3-Ethyl-4-[(E)-2-methyl­benzyl­idene­amino]-1H-1,2,4-triazole-5(4H)-thione

Shan-Heng Wang; Ying-Li Xu; Pei-Jin Xie; Wen-Long Wang; Shang Shan

doi:10.1107/S1600536808019867

. 2008 Jul 5;64(Pt 8):o1400. doi: 10.1107/S1600536808019867

3-Ethyl-4-[(E)-2-methylbenzylideneamino]-1H-1,2,4-triazole-5(4H)-thione

Shan-Heng Wang ^a, Ying-Li Xu ^a, Pei-Jin Xie ^a, Wen-Long Wang ^a, Shang Shan ^a,^*

PMCID: PMC2962033 PMID: 21203120

Abstract

Crystals of the title compound, C₁₂H₁₄N₄S, were obtained from a condensation reaction of 4-amino-3-ethyl-1H-1,2,4-triazole-5(4H)-thione and 2-methylbenzaldehyde. In the molecular structure, there is a short N=C double bond [1.255 (2) Å], and the benzene and triazole rings are located on opposite sites of this double bond. The two rings are approximately parallel to each other, the dihedral angle being 1.75 (11)°. A partially overlapped arrangement is observed between the nearly parallel triazole and benzene rings of adjacent molecules; the perpendicular distance of the centroid of the triazole ring from the benzene ring is 3.482 Å, indicating the existence of π–π stacking in the crystal structure.

Related literature

For general background, see: Okabe et al. (1993 ▶); Shan et al. (2003 ▶). For related structures, see: Fan et al. (2008 ▶); Shan et al. (2004 ▶, 2008 ▶). For the thickness of the aromatic ring, see: Cotton & Wilkinson (1972 ▶).

Experimental

Crystal data

C₁₂H₁₄N₄S
M _r = 246.33
Monoclinic,
a = 7.7255 (15) Å
b = 15.411 (3) Å
c = 10.685 (2) Å
β = 101.032 (12)°
V = 1248.7 (4) Å³
Z = 4
Mo Kα radiation
μ = 0.24 mm⁻¹
T = 295 (2) K
0.32 × 0.28 × 0.24 mm

Data collection

Rigaku R-AXIS RAPID IP diffractometer
Absorption correction: none
12354 measured reflections
2860 independent reflections
1777 reflections with I > 2σ(I)
R _int = 0.061

Refinement

R[F ² > 2σ(F ²)] = 0.047
wR(F ²) = 0.120
S = 1.03
2860 reflections
156 parameters
H-atom parameters constrained
Δρ_max = 0.18 e Å⁻³
Δρ_min = −0.21 e Å⁻³

Data collection: PROCESS-AUTO (Rigaku, 1998 ▶); cell refinement: PROCESS-AUTO; data reduction: CrystalStructure (Rigaku/MSC, 2002 ▶); program(s) used to solve structure: SIR92 (Altomare et al., 1993 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997 ▶); software used to prepare material for publication: WinGX (Farrugia, 1999 ▶).

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536808019867/xu2434sup1.cif

e-64-o1400-sup1.cif^{(15.7KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536808019867/xu2434Isup2.hkl

e-64-o1400-Isup2.hkl^{(137.5KB, 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—H1N⋯Sⁱ	0.93	2.37	3.2899 (19)	169
C5—H5⋯S	0.93	2.54	3.239 (2)	132

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Symmetry code: (i) Inline graphic .

Acknowledgments

The work was supported by the Natural Science Foundation of Zhejiang Province, China (grant No. M203027).

supplementary crystallographic information

Comment

Since some hydrazone derivatives have shown to be potential DNA damaging and mutagenic agents (Okabe et al., 1993), a series of new hydrazone derivatives have been prepared in our laboratory (Shan et al., 2003). As part of the ongoing investigation, the title compound has recently been prepared and its crystal structure is reported here.

The molecular structure of the title compound is shown in Fig. 1. The N4—C5 bond distance of 1.255 (2) Å is significantly shorter than C═N bond distances found in related hydrazone structures, i.g. 1.295 (2) Å in (E)-3-methoxyacetophenone 4-nitrophenylhydrazone (Fan et al., 2008), 1.2977 (18) Å in (E)-2-furyl methyl ketone 2,4-dinitrophenylhydrazone (Shan et al., 2008) and 1.293 (2) Å in benzylideneacetone 2,4-dinitrophenylhydrazone (Shan et al., 2004). The benzene and triazole rings are located on the opposite sites of the N4═C5 double bond, the molecule assumes an E-configuration.

The molecule displays a nearly coplanar structure except for methyl H atoms, the maximum atomic deviation for non-H atom is 0.1457 (18) Å (N4), and the atomic deviations for ehtyl C3 and C4 atoms are 0.011 (2) and 0.037 (2) Å, respectively. The methine group is linked to the triazolethione via intramolecular C5—H5···S hydrogen bonding (Fig. 1 and Table 1). The adjacent molecules are linked together with N1—H1N···S hydrogen bonding (Table 1), forming the centro-symmetric supramolecular dimer.

A partially overlapped arrangement is observed between the nearly parallel triazole ring and benzene ring of the adjacent molecule [dihedral angle 1.75 (11)°] (Fig. 2), the perpendicular distance of the centroid of the N3-triazole ring on the C6ⁱⁱ-benzene ring is 3.482 Å and the perpendicular distance of the centroid of the C6ⁱⁱ-benzene ring on the N3-triazole ring is 3.504 Å [symmetry code: (ii) 1 + x, y, z], these are significantly shorter than the van der Waals thickness of the aromatic ring (3.7 Å; Cotton & Wilkinson, 1972) and suggest the existence of π-π stacking in the crystal structure.

Experimental

4-Amino-3-ethyl-1H-1,2,4-triazole-5(4H)-thione (0.29 g, 2 mmol) was dissolved in ethanol (25 ml), then acetic acid (1 ml) was added slowly to the ethanol solution with stirring. The solution was heated at 333 K for several minutes until the solution cleared. 2-Methylbenzaldehyde (0.24 g, 2 mmol) was then dropped slowly into the solution, and the mixture was refluxed for 5 h. After the solution had cooled to room temperature yellow powder crystals appeared. The powder crystals were separated and washed with water three times. Single crystals of the title compound were obtained by recrystallization from an absolute ethanol solution.