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

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, P 2₁ /n

• a = 7.7255 (15) Å

• b = 15.411 (3) Å

• c = 10.685 (2) Å

• β = 101.032 (12)°

• V = 1248.7 (4) ų

• 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[F² > 2σ(F²)] = 0.047

• wR(F²) = 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

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N1—H1N⋯S^i	0.93	2.37	3.2899 (19)	169
C5—H5⋯S	0.93	2.54	3.239 (2)	132
Symmetry code: (i) -x+2, -y, -z+1.

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).

Supporting information

S1. 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.

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).

S2. 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.

S3. Refinement

H atom bonded to N atom was located in a difference Fourier map and refined as riding in its as-found relative position with U_iso(H) = 1.5U_eq(N). Methyl H atoms were placed in calculated positions with C—H = 0.96 Å and the torsion angles were refined to fit the electron density, U_iso(H) = 1.5U_eq(C). Other H atoms were placed in calculated positions with C—H = 0.93 (aromatic) and 0.97 Å (methylene), and refined in riding mode with U_iso(H) = 1.2U_eq(C).

Computing details

Data collection: PROCESS-AUTO (Rigaku, 1998); cell refinement: PROCESS-AUTO (Rigaku, 1998); 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).

Figures

	Fig. 1. The molecular structure of the title compound with 40% probability displacement ellipsoids for non-H atoms. Dashed line indicates hydrogen bonding.
	Fig. 2. A diagram showing π-π stacking between aromatic rings [symmetry code: (ii) 1 + x, y, z].

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

Crystal data

C12H14N4S	F(000) = 520
Mr = 246.33	Dx = 1.310 Mg m^−3
Monoclinic, P21/n	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2yn	Cell parameters from 4278 reflections
a = 7.7255 (15) Å	θ = 2.8–24.5°
b = 15.411 (3) Å	µ = 0.24 mm^−1
c = 10.685 (2) Å	T = 295 K
β = 101.032 (12)°	Prism, yellow
V = 1248.7 (4) Å^3	0.32 × 0.28 × 0.24 mm
Z = 4

Data collection

Rigaku R-AXIS RAPID IP diffractometer	1777 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.061
Graphite monochromator	θmax = 27.6°, θmin = 2.6°
Detector resolution: 10.00 pixels mm^-1	h = −9→10
ω scans	k = −20→16
12354 measured reflections	l = −13→13
2860 independent reflections

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.047	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.121	H-atom parameters constrained
S = 1.03	w = 1/[σ^2(Fo^2) + (0.0463P)^2 + 0.2633P] where P = (Fo^2 + 2Fc^2)/3
2860 reflections	(Δ/σ)max < 0.001
156 parameters	Δρmax = 0.18 e Å^−3
0 restraints	Δρmin = −0.21 e Å^−3

Special details

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes.

Refinement. Refinement of F² against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F², conventional R-factors R are based on F, with F set to zero for negative F². The threshold expression of F² > σ(F²) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F² are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
S	0.70986 (7)	−0.00644 (3)	0.39484 (6)	0.0542 (2)
N1	0.9437 (2)	0.12184 (11)	0.47565 (18)	0.0453 (5)
H1N	1.0320	0.0826	0.5095	0.068*
N2	0.9697 (2)	0.20996 (11)	0.47450 (18)	0.0449 (5)
N3	0.70093 (19)	0.17368 (10)	0.37970 (15)	0.0356 (4)
N4	0.5343 (2)	0.19429 (11)	0.31007 (17)	0.0424 (5)
C1	0.7829 (3)	0.09601 (13)	0.4175 (2)	0.0388 (5)
C2	0.8200 (3)	0.24045 (13)	0.4152 (2)	0.0387 (5)
C3	0.7750 (3)	0.33278 (13)	0.3886 (2)	0.0486 (6)
H3A	0.6760	0.3482	0.4279	0.058*
H3B	0.7391	0.3408	0.2973	0.058*
C4	0.9288 (3)	0.39305 (14)	0.4383 (3)	0.0627 (7)
H4A	0.9624	0.3868	0.5291	0.094*
H4B	0.8942	0.4520	0.4180	0.094*
H4C	1.0270	0.3784	0.3991	0.094*
C5	0.4118 (3)	0.13985 (14)	0.3022 (2)	0.0443 (6)
H5	0.4330	0.0856	0.3402	0.053*
C6	0.2346 (3)	0.16241 (14)	0.2325 (2)	0.0412 (5)
C7	0.1079 (3)	0.09783 (15)	0.1958 (2)	0.0484 (6)
C8	−0.0589 (3)	0.1238 (2)	0.1313 (2)	0.0631 (7)
H8	−0.1454	0.0820	0.1064	0.076*
C9	−0.0980 (3)	0.2091 (2)	0.1040 (3)	0.0688 (8)
H9	−0.2105	0.2245	0.0618	0.083*
C10	0.0279 (3)	0.27235 (18)	0.1386 (2)	0.0621 (7)
H10	0.0019	0.3302	0.1182	0.074*
C11	0.1935 (3)	0.24901 (15)	0.2038 (2)	0.0502 (6)
H11	0.2783	0.2916	0.2288	0.060*
C12	0.1452 (3)	0.00349 (16)	0.2212 (3)	0.0700 (8)
H12A	0.2246	−0.0169	0.1687	0.105*
H12B	0.0369	−0.0287	0.2019	0.105*
H12C	0.1978	−0.0045	0.3094	0.105*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
S	0.0374 (3)	0.0352 (3)	0.0829 (5)	−0.0002 (2)	−0.0066 (3)	−0.0011 (3)
N1	0.0309 (9)	0.0361 (9)	0.0641 (12)	0.0015 (7)	−0.0027 (8)	0.0017 (9)
N2	0.0339 (9)	0.0374 (10)	0.0598 (12)	−0.0031 (7)	−0.0003 (8)	0.0001 (9)
N3	0.0273 (8)	0.0326 (8)	0.0443 (10)	0.0001 (7)	0.0000 (7)	0.0000 (7)
N4	0.0305 (9)	0.0416 (10)	0.0507 (11)	0.0016 (8)	−0.0031 (8)	0.0013 (8)
C1	0.0304 (10)	0.0400 (11)	0.0444 (12)	0.0025 (8)	0.0028 (9)	0.0000 (9)
C2	0.0333 (11)	0.0368 (11)	0.0449 (12)	−0.0042 (8)	0.0042 (9)	−0.0016 (9)
C3	0.0468 (12)	0.0380 (12)	0.0586 (14)	−0.0010 (10)	0.0044 (11)	0.0004 (11)
C4	0.0662 (16)	0.0398 (13)	0.0762 (18)	−0.0139 (11)	−0.0015 (14)	0.0007 (12)
C5	0.0336 (11)	0.0393 (11)	0.0568 (14)	0.0026 (9)	0.0011 (10)	0.0017 (10)
C6	0.0297 (10)	0.0505 (12)	0.0423 (12)	0.0011 (9)	0.0042 (9)	0.0005 (10)
C7	0.0349 (11)	0.0594 (15)	0.0493 (14)	−0.0029 (10)	0.0042 (10)	−0.0021 (11)
C8	0.0336 (12)	0.090 (2)	0.0625 (17)	−0.0080 (13)	0.0014 (12)	−0.0046 (15)
C9	0.0353 (13)	0.104 (2)	0.0637 (17)	0.0157 (15)	−0.0003 (12)	0.0089 (16)
C10	0.0513 (14)	0.0725 (17)	0.0615 (16)	0.0261 (13)	0.0086 (13)	0.0125 (14)
C11	0.0413 (12)	0.0545 (14)	0.0538 (14)	0.0100 (10)	0.0069 (11)	0.0033 (11)
C12	0.0550 (15)	0.0620 (17)	0.089 (2)	−0.0124 (13)	0.0029 (14)	−0.0045 (15)

Geometric parameters (Å, º)

S—C1	1.679 (2)	C5—C6	1.469 (3)
N1—C1	1.338 (2)	C5—H5	0.9300
N1—N2	1.373 (2)	C6—C11	1.393 (3)
N1—H1N	0.9314	C6—C7	1.399 (3)
N2—C2	1.296 (2)	C7—C8	1.398 (3)
N3—C1	1.378 (2)	C7—C12	1.497 (3)
N3—C2	1.384 (2)	C8—C9	1.369 (4)
N3—N4	1.395 (2)	C8—H8	0.9300
N4—C5	1.255 (2)	C9—C10	1.376 (4)
C2—C3	1.479 (3)	C9—H9	0.9300
C3—C4	1.522 (3)	C10—C11	1.382 (3)
C3—H3A	0.9700	C10—H10	0.9300
C3—H3B	0.9700	C11—H11	0.9300
C4—H4A	0.9600	C12—H12A	0.9600
C4—H4B	0.9600	C12—H12B	0.9600
C4—H4C	0.9600	C12—H12C	0.9600
C1—N1—N2	114.48 (16)	N4—C5—H5	120.2
C1—N1—H1N	122.2	C6—C5—H5	120.2
N2—N1—H1N	123.2	C11—C6—C7	120.14 (19)
C2—N2—N1	104.15 (15)	C11—C6—C5	119.32 (19)
C1—N3—C2	108.74 (15)	C7—C6—C5	120.53 (19)
C1—N3—N4	132.83 (15)	C8—C7—C6	117.7 (2)
C2—N3—N4	118.30 (15)	C8—C7—C12	119.6 (2)
C5—N4—N3	119.38 (17)	C6—C7—C12	122.71 (19)
N1—C1—N3	102.21 (16)	C9—C8—C7	121.7 (2)
N1—C1—S	127.10 (15)	C9—C8—H8	119.2
N3—C1—S	130.66 (14)	C7—C8—H8	119.2
N2—C2—N3	110.40 (17)	C8—C9—C10	120.5 (2)
N2—C2—C3	126.69 (18)	C8—C9—H9	119.8
N3—C2—C3	122.91 (17)	C10—C9—H9	119.8
C2—C3—C4	112.41 (18)	C9—C10—C11	119.3 (2)
C2—C3—H3A	109.1	C9—C10—H10	120.3
C4—C3—H3A	109.1	C11—C10—H10	120.3
C2—C3—H3B	109.1	C10—C11—C6	120.7 (2)
C4—C3—H3B	109.1	C10—C11—H11	119.6
H3A—C3—H3B	107.9	C6—C11—H11	119.6
C3—C4—H4A	109.5	C7—C12—H12A	109.5
C3—C4—H4B	109.5	C7—C12—H12B	109.5
H4A—C4—H4B	109.5	H12A—C12—H12B	109.5
C3—C4—H4C	109.5	C7—C12—H12C	109.5
H4A—C4—H4C	109.5	H12A—C12—H12C	109.5
H4B—C4—H4C	109.5	H12B—C12—H12C	109.5
N4—C5—C6	119.54 (19)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1N···S^i	0.93	2.37	3.2899 (19)	169
C5—H5···S	0.93	2.54	3.239 (2)	132

Symmetry code: (i) −x+2, −y, −z+1.