organic compounds
3-(Trimethylsilyl)prop-2-ynyl p-toluenesulfonate
aDepartment of Chemistry, Louisiana State University, Baton Rouge, LA 70803-1804, USA
*Correspondence e-mail: ffroncz@lsu.edu
In the title compound, C13H18O3SSi, the SO3 group displays a partial rotational (ca 50°) disorder about the C—S bond, with relative proportions 0.7744 (13):0.2256 (13). This disorder also forces the propynyl CH2 group to be disordered.
Related literature
For information on the title compound, see: Westmijze & Vermeer (1979); Tanabe et al. (1995); Morales (1995).
Experimental
Crystal data
|
Data collection: COLLECT (Nonius, 2000); cell DENZO/SCALEPACK (Otwinowski & Minor, 1997); data reduction: DENZO/SCALEPACK; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997); software used to prepare material for publication: WinGX (Farrugia, 1999).
Supporting information
10.1107/S1600536811043595/fj2461sup1.cif
contains datablocks global, I. DOI:Structure factors: contains datablock I. DOI: 10.1107/S1600536811043595/fj2461Isup2.hkl
Supporting information file. DOI: 10.1107/S1600536811043595/fj2461Isup3.cml
The title compound was prepared according to the procedure of Westmijze & Vermeer (1979): Commercially available 3-trimethylsilylpropargyl alcohol (5.13 g, 40.0 mmol) and freshly purified tosyl chloride (9.53 g, 50.0 mmol) were mixed in anhydrous diethyl ether under an Ar atmosphere. The mixture was cooled to -50 °C, and freshly powdered KOH (15.0 g, 268 mmol) was added at once under vigorous stirring. The temperature of the resulting thick mixture was slowly raised to 0 °C, and the mixture was stirred at this temperature for 30 min. This mixture was poured onto water (200 ml), extracted with ethyl ether (3 τimes 50 ml), washed with water (100 ml), and concentrated under reduced pressure to give a light brown oil. Repeated crystallization from hexanes afforded colorless needles (7.93 g, 70.3% yield).
The site occupation factor was constrained to be x for O1, O2, O3, H8A, H8B, and 1 - x for O1A, O2A, O3A, H8A', H8B'. Atomic displacement parameters were constrained to be equal for the following disordered atom pairs: O1 and O1A, O2 and O2A, O3 and O3A, and interatomic distances C8—O1 and C8—O1A were restrained to be equal to within σ = 0.002.
All H atoms were placed in calculated positions, guided by difference maps, with C—H bond distances 0.95 (aromatic-H), 0.98 (methyl-H), and 0.99 (alkyl-H) Å, and displacement parameters Uiso=1.2Ueq (aromatic and alkyl C) and 1.5Ueq (methyl-C), and thereafter refined as riding.
Data collection: COLLECT (Nonius, 2000); cell
DENZO/SCALEPACK (Otwinowski & Minor, 1997); data reduction: DENZO/SCALEPACK (Otwinowski & Minor, 1997); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997); software used to prepare material for publication: WinGX (Farrugia, 1999).C13H18O3SSi | F(000) = 600 |
Mr = 282.42 | Dx = 1.245 Mg m−3 |
Monoclinic, P21/c | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -P 2ybc | Cell parameters from 4768 reflections |
a = 10.6857 (4) Å | θ = 2.6–31.0° |
b = 12.9413 (5) Å | µ = 0.29 mm−1 |
c = 11.8793 (4) Å | T = 90 K |
β = 113.471 (2)° | Needle, colorless |
V = 1506.83 (10) Å3 | 0.33 × 0.18 × 0.17 mm |
Z = 4 |
Nonius KappaCCD diffractometer | 4721 independent reflections |
Radiation source: fine-focus sealed tube | 3257 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.041 |
Detector resolution: 9 pixels mm-1 | θmax = 30.9°, θmin = 2.6° |
ω and ϕ scans | h = −15→15 |
Absorption correction: multi-scan (SCALEPACK; Otwinowski & Minor, 1997) | k = −18→18 |
Tmin = 0.910, Tmax = 0.952 | l = −17→16 |
9135 measured reflections |
Refinement on F2 | Primary atom site location: structure-invariant direct methods |
Least-squares matrix: full | Secondary atom site location: difference Fourier map |
R[F2 > 2σ(F2)] = 0.045 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.108 | H-atom parameters constrained |
S = 1.03 | w = 1/[σ2(Fo2) + (0.0404P)2 + 0.7293P] where P = (Fo2 + 2Fc2)/3 |
4721 reflections | (Δ/σ)max = 0.001 |
177 parameters | Δρmax = 0.76 e Å−3 |
1 restraint | Δρmin = −0.54 e Å−3 |
3 constraints |
C13H18O3SSi | V = 1506.83 (10) Å3 |
Mr = 282.42 | Z = 4 |
Monoclinic, P21/c | Mo Kα radiation |
a = 10.6857 (4) Å | µ = 0.29 mm−1 |
b = 12.9413 (5) Å | T = 90 K |
c = 11.8793 (4) Å | 0.33 × 0.18 × 0.17 mm |
β = 113.471 (2)° |
Nonius KappaCCD diffractometer | 4721 independent reflections |
Absorption correction: multi-scan (SCALEPACK; Otwinowski & Minor, 1997) | 3257 reflections with I > 2σ(I) |
Tmin = 0.910, Tmax = 0.952 | Rint = 0.041 |
9135 measured reflections |
R[F2 > 2σ(F2)] = 0.045 | 1 restraint |
wR(F2) = 0.108 | H-atom parameters constrained |
S = 1.03 | Δρmax = 0.76 e Å−3 |
4721 reflections | Δρmin = −0.54 e Å−3 |
177 parameters |
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. |
x | y | z | Uiso*/Ueq | Occ. (<1) | |
S1 | 1.00481 (4) | 0.33704 (3) | 0.46346 (4) | 0.01708 (10) | |
Si1 | 0.49810 (5) | 0.23584 (4) | 0.04270 (4) | 0.02127 (12) | |
O1 | 0.87983 (15) | 0.41268 (11) | 0.42804 (13) | 0.0207 (3) | 0.7744 (13) |
O2 | 1.08780 (16) | 0.36473 (12) | 0.39833 (15) | 0.0237 (3) | 0.7744 (13) |
O3 | 1.06468 (17) | 0.33877 (12) | 0.59590 (14) | 0.0250 (3) | 0.7744 (13) |
O1A | 0.9453 (3) | 0.4058 (4) | 0.3433 (4) | 0.0207 (3) | 0.2256 (13) |
O2A | 1.1404 (6) | 0.3363 (4) | 0.4827 (5) | 0.0237 (3) | 0.2256 (13) |
O3A | 0.9569 (6) | 0.3761 (4) | 0.5540 (5) | 0.0250 (3) | 0.2256 (13) |
C1 | 0.93291 (17) | 0.21448 (12) | 0.41521 (15) | 0.0178 (3) | |
C2 | 0.86434 (19) | 0.16667 (14) | 0.47865 (16) | 0.0240 (4) | |
H2 | 0.8564 | 0.1997 | 0.5469 | 0.029* | |
C3 | 0.8077 (2) | 0.06981 (14) | 0.44071 (17) | 0.0282 (4) | |
H3 | 0.7606 | 0.0364 | 0.4836 | 0.034* | |
C4 | 0.81874 (18) | 0.02064 (13) | 0.34052 (16) | 0.0257 (4) | |
C5 | 0.88776 (18) | 0.07073 (13) | 0.27880 (16) | 0.0246 (4) | |
H5 | 0.8955 | 0.038 | 0.2102 | 0.03* | |
C6 | 0.94568 (17) | 0.16762 (13) | 0.31531 (15) | 0.0212 (3) | |
H6 | 0.993 | 0.2011 | 0.2728 | 0.025* | |
C7 | 0.7575 (2) | −0.08509 (15) | 0.3004 (2) | 0.0377 (5) | |
H7A | 0.7553 | −0.1005 | 0.2188 | 0.057* | |
H7C | 0.6645 | −0.0864 | 0.2972 | 0.057* | |
H7B | 0.8131 | −0.137 | 0.3591 | 0.057* | |
C8 | 0.81275 (19) | 0.45147 (14) | 0.30416 (16) | 0.0272 (4) | |
H8A | 0.8829 | 0.4663 | 0.2715 | 0.033* | 0.7744 (13) |
H8B | 0.7671 | 0.5175 | 0.3066 | 0.033* | 0.7744 (13) |
H8A' | 0.8112 | 0.518 | 0.2626 | 0.033* | 0.2256 (13) |
H8B' | 0.7906 | 0.4652 | 0.3762 | 0.033* | 0.2256 (13) |
C9 | 0.71152 (19) | 0.38092 (14) | 0.21960 (16) | 0.0237 (4) | |
C10 | 0.62740 (19) | 0.32454 (14) | 0.14905 (16) | 0.0247 (4) | |
C11 | 0.58308 (19) | 0.15508 (16) | −0.03569 (18) | 0.0314 (4) | |
H11A | 0.6075 | 0.1983 | −0.0916 | 0.047* | |
H11B | 0.5207 | 0.1003 | −0.0824 | 0.047* | |
H11C | 0.6658 | 0.1241 | 0.0257 | 0.047* | |
C12 | 0.4334 (2) | 0.15281 (15) | 0.13563 (19) | 0.0333 (4) | |
H12A | 0.51 | 0.1164 | 0.1983 | 0.05* | |
H12B | 0.3686 | 0.1023 | 0.0821 | 0.05* | |
H12C | 0.3876 | 0.1959 | 0.1755 | 0.05* | |
C13 | 0.36123 (19) | 0.31849 (14) | −0.06735 (17) | 0.0270 (4) | |
H13A | 0.3137 | 0.355 | −0.0237 | 0.041* | |
H13B | 0.2962 | 0.2751 | −0.1317 | 0.041* | |
H13C | 0.4018 | 0.3688 | −0.1045 | 0.041* |
U11 | U22 | U33 | U12 | U13 | U23 | |
S1 | 0.01972 (19) | 0.01537 (18) | 0.01643 (19) | −0.00309 (16) | 0.00751 (15) | −0.00186 (15) |
Si1 | 0.0256 (2) | 0.0199 (2) | 0.0190 (2) | −0.0004 (2) | 0.00962 (19) | −0.00338 (19) |
O1 | 0.0220 (7) | 0.0174 (7) | 0.0228 (8) | −0.0009 (6) | 0.0091 (6) | −0.0038 (6) |
O2 | 0.0242 (8) | 0.0217 (8) | 0.0295 (8) | −0.0020 (6) | 0.0152 (7) | 0.0019 (6) |
O3 | 0.0322 (8) | 0.0222 (8) | 0.0168 (7) | −0.0078 (7) | 0.0058 (6) | −0.0022 (6) |
O1A | 0.0220 (7) | 0.0174 (7) | 0.0228 (8) | −0.0009 (6) | 0.0091 (6) | −0.0038 (6) |
O2A | 0.0242 (8) | 0.0217 (8) | 0.0295 (8) | −0.0020 (6) | 0.0152 (7) | 0.0019 (6) |
O3A | 0.0322 (8) | 0.0222 (8) | 0.0168 (7) | −0.0078 (7) | 0.0058 (6) | −0.0022 (6) |
C1 | 0.0199 (8) | 0.0136 (7) | 0.0176 (8) | −0.0008 (6) | 0.0050 (6) | −0.0020 (6) |
C2 | 0.0311 (9) | 0.0206 (8) | 0.0227 (8) | −0.0059 (7) | 0.0134 (7) | −0.0051 (7) |
C3 | 0.0346 (10) | 0.0207 (9) | 0.0307 (10) | −0.0075 (8) | 0.0144 (8) | −0.0006 (7) |
C4 | 0.0253 (9) | 0.0159 (8) | 0.0268 (9) | 0.0007 (7) | 0.0006 (7) | −0.0028 (7) |
C5 | 0.0294 (9) | 0.0199 (8) | 0.0200 (8) | 0.0056 (7) | 0.0049 (7) | −0.0058 (7) |
C6 | 0.0246 (8) | 0.0203 (8) | 0.0184 (8) | 0.0035 (7) | 0.0083 (7) | −0.0008 (7) |
C7 | 0.0426 (12) | 0.0185 (9) | 0.0417 (12) | −0.0053 (8) | 0.0059 (10) | −0.0078 (8) |
C8 | 0.0314 (9) | 0.0178 (8) | 0.0256 (9) | 0.0002 (7) | 0.0043 (8) | 0.0018 (7) |
C9 | 0.0291 (9) | 0.0212 (8) | 0.0224 (9) | 0.0032 (7) | 0.0120 (7) | 0.0018 (7) |
C10 | 0.0317 (10) | 0.0241 (9) | 0.0199 (8) | 0.0008 (7) | 0.0120 (7) | −0.0004 (7) |
C11 | 0.0257 (9) | 0.0394 (11) | 0.0267 (9) | 0.0020 (8) | 0.0079 (8) | −0.0119 (8) |
C12 | 0.0434 (12) | 0.0255 (10) | 0.0342 (11) | −0.0013 (9) | 0.0191 (9) | 0.0022 (8) |
C13 | 0.0299 (9) | 0.0251 (9) | 0.0250 (9) | 0.0012 (7) | 0.0100 (8) | −0.0014 (7) |
S1—O2A | 1.374 (5) | C5—C6 | 1.389 (2) |
S1—O2 | 1.4352 (15) | C5—H5 | 0.95 |
S1—O3 | 1.4434 (15) | C6—H6 | 0.95 |
S1—O3A | 1.454 (6) | C7—H7A | 0.98 |
S1—O1 | 1.5720 (15) | C7—H7C | 0.98 |
S1—O1A | 1.584 (5) | C7—H7B | 0.98 |
S1—C1 | 1.7561 (16) | C8—C9 | 1.465 (2) |
Si1—C10 | 1.8526 (19) | C8—H8A | 0.99 |
Si1—C11 | 1.8594 (19) | C8—H8B | 0.99 |
Si1—C12 | 1.8600 (19) | C8—H8A' | 0.99 |
Si1—C13 | 1.8625 (19) | C8—H8B' | 0.99 |
O1—C8 | 1.446 (2) | C9—C10 | 1.201 (3) |
O1A—C8 | 1.430 (3) | C11—H11A | 0.98 |
C1—C6 | 1.387 (2) | C11—H11B | 0.98 |
C1—C2 | 1.388 (2) | C11—H11C | 0.98 |
C2—C3 | 1.387 (2) | C12—H12A | 0.98 |
C2—H2 | 0.95 | C12—H12B | 0.98 |
C3—C4 | 1.396 (3) | C12—H12C | 0.98 |
C3—H3 | 0.95 | C13—H13A | 0.98 |
C4—C5 | 1.390 (3) | C13—H13B | 0.98 |
C4—C7 | 1.510 (2) | C13—H13C | 0.98 |
O2—S1—O3 | 118.88 (10) | C4—C7—H7A | 109.5 |
O2A—S1—O3A | 122.5 (3) | C4—C7—H7C | 109.5 |
O2—S1—O1 | 109.98 (9) | H7A—C7—H7C | 109.5 |
O3—S1—O1 | 104.04 (9) | C4—C7—H7B | 109.5 |
O2A—S1—O1A | 99.9 (3) | H7A—C7—H7B | 109.5 |
O3A—S1—O1A | 109.7 (3) | H7C—C7—H7B | 109.5 |
O2A—S1—C1 | 110.1 (2) | O1A—C8—C9 | 109.3 (2) |
O2—S1—C1 | 109.48 (9) | O1—C8—C9 | 114.37 (15) |
O3—S1—C1 | 108.43 (8) | O1—C8—H8A | 108.7 |
O3A—S1—C1 | 108.6 (2) | C9—C8—H8A | 108.7 |
O1—S1—C1 | 105.10 (8) | O1—C8—H8B | 108.7 |
O1A—S1—C1 | 104.31 (19) | C9—C8—H8B | 108.7 |
C10—Si1—C11 | 108.03 (9) | H8A—C8—H8B | 107.6 |
C10—Si1—C12 | 107.80 (9) | O1A—C8—H8A' | 109.8 |
C11—Si1—C12 | 110.10 (10) | C9—C8—H8A' | 109.8 |
C10—Si1—C13 | 106.66 (8) | O1A—C8—H8B' | 109.8 |
C11—Si1—C13 | 112.01 (9) | C9—C8—H8B' | 109.8 |
C12—Si1—C13 | 112.01 (9) | H8A'—C8—H8B' | 108.3 |
C8—O1—S1 | 120.83 (12) | C10—C9—C8 | 178.9 (2) |
C8—O1A—S1 | 121.0 (3) | C9—C10—Si1 | 178.90 (17) |
C6—C1—C2 | 121.51 (15) | Si1—C11—H11A | 109.5 |
C6—C1—S1 | 119.66 (13) | Si1—C11—H11B | 109.5 |
C2—C1—S1 | 118.83 (12) | H11A—C11—H11B | 109.5 |
C3—C2—C1 | 118.87 (16) | Si1—C11—H11C | 109.5 |
C3—C2—H2 | 120.6 | H11A—C11—H11C | 109.5 |
C1—C2—H2 | 120.6 | H11B—C11—H11C | 109.5 |
C2—C3—C4 | 121.00 (17) | Si1—C12—H12A | 109.5 |
C2—C3—H3 | 119.5 | Si1—C12—H12B | 109.5 |
C4—C3—H3 | 119.5 | H12A—C12—H12B | 109.5 |
C5—C4—C3 | 118.69 (16) | Si1—C12—H12C | 109.5 |
C5—C4—C7 | 120.67 (17) | H12A—C12—H12C | 109.5 |
C3—C4—C7 | 120.64 (18) | H12B—C12—H12C | 109.5 |
C6—C5—C4 | 121.35 (16) | Si1—C13—H13A | 109.5 |
C6—C5—H5 | 119.3 | Si1—C13—H13B | 109.5 |
C4—C5—H5 | 119.3 | H13A—C13—H13B | 109.5 |
C1—C6—C5 | 118.58 (16) | Si1—C13—H13C | 109.5 |
C1—C6—H6 | 120.7 | H13A—C13—H13C | 109.5 |
C5—C6—H6 | 120.7 | H13B—C13—H13C | 109.5 |
O2—S1—O1—C8 | 36.57 (16) | O3—S1—C1—C2 | 40.01 (17) |
O3—S1—O1—C8 | 164.93 (14) | O3A—S1—C1—C2 | −10.1 (3) |
C1—S1—O1—C8 | −81.18 (15) | O1—S1—C1—C2 | −70.77 (15) |
O2A—S1—O1A—C8 | −163.6 (4) | O1A—S1—C1—C2 | −127.00 (18) |
O3A—S1—O1A—C8 | −33.6 (5) | C6—C1—C2—C3 | 0.0 (3) |
C1—S1—O1A—C8 | 82.5 (4) | S1—C1—C2—C3 | −179.91 (14) |
O2A—S1—C1—C6 | −53.4 (3) | C1—C2—C3—C4 | −0.1 (3) |
O2—S1—C1—C6 | −8.82 (17) | C2—C3—C4—C5 | −0.1 (3) |
O3—S1—C1—C6 | −139.95 (14) | C2—C3—C4—C7 | 179.61 (18) |
O3A—S1—C1—C6 | 170.0 (3) | C3—C4—C5—C6 | 0.3 (3) |
O1—S1—C1—C6 | 109.28 (14) | C7—C4—C5—C6 | −179.42 (17) |
O1A—S1—C1—C6 | 53.05 (19) | C2—C1—C6—C5 | 0.1 (3) |
O2A—S1—C1—C2 | 126.6 (3) | S1—C1—C6—C5 | −179.91 (13) |
O2—S1—C1—C2 | 171.14 (14) | C4—C5—C6—C1 | −0.3 (3) |
Experimental details
Crystal data | |
Chemical formula | C13H18O3SSi |
Mr | 282.42 |
Crystal system, space group | Monoclinic, P21/c |
Temperature (K) | 90 |
a, b, c (Å) | 10.6857 (4), 12.9413 (5), 11.8793 (4) |
β (°) | 113.471 (2) |
V (Å3) | 1506.83 (10) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 0.29 |
Crystal size (mm) | 0.33 × 0.18 × 0.17 |
Data collection | |
Diffractometer | Nonius KappaCCD diffractometer |
Absorption correction | Multi-scan (SCALEPACK; Otwinowski & Minor, 1997) |
Tmin, Tmax | 0.910, 0.952 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 9135, 4721, 3257 |
Rint | 0.041 |
(sin θ/λ)max (Å−1) | 0.722 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.045, 0.108, 1.03 |
No. of reflections | 4721 |
No. of parameters | 177 |
No. of restraints | 1 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.76, −0.54 |
Computer programs: COLLECT (Nonius, 2000), DENZO/SCALEPACK (Otwinowski & Minor, 1997), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), ORTEP-3 for Windows (Farrugia, 1997), WinGX (Farrugia, 1999).
Footnotes
‡Current address: Morales Consulting, LLC, 11474 Perkins Street, Carmel, IN 46032 USA.
Acknowledgements
The purchase of the diffractometer was made possible by grant No. LEQSF (1999–2000)-ENH-TR-13, administered by the Louisiana Board of Regents.
References
Farrugia, L. J. (1997). J. Appl. Cryst. 30, 565. CrossRef IUCr Journals Google Scholar
Farrugia, L. J. (1999). J. Appl. Cryst. 32, 837–838. CrossRef CAS IUCr Journals Google Scholar
Morales, A. (1995). PhD dissertation, Louisiana State University, Baton Rouge, USA. Google Scholar
Nonius (2000). COLLECT. Nonius BV, Delft, The Netherlands. Google Scholar
Otwinowski, Z. & Minor, W. (1997). Methods in Enzymology, Vol. 276, Macromolecular Crystallography, Part A, edited by C. W. Carter Jr & R. M. Sweet, pp. 307–326. New York: Academic Press. Google Scholar
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar
Tanabe, Y., Yamamoto, H., Yoshida, Y., Miyawaki, T. & Utsumi, N. (1995). Bull. Chem. Soc. Jpn, 68, 297. CrossRef Web of Science Google Scholar
Westmijze, H. & Vermeer, P. (1979). Synthesis, 5, 390–392. CrossRef Google Scholar
This is an open-access article distributed under the terms of the Creative Commons Attribution (CC-BY) Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are cited.
The title compound was prepared as an intermediate in the synthesis of 3-methyl substituted benz[f]indole derivatives (Morales, 1995). It has been described as a colorless liquid at room temperature (Tanabe et al., 1995; Westmijze & Vermeer, 1979). Our initial synthesis, by treating 3-trimethylsilylpropargyl alcohol with freshly powdered KOH and freshly recrystallized p-toluenesulfonyl chloride in ether at -50°C, also yielded the desired sulfonate as a liquid. However, after several recrystallizations from hexanes, suitable single crystals were obtained as colorless needles with melting point 43–44°C.
3-Trimethylsilyl-2-propynyl p-toluenesulfonate contains a p-toluenesulfonate group with the S(O)2OCH2 group partially (22.56 (13)%) disordered by rotation of ca 50° about the C–S bond. The disorder was modelled with constrained partial occupancy of two O3 and two H2 sites. The disordered O–C bond distances were restrained to be approximately equal (to within σ = 0.002 Å) to compensate for disorder of the C atom itself. The two partial S–O bonds average 1.574 (2) Å, and the four partial S═O bonds average 1.435 (1) Å.