1-{(E)-[4-(4-Meth­oxy­phen­yl)butan-2-yl­idene]amino}-3-methyl­thio­urea

Ming-Yueh Tan; Thahira Begum S A Ravoof; Mohamed Ibrahim Mohamed Tahir; Karen A Crouse; Edward R T Tiekink

doi:10.1107/S160053681201611X

. 2012 Apr 21;68(Pt 5):o1461–o1462. doi: 10.1107/S160053681201611X

1-{(E)-[4-(4-Methoxyphenyl)butan-2-ylidene]amino}-3-methylthiourea

Ming-Yueh Tan ^a, Thahira Begum S A Ravoof ^a, Mohamed Ibrahim Mohamed Tahir ^a, Karen A Crouse ^a,^‡, Edward R T Tiekink ^b,^*

PMCID: PMC3344575 PMID: 22590337

Abstract

Two independent molecules comprise the asymmetric unit of the title compound, C₁₃H₁₉N₃OS, which differ in the conformations of the residues linking the thiourea and the terminal benzene ring, as manifested in the C_m—C_m—C_a—C_a torsion angles [78.03 (16) and −93.64 (16)°, respectively; m = methylene and a = aromatic]. The dihedral angles [84.40 (4) and 88.28 (5)°] formed between the thiourea residue and the benzene ring indicate an almost orthogonal relationship. In each thiourea residue, the N—H hydrogen atoms are anti, and the terminal N—H hydrogen atom forms an intramolecular N—H⋯N hydrogen bond with the imine-N atom. In each case, the conformation about the imine C=N double bond [1.2812 (17) and 1.2801 (17) Å] is E. In the crystal, the molecules are connected by N—H⋯S hydrogen bonds and these are connected into four molecule aggregates via N—H⋯O hydrogen bonds, which are assembled into a two-dimensional array parallel to (011) via C—H⋯π and π–π interactions [ring centroid–centroid distance = 3.8344 (9) Å].

Related literature

For background to chalcone thiosemicarbazides, see: Zhang et al. (2011 ▶). For background to hydrazinecarbodithioates, see: Khoo et al. (2005 ▶); Chan et al. (2008 ▶); Ravoof et al. (2010 ▶). For related syntheses, see: Tian et al. (1997 ▶); Tarafder et al. (2002 ▶).

Experimental

Crystal data

C₁₃H₁₉N₃OS
M _r = 265.37
Triclinic,
a = 9.6344 (4) Å
b = 11.1759 (6) Å
c = 13.4619 (8) Å
α = 80.324 (5)°
β = 87.103 (4)°
γ = 76.360 (4)°
V = 1388.48 (13) Å³
Z = 4
Cu Kα radiation
μ = 2.01 mm⁻¹
T = 100 K
0.41 × 0.23 × 0.14 mm

Data collection

Oxford Diffraction Xcaliber Eos Gemini diffractometer
Absorption correction: multi-scan (CrysAlis PRO; Agilent, 2011 ▶) T _min = 0.51, T _max = 0.75
18287 measured reflections
5312 independent reflections
4995 reflections with I > 2σ(I)
R _int = 0.022

Refinement

R[F ² > 2σ(F ²)] = 0.037
wR(F ²) = 0.101
S = 1.01
5312 reflections
343 parameters
4 restraints
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.29 e Å⁻³
Δρ_min = −0.41 e Å⁻³

Data collection: CrysAlis PRO (Agilent, 2011 ▶); 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: ORTEP-3 (Farrugia, 1997 ▶), DIAMOND (Brandenburg, 2006 ▶) and Qmol (Gans & Shalloway, 2001 ▶); software used to prepare material for publication: publCIF (Westrip, 2010 ▶).

Supplementary Material

Crystal structure: contains datablock(s) global, I. DOI: 10.1107/S160053681201611X/qm2063sup1.cif

e-68-o1461-sup1.cif^{(25.3KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S160053681201611X/qm2063Isup2.hkl

e-68-o1461-Isup2.hkl^{(254.8KB, hkl)}

Supplementary material file. DOI: 10.1107/S160053681201611X/qm2063Isup3.cml

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

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

Cg1 is the centroid of the C7–C12 ring.

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N1—H1n⋯N3	0.87 (1)	2.15 (1)	2.5931 (16)	111 (1)
N4—H4n⋯N6	0.87 (1)	2.13 (1)	2.5818 (17)	112 (1)
N2—H2n⋯S2	0.87 (1)	2.70 (1)	3.5686 (11)	176 (1)
N5—H5n⋯S1	0.88 (1)	2.65 (1)	3.5276 (11)	178 (1)
N1—H1n⋯O2ⁱ	0.87 (1)	2.51 (2)	3.0979 (16)	125 (1)
C1—H1B⋯Cg1ⁱⁱ	0.98	2.94	3.5930 (17)	125

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

Acknowledgments

Support for the project came from Universiti Putra Malaysia (UPM) under their research University Grant Scheme (RUGS Nos. 9199834 and 9174000) and from the Malaysian Ministry of Science, Technology and Innovation (grant No. 09–02-04–0752-EA001). MYT wishes to thank UPM for a Graduate Research Fellowship award. We also thank the Ministry of Higher Education (Malaysia) for funding structural studies through the High-Impact Research scheme (UM.C/HIR/MOHE/SC/12).

supplementary crystallographic information

Comment

To initiate comparative studies between hydrazinecarbothioamide Schiff bases (Zhang et al., 2011) and hydrazinecarbodithioate derivatives synthesized in our laboratory in on-going investigations (Khoo et al. 2005; Chan et al. 2008; Ravoof et al., 2010), the title compound was synthesized and characterized crystallographically.

Two independent molecules comprise the asymmetric unit of (I), Fig. 1. As evidenced from the overlay diagram, Fig. 2, while the thiourea residues are super-imposable, minor conformational differences are seen in the links between these and the terminal benzene rings. Significant differences are noted between the chemically equivalent C5—C6—C7—C8 and C18—C19—C20—C21 torsion angles of 78.03 (16) and -93.64 (16)°, respectively. The dihedral angles formed between the thiourea residues (N1,C1,S1,N2 and N4,C15,S2,N5) and the benzene rings are 84.40 (4) and 88.28 (5)°, respectively. In each case, the methoxy group is co-planar with the benzene ring to which it is connected as seen in the values of the C13—O1—C10—C9 and C26—O2—C23—C22 torsion angles of 175.41 (12) and -5.62 (19)°, respectively. In each thiourea residue, the N—H hydrogen atoms are anti, and the terminal N—H hydrogen atom forms an intramolecular N—H···N hydrogen bond with the imine-N atom, Table 1. The conformation about the imine C═N double bond [N3═C3 = 1.2812 (17) Å and N6═C16 = 1.2801 (17) Å] is E in each case.

As indicated in Fig. 1, the independent molecules are connected by N—H···S hydrogen bonds leading to an eight-membered {···HNCS}₂ synthon, Table 1. These are connected into four molecule aggregates via N—H···O hydrogen bonds, Table 1. The four molecule aggregates are assembled into a two-dimensional array parallel to (011) via C—H···π, Table 1, and π–π interactions occurring between the benzene rings [ring centroid(C7–C12)···centroid(C20–C25)ⁱ distance = 3.8344 (9) Å with a tilt angle = 2.08 (7)° for symmetry operation i: 1 + x, -1 + y, 1 + z). Layers stack without significant intermolecular interactions between them, Fig. 4.

Experimental

The title compound was synthesized following established literature procedures (Tian et al. 1997; Tarafder et al. 2002). To 4-methyl-3-thiosemicarbazide (1.05 g, 10 mmol) dissolved in hot absolute ethanol (25 ml) was added an equimolar amount of 4-(4-methoxyphenyl)butan-2-one (1.70 ml) also in hot absolute ethanol (20 ml). The mixture was stirred for about half an hour at ~340 K and then cooled to room temperature. The Schiff base precipitated was filtered and dried in vacuo over anhydrous silica gel. Colourless crystals were obtained after one week from a 1:1 mixture of 2-propanol and absolute ethanol. Yield 76%, M.pt. 356 K.