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Ethane-1,2-diyl S,S′-bis(thioacetate), H3CC(O)SCH2CH2SC(O)CH3 or C6H10O2S2, forms centrosymmetric molecules in the solid state and the molecular structure determined by X-ray crystallography is in good agreement with that obtained by density functional geometry optimization. The planarity of the O=C—S—C fragment, which is also found in structures of other thioacetates, is attributed to a strong np(S)–π*(C—O) orbital interaction.
Supporting information
CCDC reference: 162819
Key indicators
- Single-crystal X-ray study
- T = 183 K
- Mean (C-C) = 0.002 Å
- R factor = 0.040
- wR factor = 0.118
- Data-to-parameter ratio = 20.8
checkCIF results
No syntax errors found
ADDSYM reports no extra symmetry
Alert Level B:
CRYSS_02 Alert B The value of _exptl_crystal_size_max is > 1.0
Maximum crystal size given = 1.260
Alert Level C:
RINTA_01 Alert C The value of Rint is greater than 0.10
Rint given 0.101
0 Alert Level A = Potentially serious problem
1 Alert Level B = Potential problem
1 Alert Level C = Please check
Data collection: SMART (Bruker, 1998); cell refinement: SAINT (Bruker, 1998); data reduction: SAINT; program(s) used to solve structure: SIR92 (Altomare, 1994); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEPII (Johnson, 1976).
Ethanedithiol Diacetate
top
Crystal data top
C6H10O2S2 | F(000) = 188 |
Mr = 178.26 | Dx = 1.385 Mg m−3 |
Monoclinic, P21/c | Mo Kα radiation, λ = 0.71069 Å |
a = 5.1677 (6) Å | Cell parameters from 2083 reflections |
b = 7.1944 (9) Å | θ = 3.3–28.3° |
c = 11.6869 (15) Å | µ = 0.56 mm−1 |
β = 100.449 (2)° | T = 183 K |
V = 427.30 (9) Å3 | Block, colourless |
Z = 2 | 1.26 × 0.37 × 0.30 mm |
Data collection top
Smart CCD diffractometer | 968 reflections with I > 2σ(I) |
Radiation source: sealed tube | Rint = 0.101 |
Graphite monochromator | θmax = 28.3°, θmin = 3.3° |
θ and ϕ scans | h = −6→6 |
2629 measured reflections | k = −9→5 |
1042 independent reflections | l = −15→15 |
Refinement top
Refinement on F2 | Secondary atom site location: structure-invariant direct methods |
Least-squares matrix: full | Hydrogen site location: difference Fourier map |
R[F2 > 2σ(F2)] = 0.040 | H-atom parameters constrained |
wR(F2) = 0.118 | w = 1/[σ2(Fo2) + (0.0565P)2 + 0.0812P] where P = (Fo2 + 2Fc2)/3 |
S = 1.10 | (Δ/σ)max < 0.001 |
1042 reflections | Δρmax = 0.45 e Å−3 |
50 parameters | Δρmin = −0.25 e Å−3 |
0 restraints | Extinction correction: SHELXL97, Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
Primary atom site location: structure-invariant direct methods | Extinction coefficient: 0.19 (2) |
Crystal data top
C6H10O2S2 | V = 427.30 (9) Å3 |
Mr = 178.26 | Z = 2 |
Monoclinic, P21/c | Mo Kα radiation |
a = 5.1677 (6) Å | µ = 0.56 mm−1 |
b = 7.1944 (9) Å | T = 183 K |
c = 11.6869 (15) Å | 1.26 × 0.37 × 0.30 mm |
β = 100.449 (2)° | |
Data collection top
Smart CCD diffractometer | 968 reflections with I > 2σ(I) |
2629 measured reflections | Rint = 0.101 |
1042 independent reflections | |
Refinement top
R[F2 > 2σ(F2)] = 0.040 | 0 restraints |
wR(F2) = 0.118 | H-atom parameters constrained |
S = 1.10 | Δρmax = 0.45 e Å−3 |
1042 reflections | Δρmin = −0.25 e Å−3 |
50 parameters | |
Special details top
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 (Å2) top | x | y | z | Uiso*/Ueq | Occ. (<1) |
S1 | 0.27383 (8) | 0.23911 (5) | 0.49337 (3) | 0.0326 (2) | |
O1 | 0.4897 (3) | 0.22872 (17) | 0.30668 (12) | 0.0403 (4) | |
C1 | 0.5368 (3) | 0.4064 (2) | 0.52802 (11) | 0.0287 (4) | |
H1A | 0.6863 | 0.3604 | 0.4991 | 0.034 (3)* | |
H1B | 0.5743 | 0.4122 | 0.6113 | 0.034 (3)* | |
C2 | 0.3155 (3) | 0.1687 (2) | 0.35255 (11) | 0.0274 (3) | |
C3 | 0.1178 (3) | 0.0283 (2) | 0.29814 (13) | 0.0362 (4) | |
H3A | −0.0034 | 0.0008 | 0.3514 | 0.060 (8)* | 0.45 |
H3B | 0.2085 | −0.0859 | 0.2823 | 0.060 (8)* | 0.45 |
H3C | 0.0187 | 0.0779 | 0.2251 | 0.060 (8)* | 0.45 |
H3D | 0.1527 | −0.0056 | 0.2211 | 0.061 (7)* | 0.55 |
H3E | −0.0593 | 0.0811 | 0.2902 | 0.061 (7)* | 0.55 |
H3F | 0.1305 | −0.0827 | 0.3475 | 0.061 (7)* | 0.55 |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
S1 | 0.0404 (3) | 0.0322 (3) | 0.0286 (3) | −0.00492 (14) | 0.01547 (18) | −0.00315 (12) |
O1 | 0.0504 (8) | 0.0418 (7) | 0.0338 (7) | −0.0111 (5) | 0.0212 (5) | −0.0088 (4) |
C1 | 0.0341 (7) | 0.0296 (8) | 0.0221 (6) | 0.0020 (6) | 0.0046 (5) | −0.0001 (5) |
C2 | 0.0344 (7) | 0.0238 (7) | 0.0250 (6) | 0.0035 (6) | 0.0080 (5) | −0.0004 (5) |
C3 | 0.0405 (8) | 0.0284 (8) | 0.0394 (8) | −0.0021 (6) | 0.0065 (6) | −0.0061 (6) |
Geometric parameters (Å, º) top
S1—C2 | 1.7720 (13) | C1—C1i | 1.516 (3) |
S1—C1 | 1.8056 (15) | C2—C3 | 1.494 (2) |
O1—C2 | 1.2080 (18) | | |
| | | |
C2—S1—C1 | 100.69 (7) | O1—C2—S1 | 122.40 (12) |
C1i—C1—S1 | 112.06 (12) | C3—C2—S1 | 113.56 (10) |
O1—C2—C3 | 124.04 (13) | | |
| | | |
C2—S1—C1—C1i | 80.29 (14) | C1—S1—C2—C3 | −179.10 (11) |
C1—S1—C2—O1 | 1.53 (15) | | |
Symmetry code: (i) −x+1, −y+1, −z+1. |
Experimental details
Crystal data |
Chemical formula | C6H10O2S2 |
Mr | 178.26 |
Crystal system, space group | Monoclinic, P21/c |
Temperature (K) | 183 |
a, b, c (Å) | 5.1677 (6), 7.1944 (9), 11.6869 (15) |
β (°) | 100.449 (2) |
V (Å3) | 427.30 (9) |
Z | 2 |
Radiation type | Mo Kα |
µ (mm−1) | 0.56 |
Crystal size (mm) | 1.26 × 0.37 × 0.30 |
|
Data collection |
Diffractometer | Smart CCD diffractometer |
Absorption correction | – |
No. of measured, independent and observed [I > 2σ(I)] reflections | 2629, 1042, 968 |
Rint | 0.101 |
(sin θ/λ)max (Å−1) | 0.666 |
|
Refinement |
R[F2 > 2σ(F2)], wR(F2), S | 0.040, 0.118, 1.10 |
No. of reflections | 1042 |
No. of parameters | 50 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.45, −0.25 |
Comparison of selected structural parameters (Å, °) from the molecular
structures of (I) in the solid state (XRD) and from density functional (DF)
geometry optimization [B3LYP/6-311+G(2d,p)] (Frisch et al., 1995) top | XRD | DF |
S1—C1 | 1.806 (2) | 1.833 |
S1—C2 | 1.772 (1) | 1.798 |
C1—C1a | 1.516 (3) | 1.522 |
C2—C3 | 1.494 (2) | 1.511 |
O1—C2 | 1.208 (2) | 1.206 |
| | |
C2—S1—-C1 | 100.7 (1) | 100.2 |
C1a—C1–S1 | 112.1 (1) | 112.3 |
O1—C2—C3 | 124.0 (1) | 123.5 |
O1—C2—S1 | 122.4 (1) | 123.1 |
C3—C2—S1 | 113.6 (1) | 113.5 |
| | |
C2—S1—C1—C1a | 80.3 (1) | 82.0 |
C1—S1—C2—O1 | 1.5 (2) | 0.2 |
C1—S1—C2—C3 | -179.1 (1) | -179.7 |
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Thioesters are very important acetylating agents in biochemical processes as well as in many chemical transformations (Nicolaou, 1977; Hirama et al., 1979; Zheng et al., 1999). We obtained ethanedithiol diacetate, H3CC(O)SCH2CH2SC(O)CH3, (I), as a by-product in the synthesis of ethanedithiol monoacetate, HSCH2CH2SC(O)CH3, (II), according to literature procedure (Wiesler et al., 1996). Crystals of (I) precipitated at 278 K from its solution in (II). They were washed with cold petroleum ether and identified and checked for purity by 1H NMR (Bauer et al., 1965). One of them was selected for single-crystal X-ray diffraction.
The molecular structure of (I) as found in the solid state is depicted in Fig. 1. Table 1 shows selected structural parameters from the XRD experiment in comparison with those obtained by a density functional (DF) geometry optimization. Apart from the two S—C and the C2—C3 distances, the DF structural parameters agree quite well with the experimental ones, regardless that the former refer to an isolated molecule and the latter do not (see Table 1). We attribute the differences in the bond distances mentioned to the chosen level of theory and the agreement among most of the above values to the absence of significant intermolecular interactions in the crystal. The structural parameters of (I) agree well with those found for other compounds exhibiting an S-acetyl moiety (Evans et al., 1999; Divjakovic et al., 1992; Huber et al., 1984; Kiel et al., 1974; Mackay et al., 1992; Mattes et al., 1977, 1983; Shefter et al., 1969). This implies the S-acetyl fragment to be a relatively rigid structural unit. An analysis of the bonding situation in terms of natural bond orbitals (Reed at al., 1988) reveals a strong delocalization of electron density within the O═C—S fragment. The p-type lone pair of the S atom interacts strongly with the π*(C—O) orbital (see Fig. 2a) and the p-type lone pair of the O-atom interacts strongly with the σ*(S—C) orbital (see Fig. 2 b). The np(S)–π*(C—O) interaction explains very well the nearly planar conformation of the C1—S1—C2—O1 moiety.