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Acta Cryst. (2013). E69, o1612    [ doi:10.1107/S1600536813026822 ]

S,S'-Butane-1,4-diyl bis­(benzene­carbo­thio­ate)

D. Abe and Y. Sasanuma

Abstract top

The title compound, C18H18O2S2, which lies on an inversion center, adopts a gauche+-trans-trans-trans-gauche- (g+tttg-) conformation in the S-CH2-CH2-CH2-CH2-S bond sequence. In the crystal, mol­ecules are packed in a herringbone arrangement through inter­molecular C-H...[pi] inter­actions.

Comment top

In expectation of superior properties such as chemical and thermal resistance, we have investigated structures and properties of polythioesters ([–S(CH2)nSCOC6H4CO–]x, abbreviated as PnTS2), where n denotes the number of methylene units. Instead of the polymer itself, a small model compound corresponding to the repeating unit is often employed to elucidate conformational characteristics of the polymer; therefore, we have adopted oligomethylenedithiobenzoate (nDBS2). This paper describes synthesis and X-ray diffraction analysis of 4DBS2, a model compound of P4TS2.

The crystal structure of 2DBS2 was determined previously (Deguire & Brisse, 1988). In the 2DBS2 crystal, the S—CH2—CH2—S bonds lie in the gauche+ - trans - gauche- (g+tg-) conformation. Our molecular orbital calculations and NMR experiments (Abe & Sasanuma, 2012) showed that this conformation is significantly stable even in isolated and liquid states owing to the anti-parallel arrangement of S—CO dipole moments (the intramolecular dipole-dipole interaction).

Figure 1 shows the molecular structure of 4DBS2. The S—CH2—CH2—CH2—CH2—S part adopts the g+tttg- conformation, and the intramolecular dipole-dipole interaction similar to that of 2DBS2 may be formed; however, 2DBS2 and 4DBS2 have markedly different melting points and densities: 94 °C and 1.41 g cm-3 (2DBS2); 49 °C and 1.34 g cm-3 (4DBS2). These differences may be partly due to strengths of intermolecular interactions. In the 2DBS2 crystal, a number of intermolecular interactions such as CO···H—C, C—H···S, and C—H···π can be found. In contrast, the 4DBS2 crystal has only a few C—H···π interactions (Fig. 2).

Crystal structures of nDBS2 (n = 3, 5, 7, 9) were also reported (Leblanc & Brisse, 1992). The nDBS2 molecules adopt (t)n g+ conformations in the S—(CH2)n—S part. Interestingly, the nDBS2 molecules show clear odd-even effects in the alkyl conformation: g+(t)n-1 g- (n = even); (t)n g+ (n = odd).

Related literature top

For crystal structures and conformations of C6H5C( O)S(CH2)nSC(O)C6H5 (n = 2, 3, 5, 7, 9), see: for example, Deguire & Brisse (1988); Leblanc & Brisse (1992); Abe & Sasanuma (2012).

Experimental top

Benzoyl chloride (15.5 g, 0.11 mol) was added dropwise into 1,4-butanedithiol (6.1 g, 0.05 mol) and pyridine (8.7 g, 0.11 mol) kept at 0 °C, and then the mixture was stirred for 2 h. The crude product was diluted with diethyl ether (50 ml) and washed with water, 8% sodium hydrogen carbonate solution, and water. The organic layer was condensed, and white solid remained. The solid was recrystallized from ethanol to yield 4DBS2 (8.7 g, 53%).

The product was dissolved in chloroform in an open vessel. The vessel was placed in a larger one containing methanol, a poor solvent for 4DBS2, to facilitate precipitation of crystals by vapor diffusion of methanol into the chloroform solution.

Refinement top

All C—H hydrogen atoms were geometrically positioned with C—H = 0.95 and 0.99 Å for the aromatic and methylene groups, respectively, and refined as riding with Uiso(H) = 1.2Ueq(C).

Computing details top

Data collection: APEX2 (Bruker, 2007); cell refinement: SAINT (Bruker, 2007); data reduction: SAINT (Bruker, 2007); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008) and Mercury (Macrae et al., 2006); software used to prepare material for publication: SHELXTL (Sheldrick, 2008) and PLATON (Spek, 2009).

Figures top
[Figure 1] Fig. 1. Molecular structure of S,S'-butane-1,4-diyl dibenzothioate (4DBS2). Displacement ellipsoids are drawn at the 50% probability level.
[Figure 2] Fig. 2. Packing diagram of 4DBS2, viewed down the (a) a, (b) b, and (c) c axes. The dotted lines represent C—H···π interactions.
S,S'-Butane-1,4-diyl bis(benzenecarbothioate) top
Crystal data top
C18H18O2S2F(000) = 348
Mr = 330.44Dx = 1.337 Mg m3
Monoclinic, P21/cMelting point: 323 K
Hall symbol: -P 2ybcMo Kα radiation, λ = 0.71073 Å
a = 13.2230 (14) ÅCell parameters from 2016 reflections
b = 4.8903 (5) Åθ = 3.2–26.8°
c = 13.2638 (15) ŵ = 0.33 mm1
β = 106.897 (1)°T = 173 K
V = 820.67 (15) Å3Plate, colourless
Z = 20.30 × 0.30 × 0.05 mm
Data collection top
Bruker APEXII CCD
diffractometer
1845 independent reflections
Radiation source: fine-focus sealed tube1626 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.015
Detector resolution: 8.333 pixels mm-1θmax = 27.5°, θmin = 3.2°
φ and ω scansh = 1517
Absorption correction: multi-scan
(SADABS; Bruker, 2001)
k = 66
Tmin = 0.908, Tmax = 0.984l = 1317
4326 measured reflections
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.030Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.083H-atom parameters constrained
S = 1.05 w = 1/[σ2(Fo2) + (0.0413P)2 + 0.1965P]
where P = (Fo2 + 2Fc2)/3
1845 reflections(Δ/σ)max = 0.001
100 parametersΔρmax = 0.21 e Å3
0 restraintsΔρmin = 0.24 e Å3
Crystal data top
C18H18O2S2V = 820.67 (15) Å3
Mr = 330.44Z = 2
Monoclinic, P21/cMo Kα radiation
a = 13.2230 (14) ŵ = 0.33 mm1
b = 4.8903 (5) ÅT = 173 K
c = 13.2638 (15) Å0.30 × 0.30 × 0.05 mm
β = 106.897 (1)°
Data collection top
Bruker APEXII CCD
diffractometer
1845 independent reflections
Absorption correction: multi-scan
(SADABS; Bruker, 2001)
1626 reflections with I > 2σ(I)
Tmin = 0.908, Tmax = 0.984Rint = 0.015
4326 measured reflectionsθmax = 27.5°
Refinement top
R[F2 > 2σ(F2)] = 0.030H-atom parameters constrained
wR(F2) = 0.083Δρmax = 0.21 e Å3
S = 1.05Δρmin = 0.24 e Å3
1845 reflectionsAbsolute structure: ?
100 parametersAbsolute structure parameter: ?
0 restraintsRogers parameter: ?
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
xyzUiso*/Ueq
C10.70285 (9)0.4894 (3)0.15671 (9)0.0292 (3)
C20.62320 (10)0.6555 (3)0.09507 (10)0.0350 (3)
H20.60320.64020.02050.042*
C30.57314 (11)0.8429 (3)0.14248 (12)0.0422 (3)
H30.51880.95620.10030.051*
C40.60192 (12)0.8656 (3)0.25099 (12)0.0414 (3)
H40.56880.99820.28320.050*
C50.67851 (12)0.6964 (3)0.31244 (11)0.0427 (3)
H50.69680.70920.38700.051*
C60.72895 (11)0.5077 (3)0.26594 (10)0.0376 (3)
H60.78140.39050.30870.045*
C70.75788 (10)0.2993 (3)0.10215 (10)0.0311 (3)
C80.91038 (11)0.0700 (3)0.08957 (11)0.0377 (3)
H8A0.94950.23340.12440.045*
H8B0.84700.13420.03440.045*
C90.98021 (10)0.0896 (3)0.03740 (11)0.0382 (3)
H9A1.04150.16470.09240.046*
H9B0.93970.24520.00230.046*
O10.73074 (8)0.2677 (2)0.00745 (7)0.0429 (3)
S10.86863 (3)0.12549 (8)0.18584 (3)0.03886 (13)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
C10.0297 (6)0.0284 (6)0.0294 (6)0.0041 (5)0.0084 (5)0.0010 (5)
C20.0353 (7)0.0401 (7)0.0308 (6)0.0017 (5)0.0115 (5)0.0074 (5)
C30.0405 (7)0.0437 (8)0.0455 (8)0.0097 (6)0.0174 (6)0.0129 (6)
C40.0428 (8)0.0397 (7)0.0477 (8)0.0029 (6)0.0224 (6)0.0016 (6)
C50.0469 (8)0.0496 (9)0.0322 (7)0.0018 (7)0.0123 (6)0.0050 (6)
C60.0392 (7)0.0415 (8)0.0294 (6)0.0040 (6)0.0057 (5)0.0006 (6)
C70.0315 (6)0.0308 (6)0.0295 (6)0.0024 (5)0.0063 (5)0.0014 (5)
C80.0353 (7)0.0341 (7)0.0414 (7)0.0042 (5)0.0076 (6)0.0029 (6)
C90.0319 (7)0.0347 (7)0.0471 (8)0.0018 (5)0.0099 (6)0.0062 (6)
O10.0479 (6)0.0495 (6)0.0282 (5)0.0103 (5)0.0060 (4)0.0027 (4)
S10.0346 (2)0.0456 (2)0.0328 (2)0.00686 (14)0.00426 (14)0.00058 (14)
Geometric parameters (Å, º) top
C1—C61.3913 (17)C6—H60.9500
C1—C21.3916 (17)C7—O11.2117 (15)
C1—C71.4912 (17)C7—S11.7761 (13)
C2—C31.3841 (19)C8—C91.5204 (19)
C2—H20.9500C8—S11.8053 (14)
C3—C41.382 (2)C8—H8A0.9900
C3—H30.9500C8—H8B0.9900
C4—C51.377 (2)C9—C9i1.526 (3)
C4—H40.9500C9—H9A0.9900
C5—C61.384 (2)C9—H9B0.9900
C5—H50.9500
C6—C1—C2119.39 (12)C1—C6—H6120.0
C6—C1—C7122.48 (11)O1—C7—C1122.90 (12)
C2—C1—C7118.13 (11)O1—C7—S1121.94 (10)
C3—C2—C1119.98 (12)C1—C7—S1115.15 (9)
C3—C2—H2120.0C9—C8—S1113.65 (10)
C1—C2—H2120.0C9—C8—H8A108.8
C4—C3—C2120.21 (13)S1—C8—H8A108.8
C4—C3—H3119.9C9—C8—H8B108.8
C2—C3—H3119.9S1—C8—H8B108.8
C5—C4—C3120.04 (13)H8A—C8—H8B107.7
C5—C4—H4120.0C8—C9—C9i111.70 (14)
C3—C4—H4120.0C8—C9—H9A109.3
C4—C5—C6120.26 (13)C9i—C9—H9A109.3
C4—C5—H5119.9C8—C9—H9B109.3
C6—C5—H5119.9C9i—C9—H9B109.3
C5—C6—C1120.06 (13)H9A—C9—H9B107.9
C5—C6—H6120.0C7—S1—C8100.22 (6)
C6—C1—C2—C32.1 (2)C6—C1—C7—O1174.55 (14)
C7—C1—C2—C3177.31 (13)C2—C1—C7—O16.1 (2)
C1—C2—C3—C40.1 (2)C6—C1—C7—S16.66 (18)
C2—C3—C4—C51.8 (2)C2—C1—C7—S1172.72 (11)
C3—C4—C5—C61.7 (2)S1—C8—C9—C9i175.95 (10)
C4—C5—C6—C10.4 (2)O1—C7—S1—C80.26 (14)
C2—C1—C6—C52.3 (2)C1—C7—S1—C8179.07 (11)
C7—C1—C6—C5177.12 (14)C9—C8—S1—C783.52 (11)
Symmetry code: (i) x+2, y, z.
Hydrogen-bond geometry (Å, º) top
Cg1 is the centroid of the C1–C6 phenyl ring.
D—H···AD—HH···AD···AD—H···A
C4—H4···Cg1ii0.953.093.8810 (15)141
Symmetry code: (ii) x+1, y+1/2, z+1/2.
Hydrogen-bond geometry (Å, º) top
Cg1 is the centroid of the C1–C6 phenyl ring.
D—H···AD—HH···AD···AD—H···A
C4—H4···Cg1i0.953.093.8810 (15)141
Symmetry code: (i) x+1, y+1/2, z+1/2.
Acknowledgements top

We thank Dr Masu and Dr Yagishita of the Center for Analytical Instrumentation, Chiba University for helpful advice on X-ray diffraction measurements. This study was partly supported by a Grant-in-Aid for Scientific Research (C) (22550190) from the Japan Society for the Promotion of Science.

references
References top

Abe, D. & Sasanuma, Y. (2012). Polym. Chem. 3, 1576–1587.

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Leblanc, C. & Brisse, F. (1992). Can. J. Chem. 70, 900–909.

Macrae, C. F., Edgington, P. R., McCabe, P., Pidcock, E., Shields, G. P., Taylor, R., Towler, M. & van de Streek, J. (2006). J. Appl. Cryst. 39, 453–457.

Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122.

Spek, A. L. (2009). Acta Cryst. D65, 148–155.