o- and m-Benzenedicarbaldehyde

o-Benzene­dicarb­aldehyde (systematic name: benzene-1,2-dicarb­aldehyde), C₈H₆O₂, exhibits a weak intramolecular hydrogen bond between an aldehyde H atom and the O atom of the adjacent aldehyde group, with a C...O distance of 2.852 (2) Å. m-Benzene­dicarb­aldehyde (systematic name: benzene-1,3-dicarb­aldehyde), C₈H₆O₂, occurs as two different isomorphs. In all three crystals, there are intermolecular C—­H...O contacts involving both aldehyde and ring H atoms.

S1. Comment

In the structure of p-benzenedicarbaldehyde (Britton, 1998), there are short intermolecular C—H···O═C contacts involving the aldehyde H atoms. The structures of o- and m-benzenedicarbaldehyde, (I) and (II), respectively, have been determined, to look for further examples of such contacts, and the results are presented here. \sch

Views of (I) and the two isomorphs, A and B, of (II) are shown in Fig. 1. The bond lengths and angles are in the normal ranges. At the ring C atoms bonded to the aldehyde groups, the external C—C—C angles are not equal. In the ortho compound, (I), C7—C1—C2 [123.0 (2)°] and C8—C2—C1 [123.2 (2)°] are both 5–6° larger than C7—C1—C6 [117.1 (2)°] and C8—C2—C3 [117.8 (2)°]. This is consistent with the intramolecular hydrogen bonding forcing the groups apart (see below). In both polymorphs of the meta compound, (IIA) and (IIB), the external angles on the O side are about 2° larger than those on the H side. This can be attributed to the greater crowding between the O and ring H atoms than between the aldehyde H and ring H atoms.

There is one intramolecular C—H···O═C contact in the ortho compound, (I) (Fig. 2), with C8—H2···O1 112 (2)°, C8—H2 0.95 (2) Å, H2···O1 2.36 (2) Å, H2···O1═C7 98 (2)° and C8···O1 2.852 (2) Å. The corresponding values in naphthalene-2,3-dicarbaldehyde are 116 (2)°, 1.00 (2) Å, 2.30 (2) Å, 100 (2)° and 2.884 (2) Å (Britton, 1999). The two aldehyde groups are rotated by 13.3 (2) and 25.1 (2)° out of the plane of the benzene ring, compared with 7.2 (2) and 22.7 (2)° in the naphthalene compound. These rotations are both in the direction which increases the H···O distance, which is presumably the reason for the rotations. The smaller angles in the naphthalene compound are consistent with the longer C1—C2 length, 1.441 (2) versus. 1.411 (2) Å.

In the meta compound, (II), where there is less intramolecular crowding, the aldehyde groups are rotated 6.1 (2) and 6.6 (2)° in polymorph A, and 4.5 (2) and 10.1 (2)° in polymorph B.

The intermolecular H···O contacts of less than 2.82 Å are listed in Table 1 for both compounds, as well as for the para isomer (Britton, 1998) for comparison. If approximate linearity for the C—H···O angle and an approximate trigonal angle for H···O═C are taken as expected for a good C—H···O interaction, then none of the interactions in the ortho and meta compounds are as favorable as those in the para compound, although there are a number of H···O distances that are as short as those in the para compound. Overall, the contacts involving the aldehyde H atoms are no shorter than those involving the ring H atoms, suggesting there is no noticeable difference in their abilities to form C—H···O interactions. For an extended discussion of C—H···X interactions, see Desiraju & Steiner (1999).

S2. Experimental

Both compounds were obtained from Aldrich Chemical Co. Inc. Recrystallization of the ortho compound, (I), from acetone, benzene, dichloromethane or chloroform all gave similar crystals; the crystal used here was obtained from chloroform. Two polymorphs were found for the meta compound, (II). Sublimation, or recrystallization from benzene, dichloromethane or diethylether, gave polymorph A; the crystal used here was obtained from benzene. Recrystallization from acetone or chloroform gave polymorph B; the crystal used here was obtained from chloroform. Both polymorphs had the same melting points to within experimental error.

S3. Refinement

In every case, the H atoms were included at idealized positions, with C—H = 0.95 Å and U_iso(H) = 1.2 times larger than the U_av for the attached C atom. This was done to improve the data-to-parameter ratio for the ortho crystal, (I), and for the sake of consistency with the meta crystals, (II). The ortho crystals, (I), are noncentrosymmetric, but with no atoms heavier than O, the correct polarity could not be determined. The Friedel pairs were averaged for the final refinement.

Computing details

For all compounds, data collection: SMART (Siemens, 1995); cell refinement: SAINT (Siemens, 1995); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 1997); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL.

Figures

	Fig. 1. Views of the molecules of (a) (I), (b) polymorph A of (II) and (c) polymorph B of (II), showing the atom-numbering schemes. Displacement ellipsoids are shown at the 50% probability level and H atoms are shown as small spheres of arbitrary radii.
	Fig. 2. The contacts in (I). H···O contacts are shown as dotted lines and the intramolecular contact is shown as a double line.
	Fig. 3. The H···O contacts in polymorph A of (II), shown as dotted lines.
	Fig. 4. The H···O contacts in polymorph B of (II), shown as dotted lines.

(I) benzene-1,2-dicarbaldehyde

Crystal data

C8H6O2	Dx = 1.377 Mg m^−3
Mr = 134.13	Melting point = 328–331 K
Orthorhombic, Pna21	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 2c -2n	Cell parameters from 2907 reflections
a = 7.282 (2) Å	θ = 3.1–26.8°
b = 13.140 (3) Å	µ = 0.10 mm^−1
c = 6.760 (2) Å	T = 174 K
V = 646.8 (3) Å^3	Irregular prism, colorless
Z = 4	0.5 × 0.2 × 0.1 mm
F(000) = 280

Data collection

Siemens SMART area-detector diffractometer	802 independent reflections
Radiation source: fine-focus sealed tube	752 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.032
ω scans	θmax = 27.5°, θmin = 3.1°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996; Blessing, 1995)	h = −9→9
Tmin = 0.97, Tmax = 0.99	k = −17→17
7182 measured reflections	l = −8→8

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)] = 0.027	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.078	H-atom parameters constrained
S = 1.05	w = 1/[σ^2(Fo^2) + (0.051P)^2 + 0.045P] where P = (Fo^2 + 2Fc^2)/3
802 reflections	(Δ/σ)max = 0.004
91 parameters	Δρmax = 0.19 e Å^−3
1 restraint	Δρmin = −0.16 e Å^−3

Special details

Refinement. Since there are no atoms heavier than O, the Friedel pairs were averaged and no attempt was made to find the correct polarity.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
O1	0.13957 (18)	0.52733 (9)	0.3704 (3)	0.0512 (4)
O2	0.28771 (18)	0.66817 (10)	−0.1058 (2)	0.0481 (4)
C7	0.0869 (2)	0.60272 (13)	0.4565 (3)	0.0384 (4)
H1	0.0266	0.5929	0.5796	0.046*
C8	0.1907 (2)	0.65608 (12)	0.0352 (3)	0.0373 (4)
H2	0.1257	0.5937	0.0464	0.045*
C1	0.10846 (18)	0.70859 (11)	0.3865 (3)	0.0294 (3)
C2	0.16637 (19)	0.73320 (11)	0.1939 (2)	0.0287 (3)
C3	0.1924 (2)	0.83533 (12)	0.1442 (3)	0.0345 (4)
H3	0.2302	0.8530	0.0142	0.041*
C4	0.1634 (2)	0.91086 (13)	0.2830 (3)	0.0401 (4)
H4	0.1838	0.9800	0.2485	0.048*
C5	0.1047 (2)	0.88642 (13)	0.4721 (3)	0.0423 (5)
H5	0.0839	0.9387	0.5666	0.051*
C6	0.0764 (2)	0.78546 (13)	0.5229 (3)	0.0373 (4)
H6	0.0347	0.7688	0.6521	0.045*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O1	0.0605 (7)	0.0325 (6)	0.0605 (9)	0.0011 (5)	−0.0066 (8)	0.0079 (7)
O2	0.0584 (7)	0.0524 (8)	0.0336 (6)	−0.0010 (6)	0.0068 (6)	−0.0028 (7)
C7	0.0364 (8)	0.0404 (8)	0.0384 (9)	−0.0059 (7)	−0.0049 (7)	0.0109 (7)
C8	0.0458 (9)	0.0319 (8)	0.0343 (9)	−0.0042 (6)	−0.0018 (8)	−0.0005 (7)
C1	0.0250 (6)	0.0324 (7)	0.0306 (7)	−0.0019 (5)	−0.0025 (6)	0.0031 (7)
C2	0.0252 (7)	0.0286 (7)	0.0323 (8)	−0.0019 (5)	−0.0035 (6)	0.0016 (6)
C3	0.0317 (7)	0.0337 (8)	0.0382 (9)	−0.0032 (6)	−0.0046 (7)	0.0080 (7)
C4	0.0377 (9)	0.0260 (7)	0.0567 (11)	0.0010 (6)	−0.0080 (8)	0.0015 (8)
C5	0.0382 (9)	0.0378 (9)	0.0510 (11)	0.0065 (7)	−0.0018 (8)	−0.0151 (9)
C6	0.0321 (7)	0.0460 (9)	0.0337 (8)	0.0013 (7)	−0.0001 (7)	−0.0020 (8)

Geometric parameters (Å, º)

O1—C7	1.211 (2)	C2—C3	1.396 (2)
O2—C8	1.197 (2)	C3—C4	1.382 (3)
C7—C1	1.478 (2)	C3—H3	0.9500
C7—H1	0.9500	C4—C5	1.386 (3)
C8—C2	1.486 (2)	C4—H4	0.9500
C8—H2	0.9500	C5—C6	1.386 (3)
C1—C6	1.387 (2)	C5—H5	0.9500
C1—C2	1.407 (2)	C6—H6	0.9500
O1—C7—C1	125.64 (18)	C4—C3—C2	120.42 (18)
O1—C7—H1	117.2	C4—C3—H3	119.8
C1—C7—H1	117.2	C2—C3—H3	119.8
O2—C8—C2	123.70 (14)	C3—C4—C5	120.46 (16)
O2—C8—H2	118.2	C3—C4—H4	119.8
C2—C8—H2	118.2	C5—C4—H4	119.8
C6—C1—C2	119.88 (13)	C6—C5—C4	119.75 (18)
C6—C1—C7	117.07 (16)	C6—C5—H5	120.1
C2—C1—C7	122.99 (15)	C4—C5—H5	120.1
C3—C2—C1	118.97 (15)	C5—C6—C1	120.49 (17)
C3—C2—C8	117.76 (16)	C5—C6—H6	119.8
C1—C2—C8	123.17 (14)	C1—C6—H6	119.8
O1—C7—C1—C6	−166.24 (17)	C1—C2—C3—C4	0.6 (2)
O1—C7—C1—C2	11.0 (3)	C8—C2—C3—C4	176.99 (14)
C6—C1—C2—C3	0.7 (2)	C2—C3—C4—C5	−1.3 (2)
C7—C1—C2—C3	−176.57 (14)	C3—C4—C5—C6	0.5 (3)
C6—C1—C2—C8	−175.48 (14)	C4—C5—C6—C1	0.8 (3)
C7—C1—C2—C8	7.3 (2)	C2—C1—C6—C5	−1.4 (2)
O2—C8—C2—C3	26.8 (2)	C7—C1—C6—C5	176.01 (15)
O2—C8—C2—C1	−157.06 (16)

(IIA) benzene-1,3-dicarboxaldehyde, polymorph A

Crystal data

C8H6O2	F(000) = 280
Mr = 134.13	Dx = 1.392 Mg m^−3
Monoclinic, P21/n	Melting point: 360-362 K K
Hall symbol: -P 2yn	Mo Kα radiation, λ = 0.71073 Å
a = 3.776 (1) Å	Cell parameters from 1982 reflections
b = 11.171 (3) Å	θ = 2.7–25.3°
c = 15.229 (4) Å	µ = 0.10 mm^−1
β = 94.98 (1)°	T = 174 K
V = 640.0 (3) Å^3	Needle, colorless
Z = 4	0.50 × 0.15 × 0.10 mm

Data collection

Siemens SMART area-detector diffractometer	1461 independent reflections
Radiation source: fine-focus sealed tube	1138 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.040
ω scans	θmax = 27.5°, θmin = 2.3°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996; Blessing, 1995)	h = −4→4
Tmin = 0.98, Tmax = 0.99	k = −14→14
7258 measured reflections	l = −19→19

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)] = 0.039	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.099	H-atom parameters constrained
S = 1.05	w = 1/[σ^2(Fo^2) + (0.038P)^2 + 0.185P] where P = (Fo^2 + 2Fc^2)/3
1461 reflections	(Δ/σ)max = 0.001
91 parameters	Δρmax = 0.21 e Å^−3
0 restraints	Δρmin = −0.19 e Å^−3

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
O1	0.5734 (3)	0.90024 (10)	0.80041 (7)	0.0430 (3)
O3	0.8064 (3)	0.89332 (9)	0.38797 (6)	0.0369 (3)
C1	0.5787 (3)	0.82684 (12)	0.65384 (8)	0.0260 (3)
C2	0.6535 (3)	0.85677 (12)	0.56903 (9)	0.0249 (3)
H2	0.7593	0.9318	0.5579	0.030*
C3	0.5726 (3)	0.77623 (11)	0.50021 (9)	0.0254 (3)
C4	0.4192 (4)	0.66585 (12)	0.51721 (9)	0.0291 (3)
H4	0.3606	0.6116	0.4701	0.035*
C5	0.3517 (4)	0.63477 (12)	0.60246 (10)	0.0312 (3)
H5	0.2522	0.5589	0.6139	0.037*
C6	0.4300 (4)	0.71482 (12)	0.67039 (9)	0.0295 (3)
H6	0.3830	0.6940	0.7287	0.035*
C7	0.6546 (4)	0.91429 (13)	0.72568 (9)	0.0314 (3)
H1	0.7744	0.9861	0.7126	0.038*
C8	0.6506 (4)	0.80486 (13)	0.40942 (9)	0.0303 (3)
H3	0.5727	0.7497	0.3644	0.036*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O1	0.0589 (8)	0.0430 (7)	0.0280 (6)	0.0027 (5)	0.0100 (5)	−0.0015 (5)
O3	0.0472 (7)	0.0354 (6)	0.0293 (6)	−0.0051 (5)	0.0103 (5)	0.0044 (4)
C1	0.0243 (7)	0.0276 (7)	0.0263 (7)	0.0060 (5)	0.0034 (5)	0.0027 (5)
C2	0.0236 (6)	0.0228 (7)	0.0286 (7)	0.0029 (5)	0.0046 (5)	0.0030 (5)
C3	0.0234 (7)	0.0264 (7)	0.0268 (7)	0.0042 (5)	0.0037 (5)	0.0024 (5)
C4	0.0292 (7)	0.0254 (7)	0.0329 (7)	−0.0002 (6)	0.0044 (6)	−0.0018 (6)
C5	0.0313 (7)	0.0237 (7)	0.0394 (8)	−0.0003 (6)	0.0081 (6)	0.0059 (6)
C6	0.0293 (7)	0.0313 (7)	0.0291 (7)	0.0044 (6)	0.0084 (6)	0.0080 (6)
C7	0.0330 (8)	0.0328 (8)	0.0284 (7)	0.0040 (6)	0.0026 (6)	0.0016 (6)
C8	0.0339 (8)	0.0306 (7)	0.0270 (7)	−0.0001 (6)	0.0057 (6)	−0.0016 (6)

Geometric parameters (Å, º)

O1—C7	1.2143 (17)	C3—C8	1.4736 (18)
O3—C8	1.2094 (17)	C4—C5	1.389 (2)
C1—C2	1.3867 (19)	C4—H4	0.9500
C1—C6	1.4033 (19)	C5—C6	1.380 (2)
C1—C7	1.4761 (19)	C5—H5	0.9500
C2—C3	1.3948 (19)	C6—H6	0.9500
C2—H2	0.9500	C7—H1	0.9500
C3—C4	1.3961 (19)	C8—H3	0.9500
C2—C1—C6	119.95 (13)	C6—C5—C4	119.61 (13)
C2—C1—C7	119.26 (12)	C6—C5—H5	120.2
C6—C1—C7	120.80 (12)	C4—C5—H5	120.2
C1—C2—C3	119.69 (12)	C5—C6—C1	120.42 (13)
C1—C2—H2	120.2	C5—C6—H6	119.8
C3—C2—H2	120.2	C1—C6—H6	119.8
C2—C3—C4	119.84 (12)	O1—C7—C1	124.10 (14)
C2—C3—C8	121.10 (12)	O1—C7—H1	118.0
C4—C3—C8	119.05 (12)	C1—C7—H1	118.0
C5—C4—C3	120.46 (13)	O3—C8—C3	124.91 (13)
C5—C4—H4	119.8	O3—C8—H3	117.5
C3—C4—H4	119.8	C3—C8—H3	117.5
C6—C1—C2—C3	1.48 (19)	C4—C5—C6—C1	−0.3 (2)
C7—C1—C2—C3	−178.01 (12)	C2—C1—C6—C5	−1.1 (2)
C1—C2—C3—C4	−0.41 (19)	C7—C1—C6—C5	178.36 (13)
C1—C2—C3—C8	−179.60 (12)	C2—C1—C7—O1	174.03 (14)
C2—C3—C4—C5	−1.0 (2)	C6—C1—C7—O1	−5.5 (2)
C8—C3—C4—C5	178.17 (13)	C2—C3—C8—O3	5.0 (2)
C3—C4—C5—C6	1.4 (2)	C4—C3—C8—O3	−174.23 (14)

(IIB) benzene-1,3-dicarbaldehyde, polymorph B

Crystal data

C8H6O2	F(000) = 280
Mr = 134.13	Dx = 1.395 Mg m^−3
Monoclinic, P21/n	Melting point: 361-363 K K
Hall symbol: -P 2yn	Mo Kα radiation, λ = 0.71073 Å
a = 11.374 (3) Å	Cell parameters from 3560 reflections
b = 3.811 (1) Å	θ = 2.7–27.4°
c = 15.721 (4) Å	µ = 0.10 mm^−1
β = 110.419 (10)°	T = 173 K
V = 638.6 (3) Å^3	Needle, colorless
Z = 4	0.45 × 0.20 × 0.10 mm

Data collection

Siemens SMART area-detector diffractometer	1452 independent reflections
Radiation source: fine-focus sealed tube	1237 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.022
ω scans	θmax = 27.5°, θmin = 1.9°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996; Blessing, 1995)	h = −14→14
Tmin = 0.98, Tmax = 0.99	k = −4→4
6965 measured reflections	l = −20→20

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)] = 0.042	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.118	H-atom parameters constrained
S = 1.08	w = 1/[σ^2(Fo^2) + (0.063P)^2 + 0.146P] where P = (Fo^2 + 2Fc^2)/3
1452 reflections	(Δ/σ)max = 0.001
91 parameters	Δρmax = 0.23 e Å^−3
0 restraints	Δρmin = −0.14 e Å^−3

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
C1	0.35851 (11)	0.5573 (3)	0.62691 (8)	0.0277 (3)
C2	0.36368 (11)	0.6242 (3)	0.54146 (8)	0.0276 (3)
H2	0.4346	0.7393	0.5356	0.033*
C3	0.26449 (11)	0.5219 (3)	0.46424 (8)	0.0283 (3)
C4	0.16007 (12)	0.3563 (3)	0.47298 (9)	0.0312 (3)
H4	0.0929	0.2845	0.4203	0.037*
C5	0.15386 (12)	0.2957 (3)	0.55856 (9)	0.0327 (3)
H5	0.0818	0.1876	0.5644	0.039*
C6	0.25272 (12)	0.3931 (3)	0.63500 (9)	0.0304 (3)
H6	0.2490	0.3485	0.6935	0.036*
C7	0.46497 (12)	0.6640 (4)	0.70790 (9)	0.0338 (3)
H1	0.5316	0.7898	0.6986	0.041*
C8	0.26791 (13)	0.5905 (4)	0.37271 (9)	0.0348 (3)
H3	0.2050	0.4858	0.3224	0.042*
O1	0.47326 (10)	0.6023 (3)	0.78532 (6)	0.0459 (3)
O3	0.34604 (10)	0.7722 (3)	0.35779 (7)	0.0467 (3)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
C1	0.0301 (6)	0.0258 (6)	0.0274 (6)	0.0036 (5)	0.0102 (5)	0.0002 (5)
C2	0.0281 (6)	0.0272 (6)	0.0291 (6)	0.0020 (5)	0.0121 (5)	0.0012 (5)
C3	0.0309 (6)	0.0272 (6)	0.0272 (6)	0.0056 (5)	0.0108 (5)	0.0016 (5)
C4	0.0286 (6)	0.0308 (7)	0.0316 (6)	0.0016 (5)	0.0072 (5)	−0.0032 (5)
C5	0.0308 (6)	0.0300 (7)	0.0401 (7)	−0.0014 (5)	0.0160 (5)	−0.0008 (5)
C6	0.0365 (7)	0.0289 (7)	0.0298 (6)	0.0030 (5)	0.0166 (5)	0.0022 (5)
C7	0.0343 (7)	0.0372 (7)	0.0295 (6)	0.0020 (5)	0.0109 (5)	−0.0020 (5)
C8	0.0368 (7)	0.0395 (8)	0.0273 (6)	0.0081 (6)	0.0101 (5)	0.0023 (5)
O1	0.0472 (6)	0.0622 (7)	0.0262 (5)	0.0001 (5)	0.0101 (4)	−0.0001 (5)
O3	0.0534 (7)	0.0560 (7)	0.0358 (6)	−0.0003 (5)	0.0219 (5)	0.0087 (5)

Geometric parameters (Å, º)

C1—C2	1.3886 (17)	C4—H4	0.9500
C1—C6	1.4009 (18)	C5—C6	1.3797 (19)
C1—C7	1.4754 (18)	C5—H5	0.9500
C2—C3	1.3938 (18)	C6—H6	0.9500
C2—H2	0.9500	C7—O1	1.2106 (16)
C3—C4	1.3934 (18)	C7—H1	0.9500
C3—C8	1.4764 (17)	C8—O3	1.2122 (18)
C4—C5	1.3910 (18)	C8—H3	0.9500
C2—C1—C6	119.83 (11)	C6—C5—C4	119.80 (12)
C2—C1—C7	119.03 (11)	C6—C5—H5	120.1
C6—C1—C7	121.14 (11)	C4—C5—H5	120.1
C1—C2—C3	119.78 (11)	C5—C6—C1	120.39 (11)
C1—C2—H2	120.1	C5—C6—H6	119.8
C3—C2—H2	120.1	C1—C6—H6	119.8
C4—C3—C2	119.98 (11)	O1—C7—C1	124.52 (13)
C4—C3—C8	119.30 (11)	O1—C7—H1	117.7
C2—C3—C8	120.72 (11)	C1—C7—H1	117.7
C5—C4—C3	120.21 (11)	O3—C8—C3	124.06 (12)
C5—C4—H4	119.9	O3—C8—H3	118.0
C3—C4—H4	119.9	C3—C8—H3	118.0
C6—C1—C2—C3	−1.13 (18)	C4—C5—C6—C1	0.95 (19)
C7—C1—C2—C3	179.34 (11)	C2—C1—C6—C5	0.34 (18)
C1—C2—C3—C4	0.64 (18)	C7—C1—C6—C5	179.86 (12)
C1—C2—C3—C8	179.96 (11)	C2—C1—C7—O1	−175.92 (13)
C2—C3—C4—C5	0.65 (19)	C6—C1—C7—O1	4.6 (2)
C8—C3—C4—C5	−178.68 (12)	C4—C3—C8—O3	169.90 (13)
C3—C4—C5—C6	−1.45 (19)	C2—C3—C8—O3	−9.4 (2)