4-Phenyl-1H-imidazole-2(3H)-thione

Anita M Owczarzak; Maciej Kubicki

doi:10.1107/S1600536812020090

. 2012 May 12;68(Pt 6):o1686. doi: 10.1107/S1600536812020090

4-Phenyl-1H-imidazole-2(3H)-thione

Anita M Owczarzak ^a, Maciej Kubicki ^a,^*

PMCID: PMC3379282 PMID: 22719480

Abstract

In the asymmetric unit of the title compound, C₉H₈N₂S, there are four symmetry-independent molecules (Z′ = 4). The geometrical features of these molecules are quite similar: in the normal probability plots the R ² correlation factors for bond lengths and angles are generally around 0.95. The twist angles between the imidazole and phenyl rings (which are planar within 3σ) range from 9.0 (6) to 13.1 (5)°. In the crystal, pairs of independent molecules are joined by linear N—H⋯S and weak C—H⋯S hydrogen bonds, forming infinite ribbons, of the type ∼ABABAB∼ and ∼CDCDCD∼, propagating along [110]. Second-order hydrogen-bonded R ₂ ²(8) rings are formed via interweaving infinite C ₂ ²(8) chains.

Related literature

For related structures, see: Conde et al. (1977 ▶); Raper et al. (1984 ▶). For general background to thioamides, see: Martindale (1982 ▶); Hussain et al. (1990 ▶); Buxeraud (1995 ▶). For normal probability plots, see: Abrahams & Keve (1971 ▶); International Tables for X-ray Crystallography (1974 ▶). For a description of the Cambridge Structural Database, see: Allen (2002 ▶). For graph-set notation, see: Bernstein et al. (1995 ▶); Etter et al. (1990 ▶).

Experimental

Crystal data

C₉H₈N₂S
M _r = 176.23
Monoclinic,
a = 11.7578 (5) Å
b = 11.8071 (5) Å
c = 25.1339 (18) Å
β = 91.858 (6)°
V = 3487.4 (3) Å³
Z = 16
Mo Kα radiation
μ = 0.31 mm⁻¹
T = 295 K
0.2 × 0.16 × 0.03 mm

Data collection

Agilent Xcalibur, Eos diffractometer
Absorption correction: multi-scan (CrysAlis PRO; Agilent, 2011 ▶) T _min = 0.928, T _max = 1.000
11682 measured reflections
5247 independent reflections
4168 reflections with I > 2σ(I)
R _int = 0.045

Refinement

R[F ² > 2σ(F ²)] = 0.065
wR(F ²) = 0.165
S = 1.08
5247 reflections
433 parameters
2 restraints
H-atom parameters constrained
Δρ_max = 0.80 e Å⁻³
Δρ_min = −0.27 e Å⁻³
Absolute structure: Flack (1983 ▶), 1447 Friedel pairs
Flack parameter: 0.01 (13)

Data collection: CrysAlis PRO (Agilent, 2011 ▶); cell refinement: CrysAlis PRO; data reduction: CrysAlis PRO; program(s) used to solve structure: SIR92 (Altomare et al., 1993 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: XP (Sheldrick, 2008 ▶) and Mercury (Macrae et al., 2008 ▶); software used to prepare material for publication: SHELXL97.

Supplementary Material

Crystal structure: contains datablock(s) I, global. DOI: 10.1107/S1600536812020090/nk2157sup1.cif

e-68-o1686-sup1.cif^{(34.7KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536812020090/nk2157Isup2.hkl

e-68-o1686-Isup2.hkl^{(251.8KB, hkl)}

Supplementary material file. DOI: 10.1107/S1600536812020090/nk2157Isup3.cml

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Table 1. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N1A—H1A⋯S2B	0.86	2.44	3.274 (6)	163
N3A—H3A⋯S2Bⁱ	0.86	2.50	3.350 (5)	172
C42A—H42A⋯S2Bⁱ	0.93	2.85	3.723 (9)	156
N1B—H1B⋯S2Aⁱⁱ	0.86	2.46	3.290 (5)	163
N3B—H3B⋯S2A	0.86	2.48	3.343 (5)	176
C42B—H42B⋯S2A	0.93	2.79	3.686 (9)	161
N1C—H1C⋯S2D	0.86	2.45	3.288 (5)	166
N3C—H3C⋯S2Dⁱⁱ	0.86	2.50	3.348 (5)	172
C42C—H42C⋯S2Dⁱⁱ	0.93	2.89	3.741 (8)	153
N1D—H1D⋯S2Cⁱ	0.86	2.43	3.271 (6)	166
N3D—H3D⋯S2C	0.86	2.50	3.353 (6)	172
C42D—H42D⋯S2C	0.93	2.85	3.766 (9)	169

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Symmetry codes: (i) Inline graphic ; (ii) .

supplementary crystallographic information

Comment

Heterocyclic thioamides are an important class of N, S-donor ligands, which display both hard and soft donor sites. They form a huge variety of coordination compounds and consequently have wide-ranging applications: for instance, as analytical reagents or metal corrosion inhibitors. They are also used as biologically active molecules (e.g. Hussain et al., 1990, and references therein). Among the anti-thyroidal agents most widely used for the treatment of Graves' disease are some derivatives of imidazole-2-thiol as N-methylimidazoline-2-thione (Methimazole) as well as other thioamides, e.g. 3-methyl-2-thioxo-4-imidazoline-1-carboxylate (Carbimazole) and propylthiouracil (Martindale, 1982, Buxeraud, 1995). Here we present the crystal structure of simple thioamide, 4-phenyl-1,3-dihydro-2H-imidazole-2-thione (1, Scheme 1), which turned out to crystallize with Z'=4.

The Cambridge Structural Database (Allen, 2002) contains only a handful of 1,3-dihydroimidazole-2-thione derivatives. These are mainly S-metal complexes and few simple organic derivatives, for instance 1,3-dihydro-2H-imidazole-2-thione hydrate (Raper et al., 1984) and 4-formyl-1,3-dihydro-2H-imidazole-2-thione (Conde et al., 1977).

The asymmetric part of the unit cell of 1 contains four independent molecules, Fig. 1 shows one of them. These molecules are similar; the results of the normal probability plot analysis (International Tables for X-ray Crystallography, 1974; Abrahams & Keve, 1971) for bond lengths and angles show that there are no systematical differences between the molecules, and the actual differences are only of statistical nature: R² correlation factors for bond lengths and angles are generally around 0.95.

Overall conformation of the molecules can be described here by the dihedral angles between two almost perfectly planar (within 3 s.u.'s) rings, imidazole and phenyl. These angles are relatively small - thanks partially at least to the lack of the sterical hindrance - and range from 9.0 (6)° for molecule B to 13.1 (5)° for molecule C. The bond length and angles are typical, with the C—S bond distance confirming its double-bond character, the mean value of this length is 1.694 (4) Å.

In the crystal structure the pairs of molecules A—B and C—D create identical but independent motifs. They are joined into infinite ribbons (along [110]) by means of relatively short and linear N—H···S hydrogen bonds (Table 1, Fig. 2), and additionally by weaker, secondary C—H···S hydrogen bonds. Using graph-set notation (Etter, et al., 1990, Bernstein et al., 1995), one can identify the second-order rings R²₂(8) which are made by interweaving C²₂(8) chains. These almost independent ribbons combine together to make the overall three-dimensional structure (Fig. 3).

Experimental

The title compound was prepared by adding hydrochloric acid to acetonitrile solution of 4-phenyl-imidazole-2-thiol in molar ratio 1:1. After a few minutes colourless, thin crystals of 1, suitable for single-crystal X-ray analysis appeared and were filtered off.