Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536807047599/bt2521sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S1600536807047599/bt2521Isup2.hkl |
CCDC reference: 667280
Key indicators
- Single-crystal X-ray study
- T = 200 K
- Mean (C-C)= 0.002 Å
- R factor = 0.041
- wR factor = 0.118
- Data-to-parameter ratio = 18.2
checkCIF/PLATON results
No syntax errors found No errors found in this datablock
The title compound was prepared according to a modified procedure as previously described by Plater et al. (2002).
A recent analysis, including an identification of the acceptor lone pair and the considerable strength of hydrogen bonds to sulfur acceptors, has been published by Wennmohs et al. (2003) who use the NBO method as the localization algorithm. The metric aspects of hydrogen bonding to C═S acceptors have been reviewed by Allen et al. (1997). The structure of a related, dimer-forming oxo analogue has recently been reported by Ramos Silva et al. (2007). A related N—H···S═C-linked, but non-centrosymmetric, dimer has been found for a morpholine-dithione derivative (Linden et al., 2001).
For related literature, see: Voet et al. (1999).
The title compound, C8H11NOS, was prepared upon the reaction of thiophosgene with 3,3'-dimethylpyrrole in diethylether under ice cooling, subsequent heat up to room temperature, and quenching of the reaction products with methanol after 30 minutes' reaction time. Subsequent workup with column chromatography on silica with chloroform as the mobile phase yielded pale yellow crystals. Sublimation of the raw product yielded colourless crystals of the title compound.
All H atoms were located in a difference map. C-bonded H atoms were refined as riding on their parent atoms. One common isotropic displacement parameter for the methyl-H atoms was refined, individual U values were refined for the methylidine-H and the N-bonded H. The positional parameters of the N-bonded H atom were refined freely.
The title compound, C8H11NOS, was prepared as the parent acid of a potentially chelating ligand.
The flat molecules of the title compound combine to centrosymmetric dimers by means of two hydrogen bonds of the N—H···S=C type (Figure 2). The dimeric structure reflects the nature of the hydrogen-bond acceptor orbital at the sulfur atom: one of the sulfur lone pairs – the HOMO of the molecule which, in terms of an NBO analysis, exhibits S(3p) character – is the best suited acceptor orbital in terms of hydrogen-bond strength. This orbital lies in the molecular plane, perpendicular to the C=S axis. Almost flat dimers thus have to be expected with H···S=C angles close to 90°. Accordingly, the dimers are flat. The C=S···H angle, however, is unusually obtuse (127°) compared with the expectation values [approx. 90° from frontier-orbital considerations, approx. 100° as the experimental mean value, compare with Allen et al. (1997)]. The reason is the double-donor-double-acceptor situation in the dimer. The smaller the acceptor angle, the closer the repulsive N—H···H—N contact. The experimentally determined 127° angle is thus a compromise (note a somewhat different view on the dimer by counting the intramolecular H···S contact despite the small N—H···S angle of 108° as a hydrogen bond as well, ending up with bifurcated bonds). Though the acceptor angle is unusually large for a sulfur compound, it is much smaller than the acceptor angle in related oxo compounds due to the different acceptor-orbital situation in the oxo case (Ramos Silva et al., 2007).
The packing of the dimers is determined by van-der-Waals forces. Figure 3 shows the stacking of the flat molecules. The normal distance of the molecular planes is 3.352 Å and thus resembles the typical 3.4-Å distance of π-stacked nucleic bases. However, the typical partial overlap of the DNA azaaromates (Voet et al., 1999) is not observed in (I). Instead, a close perpendicular contact is found for a single ring atom only (C4). Figure 4 shows this situation in a normal view. The figure suggests that, possibly, the methyl groups prohibit a more extended π-stacking-type contact.
The title compound was prepared according to a modified procedure as previously described by Plater et al. (2002).
A recent analysis, including an identification of the acceptor lone pair and the considerable strength of hydrogen bonds to sulfur acceptors, has been published by Wennmohs et al. (2003) who use the NBO method as the localization algorithm. The metric aspects of hydrogen bonding to C═S acceptors have been reviewed by Allen et al. (1997). The structure of a related, dimer-forming oxo analogue has recently been reported by Ramos Silva et al. (2007). A related N—H···S═C-linked, but non-centrosymmetric, dimer has been found for a morpholine-dithione derivative (Linden et al., 2001).
For related literature, see: Voet et al. (1999).
Data collection: COLLECT (Nonius, 2004); cell refinement: SCALEPACK (Otwinowski & Minor, 1997); data reduction: SCALEPACK and DENZO (Otwinowski & Minor, 1997); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEPIII (Burnett & Johnson, 1996); software used to prepare material for publication: SHELXL97 (Sheldrick, 1997).
C8H11NOS | F(000) = 360 |
Mr = 169.24 | Dx = 1.298 Mg m−3 |
Monoclinic, P21/c | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -P 2ybc | Cell parameters from 15311 reflections |
a = 7.4399 (2) Å | θ = 3.1–27.5° |
b = 13.9413 (5) Å | µ = 0.32 mm−1 |
c = 8.4118 (2) Å | T = 200 K |
β = 96.928 (2)° | Block, colourless |
V = 866.12 (4) Å3 | 0.25 × 0.21 × 0.18 mm |
Z = 4 |
Nonius KappaCCD diffractometer | 1724 reflections with I > 2σ(I) |
Radiation source: rotating anode | Rint = 0.015 |
MONTEL, graded multilayered X-ray optics monochromator | θmax = 27.5°, θmin = 3.8° |
CCD; rotation images; thick slices scans | h = −9→9 |
3806 measured reflections | k = −18→17 |
1980 independent reflections | l = −10→10 |
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)] = 0.041 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.118 | Only H-atom displacement parameters refined |
S = 1.10 | w = 1/[σ2(Fo2) + (0.0618P)2 + 0.2807P] where P = (Fo2 + 2Fc2)/3 |
1980 reflections | (Δ/σ)max < 0.001 |
109 parameters | Δρmax = 0.33 e Å−3 |
0 restraints | Δρmin = −0.29 e Å−3 |
C8H11NOS | V = 866.12 (4) Å3 |
Mr = 169.24 | Z = 4 |
Monoclinic, P21/c | Mo Kα radiation |
a = 7.4399 (2) Å | µ = 0.32 mm−1 |
b = 13.9413 (5) Å | T = 200 K |
c = 8.4118 (2) Å | 0.25 × 0.21 × 0.18 mm |
β = 96.928 (2)° |
Nonius KappaCCD diffractometer | 1724 reflections with I > 2σ(I) |
3806 measured reflections | Rint = 0.015 |
1980 independent reflections |
R[F2 > 2σ(F2)] = 0.041 | 0 restraints |
wR(F2) = 0.118 | Only H-atom displacement parameters refined |
S = 1.10 | Δρmax = 0.33 e Å−3 |
1980 reflections | Δρmin = −0.29 e Å−3 |
109 parameters |
Refinement. The refU entry for H-atom refinement summarizes: individual U for the single C-bonded H, one common U for the methyl-Hs. All H-atom parameters refined for the N-bonded H. |
x | y | z | Uiso*/Ueq | ||
S | 0.45898 (6) | 0.33388 (3) | 0.54208 (6) | 0.04671 (18) | |
O | 0.68081 (15) | 0.20285 (8) | 0.44864 (14) | 0.0402 (3) | |
N | 0.73885 (19) | 0.45490 (10) | 0.39510 (17) | 0.0379 (3) | |
H7 | 0.658 (3) | 0.4848 (15) | 0.435 (3) | 0.048 (6)* | |
C1 | 0.7642 (2) | 0.35680 (11) | 0.39575 (18) | 0.0324 (3) | |
C2 | 0.9182 (2) | 0.33903 (10) | 0.31993 (18) | 0.0329 (3) | |
C3 | 0.9836 (2) | 0.42870 (11) | 0.27372 (19) | 0.0367 (3) | |
C4 | 0.8693 (2) | 0.49803 (12) | 0.3232 (2) | 0.0408 (4) | |
H4 | 0.8810 | 0.5652 | 0.3087 | 0.054 (6)* | |
C5 | 1.0016 (2) | 0.24411 (12) | 0.2895 (2) | 0.0405 (4) | |
H51 | 0.9072 | 0.1997 | 0.2434 | 0.097 (3)* | |
H52 | 1.0608 | 0.2179 | 0.3906 | 0.097 (3)* | |
H53 | 1.0915 | 0.2525 | 0.2145 | 0.097 (3)* | |
C6 | 1.1463 (2) | 0.44705 (14) | 0.1889 (2) | 0.0482 (4) | |
H61 | 1.1655 | 0.5163 | 0.1810 | 0.097 (3)* | |
H62 | 1.1266 | 0.4193 | 0.0812 | 0.097 (3)* | |
H63 | 1.2531 | 0.4175 | 0.2491 | 0.097 (3)* | |
C7 | 0.6373 (2) | 0.29558 (11) | 0.46148 (18) | 0.0331 (3) | |
C8 | 0.5583 (2) | 0.13178 (13) | 0.4981 (2) | 0.0457 (4) | |
H81 | 0.4432 | 0.1349 | 0.4281 | 0.097 (3)* | |
H82 | 0.5369 | 0.1442 | 0.6089 | 0.097 (3)* | |
H83 | 0.6114 | 0.0678 | 0.4909 | 0.097 (3)* |
U11 | U22 | U33 | U12 | U13 | U23 | |
S | 0.0442 (3) | 0.0386 (3) | 0.0618 (3) | 0.00333 (17) | 0.0247 (2) | 0.00071 (18) |
O | 0.0395 (6) | 0.0279 (6) | 0.0560 (7) | −0.0006 (4) | 0.0165 (5) | 0.0023 (5) |
N | 0.0409 (7) | 0.0272 (7) | 0.0481 (8) | 0.0021 (5) | 0.0153 (6) | −0.0026 (6) |
C1 | 0.0348 (7) | 0.0260 (7) | 0.0367 (7) | 0.0016 (6) | 0.0062 (6) | −0.0008 (5) |
C2 | 0.0349 (7) | 0.0299 (7) | 0.0340 (7) | 0.0018 (6) | 0.0047 (6) | −0.0011 (6) |
C3 | 0.0380 (8) | 0.0330 (8) | 0.0403 (8) | −0.0015 (6) | 0.0093 (6) | 0.0009 (6) |
C4 | 0.0453 (9) | 0.0274 (7) | 0.0516 (9) | −0.0024 (6) | 0.0140 (7) | 0.0018 (6) |
C5 | 0.0396 (8) | 0.0332 (8) | 0.0500 (9) | 0.0067 (6) | 0.0104 (7) | −0.0020 (7) |
C6 | 0.0451 (9) | 0.0466 (10) | 0.0563 (10) | −0.0021 (8) | 0.0202 (8) | 0.0057 (8) |
C7 | 0.0342 (7) | 0.0312 (7) | 0.0341 (7) | 0.0008 (6) | 0.0043 (6) | −0.0005 (6) |
C8 | 0.0456 (9) | 0.0325 (8) | 0.0618 (11) | −0.0076 (7) | 0.0176 (8) | 0.0040 (8) |
S—C7 | 1.6498 (16) | C3—C6 | 1.499 (2) |
O—C7 | 1.3403 (19) | C4—H4 | 0.9500 |
O—C8 | 1.441 (2) | C5—H51 | 0.9800 |
N—C4 | 1.346 (2) | C5—H52 | 0.9800 |
N—C1 | 1.381 (2) | C5—H53 | 0.9800 |
N—H7 | 0.84 (2) | C6—H61 | 0.9800 |
C1—C2 | 1.399 (2) | C6—H62 | 0.9800 |
C1—C7 | 1.432 (2) | C6—H63 | 0.9800 |
C2—C3 | 1.413 (2) | C8—H81 | 0.9800 |
C2—C5 | 1.497 (2) | C8—H82 | 0.9800 |
C3—C4 | 1.385 (2) | C8—H83 | 0.9800 |
C7—O—C8 | 118.20 (13) | C2—C5—H53 | 109.5 |
C4—N—C1 | 109.80 (14) | H51—C5—H53 | 109.5 |
C4—N—H7 | 123.6 (14) | H52—C5—H53 | 109.5 |
C1—N—H7 | 126.6 (14) | C3—C6—H61 | 109.5 |
N—C1—C2 | 107.02 (13) | C3—C6—H62 | 109.5 |
N—C1—C7 | 119.71 (14) | H61—C6—H62 | 109.5 |
C2—C1—C7 | 133.22 (14) | C3—C6—H63 | 109.5 |
C1—C2—C3 | 107.27 (13) | H61—C6—H63 | 109.5 |
C1—C2—C5 | 127.87 (14) | H62—C6—H63 | 109.5 |
C3—C2—C5 | 124.85 (15) | O—C7—C1 | 111.52 (13) |
C4—C3—C2 | 106.88 (14) | O—C7—S | 124.00 (12) |
C4—C3—C6 | 125.78 (15) | C1—C7—S | 124.48 (12) |
C2—C3—C6 | 127.34 (15) | O—C8—H81 | 109.5 |
N—C4—C3 | 109.02 (14) | O—C8—H82 | 109.5 |
N—C4—H4 | 125.5 | H81—C8—H82 | 109.5 |
C3—C4—H4 | 125.5 | O—C8—H83 | 109.5 |
C2—C5—H51 | 109.5 | H81—C8—H83 | 109.5 |
C2—C5—H52 | 109.5 | H82—C8—H83 | 109.5 |
H51—C5—H52 | 109.5 |
D—H···A | D—H | H···A | D···A | D—H···A |
N—H7···Si | 0.84 (2) | 2.69 (2) | 3.3622 (15) | 138.7 (18) |
Symmetry code: (i) −x+1, −y+1, −z+1. |
Experimental details
Crystal data | |
Chemical formula | C8H11NOS |
Mr | 169.24 |
Crystal system, space group | Monoclinic, P21/c |
Temperature (K) | 200 |
a, b, c (Å) | 7.4399 (2), 13.9413 (5), 8.4118 (2) |
β (°) | 96.928 (2) |
V (Å3) | 866.12 (4) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 0.32 |
Crystal size (mm) | 0.25 × 0.21 × 0.18 |
Data collection | |
Diffractometer | Nonius KappaCCD |
Absorption correction | – |
No. of measured, independent and observed [I > 2σ(I)] reflections | 3806, 1980, 1724 |
Rint | 0.015 |
(sin θ/λ)max (Å−1) | 0.649 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.041, 0.118, 1.10 |
No. of reflections | 1980 |
No. of parameters | 109 |
H-atom treatment | Only H-atom displacement parameters refined |
Δρmax, Δρmin (e Å−3) | 0.33, −0.29 |
Computer programs: COLLECT (Nonius, 2004), SCALEPACK (Otwinowski & Minor, 1997), SCALEPACK and DENZO (Otwinowski & Minor, 1997), SHELXS97 (Sheldrick, 1997), SHELXL97 (Sheldrick, 1997), ORTEPIII (Burnett & Johnson, 1996).
D—H···A | D—H | H···A | D···A | D—H···A |
N—H7···Si | 0.84 (2) | 2.69 (2) | 3.3622 (15) | 138.7 (18) |
Symmetry code: (i) −x+1, −y+1, −z+1. |
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The title compound, C8H11NOS, was prepared as the parent acid of a potentially chelating ligand.
The flat molecules of the title compound combine to centrosymmetric dimers by means of two hydrogen bonds of the N—H···S=C type (Figure 2). The dimeric structure reflects the nature of the hydrogen-bond acceptor orbital at the sulfur atom: one of the sulfur lone pairs – the HOMO of the molecule which, in terms of an NBO analysis, exhibits S(3p) character – is the best suited acceptor orbital in terms of hydrogen-bond strength. This orbital lies in the molecular plane, perpendicular to the C=S axis. Almost flat dimers thus have to be expected with H···S=C angles close to 90°. Accordingly, the dimers are flat. The C=S···H angle, however, is unusually obtuse (127°) compared with the expectation values [approx. 90° from frontier-orbital considerations, approx. 100° as the experimental mean value, compare with Allen et al. (1997)]. The reason is the double-donor-double-acceptor situation in the dimer. The smaller the acceptor angle, the closer the repulsive N—H···H—N contact. The experimentally determined 127° angle is thus a compromise (note a somewhat different view on the dimer by counting the intramolecular H···S contact despite the small N—H···S angle of 108° as a hydrogen bond as well, ending up with bifurcated bonds). Though the acceptor angle is unusually large for a sulfur compound, it is much smaller than the acceptor angle in related oxo compounds due to the different acceptor-orbital situation in the oxo case (Ramos Silva et al., 2007).
The packing of the dimers is determined by van-der-Waals forces. Figure 3 shows the stacking of the flat molecules. The normal distance of the molecular planes is 3.352 Å and thus resembles the typical 3.4-Å distance of π-stacked nucleic bases. However, the typical partial overlap of the DNA azaaromates (Voet et al., 1999) is not observed in (I). Instead, a close perpendicular contact is found for a single ring atom only (C4). Figure 4 shows this situation in a normal view. The figure suggests that, possibly, the methyl groups prohibit a more extended π-stacking-type contact.