2-(4-Bromo­phenyl)-5-methyl-2,3-di­hydro-4H-1,2,4-triazol-3-one

In the title compound, C₉H₈BrN₃O, the dihedral angle between the phenyl and triazole rings is 8.93 (14)°. In the crystal, the mol­ecules exist as centrosymmetrically related N—H...O hydrogen-bonded dimers.

Key indicators

• Single-crystal X-ray study
• T = 160 K
• Mean [sigma](C-C) = 0.003 Å
• R factor = 0.038
• wR factor = 0.092
• Data-to-parameter ratio = 20.4

checkCIF results

No syntax errors found

ADDSYM reports no extra symmetry

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S1. Comment

1,2,4-Triazole derivatives are found to be associated with diverse pharmacological activities, such as analgesic, anti-asthmatic, diuretic, antifungal, antibacterial, pesticidal and anti-inflammatory activities (Thamotharan et al., 2003, and references therein). Triazole derivatives have been synthesized as possible anticonvulsants, antidepressants, tranquilizers and plant-growth regulators (Bradbury & Rivett, 1991; Hirota et al., 1991; Walser et al., 1991). In view of this, the crystal structure determination of the title triazole derivative, (I), has been carried out in order to elucidate the molecular conformation.

The bond lengths and angles in (I) are unexceptional and comparable with those reported for related structures (Chen et al., 1998; Wang et al., 1998; Thamotharan et al., 2003). The phenyl ring is oriented at an angle of 8.93 (14)° with respect to the plane of the triazole ring, compared with a value of 30.63 (9)° reported for our previous chloro derivative of triazole (Thamotharan et al., 2003). In the crystal, centrosymmetrically related molecules form dimeric pairs through N—H···O intermolecular hydrogen bonds and have a graph set motif of R²₂(8) (Bernstein et al., 1995).

S2. Experimental

The title compound was prepared by refluxing 2-(4-bromophenyl)-5-methyl-1,3,4-oxadiazolin-2-one with formamide. The solid obtained, (I), was crystallized from benzene (m.p. 503 K).

S3. Refinement

The position of the amine H atom was determined from a difference Fourier map and refined freely along with its isotropic displacement parameter. The methyl H atoms were constrained to an ideal geometry (C—H = 0.98 Å), with U_iso(H) = 1.5U_eq(C), but were allowed to rotate freely about the parent C—C bond. All remaining H atoms were placed in geometrically idealized positions (C—H = 0.95–0.99 Å) and constrained to ride on their parent atoms, with U_iso(H) = 1.2U_eq(C).

Computing details

Data collection: COLLECT (Nonius, 2000); cell refinement: DENZO–SMN (Otwinowski & Minor, 1997); data reduction: DENZO–SMN and SCALEPACK (Otwinowski & Minor, 1997); program(s) used to solve structure: SIR92 (Altomare et al., 1994); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 (Version 1.07; Farrugia, 1997); software used to prepare material for publication: SHELXL97 and PLATON (Spek, 2002).

Figures

	Fig. 1. View of the asymmetric unit of the title compound, showing the atom-labelling scheme. Displacement ellipsoids are drawn at the 50% probability level. H atoms are represented by circles of arbitrary radii.
	Fig. 2. Packing diagram of the unit cell.

2-(4-Bromophenyl)-5-methyl-2,3-dihydro-4H-1,2,4-triazol-3-one

Crystal data

C9H8BrN3O	F(000) = 504
Mr = 254.09	Dx = 1.825 Mg m^−3
Monoclinic, P21/c	Melting point: 503 K
Hall symbol: -P 2ybc	Mo Kα radiation, λ = 0.71073 Å
a = 4.0333 (1) Å	Cell parameters from 26468 reflections
b = 10.8622 (2) Å	θ = 2.0–30.0°
c = 21.1608 (4) Å	µ = 4.41 mm^−1
β = 93.9045 (7)°	T = 160 K
V = 924.91 (3) Å^3	Needle, colourless
Z = 4	0.25 × 0.08 × 0.05 mm

Data collection

Nonius KappaCCD diffractometer	2710 independent reflections
Radiation source: Nonius FR590 sealed tube generator	2239 reflections with I > 2σ(I)
Horizontally mounted graphite crystal monochromator	Rint = 0.087
Detector resolution: 9 pixels mm^-1	θmax = 30.0°, θmin = 2.1°
ϕ and ω scans with κ offsets	h = −5→5
Absorption correction: multi-scan (SORTAV; Blessing, 1995)	k = −15→15
Tmin = 0.550, Tmax = 0.818	l = −29→29
22923 measured reflections

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: geom & difmap
R[F^2 > 2σ(F^2)] = 0.038	H atoms treated by a mixture of independent and constrained refinement
wR(F^2) = 0.092	w = 1/[σ^2(Fo^2) + (0.0309P)^2 + 0.9447P] where P = (Fo^2 + 2Fc^2)/3
S = 1.07	(Δ/σ)max = 0.001
2710 reflections	Δρmax = 0.35 e Å^−3
133 parameters	Δρmin = −0.75 e Å^−3
0 restraints	Extinction correction: SHELXL97, Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.0047 (11)

Special details

Experimental. Solvent used: Benzene Cooling Device: Oxford Cryosystems Cryostream 700 Crystal mount: glued on a glass fibre Mosaicity (°.): 0.601 (1) Frames collected: 578 Seconds exposure per frame: 52 Degrees rotation per frame: 1.3 Crystal-Detector distance (mm): 32.0

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
Br1	0.47845 (7)	0.43164 (3)	0.247065 (13)	0.03786 (12)
O3	−0.3515 (5)	0.90921 (16)	0.07107 (8)	0.0317 (4)
N1	0.0777 (5)	0.7294 (2)	−0.03332 (10)	0.0293 (4)
N2	−0.0216 (5)	0.75724 (19)	0.02714 (9)	0.0257 (4)
N4	−0.2445 (5)	0.89435 (19)	−0.03592 (10)	0.0268 (4)
H4	−0.364 (8)	0.951 (3)	−0.0503 (14)	0.029 (8)*
C3	−0.2218 (6)	0.8594 (2)	0.02653 (11)	0.0257 (5)
C5	−0.0631 (6)	0.8141 (2)	−0.06907 (12)	0.0272 (5)
C6	0.0927 (6)	0.6825 (2)	0.07920 (11)	0.0250 (5)
C7	0.2578 (6)	0.5739 (2)	0.06724 (12)	0.0298 (5)
H7	0.2912	0.5507	0.0249	0.036*
C8	0.3744 (6)	0.4991 (2)	0.11710 (12)	0.0312 (5)
H8	0.4899	0.4251	0.1092	0.037*
C9	0.3206 (6)	0.5336 (2)	0.17836 (12)	0.0293 (5)
C10	0.1548 (6)	0.6416 (2)	0.19065 (12)	0.0308 (5)
H10	0.1195	0.6640	0.2331	0.037*
C11	0.0404 (6)	0.7172 (2)	0.14101 (12)	0.0291 (5)
H11	−0.0724	0.7917	0.1491	0.035*
C51	−0.0278 (8)	0.8248 (3)	−0.13792 (14)	0.0428 (7)
H511	0.0957	0.8999	−0.1465	0.064*
H512	−0.2485	0.8284	−0.1603	0.064*
H513	0.0928	0.7531	−0.1526	0.064*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Br1	0.03697 (17)	0.03874 (18)	0.03746 (17)	0.00197 (11)	−0.00042 (11)	0.01047 (11)
O3	0.0403 (10)	0.0261 (9)	0.0297 (9)	0.0065 (7)	0.0111 (7)	−0.0003 (7)
N1	0.0328 (11)	0.0312 (11)	0.0243 (10)	0.0026 (9)	0.0047 (8)	−0.0035 (8)
N2	0.0282 (10)	0.0253 (10)	0.0239 (10)	0.0012 (8)	0.0055 (7)	−0.0029 (7)
N4	0.0296 (10)	0.0242 (10)	0.0270 (10)	0.0018 (8)	0.0044 (8)	0.0017 (8)
C3	0.0265 (11)	0.0229 (11)	0.0279 (11)	−0.0023 (9)	0.0045 (9)	−0.0002 (9)
C5	0.0286 (12)	0.0267 (12)	0.0268 (11)	0.0001 (9)	0.0052 (9)	−0.0034 (9)
C6	0.0232 (11)	0.0247 (11)	0.0272 (12)	−0.0025 (9)	0.0024 (9)	−0.0008 (9)
C7	0.0305 (12)	0.0281 (12)	0.0308 (12)	0.0035 (10)	0.0036 (9)	−0.0039 (10)
C8	0.0303 (12)	0.0290 (13)	0.0340 (13)	0.0044 (10)	0.0008 (10)	−0.0012 (10)
C9	0.0257 (11)	0.0301 (12)	0.0320 (12)	−0.0027 (10)	0.0012 (9)	0.0053 (10)
C10	0.0359 (13)	0.0308 (12)	0.0262 (12)	−0.0013 (11)	0.0056 (10)	−0.0026 (10)
C11	0.0340 (13)	0.0263 (12)	0.0278 (12)	0.0030 (10)	0.0066 (9)	−0.0013 (9)
C51	0.0506 (17)	0.0473 (18)	0.0307 (14)	0.0063 (13)	0.0049 (12)	0.0008 (12)

Geometric parameters (Å, º)

Br1—C9	1.902 (2)	C7—C8	1.388 (3)
O3—C3	1.234 (3)	C7—H7	0.9500
N1—C5	1.297 (3)	C8—C9	1.381 (4)
N1—N2	1.400 (3)	C8—H8	0.9500
N2—C3	1.372 (3)	C9—C10	1.384 (4)
N2—C6	1.420 (3)	C10—C11	1.387 (4)
N4—C5	1.363 (3)	C10—H10	0.9500
N4—C3	1.372 (3)	C11—H11	0.9500
N4—H4	0.82 (3)	C51—H511	0.9800
C5—C51	1.478 (4)	C51—H512	0.9800
C6—C7	1.386 (3)	C51—H513	0.9800
C6—C11	1.391 (3)
C5—N1—N2	103.8 (2)	C9—C8—C7	119.2 (2)
C3—N2—N1	111.8 (2)	C9—C8—H8	120.4
C3—N2—C6	129.0 (2)	C7—C8—H8	120.4
N1—N2—C6	119.2 (2)	C8—C9—C10	121.0 (2)
C5—N4—C3	108.4 (2)	C8—C9—Br1	119.60 (19)
C5—N4—H4	127 (2)	C10—C9—Br1	119.40 (19)
C3—N4—H4	124 (2)	C9—C10—C11	120.0 (2)
O3—C3—N2	128.9 (2)	C9—C10—H10	120.0
O3—C3—N4	127.6 (2)	C11—C10—H10	120.0
N2—C3—N4	103.5 (2)	C10—C11—C6	119.2 (2)
N1—C5—N4	112.5 (2)	C10—C11—H11	120.4
N1—C5—C51	124.3 (2)	C6—C11—H11	120.4
N4—C5—C51	123.2 (2)	C5—C51—H511	109.5
C7—C6—C11	120.5 (2)	C5—C51—H512	109.5
C7—C6—N2	118.6 (2)	H511—C51—H512	109.5
C11—C6—N2	120.9 (2)	C5—C51—H513	109.5
C6—C7—C8	120.1 (2)	H511—C51—H513	109.5
C6—C7—H7	120.0	H512—C51—H513	109.5
C8—C7—H7	120.0
C5—N1—N2—C3	−0.1 (3)	N1—N2—C6—C7	−9.5 (3)
C5—N1—N2—C6	−179.2 (2)	C3—N2—C6—C11	−8.4 (4)
N1—N2—C3—O3	−179.8 (2)	N1—N2—C6—C11	170.5 (2)
C6—N2—C3—O3	−0.8 (4)	C11—C6—C7—C8	−0.4 (4)
N1—N2—C3—N4	0.0 (3)	N2—C6—C7—C8	179.6 (2)
C6—N2—C3—N4	179.0 (2)	C6—C7—C8—C9	0.7 (4)
C5—N4—C3—O3	179.9 (2)	C7—C8—C9—C10	−0.5 (4)
C5—N4—C3—N2	0.1 (3)	C7—C8—C9—Br1	179.88 (19)
N2—N1—C5—N4	0.2 (3)	C8—C9—C10—C11	−0.1 (4)
N2—N1—C5—C51	179.1 (2)	Br1—C9—C10—C11	179.57 (19)
C3—N4—C5—N1	−0.2 (3)	C9—C10—C11—C6	0.4 (4)
C3—N4—C5—C51	−179.1 (2)	C7—C6—C11—C10	−0.1 (4)
C3—N2—C6—C7	171.6 (2)	N2—C6—C11—C10	179.8 (2)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N4—H4···O3^i	0.82 (3)	1.94 (3)	2.756 (3)	171 (3)

Symmetry code: (i) −x−1, −y+2, −z.