1,3-Di-n-butyl­thio­urea

Andrzej Okuniewski; Agnieszka Dąbrowska; Jaroslaw Chojnacki

doi:10.1107/S1600536811009743

. 2011 Mar 19;67(Pt 4):o925. doi: 10.1107/S1600536811009743

1,3-Di-n-butylthiourea

Andrzej Okuniewski ^a, Agnieszka Dąbrowska ^a, Jaroslaw Chojnacki ^a,^*

PMCID: PMC3099899 PMID: 21754195

Abstract

In the title compound, C₉H₂₀N₂S, the n-butyl groups are in syn and anti positions in relation to the C=S bond. In the crystal, two molecules are connected by two N—H⋯S=C hydrogen bonds into a centrosymmetric dimer. Another N—H⋯S=C hydrogen bond links the dimers, forming layers with a hydrophilic interior and a hydrophobic exterior, which spread across the (100) plane. Interlacing of the external butyl groups combines these layers into a three-dimensional structure.

Related literature

For structures of N,N′-di-n-butylthiourea complexes with mercury and copper, see: Ahmad et al. (2009 ▶); Khan et al. (2007 ▶); Warda (1998 ▶). For structures of other symmetrically substituted thiourea derivatives, see: Custelcean et al. (2005 ▶); Djurdjevic et al. (2007 ▶); Ramnathan et al. (1995 ▶). For synthetic methods, see: Herr et al. (2000 ▶); Kricheldorf (1970 ▶); Ranu et al. (2003 ▶).

Experimental

Crystal data

C₉H₂₀N₂S
M _r = 188.33
Monoclinic,
a = 12.6395 (6) Å
b = 10.0836 (6) Å
c = 9.0128 (5) Å
β = 90.476 (5)°
V = 1148.66 (11) Å³
Z = 4
Mo Kα radiation
μ = 0.24 mm⁻¹
T = 120 K
0.48 × 0.29 × 0.09 mm

Data collection

Oxford Diffraction Xcalibur Sapphire2 diffractometer
Absorption correction: analytical [CrysAlis PRO (Oxford Diffraction, 2010 ▶; based on Clark & Reid, 1995 ▶)] T _min = 0.94, T _max = 0.978
5268 measured reflections
2247 independent reflections
1656 reflections with I > 2σ(I)
R _int = 0.038

Refinement

R[F ² > 2σ(F ²)] = 0.046
wR(F ²) = 0.116
S = 0.97
2247 reflections
119 parameters
2 restraints
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.45 e Å⁻³
Δρ_min = −0.27 e Å⁻³

Data collection: CrysAlis PRO (Oxford Diffraction, 2010 ▶); cell refinement: CrysAlis PRO; data reduction: CrysAlis PRO; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: OLEX2 (Dolomanov et al., 2009 ▶) and Mercury (Macrae et al., 2008 ▶); software used to prepare material for publication: WinGX (Farrugia, 1999 ▶) and PLATON (Spek, 2009 ▶).

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536811009743/si2344sup1.cif

e-67-0o925-sup1.cif^{(16KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536811009743/si2344Isup2.hkl

e-67-0o925-Isup2.hkl^{(108.2KB, hkl)}

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
N1—H1⋯S1ⁱ	0.84 (1)	2.58 (1)	3.3943 (17)	164 (2)
N2—H2⋯S1ⁱⁱ	0.85 (1)	2.52 (1)	3.3319 (17)	159 (2)

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

Acknowledgments

Financial support from the Polish Ministry of Science and Higher Education to AO (project No. N N204 543339) is gratefully acknowledged.

supplementary crystallographic information

Comment

N,N'-Di-n-butylthiourea, S═C(NHⁿBu)₂, is commonly used as a vulcanization accelerator in rubber processing, as an insecticide, as an additive to fertilizers, as a corrosion inhibitor, as an agent for metal treatments, etc.

No X-ray structure of pure compound was known until now, although the Cambridge Structural Database contains data on its mercury(ii) (Ahmad et al., 2009), copper(i) (Khan et al., 2007) and copper(ii) (Warda, 1998) complexes. In their structures one of the n-butyl groups of N,N'-di-n-butylthiourea molecule is in the syn position and the second is in the anti position in relation to the C═S bond. The same conformation is present in the title compound and this allows the formation of the centrosymmetric dimers (see Fig. 1) held together by two N1—H···S1ⁱ═C1ⁱ hydrogen bonds [symmetry code: (i): –x, –y + 1, –z + 2]. Namely, motif R₂²(8) is formed. Furthermore, there are additional N2—H···S1ⁱⁱ═C1ⁱⁱ hydrogen bonds [symmetry code: (ii): x, –y + 3/2, z–1/2], which link the dimers to form the two-dimensional layers (see Fig. 2). Hydrogen bonds parameters are summarized in Tab. 1. Hydrocarbon chains pointing outside the layer interact with those from the neighbouring ones by van der Waals forces to form a three-dimensional crystal structure. The same packing patterns can be found in syn,anti isomers of other analogues: N,N'-diethylthiourea and N,N'-diisopropylthiourea (Ramnathan et al., 1995) and similar in N,N'-bis(prop-2-en-1-yl)thiourea (Djurdjevic et al., 2007). The case of N,N'-di-tert-butylthiourea is different, because the molecules adopt syn,syn conformation (Custelcean et al., 2005).

There are several synthetic methods to obtain symmetrical thioureas. For example condensation of amine hydrochlorides with potassium thiocyanate (Herr et al., 2000) or reaction of N-silylated amines with carbon disulfide (Kricheldorf, 1970). The very simple, quick and solvent-free method was proposed by Ranu et al. (2003) incorporating addition of amines to carbon disulfide on the surface of alumina under microwave irradition. In the case of n-butylamine, mixture was irradiated for 2 minutes and the yield was 89%.

We found that good quality crystals can be obtained by recrystallization from ethyl acetate or acetylacetone (2,4-pentanedione).

Experimental

0.25 g (1.33 mmol) of commercially available N,N'-di-n-butylthiourea was dissolved in 2 ml of freshly distilled acetylacetone. The mixture was filtered and the filtrate was left for crystallization in a refrigerator. After several days well formed, colorless crystals were collected. Melting point: 335 - 337 K.