (2)	0.030 (2)	0.025 (2)	0.007 (2)	−0.006 (2)	0.002 (2)
C9	0.036 (2)	0.026 (2)	0.031 (2)	0.002 (2)	0.004 (2)	0.003 (2)
C10	0.028 (2)	0.026 (2)	0.028 (3)	−0.003 (2)	−0.006 (2)	−0.002 (2)
C11	0.029 (2)	0.033 (2)	0.042 (3)	−0.008 (2)	0.000 (2)	−0.003 (3)
C12	0.042 (3)	0.024 (2)	0.040 (3)	−0.006 (2)	−0.007 (2)	0.004 (2)
C13	0.038 (3)	0.027 (2)	0.049 (3)	0.000 (2)	−0.016 (2)	−0.004 (3)
C14	0.038 (2)	0.028 (2)	0.050 (3)	−0.001 (2)	0.007 (2)	−0.002 (3)
C15	0.044 (3)	0.025 (2)	0.031 (3)	−0.002 (2)	0.001 (2)	−0.001 (2)

Geometric parameters (Å, º)

Cl1—C8	1.734 (4)	C3—H3C	0.9600
Cl2—C6	1.732 (4)	C4—C5	1.386 (5)
Cl3—C14	1.736 (4)	C4—C9	1.399 (5)
Cl4—C12	1.732 (4)	C5—C6	1.380 (5)
O1—C7	1.359 (4)	C5—H5	0.9300
O1—H1	0.8200	C6—C7	1.394 (5)
O2—C13	1.363 (4)	C7—C8	1.379 (5)
O2—H2	0.8200	C8—C9	1.368 (5)
C1—C4	1.526 (5)	C9—H9	0.9300
C1—C10	1.533 (5)	C10—C11	1.380 (5)
C1—C3	1.540 (6)	C10—C15	1.391 (5)
C1—C2	1.542 (5)	C11—C12	1.381 (5)
C2—H2A	0.9600	C11—H11	0.9300
C2—H2B	0.9600	C12—C13	1.387 (5)
C2—H2C	0.9600	C13—C14	1.394 (5)
C3—H3A	0.9600	C14—C15	1.361 (5)
C3—H3B	0.9600	C15—H15	0.9300
C7—O1—H1	109.5	C7—C6—Cl2	118.5 (3)
C13—O2—H2	109.5	O1—C7—C8	120.3 (4)
C4—C1—C10	108.1 (3)	O1—C7—C6	123.0 (4)
C4—C1—C3	112.3 (4)	C8—C7—C6	116.8 (4)
C10—C1—C3	109.2 (3)	C9—C8—C7	122.2 (3)
C4—C1—C2	106.8 (3)	C9—C8—Cl1	119.4 (3)
C10—C1—C2	111.7 (3)	C7—C8—Cl1	118.3 (3)
C3—C1—C2	108.8 (3)	C8—C9—C4	121.4 (4)
C1—C2—H2A	109.5	C8—C9—H9	119.3
C1—C2—H2B	109.5	C4—C9—H9	119.3
H2A—C2—H2B	109.5	C11—C10—C15	117.9 (4)
C1—C2—H2C	109.5	C11—C10—C1	124.0 (4)
H2A—C2—H2C	109.5	C15—C10—C1	118.1 (3)
H2B—C2—H2C	109.5	C10—C11—C12	120.4 (4)
C1—C3—H3A	109.5	C10—C11—H11	119.8
C1—C3—H3B	109.5	C12—C11—H11	119.8
H3A—C3—H3B	109.5	C11—C12—C13	121.9 (4)
C1—C3—H3C	109.5	C11—C12—Cl4	120.0 (3)
H3A—C3—H3C	109.5	C13—C12—Cl4	118.0 (3)
H3B—C3—H3C	109.5	O2—C13—C12	120.1 (4)
C5—C4—C9	116.4 (4)	O2—C13—C14	122.8 (4)
C5—C4—C1	123.0 (3)	C12—C13—C14	117.1 (4)
C9—C4—C1	120.5 (3)	C15—C14—C13	121.1 (4)
C6—C5—C4	121.8 (4)	C15—C14—Cl3	120.0 (3)
C6—C5—H5	119.1	C13—C14—Cl3	118.8 (3)
C4—C5—H5	119.1	C14—C15—C10	121.6 (4)
C5—C6—C7	121.2 (4)	C14—C15—H15	119.2
C5—C6—Cl2	120.2 (3)	C10—C15—H15	119.2
C10—C1—C4—C5	−148.3 (4)	C4—C1—C10—C11	−125.9 (4)
C3—C1—C4—C5	−27.8 (5)	C3—C1—C10—C11	111.7 (4)
C2—C1—C4—C5	91.4 (5)	C2—C1—C10—C11	−8.7 (5)
C10—C1—C4—C9	32.9 (5)	C4—C1—C10—C15	51.7 (4)
C3—C1—C4—C9	153.3 (4)	C3—C1—C10—C15	−70.7 (4)
C2—C1—C4—C9	−87.5 (4)	C2—C1—C10—C15	168.9 (4)
C9—C4—C5—C6	−2.3 (6)	C15—C10—C11—C12	−2.8 (6)
C1—C4—C5—C6	178.8 (3)	C1—C10—C11—C12	174.8 (4)
C4—C5—C6—C7	−0.6 (6)	C10—C11—C12—C13	0.8 (6)
C4—C5—C6—Cl2	−177.6 (3)	C10—C11—C12—Cl4	−174.6 (3)
C5—C6—C7—O1	−176.8 (4)	C11—C12—C13—O2	−178.9 (3)
Cl2—C6—C7—O1	0.3 (5)	Cl4—C12—C13—O2	−3.5 (5)
C5—C6—C7—C8	2.3 (6)	C11—C12—C13—C14	1.1 (6)
Cl2—C6—C7—C8	179.4 (3)	Cl4—C12—C13—C14	176.5 (3)
O1—C7—C8—C9	178.0 (3)	O2—C13—C14—C15	179.2 (4)
C6—C7—C8—C9	−1.0 (6)	C12—C13—C14—C15	−0.8 (6)
O1—C7—C8—Cl1	−1.9 (5)	O2—C13—C14—Cl3	3.1 (6)
C6—C7—C8—Cl1	179.0 (3)	C12—C13—C14—Cl3	−176.9 (3)
C7—C8—C9—C4	−1.9 (6)	C13—C14—C15—C10	−1.3 (6)
Cl1—C8—C9—C4	178.0 (3)	Cl3—C14—C15—C10	174.7 (3)
C5—C4—C9—C8	3.5 (5)	C11—C10—C15—C14	3.1 (6)
C1—C4—C9—C8	−177.5 (4)	C1—C10—C15—C14	−174.7 (4)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O1—H1···O2^i	0.82	2.11	2.723 (3)	131
O2—H2···O2^ii	0.82	2.22	2.773 (5)	125

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

(II) 3,3',5'-Tribromo-4,4'-dihydroxy-diphenyl-dimethyl-methane

Crystal data

C15H13Br3O2	F(000) = 3584
Mr = 464.98	Dx = 2.034 Mg m^−3
Orthorhombic, Fdd2	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: F 2 -2d	Cell parameters from 1230 reflections
a = 19.545 (3) Å	θ = 1.7–26.1°
b = 30.971 (4) Å	µ = 7.97 mm^−1
c = 10.0335 (19) Å	T = 293 K
V = 6073.6 (16) Å^3	Prism, colourless
Z = 16	0.31 × 0.27 × 0.22 mm

Data collection

Stoe IPDS area-detector diffractometer	1559 independent reflections
Radiation source: fine-focus sealed tube	1500 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.066
Detector resolution: 6.0 pixels mm^-1	θmax = 25.9°, θmin = 2.4°
area detector scans	h = −23→23
Absorption correction: numerical (X-RED; Stoe, 1997)	k = −36→37
Tmin = 0.086, Tmax = 0.167	l = −12→12
10060 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)] = 0.026	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.063	H-atom parameters constrained
S = 1.16	w = 1/[σ^2(Fo^2) + (0.04P)^2] where P = (Fo^2 + 2Fc^2)/3
1559 reflections	(Δ/σ)max = 0.001
185 parameters	Δρmax = 1.50 e Å^−3
1 restraint	Δρmin = −0.41 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	0.04130 (3)	0.251655 (17)	0.20723 (6)	0.01990 (14)
Br2	0.36051 (3)	0.238662 (17)	−0.14632 (5)	0.02046 (14)
Br3	0.26465 (4)	0.400527 (18)	−0.32651 (5)	0.02824 (16)
O1	0.3320 (2)	0.31433 (13)	−0.3416 (4)	0.0237 (9)
H1	0.3586	0.2938	−0.3424	0.036*
O2	0.0917 (2)	0.24357 (14)	0.5008 (4)	0.0245 (9)
H2	0.0524	0.2436	0.4722	0.037*
C1	0.2617 (3)	0.35635 (16)	0.1956 (5)	0.0138 (11)
C2	0.2242 (3)	0.39992 (16)	0.2086 (6)	0.0178 (12)
H2A	0.1791	0.3975	0.1714	0.027*
H2B	0.2493	0.4218	0.1616	0.027*
H2C	0.2209	0.4077	0.3010	0.027*
C3	0.3334 (3)	0.3616 (2)	0.2562 (6)	0.0219 (12)
H3A	0.3297	0.3746	0.3427	0.033*
H3B	0.3607	0.3796	0.1993	0.033*
H3C	0.3546	0.3337	0.2644	0.033*
C4	0.2189 (3)	0.32320 (16)	0.2718 (5)	0.0120 (10)
C5	0.1617 (3)	0.30387 (15)	0.2131 (5)	0.0118 (9)
H5	0.1521	0.3088	0.1236	0.014*
C6	0.1194 (3)	0.27745 (17)	0.2879 (5)	0.0134 (10)
C7	0.1320 (3)	0.26925 (17)	0.4211 (6)	0.0157 (11)
C8	0.1889 (3)	0.28782 (18)	0.4793 (6)	0.0189 (11)
H8	0.1986	0.2825	0.5686	0.023*
C9	0.2314 (3)	0.31417 (17)	0.4056 (5)	0.0158 (11)
H9	0.2695	0.3263	0.4464	0.019*
C10	0.2724 (3)	0.34332 (16)	0.0512 (5)	0.0110 (10)
C11	0.2603 (3)	0.37152 (16)	−0.0552 (6)	0.0162 (11)
H11	0.2390	0.3979	−0.0391	0.019*
C12	0.2795 (3)	0.36073 (17)	−0.1853 (5)	0.0155 (11)
C13	0.3108 (3)	0.32183 (18)	−0.2145 (5)	0.0142 (10)
C14	0.3197 (3)	0.29320 (16)	−0.1094 (5)	0.0135 (10)
C15	0.3013 (3)	0.30340 (17)	0.0206 (5)	0.0140 (10)
H15	0.3083	0.2833	0.0882	0.017*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Br1	0.0136 (3)	0.0242 (3)	0.0219 (3)	−0.0077 (2)	−0.0028 (2)	0.0005 (2)
Br2	0.0214 (3)	0.0202 (3)	0.0197 (3)	0.0047 (2)	0.0039 (2)	−0.0015 (2)
Br3	0.0455 (4)	0.0232 (3)	0.0160 (3)	0.0082 (3)	−0.0032 (2)	0.0040 (2)
O1	0.029 (2)	0.029 (2)	0.0128 (18)	0.0070 (18)	−0.0002 (16)	−0.0004 (16)
O2	0.019 (2)	0.032 (2)	0.022 (2)	−0.0091 (19)	0.0000 (18)	0.0102 (17)
C1	0.008 (3)	0.016 (2)	0.018 (3)	−0.0016 (19)	0.000 (2)	−0.002 (2)
C2	0.024 (3)	0.012 (3)	0.018 (3)	0.001 (2)	0.006 (2)	−0.002 (2)
C3	0.016 (3)	0.032 (3)	0.019 (3)	−0.012 (2)	−0.001 (2)	−0.005 (2)
C4	0.009 (3)	0.014 (2)	0.014 (2)	0.0008 (19)	0.0012 (19)	0.0001 (19)
C5	0.012 (3)	0.013 (2)	0.010 (2)	0.0000 (19)	0.0000 (19)	0.0004 (19)
C6	0.006 (3)	0.016 (2)	0.019 (3)	0.0038 (19)	−0.002 (2)	−0.002 (2)
C7	0.017 (3)	0.013 (2)	0.017 (3)	0.003 (2)	0.004 (2)	0.004 (2)
C8	0.023 (3)	0.023 (3)	0.011 (2)	0.001 (2)	−0.001 (2)	0.005 (2)
C9	0.014 (3)	0.019 (3)	0.014 (3)	−0.004 (2)	−0.004 (2)	0.002 (2)
C10	0.006 (2)	0.015 (2)	0.012 (2)	−0.0034 (19)	0.0007 (18)	0.0011 (19)
C11	0.017 (3)	0.015 (2)	0.016 (3)	0.003 (2)	−0.002 (2)	−0.001 (2)
C12	0.018 (3)	0.015 (2)	0.014 (2)	0.001 (2)	−0.004 (2)	0.004 (2)
C13	0.012 (3)	0.022 (2)	0.009 (2)	−0.003 (2)	−0.0035 (19)	−0.004 (2)
C14	0.007 (3)	0.015 (2)	0.018 (3)	0.0018 (19)	−0.0023 (19)	−0.002 (2)
C15	0.010 (3)	0.016 (3)	0.016 (3)	0.001 (2)	0.000 (2)	0.002 (2)

Geometric parameters (Å, º)

Br1—C6	1.903 (5)	C4—C9	1.393 (7)
Br2—C14	1.905 (5)	C4—C5	1.398 (7)
Br3—C12	1.900 (5)	C5—C6	1.385 (7)
O1—C13	1.361 (7)	C5—H5	0.9300
O1—H1	0.8200	C6—C7	1.382 (7)
O2—C7	1.376 (7)	C7—C8	1.381 (8)
O2—H2	0.8200	C8—C9	1.380 (8)
C1—C10	1.520 (7)	C8—H8	0.9300
C1—C4	1.528 (7)	C9—H9	0.9300
C1—C3	1.537 (7)	C10—C15	1.393 (7)
C1—C2	1.541 (7)	C10—C11	1.400 (7)
C2—H2A	0.9600	C11—C12	1.398 (8)
C2—H2B	0.9600	C11—H11	0.9300
C2—H2C	0.9600	C12—C13	1.383 (8)
C3—H3A	0.9600	C13—C14	1.388 (7)
C3—H3B	0.9600	C14—C15	1.390 (7)
C3—H3C	0.9600	C15—H15	0.9300
C13—O1—H1	109.5	C5—C6—Br1	119.8 (4)
C7—O2—H2	109.5	O2—C7—C8	117.1 (5)
C10—C1—C4	112.0 (4)	O2—C7—C6	124.4 (5)
C10—C1—C3	106.2 (4)	C8—C7—C6	118.5 (5)
C4—C1—C3	111.8 (5)	C9—C8—C7	120.2 (5)
C10—C1—C2	112.3 (4)	C9—C8—H8	119.9
C4—C1—C2	106.6 (4)	C7—C8—H8	119.9
C3—C1—C2	107.9 (5)	C8—C9—C4	122.1 (5)
C1—C2—H2A	109.5	C8—C9—H9	119.0
C1—C2—H2B	109.5	C4—C9—H9	119.0
H2A—C2—H2B	109.5	C15—C10—C11	117.1 (5)
C1—C2—H2C	109.5	C15—C10—C1	120.1 (4)
H2A—C2—H2C	109.5	C11—C10—C1	122.6 (5)
H2B—C2—H2C	109.5	C12—C11—C10	121.1 (5)
C1—C3—H3A	109.5	C12—C11—H11	119.4
C1—C3—H3B	109.5	C10—C11—H11	119.4
H3A—C3—H3B	109.5	C13—C12—C11	121.7 (5)
C1—C3—H3C	109.5	C13—C12—Br3	118.3 (4)
H3A—C3—H3C	109.5	C11—C12—Br3	120.0 (4)
H3B—C3—H3C	109.5	O1—C13—C12	118.8 (5)
C9—C4—C5	117.4 (5)	O1—C13—C14	124.4 (5)
C9—C4—C1	121.4 (5)	C12—C13—C14	116.8 (5)
C5—C4—C1	121.0 (5)	C13—C14—C15	122.4 (5)
C6—C5—C4	120.2 (5)	C13—C14—Br2	118.1 (4)
C6—C5—H5	119.9	C15—C14—Br2	119.5 (4)
C4—C5—H5	119.9	C14—C15—C10	120.8 (5)
C7—C6—C5	121.7 (5)	C14—C15—H15	119.6
C7—C6—Br1	118.5 (4)	C10—C15—H15	119.6
C10—C1—C4—C9	144.8 (5)	C2—C1—C10—C15	−175.6 (5)
C3—C1—C4—C9	25.8 (7)	C4—C1—C10—C11	130.4 (5)
C2—C1—C4—C9	−92.0 (6)	C3—C1—C10—C11	−107.3 (6)
C10—C1—C4—C5	−41.3 (6)	C2—C1—C10—C11	10.4 (7)
C3—C1—C4—C5	−160.4 (5)	C15—C10—C11—C12	−3.1 (8)
C2—C1—C4—C5	81.8 (6)	C1—C10—C11—C12	171.1 (5)
C9—C4—C5—C6	1.0 (7)	C10—C11—C12—C13	0.4 (9)
C1—C4—C5—C6	−173.1 (5)	C10—C11—C12—Br3	−178.1 (4)
C4—C5—C6—C7	−0.2 (8)	C11—C12—C13—O1	−176.1 (5)
C4—C5—C6—Br1	179.6 (4)	Br3—C12—C13—O1	2.4 (7)
C5—C6—C7—O2	179.5 (5)	C11—C12—C13—C14	2.6 (8)
Br1—C6—C7—O2	−0.2 (7)	Br3—C12—C13—C14	−178.8 (4)
C5—C6—C7—C8	−0.5 (8)	O1—C13—C14—C15	175.6 (5)
Br1—C6—C7—C8	179.7 (4)	C12—C13—C14—C15	−3.0 (8)
O2—C7—C8—C9	−179.6 (5)	O1—C13—C14—Br2	−2.9 (7)
C6—C7—C8—C9	0.5 (8)	C12—C13—C14—Br2	178.4 (4)
C7—C8—C9—C4	0.3 (9)	C13—C14—C15—C10	0.4 (8)
C5—C4—C9—C8	−1.0 (8)	Br2—C14—C15—C10	178.9 (4)
C1—C4—C9—C8	173.0 (5)	C11—C10—C15—C14	2.7 (8)
C4—C1—C10—C15	−55.7 (7)	C1—C10—C15—C14	−171.6 (5)
C3—C1—C10—C15	66.7 (6)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O1—H1···O2^i	0.82	2.18	2.818 (5)	134

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

(III) 3,3',5,5'-Tetrabromo-4,4'-dihydroxy-diphenyl-dimethyl-methane

Crystal data

C15H12Br4O2	Dx = 2.158 Mg m^−3
Mr = 543.89	Mo Kα radiation, λ = 0.71073 Å
Tetragonal, P43212	Cell parameters from 1720 reflections
Hall symbol: P 41n 2abw	θ = 1.7–26.1°
a = 12.0038 (16) Å	µ = 9.62 mm^−1
c = 11.618 (3) Å	T = 293 K
V = 1674.1 (5) Å^3	Prism, colourless
Z = 4	0.15 × 0.14 × 0.12 mm
F(000) = 1032

Data collection

Stoe IPDS area-detector diffractometer	1625 independent reflections
Radiation source: fine-focus sealed tube	915 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.171
Detector resolution: 6.0 pixels mm^-1	θmax = 25.9°, θmin = 2.4°
area detector scans	h = −14→14
Absorption correction: numerical (X-RED; Stoe, 1997)	k = −14→14
Tmin = 0.236, Tmax = 0.302	l = −14→14
13032 measured reflections

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)] = 0.039	H-atom parameters constrained
wR(F^2) = 0.060	w = 1/[σ^2(Fo^2) + (0.01P)^2] where P = (Fo^2 + 2Fc^2)/3
S = 0.81	(Δ/σ)max = 0.001
1625 reflections	Δρmax = 0.42 e Å^−3
98 parameters	Δρmin = −0.39 e Å^−3
26 restraints	Absolute structure: Flack (1983)
Primary atom site location: structure-invariant direct methods	Absolute structure parameter: 0.03 (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	0.14857 (8)	0.55894 (7)	0.18353 (8)	0.0590 (3)
Br2	0.38816 (7)	0.15045 (7)	0.18750 (8)	0.0533 (3)
C1	0.4670 (6)	0.4670 (6)	0.5000	0.035 (3)
C2	0.5901 (6)	0.4518 (7)	0.4685 (7)	0.048 (3)
H2A	0.6047	0.3744	0.4540	0.073*
H2B	0.6358	0.4770	0.5311	0.073*
H2C	0.6068	0.4944	0.4007	0.073*
C3	0.3971 (6)	0.4312 (6)	0.3961 (6)	0.0286 (19)
C4	0.3171 (6)	0.4986 (6)	0.3447 (7)	0.033 (2)
H4	0.3040	0.5689	0.3754	0.039*
C5	0.2560 (6)	0.4648 (7)	0.2491 (6)	0.0326 (19)
C6	0.2740 (6)	0.3579 (8)	0.2021 (7)	0.038 (2)
C7	0.3546 (7)	0.2887 (6)	0.2513 (6)	0.0328 (19)
C8	0.4104 (6)	0.3260 (6)	0.3479 (6)	0.033 (2)
H8	0.4604	0.2774	0.3830	0.040*
O1	0.2159 (6)	0.3255 (5)	0.1073 (5)	0.0598 (18)
H1	0.1905	0.2629	0.1177	0.090*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Br1	0.0506 (6)	0.0730 (7)	0.0534 (6)	0.0257 (6)	−0.0076 (6)	0.0146 (6)
Br2	0.0608 (6)	0.0385 (5)	0.0606 (6)	−0.0011 (5)	−0.0017 (5)	−0.0083 (5)
C1	0.032 (4)	0.032 (4)	0.042 (7)	−0.003 (7)	0.001 (4)	−0.001 (4)
C2	0.045 (6)	0.052 (6)	0.048 (6)	−0.009 (5)	−0.003 (5)	0.010 (5)
C3	0.032 (4)	0.028 (4)	0.026 (5)	−0.002 (4)	−0.004 (3)	0.010 (3)
C4	0.037 (5)	0.028 (4)	0.033 (5)	0.006 (4)	0.010 (4)	0.003 (4)
C5	0.039 (5)	0.029 (5)	0.029 (5)	−0.001 (4)	0.008 (4)	0.008 (4)
C6	0.027 (4)	0.059 (5)	0.028 (5)	−0.010 (4)	−0.005 (4)	0.004 (5)
C7	0.027 (4)	0.035 (5)	0.036 (5)	0.000 (4)	−0.007 (4)	0.007 (4)
C8	0.035 (5)	0.026 (5)	0.038 (5)	0.009 (4)	0.000 (4)	0.003 (4)
O1	0.062 (4)	0.069 (6)	0.048 (4)	−0.016 (4)	−0.019 (3)	0.001 (3)

Geometric parameters (Å, º)

Br1—C5	1.877 (7)	C3—C8	1.391 (10)
Br2—C7	1.862 (7)	C4—C5	1.391 (10)
C1—C3	1.532 (9)	C4—H4	0.9300
C1—C3^i	1.532 (9)	C5—C6	1.412 (11)
C1—C2^i	1.533 (9)	C6—O1	1.360 (9)
C1—C2	1.533 (9)	C6—C7	1.397 (10)
C2—H2A	0.9600	C7—C8	1.381 (9)
C2—H2B	0.9600	C8—H8	0.9300
C2—H2C	0.9600	O1—H1	0.8200
C3—C4	1.389 (9)
C3—C1—C3^i	108.3 (8)	C3—C4—H4	118.8
C3—C1—C2^i	113.1 (4)	C5—C4—H4	118.8
C3^i—C1—C2^i	107.9 (5)	C4—C5—C6	119.6 (7)
C3—C1—C2	107.9 (5)	C4—C5—Br1	120.7 (6)
C3^i—C1—C2	113.1 (4)	C6—C5—Br1	119.7 (6)
C2^i—C1—C2	106.6 (10)	O1—C6—C7	121.1 (8)
C1—C2—H2A	109.5	O1—C6—C5	119.6 (8)
C1—C2—H2B	109.5	C7—C6—C5	119.2 (7)
H2A—C2—H2B	109.5	C8—C7—C6	118.4 (7)
C1—C2—H2C	109.5	C8—C7—Br2	120.5 (6)
H2A—C2—H2C	109.5	C6—C7—Br2	121.1 (6)
H2B—C2—H2C	109.5	C7—C8—C3	124.4 (7)
C4—C3—C8	115.8 (7)	C7—C8—H8	117.8
C4—C3—C1	123.6 (6)	C3—C8—H8	117.8
C8—C3—C1	120.5 (6)	C6—O1—H1	109.5
C3—C4—C5	122.5 (7)
C3^i—C1—C3—C4	111.5 (8)	Br1—C5—C6—O1	2.1 (10)
C2^i—C1—C3—C4	−8.0 (10)	C4—C5—C6—C7	−1.2 (11)
C2—C1—C3—C4	−125.7 (7)	Br1—C5—C6—C7	179.7 (5)
C3^i—C1—C3—C8	−67.9 (6)	O1—C6—C7—C8	−179.7 (7)
C2^i—C1—C3—C8	172.6 (8)	C5—C6—C7—C8	2.8 (11)
C2—C1—C3—C8	54.9 (9)	O1—C6—C7—Br2	1.4 (10)
C8—C3—C4—C5	−1.7 (11)	C5—C6—C7—Br2	−176.2 (6)
C1—C3—C4—C5	178.9 (7)	C6—C7—C8—C3	−4.2 (12)
C3—C4—C5—C6	0.6 (11)	Br2—C7—C8—C3	174.8 (6)
C3—C4—C5—Br1	179.7 (5)	C4—C3—C8—C7	3.5 (11)
C4—C5—C6—O1	−178.7 (7)	C1—C3—C8—C7	−177.1 (7)

Symmetry code: (i) y, x, −z+1.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O1—H1···O1^ii	0.82	3.13	3.11 (1)	81

Symmetry code: (ii) y, x, −z.