13-cis-β,β-Carotene and 15-cis-β,β-carotene

13-cis-β,β-Carotene, C₄₀H₅₆, crystallizes with a complete mol­ecule in the asymmetric unit, whereas 15-cis-β,β-carotene, also C₄₀H₅₆, has twofold symmetry about an axis through the central bond of the polyene chain. The polyene methyl groups are arranged on one side of the polyene chains for each mol­ecule and the 6-s-cis β end groups, with the cyclohexene rings in half-chair conformations, are twisted out of the planes of the polyene chains by angles ranging from 41.37 (17) to 52.2 (4)°. The mol­ecules in each structure pack so that the arms of one occupy the cleft of the next, and there is significant π–π stacking of the almost-parallel polyene chains of the 15-cis isomer, which approach at distances of 3.319 (1)–3.591 (1) Å.

S1. Comment

Carotenes have the general formula C₄₀H₅₆, and are chromophores responsible for the orange colour in carrots and many other fruits and vegetables. The structure of all-trans-β,β-carotene has been determined a number of times [Sterling, 1964; Senge et al., 1992; Hursthouse et al., 2004; Cambridge Structural Database (CSD; Allen, 2002) refcodes CARTEN, CARTEN01 and CARTEN02], but none of the cis-isomers has been characterized crystallographically. Carotenoids readily undergo trans–cis (E/Z) isomerization in organic solvents (Zechmeister, 1963) and cis-isomers are the most abundant artefacts formed during isolation procedures (Liaaen-Jensen, 1997). Kinetic and thermodynamic data for the thermal interconversion of all-trans-beta-carotene and the 13-cis-, (I), and 15-cis-, (II), isomers have been published (von Doering et al., 1995). The 13-cis isomer, (I), is formed readily in a kinetically controlled process, whereas the 9-cis-isomer is the dominant cis-isomer in iodine-catalyzed equilibrium mixtures (Zechmeister, 1963; Molnár & Szabolcs, 1993), assumed to represent the thermodynamic equilibrium (Refvem et al., 1999). The 15-cis-isomer, (II), is formed only in minor quantities at equilibrium conditions (Zechmeister, 1963; Molnár & Szabolcs, 1993; Schirle et al., 1995). Nevertheless, the natural occurrence of the 15-cis-isomer, (II), is well demonstrated in photosynthetic systems, where it serves an important function (Koyama & Mubai, 1993). The kinetically favoured 13-cis-isomer, (I), has been reported, e.g. from human tissues, including serum (Stahl et al., 1992). The 9-cis-isomer is a dominant isomer of beta-carotene in the green alga Dunaliella spp. grown under stressed conditions (Ben-Amotz et al., 1988). Here, we report the structures of 13-cis-beta-carotene, (I), and 15-cis-beta-carotene, (II).

The structures of the (I) and (II) are shown in Figs. 1 and 2, respectively. For (I), the asymmetric unit consists of the whole molecule, due to the asymmetry of the polyene chain. The methyl groups along the polyene chain are all on the outside of the bent chain, presumably to minimize steric crowding of the methyl groups. The end rings are in the 6 - s-cis conformation, where 6 - s-cis (6-single-cis) defines the conformation of the single bond at the 6-position, connecting the substituted cyclohexene ring and the polyene chain. The other alternative is 6 - s-trans, which is shown in the second scheme. The end rings are twisted out of the plane of the polyene chain by angles defined by the C5—C6—C7—C8 and C5A—C6A—C7A—C8A torsion angles of 47.6 (4) and 52.2 (4)°, respectively. Although the end rings are nonplanar, the C5—C6—C7—C8 torsion angle is normally used to define the angle of twist, since it describes the nonplanarity between the best planes through the double-bond systems of the ring and the polyene chain (Sundaralingam & Beddell, 1972; Mo, 1995). In (II), the asymmetric unit contains half the molecule, and the entire molecule is generated by means of a twofold axis at the centre of the C15—C15A bond. As for (I), the methyl groups along the bent polyene chain are all on the outside, and the crystallographically equivalent end rings are in the 6 - s-cis conformation at an angle to the plane of the polyene chain of -41.37 (17)°.

In both structures, the cyclohexene end rings are in the half-chair conformation, as is generally found for carotenoids with cyclohexene β end rings (Sundaralingam & Beddell, 1972; Mo, 1995). In the half-chair conformation, which is the most stable conformation for cyclohexene rings, four atoms are approximately coplanar and the fifth and sixth atoms, opposite the double bond, lie above and below this plane. For (I), atoms C2 and C3 are displaced from the best plane through atoms C1/C4–C6 by -0.334 (3) and 0.422 (3) Å, respectively, and atoms C2A and C3A are displaced from the plane defined by atoms C1A/C4–C6 by 0.325 (3) and -0.434 (3) Å, respectively. Similarly, atoms C2 and C3 in (II) are displaced from the corresponding plane by 0.402 (1) and -0.342 (1) Å, respectively. Within the cyclohexene ring, the largest torsion angle is about the C2—C3 bond (Clayden et al., 2000; Sundaralingam & Beddell, 1972; Mo, 1995; Table 1) and takes values of 62.9 (3) and 62.7 (3)° for the two end rings of (I), and -61.70 (12)° for (II) (where the two end rings are crystallographically equivalent). The smallest torsion angle is about the C5═C6 double bond (Table 1).

The structures of (I) and (II) can be compared with that of all-trans-β,β-carotene, which is centrosymmetric, with the four polyene chain methyl groups arranged in pairs along each side of the polyene chain and a pronounced S-shape of the chain, arising from steric crowding of the methyl groups. Again, the β end rings are in the 6 - s-cis conformation and the C5—C6—C7—C8 torsion angle is -41.6 (6)° (Senge et al., 1992; CSD refcode CARTEN01; Allen, 2002). The end rings are in the half-chair conformation, but disorder in a 0.5:0.5 ratio of atoms C2 and C3 was seen, indicating that both possible half-chair conformations are present in the crystal structure. This is in contrast with the structures of (I) and (II), where no such disorder is observed. The fact that, in all three structures, the end rings are found to be in the 6 - s-cis conformation and twisted out of the plane of the polyene chain by about 40–50° is in keeping with most of the other carotenoids and xanthophyll structures with β end rings (Mo, 1995), and agrees with calculated values for a number of such molecules (Hashimoto et al., 2002). It is assumed that this preferred conformation arises from steric crowding between the end-ring methyl groups and the H atoms bonded to atoms C7 and C8. There are some exceptions including, for example, (3R,3S',meso)-zeaxanthin, with 6 - s-cis end rings and a C5—C6—C7—C8 torsion angle of ±74.9 (3)° (Bartalucci et al., 2007), zeaxanthin-3,3'-diyl bis[(-)-(1R)-2-methyl-5-(1-methylethyl)cyclohexyl [closing] missing - please complete] (Linden et al. 2004), which has one β end ring in the s-trans conformation and the other in the s-cis conformation, with C5—C6—C7—C8 torsion angles of 144.5 (6) and 48.5 (8)°, respectively, and β-8'-β-apocarotenal (Drikos et al., 1988), with an s-trans β end ring and a C5—C6—C7—C8 torsion angle of -158.4 (8)°; these deviations from the expected values may arise from packing forces in the crystal structures (Mo, 1995).

The polyene chains in (I), (II) and all-trans-β,β-carotene are significantly nonplanar, as shown by the torsion angles along the polyene chains, which deviate by up to about 8° from 180° for (I), 9° for (II) and 5° for all-trans-β,β-carotene. The methyl groups deviate likewise from the plane of the polyene chain.

Fig. 3. shows the packing of (I), illustrating how the short arm of one molecule fits into the cleft made by the next molecule. There is often a high degree of π–π stacking between the polyene chains of carotenoid molecules aligned above one other (Bartalucci et al., 2007). In this case, there is a close approach of the molecules of 3.465 (4) Å between atoms C10 and C14A(1 + x, y, z), but the polyene chains become further and further apart, away from this point of minimum distance (Fig. 4). In addition, atom C12 shows a short contact to the methyl group C20A(1 + x, y, z) of 3.415 (4) Å, and the C12 and C13 distances to H20F(1 + x, y, z) are 2.711 (3) and 2.797 (3) Å, respectively (Fig. 4). Other contacts are van der Waals interactions, with the shortest contact between adjacent molecules being 3.374 (4) Å between methyl groups C19A and C19A(-x - 1,-y + 1,-z) (Fig. 4).

The packing of (II) is shown in Fig. 5 and again the molecules fit together so that the arms of one molecule fit into the cleft of the next. This time, however, there is significant π–π stacking between adjacent polyene chains which are arranged almost parallel above one other, with intermolecular distances ranging from 3.319 (1) to 3.591 (1) Å between atom pairs C9 and C15(1 - x, 1 - y, 2 - z), and C13 and C10(1 - x, 1 - y, 2 - z) (Fig. 6). Other contacts are normal van der Waals interactions.

Related literature

For related literature, see: Allen (2002); Bartalucci et al. (2007); Ben-Amotz, Lers & Avron (1988); Bernhard & Mayer (1991); Clayden et al. (2000); Doering et al. (1995); Drikos et al. (1988); Hashimoto (2002); Hursthouse et al. (2004); Koyama & Mubai (1993); Liaaen-Jensen (1997); Linden et al. (2004); Mo (1995); Molnár & Szabolcs (1993); Refvem et al. (1999); Schirle et al. (1995); Senge et al. (1992); Sheldrick (2008); Stahl et al. (1992); Sterling (1964); Sundaralingam & Beddell (1972); Zechmeister (1963).

S2. Experimental

The 13-cis- [(I)] and 15-cis- [(II)] isomers of beta-carotene used here were samples prepared by total synthesis (Ben-Amotz et al., 1988; Bernhard & Mayer, 1991), kindly provided by Hoffmann–La Roche, Basel. Both isomers were recrystallized from pyridine and water [Ratio of solvents?] by vapour diffusion techniques.

S3. Refinement

H atoms were included in calculated positions, with C—H distances varying in the range 0.95–0.99 Å and with U_iso(H) = 1.2 or 1.5U_eq(C). Methyl group H atoms were defined using the AFIX 137 command (SHELXL97; Sheldrick, 2008), which varies the torsion angle to maximize the electron density at the three H-atom positions.

Computing details

For both compounds, data collection: SMART (Bruker, 2001); cell refinement: SMART (Bruker, 2001); data reduction: SAINT (Bruker, 2002); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Bruker, 2001); software used to prepare material for publication: SHELXTL (Bruker, 2001), PLATON (Spek 2003), WinGX (Farrugia, 1999) and PARST (Nardelli, 1995).

Figures

	Fig. 1. A view of (I), with the atom-numbering scheme. Displacement ellipsoids are drawn at the 50% probability level and H atoms are shown as small spheres of arbitrary radii.
	Fig. 2. A view of (II), with the atom-numbering scheme. Displacement ellipsoids are drawn at the 50% probability level and H atoms are shown as small spheres of arbitrary radii.
	Fig. 3. A packing diagram for (I), viewed down a, showing the arms of each molecule fitting into the cleft of the next. H atoms have been omitted for clarity.
	Fig. 4. A plot of the short intermolecular C10—C14A(1 + x, y, z), C12—C20A(1 + x, y, z) and C19A—C19A(-x - 1,-y + 1,-z) contacts of (I) (dashed lines). H atoms have been omitted for clarity.
	Fig. 5. A packing diagram for (II), showing the arms of each molecule fitting into the cleft of the next. The π–π stacking of the polyene chains can also be seen. H atoms have been omitted for clarity.
	Fig. 6. A plot showing the π–π stacking interactions of (II) (dashed lines). H atoms have been omitted for clarity.

(I) 13-cis-β,β-Carotene

Crystal data

C40H56	Z = 2
Mr = 536.85	F(000) = 592
Triclinic, P1	Dx = 1.052 Mg m^−3
Hall symbol: -P1	Mo Kα radiation, λ = 0.71073 Å
a = 8.076 (3) Å	Cell parameters from 1562 reflections
b = 15.482 (5) Å	θ = 2.5–26.3°
c = 15.636 (5) Å	µ = 0.06 mm^−1
α = 60.751 (6)°	T = 100 K
β = 84.929 (6)°	Plate, orange
γ = 83.967 (6)°	0.60 × 0.40 × 0.10 mm
V = 1694.6 (10) Å^3

Data collection

Bruker SMART CCD area-detector diffractometer	2959 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.067
Graphite monochromator	θmax = 25.0°, θmin = 1.5°
ϕ and ω scans	h = −9→8
8509 measured reflections	k = −12→18
5860 independent reflections	l = −18→18

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)] = 0.049	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.113	H-atom parameters constrained
S = 0.83	w = 1/[σ^2(Fo^2) + (0.0394P)^2] where P = (Fo^2 + 2Fc^2)/3
5860 reflections	(Δ/σ)max < 0.001
371 parameters	Δρmax = 0.22 e Å^−3
0 restraints	Δρmin = −0.15 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
C1	1.8306 (3)	−0.10025 (19)	0.42400 (17)	0.0302 (6)
C2	1.8909 (3)	−0.1377 (2)	0.52738 (18)	0.0377 (7)
H2A	1.9178	−0.2102	0.5582	0.045*
H2B	1.9945	−0.1062	0.5223	0.045*
C3	1.7640 (3)	−0.1159 (2)	0.59231 (17)	0.0371 (7)
H3A	1.7342	−0.0436	0.5617	0.045*
H3B	1.8113	−0.1377	0.6566	0.045*
C4	1.6103 (3)	−0.17010 (19)	0.60657 (16)	0.0313 (6)
H4A	1.6338	−0.2414	0.6532	0.038*
H4B	1.5187	−0.1442	0.6361	0.038*
C5	1.5534 (3)	−0.15986 (17)	0.51253 (16)	0.0262 (6)
C6	1.6487 (3)	−0.12456 (17)	0.42910 (17)	0.0254 (6)
C7	1.5867 (3)	−0.10217 (17)	0.33344 (16)	0.0269 (6)
H7	1.6541	−0.1266	0.2958	0.032*
C8	1.4442 (3)	−0.05050 (17)	0.29590 (16)	0.0280 (6)
H8	1.3761	−0.0285	0.3352	0.034*
C9	1.3819 (3)	−0.02426 (17)	0.20102 (16)	0.0270 (6)
C10	1.2339 (3)	0.02928 (18)	0.17470 (17)	0.0300 (6)
H10	1.1772	0.0448	0.2219	0.036*
C11	1.1518 (3)	0.06561 (18)	0.08439 (17)	0.0299 (6)
H11	1.2093	0.0567	0.0333	0.036*
C12	0.9976 (3)	0.11172 (17)	0.06818 (18)	0.0302 (6)
H12	0.9412	0.1196	0.1201	0.036*
C13	0.9108 (3)	0.15027 (17)	−0.02197 (17)	0.0276 (6)
C14	0.7517 (3)	0.19046 (18)	−0.02991 (18)	0.0316 (6)
H14	0.7056	0.2134	−0.0918	0.038*
C15	0.6429 (3)	0.20355 (18)	0.04066 (17)	0.0295 (6)
H15	0.6819	0.1808	0.1043	0.035*
C16	1.9454 (3)	−0.1519 (2)	0.37548 (19)	0.0404 (7)
H16A	2.0621	−0.1477	0.3848	0.061*
H16B	1.9257	−0.1191	0.3052	0.061*
H16C	1.9212	−0.2218	0.4057	0.061*
C17	1.8433 (3)	0.01240 (19)	0.36130 (19)	0.0390 (7)
H17A	1.7776	0.0462	0.3935	0.059*
H17B	1.8001	0.0352	0.2965	0.059*
H17C	1.9601	0.0276	0.3539	0.059*
C18	1.3834 (3)	−0.19605 (19)	0.52388 (17)	0.0322 (6)
H18A	1.2992	−0.1492	0.5308	0.048*
H18B	1.3778	−0.2614	0.5824	0.048*
H18C	1.3621	−0.2012	0.4658	0.048*
C19	1.4862 (3)	−0.05745 (19)	0.13702 (17)	0.0350 (6)
H19A	1.4262	−0.0392	0.0781	0.053*
H19B	1.5092	−0.1296	0.1730	0.053*
H19C	1.5915	−0.0252	0.1180	0.053*
C20	1.0031 (3)	0.14791 (19)	−0.10760 (17)	0.0352 (6)
H20A	0.9279	0.1723	−0.1619	0.053*
H20B	1.0453	0.0796	−0.0891	0.053*
H20C	1.0967	0.1902	−0.1282	0.053*
C1A	−0.7834 (3)	0.53346 (18)	0.33555 (17)	0.0277 (6)
C2A	−0.8652 (3)	0.59760 (19)	0.37929 (17)	0.0320 (6)
H2C	−0.8933	0.6652	0.3254	0.038*
H2D	−0.9705	0.5695	0.4149	0.038*
C3A	−0.7545 (3)	0.60444 (19)	0.44912 (17)	0.0323 (6)
H3C	−0.7237	0.5372	0.5029	0.039*
H3D	−0.8149	0.6435	0.4783	0.039*
C4A	−0.5985 (3)	0.65443 (19)	0.39226 (17)	0.0330 (6)
H4C	−0.6274	0.7264	0.3514	0.040*
H4D	−0.5160	0.6462	0.4394	0.040*
C5A	−0.5204 (3)	0.61391 (18)	0.32734 (16)	0.0267 (6)
C6A	−0.6001 (3)	0.55691 (17)	0.30365 (16)	0.0263 (6)
C7A	−0.5210 (3)	0.51430 (17)	0.24278 (17)	0.0273 (6)
H7A	−0.5802	0.5262	0.1877	0.033*
C8A	−0.3745 (3)	0.46042 (17)	0.25636 (17)	0.0275 (6)
H8A	−0.3162	0.4449	0.3129	0.033*
C9A	−0.2986 (3)	0.42408 (18)	0.19116 (16)	0.0265 (6)
C10A	−0.1415 (3)	0.38073 (17)	0.20453 (16)	0.0273 (6)
H10A	−0.0918	0.3645	0.2639	0.033*
C11A	−0.0439 (3)	0.35730 (17)	0.13611 (17)	0.0287 (6)
H11A	−0.0976	0.3692	0.0793	0.034*
C12A	0.1158 (3)	0.32022 (17)	0.14441 (17)	0.0301 (6)
H12A	0.1677	0.3018	0.2037	0.036*
C13A	0.2143 (3)	0.30630 (17)	0.06960 (17)	0.0278 (6)
C14A	0.3721 (3)	0.26368 (17)	0.08662 (17)	0.0297 (6)
H14A	0.4107	0.2425	0.1500	0.036*
C15A	0.4865 (3)	0.24695 (18)	0.02070 (18)	0.0306 (6)
H15A	0.4498	0.2682	−0.0431	0.037*
C16A	−0.7904 (3)	0.42242 (18)	0.41092 (19)	0.0392 (7)
H16D	−0.7307	0.3825	0.3834	0.059*
H16E	−0.9069	0.4057	0.4262	0.059*
H16F	−0.7382	0.4086	0.4710	0.059*
C17A	−0.8833 (3)	0.5552 (2)	0.24664 (18)	0.0380 (7)
H17D	−0.8646	0.6222	0.1932	0.057*
H17E	−1.0023	0.5504	0.2657	0.057*
H17F	−0.8464	0.5067	0.2245	0.057*
C18A	−0.3476 (3)	0.64624 (18)	0.28982 (17)	0.0323 (6)
H18D	−0.2697	0.6094	0.3427	0.049*
H18E	−0.3462	0.7175	0.2669	0.049*
H18F	−0.3140	0.6329	0.2353	0.049*
C19A	−0.3968 (3)	0.44426 (19)	0.10514 (17)	0.0337 (6)
H19D	−0.4047	0.5157	0.0591	0.051*
H19E	−0.5090	0.4215	0.1282	0.051*
H19F	−0.3407	0.4088	0.0720	0.051*
C20A	0.1360 (3)	0.34328 (18)	−0.02627 (16)	0.0319 (6)
H20D	0.2144	0.3302	−0.0708	0.048*
H20E	0.1075	0.4149	−0.0552	0.048*
H20F	0.0346	0.3091	−0.0158	0.048*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
C1	0.0255 (13)	0.0345 (16)	0.0336 (15)	−0.0006 (12)	−0.0001 (11)	−0.0193 (13)
C2	0.0280 (14)	0.0452 (18)	0.0465 (17)	−0.0034 (13)	−0.0054 (12)	−0.0266 (15)
C3	0.0405 (16)	0.0417 (17)	0.0337 (15)	−0.0026 (13)	−0.0054 (12)	−0.0213 (14)
C4	0.0318 (14)	0.0338 (16)	0.0273 (14)	0.0020 (12)	−0.0046 (11)	−0.0142 (13)
C5	0.0244 (13)	0.0260 (14)	0.0295 (14)	0.0047 (11)	−0.0035 (11)	−0.0152 (12)
C6	0.0226 (13)	0.0229 (14)	0.0320 (15)	0.0018 (11)	−0.0042 (11)	−0.0144 (12)
C7	0.0245 (13)	0.0287 (15)	0.0319 (15)	−0.0039 (11)	0.0001 (11)	−0.0179 (13)
C8	0.0292 (14)	0.0275 (15)	0.0284 (14)	−0.0032 (12)	0.0024 (11)	−0.0147 (12)
C9	0.0269 (14)	0.0260 (14)	0.0276 (14)	−0.0021 (11)	−0.0010 (11)	−0.0126 (12)
C10	0.0259 (14)	0.0323 (15)	0.0320 (15)	−0.0044 (12)	0.0039 (11)	−0.0160 (13)
C11	0.0257 (14)	0.0305 (15)	0.0319 (15)	−0.0034 (12)	0.0003 (11)	−0.0140 (13)
C12	0.0250 (14)	0.0242 (14)	0.0389 (16)	−0.0035 (11)	0.0037 (11)	−0.0138 (13)
C13	0.0254 (14)	0.0200 (14)	0.0350 (15)	−0.0013 (11)	−0.0029 (11)	−0.0112 (12)
C14	0.0306 (14)	0.0310 (15)	0.0334 (15)	−0.0038 (12)	−0.0032 (11)	−0.0152 (13)
C15	0.0306 (14)	0.0290 (15)	0.0285 (14)	−0.0042 (12)	0.0030 (11)	−0.0139 (13)
C16	0.0277 (14)	0.0481 (18)	0.0515 (18)	−0.0003 (13)	0.0025 (12)	−0.0299 (16)
C17	0.0319 (15)	0.0443 (18)	0.0485 (17)	−0.0101 (13)	0.0074 (12)	−0.0285 (15)
C18	0.0309 (14)	0.0345 (16)	0.0330 (15)	−0.0031 (12)	0.0024 (11)	−0.0181 (13)
C19	0.0346 (15)	0.0406 (17)	0.0281 (14)	0.0041 (13)	−0.0025 (11)	−0.0163 (13)
C20	0.0297 (14)	0.0362 (17)	0.0393 (16)	0.0002 (12)	−0.0011 (12)	−0.0185 (14)
C1A	0.0209 (13)	0.0275 (15)	0.0336 (15)	0.0007 (11)	0.0010 (11)	−0.0147 (13)
C2A	0.0220 (13)	0.0353 (16)	0.0377 (15)	0.0004 (12)	0.0006 (11)	−0.0176 (13)
C3A	0.0272 (14)	0.0359 (16)	0.0340 (15)	0.0035 (12)	0.0015 (11)	−0.0185 (13)
C4A	0.0256 (13)	0.0375 (16)	0.0425 (16)	−0.0006 (12)	−0.0014 (11)	−0.0248 (14)
C5A	0.0204 (12)	0.0277 (15)	0.0287 (14)	0.0020 (11)	−0.0016 (10)	−0.0117 (12)
C6A	0.0221 (13)	0.0239 (14)	0.0258 (14)	0.0017 (11)	−0.0002 (10)	−0.0073 (12)
C7A	0.0224 (13)	0.0295 (15)	0.0303 (14)	−0.0047 (12)	0.0002 (11)	−0.0143 (13)
C8A	0.0252 (13)	0.0280 (15)	0.0265 (14)	−0.0030 (11)	−0.0022 (11)	−0.0108 (12)
C9A	0.0240 (13)	0.0258 (14)	0.0277 (14)	−0.0037 (11)	0.0003 (11)	−0.0112 (12)
C10A	0.0258 (14)	0.0285 (15)	0.0269 (14)	0.0005 (11)	−0.0021 (11)	−0.0131 (12)
C11A	0.0263 (14)	0.0294 (15)	0.0306 (15)	−0.0008 (12)	−0.0004 (11)	−0.0151 (13)
C12A	0.0259 (14)	0.0286 (15)	0.0334 (15)	−0.0005 (12)	−0.0021 (11)	−0.0132 (13)
C13A	0.0251 (14)	0.0219 (14)	0.0335 (15)	−0.0034 (11)	−0.0003 (11)	−0.0110 (12)
C14A	0.0294 (14)	0.0261 (15)	0.0338 (15)	−0.0025 (12)	−0.0050 (11)	−0.0141 (13)
C15A	0.0307 (14)	0.0276 (15)	0.0324 (15)	−0.0033 (12)	−0.0053 (11)	−0.0129 (13)
C16A	0.0310 (15)	0.0345 (17)	0.0497 (18)	−0.0046 (12)	0.0081 (12)	−0.0195 (15)
C17A	0.0242 (14)	0.0469 (18)	0.0486 (17)	−0.0011 (13)	0.0005 (12)	−0.0282 (15)
C18A	0.0299 (14)	0.0314 (16)	0.0358 (15)	−0.0003 (12)	0.0006 (11)	−0.0170 (13)
C19A	0.0282 (14)	0.0378 (16)	0.0404 (16)	−0.0014 (12)	−0.0018 (12)	−0.0233 (14)
C20A	0.0267 (14)	0.0328 (16)	0.0350 (15)	−0.0011 (12)	0.0013 (11)	−0.0161 (13)

Geometric parameters (Å, º)

C1—C2	1.533 (3)	C1A—C2A	1.529 (3)
C1—C17	1.537 (3)	C1A—C16A	1.541 (3)
C1—C6	1.541 (3)	C1A—C6A	1.542 (3)
C1—C16	1.545 (3)	C1A—C17A	1.543 (3)
C2—C3	1.508 (3)	C2A—C3A	1.519 (3)
C2—H2A	0.9900	C2A—H2C	0.9900
C2—H2B	0.9900	C2A—H2D	0.9900
C3—C4	1.511 (3)	C3A—C4A	1.520 (3)
C3—H3A	0.9900	C3A—H3C	0.9900
C3—H3B	0.9900	C3A—H3D	0.9900
C4—C5	1.508 (3)	C4A—C5A	1.499 (3)
C4—H4A	0.9900	C4A—H4C	0.9900
C4—H4B	0.9900	C4A—H4D	0.9900
C5—C6	1.344 (3)	C5A—C6A	1.346 (3)
C5—C18	1.501 (3)	C5A—C18A	1.503 (3)
C6—C7	1.482 (3)	C6A—C7A	1.472 (3)
C7—C8	1.333 (3)	C7A—C8A	1.343 (3)
C7—H7	0.9500	C7A—H7A	0.9500
C8—C9	1.456 (3)	C8A—C9A	1.452 (3)
C8—H8	0.9500	C8A—H8A	0.9500
C9—C10	1.353 (3)	C9A—C10A	1.354 (3)
C9—C19	1.496 (3)	C9A—C19A	1.504 (3)
C10—C11	1.436 (3)	C10A—C11A	1.438 (3)
C10—H10	0.9500	C10A—H10A	0.9500
C11—C12	1.348 (3)	C11A—C12A	1.346 (3)
C11—H11	0.9500	C11A—H11A	0.9500
C12—C13	1.449 (3)	C12A—C13A	1.447 (3)
C12—H12	0.9500	C12A—H12A	0.9500
C13—C14	1.355 (3)	C13A—C14A	1.357 (3)
C13—C20	1.488 (3)	C13A—C20A	1.493 (3)
C14—C15	1.429 (3)	C14A—C15A	1.423 (3)
C14—H14	0.9500	C14A—H14A	0.9500
C15—C15A	1.353 (3)	C15A—H15A	0.9500
C15—H15	0.9500	C16A—H16D	0.9800
C16—H16A	0.9800	C16A—H16E	0.9800
C16—H16B	0.9800	C16A—H16F	0.9800
C16—H16C	0.9800	C17A—H17D	0.9800
C17—H17A	0.9800	C17A—H17E	0.9800
C17—H17B	0.9800	C17A—H17F	0.9800
C17—H17C	0.9800	C18A—H18D	0.9800
C18—H18A	0.9800	C18A—H18E	0.9800
C18—H18B	0.9800	C18A—H18F	0.9800
C18—H18C	0.9800	C19A—H19D	0.9800
C19—H19A	0.9800	C19A—H19E	0.9800
C19—H19B	0.9800	C19A—H19F	0.9800
C19—H19C	0.9800	C20A—H20D	0.9800
C20—H20A	0.9800	C20A—H20E	0.9800
C20—H20B	0.9800	C20A—H20F	0.9800
C20—H20C	0.9800
C2—C1—C17	110.8 (2)	C2A—C1A—C16A	110.5 (2)
C2—C1—C6	110.43 (19)	C2A—C1A—C6A	110.7 (2)
C17—C1—C6	109.26 (19)	C16A—C1A—C6A	109.19 (18)
C2—C1—C16	107.87 (19)	C2A—C1A—C17A	107.80 (19)
C17—C1—C16	108.30 (19)	C16A—C1A—C17A	108.2 (2)
C6—C1—C16	110.18 (19)	C6A—C1A—C17A	110.47 (19)
C3—C2—C1	113.0 (2)	C3A—C2A—C1A	112.86 (18)
C3—C2—H2A	109.0	C3A—C2A—H2C	109.0
C1—C2—H2A	109.0	C1A—C2A—H2C	109.0
C3—C2—H2B	109.0	C3A—C2A—H2D	109.0
C1—C2—H2B	109.0	C1A—C2A—H2D	109.0
H2A—C2—H2B	107.8	H2C—C2A—H2D	107.8
C2—C3—C4	109.2 (2)	C2A—C3A—C4A	108.75 (19)
C2—C3—H3A	109.8	C2A—C3A—H3C	109.9
C4—C3—H3A	109.8	C4A—C3A—H3C	109.9
C2—C3—H3B	109.8	C2A—C3A—H3D	109.9
C4—C3—H3B	109.8	C4A—C3A—H3D	109.9
H3A—C3—H3B	108.3	H3C—C3A—H3D	108.3
C5—C4—C3	113.31 (19)	C5A—C4A—C3A	113.4 (2)
C5—C4—H4A	108.9	C5A—C4A—H4C	108.9
C3—C4—H4A	108.9	C3A—C4A—H4C	108.9
C5—C4—H4B	108.9	C5A—C4A—H4D	108.9
C3—C4—H4B	108.9	C3A—C4A—H4D	108.9
H4A—C4—H4B	107.7	H4C—C4A—H4D	107.7
C6—C5—C18	124.5 (2)	C6A—C5A—C4A	122.9 (2)
C6—C5—C4	122.8 (2)	C6A—C5A—C18A	124.2 (2)
C18—C5—C4	112.7 (2)	C4A—C5A—C18A	112.9 (2)
C5—C6—C7	123.2 (2)	C5A—C6A—C7A	122.8 (2)
C5—C6—C1	122.7 (2)	C5A—C6A—C1A	122.7 (2)
C7—C6—C1	114.05 (19)	C7A—C6A—C1A	114.5 (2)
C8—C7—C6	125.3 (2)	C8A—C7A—C6A	127.3 (2)
C8—C7—H7	117.4	C8A—C7A—H7A	116.4
C6—C7—H7	117.4	C6A—C7A—H7A	116.4
C7—C8—C9	126.9 (2)	C7A—C8A—C9A	124.9 (2)
C7—C8—H8	116.6	C7A—C8A—H8A	117.5
C9—C8—H8	116.6	C9A—C8A—H8A	117.5
C10—C9—C8	118.7 (2)	C10A—C9A—C8A	120.5 (2)
C10—C9—C19	123.3 (2)	C10A—C9A—C19A	122.4 (2)
C8—C9—C19	118.0 (2)	C8A—C9A—C19A	116.9 (2)
C9—C10—C11	128.1 (2)	C9A—C10A—C11A	125.3 (2)
C9—C10—H10	115.9	C9A—C10A—H10A	117.4
C11—C10—H10	115.9	C11A—C10A—H10A	117.4
C12—C11—C10	123.6 (2)	C12A—C11A—C10A	126.6 (2)
C12—C11—H11	118.2	C12A—C11A—H11A	116.7
C10—C11—H11	118.2	C10A—C11A—H11A	116.7
C11—C12—C13	125.4 (2)	C11A—C12A—C13A	124.8 (2)
C11—C12—H12	117.3	C11A—C12A—H12A	117.6
C13—C12—H12	117.3	C13A—C12A—H12A	117.6
C14—C13—C12	121.4 (2)	C14A—C13A—C12A	120.5 (2)
C14—C13—C20	120.4 (2)	C14A—C13A—C20A	122.5 (2)
C12—C13—C20	118.1 (2)	C12A—C13A—C20A	117.0 (2)
C13—C14—C15	129.9 (2)	C13A—C14A—C15A	127.6 (2)
C13—C14—H14	115.1	C13A—C14A—H14A	116.2
C15—C14—H14	115.1	C15A—C14A—H14A	116.2
C15A—C15—C14	122.8 (2)	C15—C15A—C14A	125.9 (2)
C15A—C15—H15	118.6	C15—C15A—H15A	117.0
C14—C15—H15	118.6	C14A—C15A—H15A	117.0
C1—C16—H16A	109.5	C1A—C16A—H16D	109.5
C1—C16—H16B	109.5	C1A—C16A—H16E	109.5
H16A—C16—H16B	109.5	H16D—C16A—H16E	109.5
C1—C16—H16C	109.5	C1A—C16A—H16F	109.5
H16A—C16—H16C	109.5	H16D—C16A—H16F	109.5
H16B—C16—H16C	109.5	H16E—C16A—H16F	109.5
C1—C17—H17A	109.5	C1A—C17A—H17D	109.5
C1—C17—H17B	109.5	C1A—C17A—H17E	109.5
H17A—C17—H17B	109.5	H17D—C17A—H17E	109.5
C1—C17—H17C	109.5	C1A—C17A—H17F	109.5
H17A—C17—H17C	109.5	H17D—C17A—H17F	109.5
H17B—C17—H17C	109.5	H17E—C17A—H17F	109.5
C5—C18—H18A	109.5	C5A—C18A—H18D	109.5
C5—C18—H18B	109.5	C5A—C18A—H18E	109.5
H18A—C18—H18B	109.5	H18D—C18A—H18E	109.5
C5—C18—H18C	109.5	C5A—C18A—H18F	109.5
H18A—C18—H18C	109.5	H18D—C18A—H18F	109.5
H18B—C18—H18C	109.5	H18E—C18A—H18F	109.5
C9—C19—H19A	109.5	C9A—C19A—H19D	109.5
C9—C19—H19B	109.5	C9A—C19A—H19E	109.5
H19A—C19—H19B	109.5	H19D—C19A—H19E	109.5
C9—C19—H19C	109.5	C9A—C19A—H19F	109.5
H19A—C19—H19C	109.5	H19D—C19A—H19F	109.5
H19B—C19—H19C	109.5	H19E—C19A—H19F	109.5
C13—C20—H20A	109.5	C13A—C20A—H20D	109.5
C13—C20—H20B	109.5	C13A—C20A—H20E	109.5
H20A—C20—H20B	109.5	H20D—C20A—H20E	109.5
C13—C20—H20C	109.5	C13A—C20A—H20F	109.5
H20A—C20—H20C	109.5	H20D—C20A—H20F	109.5
H20B—C20—H20C	109.5	H20E—C20A—H20F	109.5
C17—C1—C2—C3	77.6 (3)	C6A—C1A—C2A—C3A	−43.7 (3)
C6—C1—C2—C3	−43.5 (3)	C17A—C1A—C2A—C3A	−164.6 (2)
C16—C1—C2—C3	−164.0 (2)	C1A—C2A—C3A—C4A	62.7 (3)
C1—C2—C3—C4	62.9 (3)	C2A—C3A—C4A—C5A	−46.6 (3)
C2—C3—C4—C5	−46.0 (3)	C3A—C4A—C5A—C6A	15.0 (3)
C3—C4—C5—C6	13.3 (3)	C3A—C4A—C5A—C18A	−166.74 (19)
C3—C4—C5—C18	−168.4 (2)	C4A—C5A—C6A—C7A	−177.8 (2)
C18—C5—C6—C7	10.0 (4)	C18A—C5A—C6A—C7A	4.2 (4)
C4—C5—C6—C7	−172.0 (2)	C4A—C5A—C6A—C1A	4.1 (4)
C18—C5—C6—C1	−172.3 (2)	C18A—C5A—C6A—C1A	−174.0 (2)
C4—C5—C6—C1	5.7 (4)	C2A—C1A—C6A—C5A	10.2 (3)
C2—C1—C6—C5	9.2 (3)	C16A—C1A—C6A—C5A	−111.6 (3)
C17—C1—C6—C5	−112.9 (3)	C17A—C1A—C6A—C5A	129.5 (2)
C16—C1—C6—C5	128.3 (2)	C2A—C1A—C6A—C7A	−168.10 (19)
C2—C1—C6—C7	−172.9 (2)	C16A—C1A—C6A—C7A	70.1 (3)
C17—C1—C6—C7	65.1 (3)	C17A—C1A—C6A—C7A	−48.8 (3)
C16—C1—C6—C7	−53.8 (3)	C5A—C6A—C7A—C8A	52.2 (4)
C5—C6—C7—C8	47.6 (4)	C1A—C6A—C7A—C8A	−129.5 (2)
C1—C6—C7—C8	−130.3 (2)	C6A—C7A—C8A—C9A	−176.9 (2)
C6—C7—C8—C9	177.8 (2)	C7A—C8A—C9A—C10A	172.0 (2)
C7—C8—C9—C10	−179.7 (2)	C7A—C8A—C9A—C19A	−3.3 (4)
C7—C8—C9—C19	−0.2 (4)	C8A—C9A—C10A—C11A	−169.0 (2)
C8—C9—C10—C11	178.0 (2)	C19A—C9A—C10A—C11A	6.1 (4)
C19—C9—C10—C11	−1.5 (4)	C9A—C10A—C11A—C12A	175.4 (2)
C9—C10—C11—C12	174.5 (3)	C10A—C11A—C12A—C13A	−173.9 (2)
C10—C11—C12—C13	179.4 (2)	C11A—C12A—C13A—C14A	−176.7 (2)
C11—C12—C13—C14	176.0 (2)	C11A—C12A—C13A—C20A	5.0 (3)
C11—C12—C13—C20	−6.1 (4)	C12A—C13A—C14A—C15A	−178.2 (2)
C12—C13—C14—C15	0.2 (4)	C20A—C13A—C14A—C15A	0.0 (4)
C20—C13—C14—C15	−177.6 (2)	C14—C15—C15A—C14A	−179.1 (2)
C13—C14—C15—C15A	178.9 (3)	C13A—C14A—C15A—C15	−179.6 (3)
C16A—C1A—C2A—C3A	77.4 (2)

(II) 15-cis-β,β-carotene

Crystal data

C40H56	F(000) = 1184
Mr = 536.85	Dx = 1.058 Mg m^−3
Monoclinic, C2/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -C2yc	Cell parameters from 5310 reflections
a = 17.6168 (13) Å	θ = 2.3–26.4°
b = 11.5544 (9) Å	µ = 0.06 mm^−1
c = 17.4124 (13) Å	T = 100 K
β = 108.084 (1)°	Prismatic, orange
V = 3369.2 (4) Å^3	0.5 × 0.3 × 0.3 mm
Z = 4

Data collection

Bruker SMART CCD area-detector diffractometer	2981 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.029
Graphite monochromator	θmax = 26.4°, θmin = 2.1°
ϕ and ω scans	h = −22→17
9559 measured reflections	k = −14→13
3451 independent reflections	l = −21→21

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) = 0.111	H-atom parameters constrained
S = 1.07	w = 1/[σ^2(Fo^2) + (0.0667P)^2 + 0.8286P] where P = (Fo^2 + 2Fc^2)/3
3451 reflections	(Δ/σ)max = 0.001
186 parameters	Δρmax = 0.29 e Å^−3
0 restraints	Δρmin = −0.17 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
C1	0.34561 (6)	−0.04798 (9)	1.25799 (6)	0.0228 (2)
C2	0.33220 (7)	−0.17609 (9)	1.27371 (7)	0.0244 (2)
H2A	0.3458	−0.1887	1.3315	0.029*
H2B	0.2761	−0.1945	1.2497	0.029*
C3	0.38146 (7)	−0.25689 (10)	1.23960 (7)	0.0266 (3)
H3A	0.4378	−0.2394	1.2634	0.032*
H3B	0.3727	−0.3363	1.2528	0.032*
C4	0.35763 (8)	−0.24258 (10)	1.14871 (7)	0.0286 (3)
H4A	0.3985	−0.2773	1.1295	0.034*
H4B	0.3083	−0.2846	1.1244	0.034*
C5	0.34593 (7)	−0.11854 (9)	1.12037 (6)	0.0243 (3)
C6	0.34238 (6)	−0.02993 (9)	1.16924 (6)	0.0208 (2)
C7	0.33465 (6)	0.09178 (9)	1.14172 (6)	0.0217 (2)
H7	0.3000	0.1384	1.1588	0.026*
C8	0.37266 (6)	0.14155 (9)	1.09460 (6)	0.0212 (2)
H8	0.4086	0.0959	1.0787	0.025*
C9	0.36268 (6)	0.26073 (9)	1.06603 (6)	0.0203 (2)
C10	0.39725 (6)	0.29395 (9)	1.01002 (6)	0.0211 (2)
H10	0.4268	0.2378	0.9936	0.025*
C11	0.39359 (6)	0.40601 (9)	0.97305 (6)	0.0212 (2)
H11	0.3655	0.4646	0.9889	0.025*
C12	0.42901 (6)	0.43006 (9)	0.91656 (6)	0.0207 (2)
H12	0.4547	0.3689	0.9002	0.025*
C13	0.43134 (6)	0.54072 (9)	0.87864 (6)	0.0198 (2)
C14	0.46965 (6)	0.54768 (9)	0.82185 (6)	0.0193 (2)
H14	0.4888	0.4783	0.8080	0.023*
C15	0.48409 (6)	0.64894 (9)	0.78086 (6)	0.0196 (2)
H15	0.4706	0.7202	0.7979	0.023*
C16	0.42704 (7)	−0.00734 (11)	1.31456 (7)	0.0299 (3)
H16A	0.4369	0.0706	1.3012	0.045*
H16B	0.4684	−0.0571	1.3082	0.045*
H16C	0.4267	−0.0103	1.3695	0.045*
C17	0.28059 (7)	0.02230 (10)	1.27855 (7)	0.0279 (3)
H17A	0.2298	0.0070	1.2392	0.042*
H17B	0.2926	0.1033	1.2782	0.042*
H17C	0.2787	0.0006	1.3312	0.042*
C18	0.33567 (8)	−0.10740 (10)	1.03133 (7)	0.0329 (3)
H18A	0.3082	−0.0366	1.0112	0.049*
H18B	0.3051	−0.1717	1.0029	0.049*
H18C	0.3872	−0.1069	1.0233	0.049*
C19	0.31295 (7)	0.34069 (9)	1.09883 (6)	0.0232 (2)
H19A	0.3195	0.4187	1.0831	0.035*
H19B	0.3298	0.3355	1.1567	0.035*
H19C	0.2578	0.3189	1.0777	0.035*
C20	0.39219 (7)	0.64249 (9)	0.90474 (7)	0.0241 (2)
H20A	0.3973	0.7096	0.8742	0.036*
H20B	0.4176	0.6569	0.9612	0.036*
H20C	0.3367	0.6260	0.8955	0.036*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
C1	0.0241 (6)	0.0216 (5)	0.0250 (6)	−0.0002 (4)	0.0106 (4)	0.0041 (4)
C2	0.0248 (6)	0.0236 (5)	0.0266 (5)	0.0002 (4)	0.0106 (4)	0.0070 (4)
C3	0.0267 (6)	0.0219 (5)	0.0325 (6)	0.0023 (4)	0.0110 (5)	0.0072 (4)
C4	0.0349 (6)	0.0214 (6)	0.0311 (6)	0.0008 (5)	0.0126 (5)	0.0007 (4)
C5	0.0247 (6)	0.0231 (5)	0.0245 (6)	−0.0013 (4)	0.0068 (4)	0.0029 (4)
C6	0.0178 (5)	0.0220 (5)	0.0233 (5)	−0.0011 (4)	0.0073 (4)	0.0035 (4)
C7	0.0223 (5)	0.0209 (5)	0.0221 (5)	0.0002 (4)	0.0074 (4)	0.0015 (4)
C8	0.0213 (5)	0.0206 (5)	0.0219 (5)	0.0003 (4)	0.0070 (4)	0.0004 (4)
C9	0.0201 (5)	0.0205 (5)	0.0194 (5)	−0.0028 (4)	0.0050 (4)	−0.0002 (4)
C10	0.0228 (5)	0.0208 (5)	0.0205 (5)	−0.0019 (4)	0.0077 (4)	−0.0020 (4)
C11	0.0231 (5)	0.0211 (5)	0.0198 (5)	−0.0022 (4)	0.0072 (4)	−0.0014 (4)
C12	0.0237 (5)	0.0192 (5)	0.0194 (5)	−0.0020 (4)	0.0070 (4)	−0.0021 (4)
C13	0.0210 (5)	0.0206 (5)	0.0173 (5)	−0.0023 (4)	0.0054 (4)	−0.0016 (4)
C14	0.0220 (5)	0.0179 (5)	0.0180 (5)	−0.0003 (4)	0.0060 (4)	−0.0023 (4)
C15	0.0225 (5)	0.0171 (5)	0.0189 (5)	0.0010 (4)	0.0062 (4)	−0.0016 (4)
C16	0.0302 (6)	0.0339 (6)	0.0249 (6)	−0.0049 (5)	0.0076 (5)	0.0008 (5)
C17	0.0336 (6)	0.0254 (6)	0.0295 (6)	0.0012 (5)	0.0167 (5)	0.0035 (5)
C18	0.0476 (8)	0.0253 (6)	0.0259 (6)	−0.0033 (5)	0.0117 (5)	−0.0012 (5)
C19	0.0260 (6)	0.0223 (5)	0.0234 (5)	0.0008 (4)	0.0107 (4)	0.0039 (4)
C20	0.0282 (6)	0.0224 (5)	0.0250 (5)	0.0014 (4)	0.0131 (5)	0.0018 (4)

Geometric parameters (Å, º)

C1—C17	1.5344 (15)	C11—H11	0.9300
C1—C2	1.5369 (14)	C12—C13	1.4454 (14)
C1—C16	1.5399 (16)	C12—H12	0.9300
C1—C6	1.5428 (15)	C13—C14	1.3616 (15)
C2—C3	1.5158 (15)	C13—C20	1.5032 (14)
C2—H2A	0.9700	C14—C15	1.4339 (14)
C2—H2B	0.9700	C14—H14	0.9300
C3—C4	1.5151 (16)	C15—C15^i	1.358 (2)
C3—H3A	0.9700	C15—H15	0.9300
C3—H3B	0.9700	C16—H16A	0.9600
C4—C5	1.5090 (15)	C16—H16B	0.9600
C4—H4A	0.9700	C16—H16C	0.9600
C4—H4B	0.9700	C17—H17A	0.9600
C5—C6	1.3452 (16)	C17—H17B	0.9600
C5—C18	1.5096 (15)	C17—H17C	0.9600
C6—C7	1.4782 (14)	C18—H18A	0.9600
C7—C8	1.3393 (15)	C18—H18B	0.9600
C7—H7	0.9300	C18—H18C	0.9600
C8—C9	1.4561 (14)	C19—H19A	0.9600
C8—H8	0.9300	C19—H19B	0.9600
C9—C10	1.3558 (15)	C19—H19C	0.9600
C9—C19	1.5026 (15)	C20—H20A	0.9600
C10—C11	1.4384 (14)	C20—H20B	0.9600
C10—H10	0.9300	C20—H20C	0.9600
C11—C12	1.3474 (15)
C17—C1—C2	107.52 (9)	C10—C11—H11	118.5
C17—C1—C16	107.70 (9)	C11—C12—C13	126.96 (10)
C2—C1—C16	110.12 (9)	C11—C12—H12	116.5
C17—C1—C6	111.35 (9)	C13—C12—H12	116.5
C2—C1—C6	110.41 (9)	C14—C13—C12	118.34 (9)
C16—C1—C6	109.68 (9)	C14—C13—C20	123.41 (9)
C3—C2—C1	112.65 (9)	C12—C13—C20	118.24 (9)
C3—C2—H2A	109.1	C13—C14—C15	127.90 (10)
C1—C2—H2A	109.1	C13—C14—H14	116.1
C3—C2—H2B	109.1	C15—C14—H14	116.1
C1—C2—H2B	109.1	C15^i—C15—C14	125.08 (6)
H2A—C2—H2B	107.8	C15^i—C15—H15	117.5
C4—C3—C2	109.60 (9)	C14—C15—H15	117.5
C4—C3—H3A	109.8	C1—C16—H16A	109.5
C2—C3—H3A	109.8	C1—C16—H16B	109.5
C4—C3—H3B	109.8	H16A—C16—H16B	109.5
C2—C3—H3B	109.8	C1—C16—H16C	109.5
H3A—C3—H3B	108.2	H16A—C16—H16C	109.5
C5—C4—C3	114.25 (9)	H16B—C16—H16C	109.5
C5—C4—H4A	108.7	C1—C17—H17A	109.5
C3—C4—H4A	108.7	C1—C17—H17B	109.5
C5—C4—H4B	108.7	H17A—C17—H17B	109.5
C3—C4—H4B	108.7	C1—C17—H17C	109.5
H4A—C4—H4B	107.6	H17A—C17—H17C	109.5
C6—C5—C4	122.99 (10)	H17B—C17—H17C	109.5
C6—C5—C18	124.79 (10)	C5—C18—H18A	109.5
C4—C5—C18	112.18 (9)	C5—C18—H18B	109.5
C5—C6—C7	122.45 (10)	H18A—C18—H18B	109.5
C5—C6—C1	122.43 (9)	C5—C18—H18C	109.5
C7—C6—C1	115.11 (9)	H18A—C18—H18C	109.5
C8—C7—C6	126.43 (10)	H18B—C18—H18C	109.5
C8—C7—H7	116.8	C9—C19—H19A	109.5
C6—C7—H7	116.8	C9—C19—H19B	109.5
C7—C8—C9	125.80 (10)	H19A—C19—H19B	109.5
C7—C8—H8	117.1	C9—C19—H19C	109.5
C9—C8—H8	117.1	H19A—C19—H19C	109.5
C10—C9—C8	118.68 (10)	H19B—C19—H19C	109.5
C10—C9—C19	122.98 (9)	C13—C20—H20A	109.5
C8—C9—C19	118.33 (9)	C13—C20—H20B	109.5
C9—C10—C11	127.52 (10)	H20A—C20—H20B	109.5
C9—C10—H10	116.2	C13—C20—H20C	109.5
C11—C10—H10	116.2	H20A—C20—H20C	109.5
C12—C11—C10	123.08 (10)	H20B—C20—H20C	109.5
C12—C11—H11	118.5
C17—C1—C2—C3	168.11 (9)	C16—C1—C6—C7	−72.82 (12)
C16—C1—C2—C3	−74.82 (12)	C5—C6—C7—C8	−41.35 (17)
C6—C1—C2—C3	46.45 (12)	C1—C6—C7—C8	138.99 (11)
C1—C2—C3—C4	−61.70 (12)	C6—C7—C8—C9	178.09 (10)
C2—C3—C4—C5	42.70 (13)	C7—C8—C9—C10	−171.26 (11)
C3—C4—C5—C6	−11.60 (16)	C7—C8—C9—C19	7.48 (16)
C3—C4—C5—C18	170.61 (10)	C8—C9—C10—C11	178.80 (10)
C4—C5—C6—C7	177.09 (10)	C19—C9—C10—C11	0.13 (17)
C18—C5—C6—C7	−5.40 (18)	C9—C10—C11—C12	−178.75 (11)
C4—C5—C6—C1	−3.27 (17)	C10—C11—C12—C13	−177.25 (10)
C18—C5—C6—C1	174.24 (10)	C11—C12—C13—C14	−179.34 (10)
C17—C1—C6—C5	−133.37 (11)	C11—C12—C13—C20	1.40 (16)
C2—C1—C6—C5	−14.01 (14)	C12—C13—C14—C15	−175.32 (10)
C16—C1—C6—C5	107.51 (12)	C20—C13—C14—C15	3.90 (18)
C17—C1—C6—C7	46.29 (12)	C13—C14—C15—C15^i	−173.31 (13)
C2—C1—C6—C7	165.66 (9)

Symmetry code: (i) −x+1, y, −z+3/2.