Conformation and hydrogen bonding for the bicyclic compound 3-thia­bicyclo­[3.2.0]heptane-6,7-dicarboxylic acid 3,3-dioxide

The initial goal of this work was to verify the geometry of the product of a photochemical reaction, viz. the title compound, C₈H₁₀O₆S, (II). Our crystallographic study firmly establishes the cis-anti-cis nature of the substituents on the cyclo­butane ring. The geometry is also designated as exo, where exo signifies that the five-membered ring is on the opposite side of the central cyclo­butane ring from the carboxylic acid substituents. The structure determination reveals two mol­ecules, A and B, in the asymmetric unit that display substanti­ally different conformations of the bicyclic core: the cyclo­butane ring puckering angles are 22 and 3°, and the sulfolane ring conformations are twist (S-exo) and envelope (S-endo). Intrigued by this variation, we then compared the conformations of other mol­ecules in the Cambridge Structural Database that have sulfolane rings fused to cyclo­butane rings. In this class of compound, there are five examples of saturated cyclo­butane rings, with ring puckering angles ranging from 3 to 35°. The sulfolane rings were more similar: four of the six mol­ecules exhibit envelope conformations with S-endo, as in mol­ecule B of (II). Despite the conformational differences, the hydrogen-bonding scheme for both mol­ecules is similar: carboxyl -OH groups form hydrogen bonds with carboxyl and sulfone O atoms. Alternating A and B mol­ecules joined by hydrogen bonds between sulfone O atoms and carboxyl -OH groups form parallel chains that extend in the ac plane. Other hydrogen bonds between the carboxyl groups link the chains along the b axis.

S1. Comment

The photochemical addition of 3-sulfolene to maleic anhydride and its derivatives was first reported by Shaikhrazieva et al. (1971, 1972). A few years later the anhydride product, (I), the Bloomfield adduct, was patented by Monsanto as a chemical regulator of plant growth or development (Bloomfield, 1975). The various adducts formed by the addition of an alkene to 3-sulfolene have found considerable use in synthesis (Aitken et al., 1999). The structure of (I) was determined at BP Research Centre, Sunbury-on-Thames, in 1982 by Smith (2003; see also Cadogan et al., 1982) and the exo configuration was established by single-crystal X-ray diffraction; unfortunately the crystallographic data were never published and are no longer available. Although the geometry of (I) could be predicted on mechanistic grounds, we deemed it worthwhile to determine it with certainty using X-ray crystallography. However, during the crystallization process, or at some other point, the anhydride ring was opened by water so that the structure actually determined was the title dicarboxylic acid, (II). The opening of the anhydride would not change the configuration of the substituents on the central cyclobutane ring.

The X-ray crystal structure determination of (II) reveals two molecules, A and B, in the asymmetric unit. In both molecules, the geometry of the substituents on the central cyclobutane ring is cis–anti–cis. As shown in Fig. 1, each molecule has a chair-like structure, with the cyclobutane ring as the seat, the carboxylic acid groups the legs, the sulfolane ring the back and the sulfone group the headrest. The two molecules differ in the orientation of the sulfone group. In molecule A the headrest is tilted back, away from the cyclobutane ring, while in molecule B the headrest is tilted forward toward the cyclobutane ring, and the distance between O3'B and the plane of the cyclobutane ring is 2.96 Å. Other interatomic distances are shown in Table 1.

In the ac plane, chains of alternating A and B molecules are linked headrest-to-legs by hydrogen bonds between the –OH group of the carboxylic acid and one O atom of the sulfone group (Fig. 2). Along the b axis, hydrogen bonds between the carboxyl groups join molecule A to B and molecule B to A. Details of the hydrogen-bonding scheme are given in Table 2.

The two molecules in the asymmetric unit of this structure exhibit two different low-energy conformations of the cyclobutane ring that are possible for this bicyclic compound. Cyclobutane in the gas phase has a ring puckering angle of 28° (Egawa et al., 1987). Presumably, puckering relieves torsional strain (Allen, 1984), but the solid-state structures of substituted cyclobutanes exhibit a wide range of puckering angles (Powell et al., 1997; Allen et al., 2005). For instance, in the structure of (II), molecule A is similar to an unsubstituted cyclobutane with a puckering angle of 22°, but the cyclobutane ring of molecule B is almost planar (puckering angle 3°). Despite these differences in ring puckering, the average C—C distances and C—C—C angles in the two cyclobutane rings are the same within the uncertainty of measurement (Table 1), and agree closely with those from a study (Allen, 1984) of puckered and planar cyclobutane derivatives in the Cambridge Structural Database.

Cyclopentane and substituted cyclopentane rings are non-planar, with two low-energy conformations, the twist (half-chair, symmetry C₂) and the envelope (symmetry C_s) (Han & Kang, 1996; Riddell et al., 1997). The various possible conformations are described by an imaginary pseudorotation process in which each atom in the ring in turn is displaced out of the plane, becoming the tip of the flap of the envelope. Envelope and twist conformations alternate every 18°. Traversing the complete pseudorotation cycle of 360° returns the ring to its original conformation. In actual cyclopentane structures, conformations intermediate between pure envelope and pure twist are observed. The calculated phase angle of pseudorotation (Altona & Sundaralingam, 1972) is useful to describe these intermediate conformations. For the sulfolane ring of molecule A, the pseudorotation angle is 246°, closest to pure twist at 252°, with S exo (away from the cyclobutane ring) and C2 endo. In contrast, molecule B exhibits the envelope conformation (pseudorotation angle 86°, closest to envelope at 90°), with S at the tip of the flap, endo with respect to the cyclobutane ring.

Because of the two very different conformations exhibited in this structure, it is interesting to compare the conformations of other bicyclic and tricylic compounds containing fused sulfolane and cyclobutane rings in the Cambridge Structural Database (CSD; Version 5.29; Allen, 2002). These comparisons are shown in Table 3. The first diagram defines the torsion angles and shows that τ₂ is zero for the pure envelope conformation. The succeeding diagrams show the twist conformation for molecule A, the envelope conformation for molecule B, and the structural diagrams of the comparison molecules. Among the five molecules with saturated cyclobutane rings, the puckering angle varies from 3 to 35°, with molecule A of (II) and DIGNOW (Williams et al., 1985) having the largest angle of puckering. DIGNOW and DIGNIQ (Williams et al., 1985) are tricyclic compounds with a cyclohexane ring fused to the cyclobutane ring; in DIGNIQ the cyclohexane ring is cis to the cyclobutane ring, while in DIGNOW it is trans. The constraints imposed by the cyclohexane ring in these two structures may explain the moderate puckering of the cyclobutane ring in DIGNIQ and the large puckering in DIGNOW. No such constraints apply for molecule A, yet its puckering angle is relatively high.

Among the six sulfolane rings fused to cyclobutane, the preferred conformation is the envelope, with the S atom at the tip of the flap and endo to the cyclobutane ring, as in molecule B, but tricyclic DIGNOW has the envelope conformation with C4 endo. There are only two examples of the twist conformation, both with the S atom and adjacent C atom out of the plane, namely tricyclic DIGNIQ and molecule A of (II). Molecule A is unusual in several respects, having a relatively high puckering of the cyclobutane ring compared with the other bicyclic compounds, and is the only molecule in this bicyclic group with a twist conformation. The two molecules in (II) thus demonstrate the wide range of conformational variability possible in this bicyclic compound.

S2. Experimental

The anhydride precursor, (I), to the title compound, (II), was synthesized by the photochemical [2+2] cycloaddition of maleic anhydride and 3-sulfolene in acetone at room temperature following the directions of Bloomfield (1975). The initial product, (I), was hydrolyzed to (II), probably during crystallization. Colourless plates of (II) suitable for X-ray crystallographic determination were formed in a solution in acetone.

S3. Refinement

In order to compare the structure of (II) with those of other molecules in the Cambridge Structural Database, PREQUEST and ACTIVATE (Cambridge Crystallographic Data Centre, 1994) were used to format the CIF file for the Database. The Database (Version 5.29; Allen, 2002) was then searched using CONQUEST (Bruno et al., 2002) for other fused sulfolane–cyclobutane structures. Torsion angles in the sulfolane ring and the dihedral angle in the cyclobutane ring were calculated using VISTA (Cambridge Crystallographic Data Centre, 1994). The pseudorotation angle for the sulfolane rings was calculated and the conformation assigned using the definitions of Altona & Sundaralingam (1972). The cyclobutane puckering angle was calculated using the definition of Allen et al. (2005).

Because they participate in a hydrogen bond, the positions of atoms H8A, H9A, H8B and H9B were refined, with U_iso(H) = 1.2U_eq(O). Idealized positions for other H atoms were calculated at 0.93 Å from bonded C atoms with U_iso(H) = 1.2U_eq(C).

Computing details

Data collection: SMART (Bruker, 2003); cell refinement: SMART (Bruker, 2003); data reduction: SHELXTL (Sheldrick, 2008); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008), ORTEP-3 (Farrugia, 1997) and Mercury (Macrae et al., 2006); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

Figures

Fig. 1. The two molecules in the asymmetric unit of (II), showing the atom-numbering scheme. Displacement ellipsoids are drawn at the 50% probability level and H atoms are shown as spheres of arbitrary radii. The dashed line indicates a hydrogen bond. Fig. 2. Packing diagram of (II) projected on the ac plane, showing parallel chains of alternating molecules A (grey) and B (black) extending along the ac plane. Two such chains lying close to the ac plane are shown as ball-and-stick structures. The chains are stabilized by dotted hydrogen bonds between the sulfone atom O3B of molecule B and the –OH group (H9A) of the carboxylic acid substituent of molecule A. Three other hydrogen bonds between the carboxylic acid groups of molecules A and B extend along the b axis to form chains of A and B molecules, represented as wire frame structures. H atoms not involved in hydrogen bonds have been omitted for clarity.

3-thiabicyclo[3.2.0]heptane-6,7-dicarboxylic acid 3,3-dioxide

Crystal data

C8H10O6S	F(000) = 976
Mr = 234.22	Dx = 1.725 Mg m^−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2YBC	Cell parameters from 7020 reflections
a = 18.497 (3) Å	θ = 2.6–28.5°
b = 6.1203 (8) Å	µ = 0.37 mm^−1
c = 17.188 (2) Å	T = 103 K
β = 112.051 (2)°	Plate, colourless
V = 1803.4 (4) Å^3	0.36 × 0.11 × 0.05 mm
Z = 8

Data collection

Bruker SMART area-detector diffractometer	4458 independent reflections
Radiation source: fine-focus sealed tube	3212 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.061
ϕ and ω scans	θmax = 28.5°, θmin = 1.2°
Absorption correction: multi-scan (SADABS; Sheldrick, 2001)	h = −22→24
Tmin = 0.877, Tmax = 0.982	k = −8→8
13348 measured reflections	l = −21→23

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)] = 0.053	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.128	H atoms treated by a mixture of independent and constrained refinement
S = 1.05	w = 1/[σ^2(Fo^2) + (0.0653P)^2 + 0.9231P] where P = (Fo^2 + 2Fc^2)/3
4458 reflections	(Δ/σ)max = 0.003
283 parameters	Δρmax = 0.71 e Å^−3
0 restraints	Δρmin = −0.66 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
S3A	0.01497 (4)	1.49593 (10)	0.16292 (4)	0.01167 (16)
O8'A	0.26140 (11)	1.1014 (3)	0.08573 (12)	0.0159 (4)
O8A	0.15180 (12)	1.0505 (3)	−0.02607 (13)	0.0158 (4)
H8A	0.178 (2)	1.020 (6)	−0.045 (3)	0.024*
O9A	0.28435 (12)	0.8652 (3)	0.24110 (13)	0.0157 (4)
H9A	0.333 (2)	0.850 (5)	0.261 (2)	0.024*
O9'A	0.31369 (11)	1.2103 (3)	0.27950 (13)	0.0182 (4)
O3'A	0.01234 (12)	1.6898 (3)	0.11450 (13)	0.0176 (4)
O3A	−0.04201 (11)	1.4798 (3)	0.20243 (12)	0.0149 (4)
C8A	0.19202 (15)	1.0738 (4)	0.05513 (17)	0.0114 (5)
C7A	0.13990 (15)	1.0654 (4)	0.10401 (16)	0.0117 (5)
H7A	0.1062	0.9322	0.0922	0.014*
C1A	0.09365 (15)	1.2828 (4)	0.09409 (16)	0.0114 (5)
H1A	0.0940	1.3766	0.0466	0.014*
C2A	0.01411 (15)	1.2637 (4)	0.10080 (17)	0.0128 (5)
H2AB	0.0094	1.1265	0.1290	0.015*
H2AA	−0.0287	1.2716	0.0450	0.015*
C9A	0.26570 (16)	1.0740 (4)	0.24309 (17)	0.0131 (5)
C6A	0.18050 (15)	1.1170 (4)	0.19870 (16)	0.0111 (5)
H6A	0.1514	1.0426	0.2298	0.013*
C5A	0.15317 (15)	1.3561 (4)	0.18249 (16)	0.0114 (5)
H5A	0.1946	1.4540	0.1779	0.014*
C4A	0.11201 (15)	1.4576 (4)	0.23652 (17)	0.0130 (5)
H4AB	0.1362	1.5985	0.2610	0.016*
H4AA	0.1132	1.3577	0.2823	0.016*
S3B	0.51397 (4)	0.93365 (10)	0.35877 (4)	0.01193 (16)
O9'B	0.74535 (12)	1.4373 (3)	0.59529 (13)	0.0183 (4)
O9B	0.63679 (12)	1.4509 (3)	0.62175 (13)	0.0179 (4)
H9B	0.659 (2)	1.546 (6)	0.654 (2)	0.027*
O8'B	0.81850 (11)	1.0853 (3)	0.49683 (12)	0.0148 (4)
O8B	0.80328 (12)	0.9807 (3)	0.61416 (12)	0.0177 (4)
H8B	0.857 (2)	1.001 (6)	0.636 (2)	0.027*
O3'B	0.52791 (12)	0.7951 (3)	0.43049 (12)	0.0169 (4)
O3B	0.44779 (11)	0.8819 (3)	0.28326 (12)	0.0161 (4)
C9B	0.68095 (16)	1.3668 (4)	0.58417 (16)	0.0118 (5)
C6B	0.64044 (15)	1.1858 (4)	0.52582 (16)	0.0112 (5)
H6B	0.6036	1.1057	0.5458	0.013*
C5B	0.59881 (15)	1.2688 (4)	0.43346 (16)	0.0120 (5)
H5B	0.6093	1.4267	0.4270	0.014*
C4B	0.51285 (15)	1.2103 (4)	0.38998 (17)	0.0135 (5)
H4BB	0.4872	1.3054	0.3407	0.016*
H4BA	0.4851	1.2248	0.4290	0.016*
C8B	0.77664 (16)	1.0385 (4)	0.53359 (17)	0.0118 (5)
C7B	0.68967 (15)	1.0255 (4)	0.49514 (16)	0.0107 (5)
H7B	0.6724	0.8718	0.4977	0.013*
C1B	0.65147 (15)	1.1133 (4)	0.40507 (16)	0.0111 (5)
H1B	0.6890	1.1950	0.3865	0.013*
C2B	0.60066 (15)	0.9543 (4)	0.33825 (17)	0.0128 (5)
H2BB	0.6264	0.8102	0.3437	0.015*
H2BA	0.5896	1.0120	0.2811	0.015*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
S3A	0.0106 (3)	0.0135 (3)	0.0105 (3)	0.0019 (2)	0.0036 (2)	0.0003 (2)
O8'A	0.0146 (10)	0.0181 (9)	0.0153 (10)	−0.0014 (8)	0.0059 (8)	−0.0005 (8)
O8A	0.0175 (11)	0.0208 (10)	0.0110 (10)	0.0047 (8)	0.0077 (8)	−0.0008 (8)
O9A	0.0129 (10)	0.0141 (9)	0.0180 (11)	0.0040 (8)	0.0033 (8)	0.0005 (8)
O9'A	0.0150 (10)	0.0196 (10)	0.0179 (11)	0.0003 (8)	0.0036 (8)	−0.0071 (8)
O3'A	0.0211 (11)	0.0138 (9)	0.0178 (11)	0.0025 (8)	0.0073 (9)	0.0039 (8)
O3A	0.0107 (9)	0.0224 (10)	0.0134 (10)	0.0026 (7)	0.0067 (8)	0.0002 (8)
C8A	0.0141 (14)	0.0090 (11)	0.0108 (13)	0.0008 (10)	0.0044 (11)	0.0000 (9)
C7A	0.0127 (13)	0.0133 (12)	0.0095 (13)	0.0013 (10)	0.0046 (11)	−0.0020 (10)
C1A	0.0124 (13)	0.0119 (11)	0.0101 (13)	0.0010 (10)	0.0045 (10)	−0.0008 (10)
C2A	0.0118 (13)	0.0154 (12)	0.0099 (13)	0.0001 (10)	0.0026 (10)	−0.0027 (10)
C9A	0.0164 (14)	0.0148 (12)	0.0095 (13)	0.0001 (11)	0.0065 (11)	−0.0003 (10)
C6A	0.0128 (13)	0.0117 (12)	0.0101 (13)	0.0001 (10)	0.0057 (11)	0.0014 (9)
C5A	0.0093 (13)	0.0134 (12)	0.0094 (13)	0.0006 (10)	0.0012 (10)	−0.0002 (10)
C4A	0.0118 (13)	0.0141 (12)	0.0099 (13)	0.0015 (10)	0.0003 (11)	−0.0028 (10)
S3B	0.0100 (3)	0.0132 (3)	0.0121 (3)	−0.0004 (2)	0.0036 (3)	−0.0023 (2)
O9'B	0.0186 (11)	0.0227 (10)	0.0155 (10)	−0.0083 (8)	0.0085 (9)	−0.0057 (8)
O9B	0.0163 (11)	0.0184 (10)	0.0205 (11)	−0.0026 (8)	0.0086 (9)	−0.0093 (8)
O8'B	0.0145 (10)	0.0161 (9)	0.0149 (10)	0.0001 (8)	0.0066 (8)	0.0005 (7)
O8B	0.0110 (10)	0.0281 (11)	0.0120 (10)	0.0002 (8)	0.0018 (8)	0.0038 (8)
O3'B	0.0190 (11)	0.0161 (9)	0.0162 (10)	−0.0020 (8)	0.0074 (8)	0.0021 (8)
O3B	0.0101 (10)	0.0212 (10)	0.0155 (10)	−0.0008 (8)	0.0030 (8)	−0.0064 (8)
C9B	0.0146 (14)	0.0120 (12)	0.0079 (12)	0.0005 (10)	0.0031 (11)	0.0017 (9)
C6B	0.0129 (13)	0.0105 (11)	0.0104 (13)	−0.0004 (10)	0.0045 (10)	−0.0019 (9)
C5B	0.0138 (13)	0.0109 (11)	0.0098 (13)	0.0011 (10)	0.0028 (11)	0.0003 (9)
C4B	0.0123 (13)	0.0140 (12)	0.0134 (14)	0.0034 (10)	0.0038 (11)	−0.0025 (10)
C8B	0.0130 (13)	0.0101 (12)	0.0111 (13)	0.0004 (9)	0.0033 (11)	−0.0013 (9)
C7B	0.0091 (12)	0.0129 (12)	0.0100 (13)	0.0004 (9)	0.0034 (10)	0.0001 (9)
C1B	0.0125 (13)	0.0114 (12)	0.0100 (13)	−0.0014 (9)	0.0049 (11)	−0.0010 (9)
C2B	0.0123 (13)	0.0156 (13)	0.0114 (13)	0.0015 (10)	0.0054 (11)	−0.0007 (10)

Geometric parameters (Å, º)

S3A—O3'A	1.440 (2)	S3B—O3'B	1.438 (2)
S3A—O3A	1.456 (2)	S3B—O3B	1.446 (2)
S3A—C2A	1.774 (3)	S3B—C2B	1.771 (3)
S3A—C4A	1.781 (3)	S3B—C4B	1.779 (3)
O8'A—C8A	1.202 (3)	O9'B—C9B	1.213 (3)
O8A—C8A	1.320 (3)	O9B—C9B	1.321 (3)
O8A—H8A	0.69 (4)	O9B—H9B	0.80 (4)
O9A—C9A	1.327 (3)	O8'B—C8B	1.203 (3)
O9A—H9A	0.84 (4)	O8B—C8B	1.332 (3)
O9'A—C9A	1.208 (3)	O8B—H8B	0.94 (4)
C8A—C7A	1.499 (4)	C9B—C6B	1.493 (3)
C7A—C6A	1.548 (4)	C6B—C7B	1.559 (4)
C7A—C1A	1.556 (4)	C6B—C5B	1.566 (4)
C7A—H7A	1.0000	C6B—H6B	1.0000
C1A—C2A	1.523 (4)	C5B—C4B	1.524 (4)
C1A—C5A	1.570 (4)	C5B—C1B	1.565 (4)
C1A—H1A	1.0000	C5B—H5B	1.0000
C2A—H2AB	0.9900	C4B—H4BB	0.9900
C2A—H2AA	0.9900	C4B—H4BA	0.9900
C9A—C6A	1.494 (4)	C8B—C7B	1.494 (4)
C6A—C5A	1.539 (3)	C7B—C1B	1.537 (4)
C6A—H6A	1.0000	C7B—H7B	1.0000
C5A—C4A	1.536 (4)	C1B—C2B	1.529 (4)
C5A—H5A	1.0000	C1B—H1B	1.0000
C4A—H4AB	0.9900	C2B—H2BB	0.9900
C4A—H4AA	0.9900	C2B—H2BA	0.9900
O3'A—S3A—O3A	116.91 (12)	O3'B—S3B—O3B	117.35 (12)
O3'A—S3A—C2A	108.76 (13)	O3'B—S3B—C2B	109.18 (12)
O3A—S3A—C2A	112.45 (12)	O3B—S3B—C2B	111.20 (12)
O3'A—S3A—C4A	108.99 (13)	O3'B—S3B—C4B	108.76 (13)
O3A—S3A—C4A	111.88 (13)	O3B—S3B—C4B	112.17 (12)
C2A—S3A—C4A	95.79 (12)	C2B—S3B—C4B	96.09 (13)
C8A—O8A—H8A	108 (3)	C9B—O9B—H9B	111 (3)
C9A—O9A—H9A	110 (2)	C8B—O8B—H8B	108 (2)
O8'A—C8A—O8A	124.3 (3)	O9'B—C9B—O9B	122.4 (2)
O8'A—C8A—C7A	124.4 (2)	O9'B—C9B—C6B	125.8 (3)
O8A—C8A—C7A	111.3 (2)	O9B—C9B—C6B	111.8 (2)
C8A—C7A—C6A	115.0 (2)	C9B—C6B—C7B	119.0 (2)
C8A—C7A—C1A	110.6 (2)	C9B—C6B—C5B	111.8 (2)
C6A—C7A—C1A	88.29 (19)	C7B—C6B—C5B	89.35 (19)
C8A—C7A—H7A	113.5	C9B—C6B—H6B	111.6
C6A—C7A—H7A	113.5	C7B—C6B—H6B	111.6
C1A—C7A—H7A	113.5	C5B—C6B—H6B	111.6
C2A—C1A—C7A	115.7 (2)	C4B—C5B—C1B	111.2 (2)
C2A—C1A—C5A	107.2 (2)	C4B—C5B—C6B	116.5 (2)
C7A—C1A—C5A	88.94 (19)	C1B—C5B—C6B	89.54 (19)
C2A—C1A—H1A	114.1	C4B—C5B—H5B	112.5
C7A—C1A—H1A	114.1	C1B—C5B—H5B	112.5
C5A—C1A—H1A	114.1	C6B—C5B—H5B	112.5
C1A—C2A—S3A	101.16 (17)	C5B—C4B—S3B	104.09 (17)
C1A—C2A—H2AB	111.5	C5B—C4B—H4BB	110.9
S3A—C2A—H2AB	111.5	S3B—C4B—H4BB	110.9
C1A—C2A—H2AA	111.5	C5B—C4B—H4BA	110.9
S3A—C2A—H2AA	111.5	S3B—C4B—H4BA	110.9
H2AB—C2A—H2AA	109.4	H4BB—C4B—H4BA	109.0
O9'A—C9A—O9A	122.1 (3)	O8'B—C8B—O8B	123.3 (2)
O9'A—C9A—C6A	124.9 (2)	O8'B—C8B—C7B	125.3 (2)
O9A—C9A—C6A	113.0 (2)	O8B—C8B—C7B	111.2 (2)
C9A—C6A—C5A	118.2 (2)	C8B—C7B—C1B	116.0 (2)
C9A—C6A—C7A	120.2 (2)	C8B—C7B—C6B	119.0 (2)
C5A—C6A—C7A	90.42 (19)	C1B—C7B—C6B	90.85 (19)
C9A—C6A—H6A	108.9	C8B—C7B—H7B	109.9
C5A—C6A—H6A	108.9	C1B—C7B—H7B	109.9
C7A—C6A—H6A	108.9	C6B—C7B—H7B	109.9
C4A—C5A—C6A	118.6 (2)	C2B—C1B—C7B	117.0 (2)
C4A—C5A—C1A	112.0 (2)	C2B—C1B—C5B	110.0 (2)
C6A—C5A—C1A	88.09 (19)	C7B—C1B—C5B	90.17 (19)
C4A—C5A—H5A	112.0	C2B—C1B—H1B	112.6
C6A—C5A—H5A	112.0	C7B—C1B—H1B	112.6
C1A—C5A—H5A	112.0	C5B—C1B—H1B	112.6
C5A—C4A—S3A	102.71 (17)	C1B—C2B—S3B	104.06 (18)
C5A—C4A—H4AB	111.2	C1B—C2B—H2BB	110.9
S3A—C4A—H4AB	111.2	S3B—C2B—H2BB	110.9
C5A—C4A—H4AA	111.2	C1B—C2B—H2BA	110.9
S3A—C4A—H4AA	111.2	S3B—C2B—H2BA	110.9
H4AB—C4A—H4AA	109.1	H2BB—C2B—H2BA	109.0
O8'A—C8A—C7A—C6A	5.6 (4)	O9'B—C9B—C6B—C7B	19.1 (4)
O8A—C8A—C7A—C6A	−173.5 (2)	O9B—C9B—C6B—C7B	−163.2 (2)
O8'A—C8A—C7A—C1A	103.6 (3)	O9'B—C9B—C6B—C5B	−82.9 (3)
O8A—C8A—C7A—C1A	−75.4 (3)	O9B—C9B—C6B—C5B	94.8 (3)
C8A—C7A—C1A—C2A	150.7 (2)	C9B—C6B—C5B—C4B	−127.5 (2)
C6A—C7A—C1A—C2A	−93.2 (2)	C7B—C6B—C5B—C4B	111.3 (2)
C8A—C7A—C1A—C5A	−100.7 (2)	C9B—C6B—C5B—C1B	118.9 (2)
C6A—C7A—C1A—C5A	15.4 (2)	C7B—C6B—C5B—C1B	−2.20 (19)
C7A—C1A—C2A—S3A	137.78 (19)	C1B—C5B—C4B—S3B	21.8 (3)
C5A—C1A—C2A—S3A	40.5 (2)	C6B—C5B—C4B—S3B	−78.8 (2)
O3'A—S3A—C2A—C1A	68.18 (19)	O3'B—S3B—C4B—C5B	78.8 (2)
O3A—S3A—C2A—C1A	−160.72 (16)	O3B—S3B—C4B—C5B	−149.72 (17)
C4A—S3A—C2A—C1A	−44.15 (19)	C2B—S3B—C4B—C5B	−33.9 (2)
O9'A—C9A—C6A—C5A	12.8 (4)	O8'B—C8B—C7B—C1B	−9.8 (4)
O9A—C9A—C6A—C5A	−169.2 (2)	O8B—C8B—C7B—C1B	173.3 (2)
O9'A—C9A—C6A—C7A	121.5 (3)	O8'B—C8B—C7B—C6B	−116.6 (3)
O9A—C9A—C6A—C7A	−60.4 (3)	O8B—C8B—C7B—C6B	66.4 (3)
C8A—C7A—C6A—C9A	−27.1 (3)	C9B—C6B—C7B—C8B	8.1 (4)
C1A—C7A—C6A—C9A	−139.1 (2)	C5B—C6B—C7B—C8B	122.9 (2)
C8A—C7A—C6A—C5A	96.3 (2)	C9B—C6B—C7B—C1B	−112.5 (2)
C1A—C7A—C6A—C5A	−15.7 (2)	C5B—C6B—C7B—C1B	2.24 (19)
C9A—C6A—C5A—C4A	−105.3 (3)	C8B—C7B—C1B—C2B	121.9 (3)
C7A—C6A—C5A—C4A	129.6 (2)	C6B—C7B—C1B—C2B	−114.9 (2)
C9A—C6A—C5A—C1A	140.6 (2)	C8B—C7B—C1B—C5B	−125.4 (2)
C7A—C6A—C5A—C1A	15.6 (2)	C6B—C7B—C1B—C5B	−2.24 (19)
C2A—C1A—C5A—C4A	−19.1 (3)	C4B—C5B—C1B—C2B	2.8 (3)
C7A—C1A—C5A—C4A	−135.7 (2)	C6B—C5B—C1B—C2B	121.2 (2)
C2A—C1A—C5A—C6A	101.1 (2)	C4B—C5B—C1B—C7B	−116.1 (2)
C7A—C1A—C5A—C6A	−15.5 (2)	C6B—C5B—C1B—C7B	2.23 (19)
C6A—C5A—C4A—S3A	−112.2 (2)	C7B—C1B—C2B—S3B	74.7 (2)
C1A—C5A—C4A—S3A	−11.9 (2)	C5B—C1B—C2B—S3B	−26.2 (2)
O3'A—S3A—C4A—C5A	−79.33 (18)	O3'B—S3B—C2B—C1B	−76.75 (19)
O3A—S3A—C4A—C5A	149.83 (16)	O3B—S3B—C2B—C1B	152.21 (16)
C2A—S3A—C4A—C5A	32.81 (19)	C4B—S3B—C2B—C1B	35.56 (19)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O8A—H8A···O9′B^i	0.69 (4)	1.99 (4)	2.686 (3)	178 (5)
O9A—H9A···O3B	0.84 (4)	2.02 (4)	2.834 (3)	163 (3)
O9B—H9B···O9′A^ii	0.80 (4)	1.83 (4)	2.618 (3)	166 (4)
O8B—H8B···O3A^iii	0.94 (4)	1.78 (4)	2.700 (3)	165 (3)

Symmetry codes: (i) −x+1, y−1/2, −z+1/2; (ii) −x+1, −y+3, −z+1; (iii) x+1, −y+5/2, z+1/2.