mer-Tri-chlorido-tris-(tetra-hydro-thio-phene-κS)iridium(III): preparation and comparison with other mer-tri-chlorido-tris-(tetra-hydro-thio-phene-κS)metal complexes.

The title complex, [IrCl3(C4H8S)3], was prepared according to a literature method. A suitable crystal was obtained by diffusion of pentane into a di-chloro-methane solution and analyzed by single-crystal X-ray diffraction at 100 K. The title complex is isotypic with mer-tri-chlorido-tris-(tetra-hydro-thio-phene-κS)rhodium(III). However, the orientation of the tetra-hydro-thio-phene rings is different from an earlier report of mer-tri-chlorido-tris-(tetra-hydro-thio-phene-κS)iridium(III) deposited in the Cambridge Structural Database. The IrS3Cl3 core shows a nearly octa-hedral structure with various bond angles within 1-2° of the perfect 90 or 180° expected for an octa-hedron. The structure of the title compound is compared with the previous iridium complex as well as the rhodium and other octa-hedral metal tris-tetra-hydro-thio-phene compounds previously structurally characterized. DFT calculations were performed, which indicate the mer isomer is significantly lower in energy than the fac isomer by 50.1 kJ mol-1, thereby accounting for all compounds in the CSD being of the mer geometry. Powder X-ray diffraction of the bulk material showed that the preparation method yielded only the isomorph reported in this communication.

Chemical context

We have been engaged in various studies of iridium chemistry for many years (Merola, 1997 ▸; Merola & Franks, 2015 ▸; Merola et al., 2013 ▸) and recently had need to find alternate routes to some iridium(III) complexes for our research. An examination of the literature led to the title compound as a possible anhydrous source of iridium(III) that we could use as a starting material (Allen & Wilkinson, 1972 ▸). mer-Tri­chlorido­tris­(tetra­hydro­thio­phene-κS)iridium(III) has been mentioned in the literature as a starting material for other organometallic iridium complexes (Hay-Motherwell et al., 1989 ▸, 1992 ▸, 1990 ▸; John et al., 2000 ▸, 2001 ▸, 2014 ▸), and most recently has been the starting material of choice for new emissive materials (Chang et al., 2008 ▸, 2011 ▸, 2013 ▸; Chiu et al., 2009 ▸; Hung et al., 2010 ▸; Lin, Chang et al., 2011 ▸; Lin, Chi et al., 2011 ▸; Lin et al., 2012 ▸). However, no crystallographic studies had been published on this compound. Given its increasing importance, we decided that a single crystal structure determination of the title compound would be worthwhile.

Structural commentary

mer-Tri­chlorido­tris­(tetra­hydro­thio­phene-κS)iridium(III) (CCDC refcode 1495966) crystallizes in the P21/n space group with one mol­ecule in the asymmetric unit (Fig. 1 ▸). The core structure (heavy atoms around the iridium) is very close to rigorous octa­hedral geometry with the largest angular variation [Cl1—Ir1—Cl33, 177.35 (3)°] being less than 2.7° from ideal linearity.

Figure 1

Displacement ellipsoid plot (50% probability) of mer-tri­chlorido­tris(tetra­hydro­thio­phene-κS)iridium(III) (CCDC 1495966).

The Ir—Cl bond lengths [range 2.3648 (8)–2.3774 (9) Å] are somewhat longer than the Ir—S bonds [range 2.3279 (9)–2.3575 (9) Å], as expected from the slightly larger radius of Cl. A search for Ir—S bonds in the CSD (Groom et al., 2016 ▸) and analyzed with Mercury (Macrae et al., 2008 ▸) found 2566 instances with distances ranging from 2.134 to 2.633 Å and a mean value of 2.358 Å. That places the bond lengths for the title compound slightly above the mean value. Similarly, a Mercury data analysis of the CSD for Ir—Cl bond lengths found 3965 instances with distances ranging from 2.121 to 2.816 Å and a mean value of 2.413 Å, which places the Ir—Cl distances for the title compound lower than the mean. This comparison should not be considered as too significant since it was not possible to compare bond lengths only for iridium(III) compounds and the analysis includes quite a few iridium(I) complexes. The tetra­hydro­thio­phene rings are well ordered in the title structure, adopting a puckered conformation consistent with trying to minimize ring strain. Two of the rings are positioned with the center of the ring aligned over a chlorine atom in the structure, while the third is aligned over a sulfur atom of another ring. More will be said about the ring conformations in the Database survey section.

Supra­molecular features

An examination of the packing diagrams for the title compound shows no unusual inter­molecular features other than van der Waals inter­actions.

Database survey

A survey of the CCDC database (Groom et al., 2016 ▸) uncovered a number of metal mer-tris­(THT-κS)metal complexes (THT= tetra­hydro­thio­phene), including one iridium structure deposited as a private communication (CCDC 1438699; Rheingold & Donovan-Merkert, 2015 ▸). The deposited structure (CCDC 1438699) packs with very different unit-cell parameters but the overall mol­ecular structure is substanti­ally the same. The results of the different packing, however, are slightly different conformations of two of the three THT ligands, as shown in Fig. 2 ▸, a structure overlay calculated in Mercury (Macrae et al., 2008 ▸). On the other hand, the rhodium(III) complex is isotypic with the title complex with similar unit-cell parameters (CCDC refcode GEZHUO; Clark et al., 1988 ▸). Fig. 3 ▸ shows an overlay calculated with Mercury (Macrae et al., 2008 ▸) of the title complex with the rhodium compound, showing the nearly perfect atomic overlay. Ruthenium(III) (VIJYAO; Yapp et al., 1990 ▸) and molybdenum(III) (REDXIH; Boorman et al., 1996 ▸) complexes were also found in the database, with all showing the same meridional arrangement of ligands with the exception that the ruthenium complex displays disorder from overlapping conformations of one of the THT ligands.

Figure 2

Calculated overlay of two polymorphs of mer-tri­chlorido­tris­(tetra­hydro­thio­phene-κS)iridium(III) (CCDC 1438699 and CCDC 1495966). Structure from this paper shown in yellow.

Figure 3

Calculated overlay of mer-tri­chlorido­tris­(tetra­hydro­thio­phene-κS)iridium(III) (CCDC 1495966) in yellow with the isotypical rhodium complex (CCDC GEZHUO) in blue.

Theoretical calculations

We were inter­ested in determining if the bulk material synthesized by this process is of a single polymorph or if both of the iridium structures reported (CCDC 1495966, this report, and CCDC 1438699, Rheingold & Donovan-Merkert, 2015 ▸) were present. Fig. 4 ▸ shows an overlay of the powder X-ray diffraction pattern for the complex reported here with the powder pattern predicted by Mercury (Macrae et al., 2008 ▸). The match is very good and quite distinct from the pattern predicted for CCDC 1438699, indicating that the bulk material formed in this process is a single polymorph matching the structure reported here.

Figure 4

Powder X-ray diffraction pattern of title compound collected on a Rigaku Miniflex 600 Powder X-ray diffractometer compared with pattern simulated by Mercury (Macrae et al., 2008 ▸). Experimental and simulated patterns scaled to highest intensity peak in each.

One feature that stands out in all cases is that the MCl3(THT)3 compounds found in the database adopt the mer configuration. Calculations were performed using density functional theory with Gaussian 09 (Frisch et al., 2009 ▸). Full geometry optimization of both the mer and fac isomers was carried out via density functional theory (DFT) with the Becke-3-parameter exchange functional (Becke, 1993 ▸) and the Lee–Yang–Parr correlation functional (Lee et al., 1988 ▸). Because iridium is not covered in the cc-PVDZ basis set used, computations involving Ir employed Stuttgart/Dresden quasi-relativistic pseudopotentials (Andrae et al., 1990 ▸). The difference between the two isomers was quite large with the mer isomer being more stable than the fac by 50.1 kJ mol−1, suggesting the occurrence of only the mer isomer for the small set of compounds surveyed may be due to thermodynamic stability.

Synthesis and crystallization

The title compound was synthesized using a slight modification of a literature procedure (John et al., 2014 ▸). IrCl3·3H2O (1.00 g, 2.84 mmol) and 2-meth­oxy­ethanol (50 mL) were added to a 250 mL round-bottomed flask fitted with a magnetic stir bar and a reflux condenser. Tetra­hydro­thio­phene (1.25 mL, 14.2 mmol) was added all at once with stirring. The resulting suspension was refluxed for 18 h, providing a clear orange solution that gave a yellow precipitate upon cooling to room temperature. Deionized water (75 mL) was added and the suspension was cooled overnight (273 K) before collection on a fine-porosity sintered glass frit. The resulting yellow powder was washed with deionized water (3 x 15 mL) then cold ethanol (3 x 15 mL). After vacuum drying overnight the yellow powder (1.40 g, 88%) was characterized by 1H and 13C NMR spectroscopy. As the NMR spectra were in agreement with previously reported data, no further purification was necessary. Single crystals for X-ray diffraction were grown by slow diffusion of n-pentane into a di­chloro­methane solution of mer-IrCl3(THT)3.

Refinement

Crystal data, data collection and structure refinement details are summarized in Table 1 ▸.

Table 1

Experimental details

Crystal data
Chemical formula	[IrCl3(C4H8S)3]
M r	563.04
Crystal system, space group	Monoclinic, P21/n
Temperature (K)	100
a, b, c (Å)	11.9160 (3), 10.2528 (2), 14.9434 (4)
β (°)	107.202 (3)
V (Å3)	1744.00 (7)
Z	4
Radiation type	Mo Kα
μ (mm−1)	8.46
Crystal size (mm)	0.51 × 0.43 × 0.32
Data collection
Diffractometer	Rigaku OD Xcalibur Eos Gemini ultra
Absorption correction	Analytical [CrysAlis PRO (Rigaku Oxford Diffraction, 2015 ▸) based on expressions derived by Clark & Reid (1995 ▸)]
T min, T max	0.064, 0.155
No. of measured, independent and observed [I > 2σ(I)] reflections	19537, 5773, 5062
R int	0.042
(sin θ/λ)max (Å−1)	0.751
Refinement
R[F 2 > 2σ(F 2)], wR(F 2), S	0.029, 0.063, 1.05
No. of reflections	5773
No. of parameters	172
H-atom treatment	H-atom parameters constrained
Δρmax, Δρmin (e Å−3)	1.54, −1.46

Computer programs: CrysAlis PRO (Rigaku Oxford Diffraction, 2015 ▸), SHELXT (Sheldrick, 2015a ▸), SHELXL2016 (Sheldrick, 2015b ▸), OLEX2 (Dolomanov et al., 2009 ▸) and Mercury (Macrae et al., 2008 ▸).

Crystal structure: contains datablock(s) I. DOI: 10.1107/S2056989016012883/pk2588sup1.cif

Structure factors: contains datablock(s) I. DOI: 10.1107/S2056989016012883/pk2588Isup2.hkl

Click here for additional data file.

Supporting information file. DOI: 10.1107/S2056989016012883/pk2588Isup3.mol

CCDC reference: 1495966

Additional supporting information: crystallographic information; 3D view; checkCIF report

[IrCl3(C4H8S)3]	F(000) = 1088
Mr = 563.04	Dx = 2.144 Mg m−3
Monoclinic, P21/n	Mo Kα radiation, λ = 0.71073 Å
a = 11.9160 (3) Å	Cell parameters from 9679 reflections
b = 10.2528 (2) Å	θ = 4.1–32.2°
c = 14.9434 (4) Å	µ = 8.46 mm−1
β = 107.202 (3)°	T = 100 K
V = 1744.00 (7) Å3	Cube, yellow
Z = 4	0.51 × 0.43 × 0.32 mm

Rigaku OD Xcalibur Eos Gemini ultra diffractometer	5773 independent reflections
Radiation source: fine-focus sealed X-ray tube, Enhance (Mo) X-ray Source	5062 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.042
Detector resolution: 8.0061 pixels mm-1	θmax = 32.2°, θmin = 3.6°
ω scans	h = −13→17
Absorption correction: analytical [CrysAlis PRO (Rigaku Oxford Diffraction, 2015) based on expressions derived by Clark & Reid (1995)]	k = −13→15
Tmin = 0.064, Tmax = 0.155	l = −22→21
19537 measured reflections

Refinement on F2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.029	H-atom parameters constrained
wR(F2) = 0.063	w = 1/[σ2(Fo2) + (0.0223P)2 + 0.8135P] where P = (Fo2 + 2Fc2)/3
S = 1.05	(Δ/σ)max = 0.002
5773 reflections	Δρmax = 1.54 e Å−3
172 parameters	Δρmin = −1.46 e Å−3
0 restraints

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes.

	x	y	z	Uiso*/Ueq
Ir1	0.45092 (2)	0.70407 (2)	0.73222 (2)	0.01133 (4)
Cl1	0.59718 (7)	0.70422 (8)	0.65431 (6)	0.01922 (17)
Cl2	0.59716 (8)	0.73216 (8)	0.87865 (6)	0.01887 (16)
Cl3	0.30344 (7)	0.71455 (8)	0.80946 (6)	0.01688 (16)
S1	0.46678 (7)	0.47667 (8)	0.74921 (6)	0.01509 (16)
S2	0.30373 (7)	0.68096 (8)	0.59053 (6)	0.01540 (16)
S3	0.44035 (7)	0.93361 (9)	0.72529 (6)	0.01636 (16)
C1	0.6230 (3)	0.4314 (4)	0.7907 (3)	0.0236 (8)
H1A	0.6388	0.3570	0.7540	0.028*
H1B	0.6727	0.5059	0.7837	0.028*
C2	0.6496 (3)	0.3940 (4)	0.8934 (3)	0.0281 (9)
H2A	0.7157	0.3314	0.9114	0.034*
H2B	0.6710	0.4722	0.9337	0.034*
C3	0.5384 (4)	0.3321 (4)	0.9044 (3)	0.0257 (8)
H3A	0.5449	0.3203	0.9715	0.031*
H3B	0.5246	0.2459	0.8732	0.031*
C4	0.4380 (3)	0.4262 (4)	0.8582 (3)	0.0216 (7)
H4A	0.4387	0.5024	0.8991	0.026*
H4B	0.3610	0.3820	0.8448	0.026*
C5	0.3455 (3)	0.5674 (4)	0.5104 (3)	0.0277 (9)
H5A	0.3271	0.6057	0.4469	0.033*
H5B	0.4308	0.5488	0.5331	0.033*
C6	0.2749 (3)	0.4419 (4)	0.5082 (3)	0.0261 (8)
H6A	0.2620	0.3969	0.4474	0.031*
H6B	0.3179	0.3822	0.5588	0.031*
C7	0.1582 (3)	0.4802 (4)	0.5219 (3)	0.0225 (8)
H7A	0.1078	0.5244	0.4654	0.027*
H7B	0.1163	0.4024	0.5348	0.027*
C8	0.1883 (3)	0.5720 (4)	0.6051 (3)	0.0192 (7)
H8A	0.2167	0.5224	0.6643	0.023*
H8B	0.1182	0.6229	0.6065	0.023*
C9	0.3843 (3)	0.9968 (4)	0.6060 (2)	0.0188 (7)
H9A	0.3912	0.9305	0.5597	0.023*
H9B	0.3010	1.0232	0.5920	0.023*
C10	0.4624 (3)	1.1147 (4)	0.6047 (3)	0.0213 (7)
H10A	0.4527	1.1433	0.5396	0.026*
H10B	0.4424	1.1883	0.6400	0.026*
C11	0.5875 (3)	1.0686 (4)	0.6510 (3)	0.0228 (8)
H11A	0.6424	1.1434	0.6631	0.027*
H11B	0.6119	1.0058	0.6099	0.027*
C12	0.5882 (3)	1.0027 (4)	0.7436 (3)	0.0209 (7)
H12A	0.6061	1.0674	0.7951	0.025*
H12B	0.6483	0.9330	0.7598	0.025*

	U11	U22	U33	U12	U13	U23
Ir1	0.01159 (6)	0.01222 (7)	0.01049 (6)	0.00034 (4)	0.00376 (5)	−0.00076 (4)
Cl1	0.0165 (4)	0.0225 (4)	0.0222 (4)	−0.0003 (3)	0.0112 (3)	−0.0008 (3)
Cl2	0.0199 (4)	0.0171 (4)	0.0157 (4)	−0.0013 (3)	−0.0007 (3)	−0.0021 (3)
Cl3	0.0183 (4)	0.0179 (4)	0.0177 (4)	0.0004 (3)	0.0102 (3)	−0.0020 (3)
S1	0.0158 (4)	0.0132 (4)	0.0156 (4)	0.0007 (3)	0.0035 (3)	−0.0012 (3)
S2	0.0151 (4)	0.0170 (4)	0.0130 (4)	0.0001 (3)	0.0024 (3)	0.0001 (3)
S3	0.0202 (4)	0.0152 (4)	0.0157 (4)	0.0008 (3)	0.0084 (3)	−0.0004 (3)
C1	0.0173 (17)	0.0225 (18)	0.032 (2)	0.0057 (14)	0.0092 (16)	0.0040 (16)
C2	0.0209 (18)	0.025 (2)	0.030 (2)	0.0032 (15)	−0.0046 (17)	0.0039 (17)
C3	0.031 (2)	0.0182 (18)	0.026 (2)	0.0064 (15)	0.0056 (17)	0.0081 (16)
C4	0.0242 (18)	0.0193 (18)	0.0240 (18)	0.0017 (14)	0.0113 (16)	0.0053 (15)
C5	0.0195 (18)	0.046 (3)	0.0179 (18)	0.0012 (17)	0.0059 (15)	−0.0126 (17)
C6	0.032 (2)	0.0249 (19)	0.0184 (18)	0.0067 (16)	0.0027 (16)	−0.0076 (16)
C7	0.0290 (19)	0.0168 (17)	0.0180 (17)	−0.0032 (14)	0.0015 (16)	−0.0019 (14)
C8	0.0143 (15)	0.0214 (17)	0.0238 (18)	−0.0031 (13)	0.0082 (14)	−0.0051 (15)
C9	0.0191 (17)	0.0207 (17)	0.0149 (16)	0.0011 (13)	0.0023 (14)	0.0031 (13)
C10	0.0262 (18)	0.0181 (17)	0.0212 (18)	0.0021 (14)	0.0097 (16)	0.0024 (15)
C11	0.0222 (18)	0.0221 (18)	0.0260 (19)	−0.0030 (14)	0.0100 (16)	0.0021 (15)
C12	0.0189 (17)	0.0199 (18)	0.0209 (18)	−0.0037 (13)	0.0013 (15)	−0.0008 (14)

Ir1—Cl1	2.3648 (8)	C5—H5A	0.9900
Ir1—Cl2	2.3774 (9)	C5—H5B	0.9900
Ir1—Cl3	2.3732 (8)	C5—C6	1.533 (6)
Ir1—S1	2.3469 (9)	C6—H6A	0.9900
Ir1—S2	2.3279 (9)	C6—H6B	0.9900
Ir1—S3	2.3575 (9)	C6—C7	1.516 (5)
S1—C1	1.839 (4)	C7—H7A	0.9900
S1—C4	1.835 (4)	C7—H7B	0.9900
S2—C5	1.841 (4)	C7—C8	1.515 (5)
S2—C8	1.834 (3)	C8—H8A	0.9900
S3—C9	1.827 (4)	C8—H8B	0.9900
S3—C12	1.843 (4)	C9—H9A	0.9900
C1—H1A	0.9900	C9—H9B	0.9900
C1—H1B	0.9900	C9—C10	1.529 (5)
C1—C2	1.522 (6)	C10—H10A	0.9900
C2—H2A	0.9900	C10—H10B	0.9900
C2—H2B	0.9900	C10—C11	1.521 (5)
C2—C3	1.521 (6)	C11—H11A	0.9900
C3—H3A	0.9900	C11—H11B	0.9900
C3—H3B	0.9900	C11—C12	1.537 (5)
C3—C4	1.533 (5)	C12—H12A	0.9900
C4—H4A	0.9900	C12—H12B	0.9900
C4—H4B	0.9900
Cl1—Ir1—Cl2	90.39 (3)	S2—C5—H5A	110.3
Cl1—Ir1—Cl3	177.35 (3)	S2—C5—H5B	110.3
Cl3—Ir1—Cl2	89.63 (3)	H5A—C5—H5B	108.6
S1—Ir1—Cl1	90.37 (3)	C6—C5—S2	107.0 (2)
S1—Ir1—Cl2	90.41 (3)	C6—C5—H5A	110.3
S1—Ir1—Cl3	92.28 (3)	C6—C5—H5B	110.3
S1—Ir1—S3	176.44 (3)	C5—C6—H6A	110.2
S2—Ir1—Cl1	91.09 (3)	C5—C6—H6B	110.2
S2—Ir1—Cl2	178.15 (3)	H6A—C6—H6B	108.5
S2—Ir1—Cl3	88.85 (3)	C7—C6—C5	107.4 (3)
S2—Ir1—S1	90.70 (3)	C7—C6—H6A	110.2
S2—Ir1—S3	92.61 (3)	C7—C6—H6B	110.2
S3—Ir1—Cl1	90.88 (3)	C6—C7—H7A	110.6
S3—Ir1—Cl2	86.25 (3)	C6—C7—H7B	110.6
S3—Ir1—Cl3	86.47 (3)	H7A—C7—H7B	108.8
C1—S1—Ir1	109.15 (13)	C8—C7—C6	105.5 (3)
C4—S1—Ir1	110.23 (12)	C8—C7—H7A	110.6
C4—S1—C1	93.79 (17)	C8—C7—H7B	110.6
C5—S2—Ir1	112.32 (13)	S2—C8—H8A	110.4
C8—S2—Ir1	110.12 (13)	S2—C8—H8B	110.4
C8—S2—C5	92.79 (17)	C7—C8—S2	106.6 (2)
C9—S3—Ir1	113.33 (12)	C7—C8—H8A	110.4
C9—S3—C12	93.79 (16)	C7—C8—H8B	110.4
C12—S3—Ir1	109.93 (12)	H8A—C8—H8B	108.6
S1—C1—H1A	110.3	S3—C9—H9A	110.9
S1—C1—H1B	110.3	S3—C9—H9B	110.9
H1A—C1—H1B	108.6	H9A—C9—H9B	108.9
C2—C1—S1	106.9 (3)	C10—C9—S3	104.2 (2)
C2—C1—H1A	110.3	C10—C9—H9A	110.9
C2—C1—H1B	110.3	C10—C9—H9B	110.9
C1—C2—H2A	110.4	C9—C10—H10A	110.7
C1—C2—H2B	110.4	C9—C10—H10B	110.7
H2A—C2—H2B	108.6	H10A—C10—H10B	108.8
C3—C2—C1	106.7 (3)	C11—C10—C9	105.5 (3)
C3—C2—H2A	110.4	C11—C10—H10A	110.7
C3—C2—H2B	110.4	C11—C10—H10B	110.7
C2—C3—H3A	110.5	C10—C11—H11A	110.4
C2—C3—H3B	110.5	C10—C11—H11B	110.4
C2—C3—C4	106.1 (3)	C10—C11—C12	106.8 (3)
H3A—C3—H3B	108.7	H11A—C11—H11B	108.6
C4—C3—H3A	110.5	C12—C11—H11A	110.4
C4—C3—H3B	110.5	C12—C11—H11B	110.4
S1—C4—H4A	110.8	S3—C12—H12A	110.4
S1—C4—H4B	110.8	S3—C12—H12B	110.4
C3—C4—S1	104.6 (2)	C11—C12—S3	106.5 (2)
C3—C4—H4A	110.8	C11—C12—H12A	110.4
C3—C4—H4B	110.8	C11—C12—H12B	110.4
H4A—C4—H4B	108.9	H12A—C12—H12B	108.6
Ir1—S1—C1—C2	106.1 (3)	C2—C3—C4—S1	43.0 (4)
Ir1—S1—C4—C3	−132.6 (2)	C4—S1—C1—C2	−6.9 (3)
Ir1—S2—C5—C6	106.8 (2)	C5—S2—C8—C7	−20.6 (3)
Ir1—S2—C8—C7	−135.6 (2)	C5—C6—C7—C8	−48.0 (4)
Ir1—S3—C9—C10	−138.6 (2)	C6—C7—C8—S2	42.1 (3)
Ir1—S3—C12—C11	114.0 (2)	C8—S2—C5—C6	−6.3 (3)
S1—C1—C2—C3	33.0 (4)	C9—S3—C12—C11	−2.5 (3)
S2—C5—C6—C7	31.9 (4)	C9—C10—C11—C12	−49.9 (4)
S3—C9—C10—C11	46.4 (3)	C10—C11—C12—S3	29.9 (4)
C1—S1—C4—C3	−20.5 (3)	C12—S3—C9—C10	−25.0 (3)
C1—C2—C3—C4	−49.8 (4)