supplementary materials


hb5764 scheme

Acta Cryst. (2011). E67, o164    [ doi:10.1107/S1600536810052025 ]

4-(1,2,4-Triazol-1-yl)aniline

H.-K. Fun, C. K. Quah, B. Chandrakantha, A. M. Isloor and P. Shetty

Abstract top

In the title compound, C8H8N4, the dihedral angle between the triazole ring [maximum deviation = 0.003 (1) Å] and the benzene ring is 34.57 (7)°. In the crystal, molecules are linked into sheets lying parallel to the ac plane via intermolecular N-H...N and C-H...N hydrogen bonds. Aromatic [pi]-[pi] [centroid-centroid distance = 3.6750 (8) Å] stacking and N-H...[pi] interactions are also observed.

Comment top

Compounds incorporating heterocyclic ring systems continue to attract considerable interests due to the wide range of biological activities they possess (Isloor et al., 2000). Triazoles are a class of heterocyclic compounds having a five-membered ring of two carbon atoms and three nitrogen atoms (Soliman et al., 2001). They have wide range of applications. In last few decades, triazoles have received much significant attention in the field of medicinal chemistry because of their diversified biological properties like antibacterial (Isloor et al., 2009) and antifungal (Holla et al., 2000) activities. In recent years, 1,2,4-triazole derivatives have been found to associate with anticancer properties (Sunil et al., 2009). It is also observed that incorporation of aryl constituent into the triazoles ring systems augments the biological activities considerably.

In the title molecule (Fig. 1), the triazol-1-yl ring (N1-N3/C1/C2, maximum deviation = 0.003 (1) Å at atom N3) is inclined at angle of 34.57 (7)° with phenyl (C3-C8) ring. Bond lengths (Allen et al., 1987) and angles are within normal ranges and are comparable to a related structure (Fun et al., 2010).

In the crystal packing (Fig. 2), the molecules are linked into two-dimensional sheets parallel to the ac-plane via intermolecular N4–H2N4···N1 and C1–H1A···N2 hydrogen bonds. π-π stacking interactions between the centroids of N1-N3/C1/C2 triazol-1-yl rings (Cg1), with Cg1···Cg1i distance of 3.6750 (8) Å [symmetry code: (i) 1-X, -Y, 2-Z] are observed. The crystal structure is further consilidated by N4–H1N4···Cg2 (Table 1) interactions, where Cg2 is the centroid of C3-C8 phenyl ring.

Related literature top

For general background to and the biological activity of triazole derivatives, see: Isloor et al. (2000, 2009); Soliman et al. (2001); Holla et al. (2000); Sunil et al. (2009). For bond-length data, see: Allen et al. (1987). For a related structure, see: Fun et al. (2010).

Experimental top

1,2,4-Triazole (2 g, 0.02 mol) was added lot-wise to a suspension of sodium hydride (60%, 1.47 g, 0.0308 mol) in dry DMF (20 ml) at 0°C. After the addition, the reaction mixture was stirred at the same temperature for 30 min. A solution of 4-fluoro nitrobenzene (2.82 g, 0.02 mol) in dry DMF (20 ml) was then added and the reaction mixture was stirred at room temperature for 18 h. The reaction mixture was then quenched with ice water and extracted with ethyl acetate. The organic layer was concentrated to afford a yellow solid as a nitro compound intermediate (3 g). This nitro compound was taken in methanol (30 ml) and hydrogenated using 10% palladium on carbon (0.2 g) at 3-kg pressure of hydrogen. After the reaction was over, the catalyst was filtered, the filtrate was concentrated to afford the title compound as a yellow solid. Yellow blocks were recrystallised from ethanol. Yield : 2.8g, 60 %. M.p. 433-435K.

Refinement top

H1N4 and H2N4 were located in a difference Fourier map and allowed to refined freely. The remaining H atoms were positioned geometrically and refined using a riding model with C–H = 0.93 Å and Uiso(H) = 1.2 Ueq(C). The highest residual electron density peak is located at 0.67 Å from C3 and the deepest hole is located at 1.27 Å from C8.

Computing details top

Data collection: APEX2 (Bruker, 2009); cell refinement: SAINT (Bruker, 2009); data reduction: SAINT (Bruker, 2009); program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXTL (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008) and PLATON (Spek, 2009).

Figures top
[Figure 1] Fig. 1. The molecular structure of the title compound showing 50% probability displacement ellipsoids for non-H atoms.
[Figure 2] Fig. 2. The crystal structure of the title compound, viewed along the b axis. H atoms not involved in hydrogen bonds (dashed lines) have been omitted for clarity.
4-(1,2,4-Triazol-1-yl)aniline top
Crystal data top
C8H8N4F(000) = 336
Mr = 160.18Dx = 1.350 Mg m3
Monoclinic, P21/cMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybcCell parameters from 3245 reflections
a = 5.5488 (1) Åθ = 3.0–29.1°
b = 7.3656 (2) ŵ = 0.09 mm1
c = 19.5477 (5) ÅT = 296 K
β = 99.416 (2)°Block, yellow
V = 788.15 (3) Å30.50 × 0.42 × 0.14 mm
Z = 4
Data collection top
Bruker SMART APEXII CCD
diffractometer
2160 independent reflections
Radiation source: fine-focus sealed tube1722 reflections with I > 2σ(I)
graphiteRint = 0.030
φ and ω scansθmax = 29.4°, θmin = 2.1°
Absorption correction: multi-scan
(SADABS; Bruker, 2009)
h = 77
Tmin = 0.957, Tmax = 0.988k = 1010
8036 measured reflectionsl = 2624
Refinement top
Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.044H atoms treated by a mixture of independent and constrained refinement
wR(F2) = 0.118 w = 1/[σ2(Fo2) + (0.0509P)2 + 0.1531P]
where P = (Fo2 + 2Fc2)/3
S = 1.05(Δ/σ)max = 0.001
2160 reflectionsΔρmax = 0.23 e Å3
110 parametersΔρmin = 0.17 e Å3
0 restraintsExtinction correction: SHELXTL (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: structure-invariant direct methodsExtinction coefficient: 0.042 (5)
Crystal data top
C8H8N4V = 788.15 (3) Å3
Mr = 160.18Z = 4
Monoclinic, P21/cMo Kα radiation
a = 5.5488 (1) ŵ = 0.09 mm1
b = 7.3656 (2) ÅT = 296 K
c = 19.5477 (5) Å0.50 × 0.42 × 0.14 mm
β = 99.416 (2)°
Data collection top
Bruker SMART APEXII CCD
diffractometer
2160 independent reflections
Absorption correction: multi-scan
(SADABS; Bruker, 2009)
1722 reflections with I > 2σ(I)
Tmin = 0.957, Tmax = 0.988Rint = 0.030
8036 measured reflectionsθmax = 29.4°
Refinement top
R[F2 > 2σ(F2)] = 0.044H atoms treated by a mixture of independent and constrained refinement
wR(F2) = 0.118Δρmax = 0.23 e Å3
S = 1.05Δρmin = 0.17 e Å3
2160 reflectionsAbsolute structure: ?
110 parametersFlack parameter: ?
0 restraintsRogers parameter: ?
Special details top

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds 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 > 2sigma(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 (Å2) top
xyzUiso*/Ueq
N10.3298 (2)0.17124 (18)1.08332 (6)0.0542 (3)
N20.58582 (19)0.24895 (17)1.00992 (6)0.0498 (3)
N30.34993 (17)0.26004 (14)0.97774 (5)0.0378 (3)
N40.0895 (3)0.4820 (2)0.70184 (6)0.0597 (4)
C10.2029 (2)0.2126 (2)1.02227 (7)0.0480 (3)
H1A0.03340.20921.01170.058*
C20.5611 (3)0.1960 (2)1.07255 (7)0.0533 (4)
H2A0.69480.17681.10720.064*
C30.2865 (2)0.31773 (16)0.90734 (6)0.0360 (3)
C40.4336 (2)0.27300 (17)0.85909 (6)0.0411 (3)
H4A0.57520.20560.87240.049*
C50.3691 (2)0.32893 (18)0.79107 (6)0.0432 (3)
H5A0.46860.29860.75890.052*
C60.1573 (2)0.43007 (17)0.76988 (6)0.0404 (3)
C70.0123 (2)0.47403 (17)0.81966 (6)0.0434 (3)
H7A0.12960.54150.80680.052*
C80.0763 (2)0.41891 (17)0.88743 (6)0.0415 (3)
H8A0.02180.44960.92000.050*
H2N40.171 (3)0.447 (2)0.6697 (8)0.065 (5)*
H1N40.029 (3)0.560 (3)0.6921 (9)0.078 (6)*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
N10.0549 (7)0.0658 (8)0.0435 (6)0.0049 (6)0.0124 (5)0.0063 (5)
N20.0340 (5)0.0681 (8)0.0452 (6)0.0015 (5)0.0006 (4)0.0051 (5)
N30.0318 (5)0.0448 (5)0.0367 (5)0.0009 (4)0.0052 (4)0.0009 (4)
N40.0711 (8)0.0683 (9)0.0406 (6)0.0212 (7)0.0116 (6)0.0085 (6)
C10.0392 (6)0.0616 (8)0.0447 (7)0.0024 (6)0.0115 (5)0.0042 (6)
C20.0485 (7)0.0650 (9)0.0439 (7)0.0014 (6)0.0002 (6)0.0047 (6)
C30.0324 (5)0.0396 (6)0.0355 (6)0.0019 (4)0.0043 (4)0.0023 (4)
C40.0313 (5)0.0480 (7)0.0445 (7)0.0041 (5)0.0074 (5)0.0005 (5)
C50.0388 (6)0.0518 (7)0.0412 (6)0.0008 (5)0.0133 (5)0.0019 (5)
C60.0427 (6)0.0395 (6)0.0386 (6)0.0027 (5)0.0051 (5)0.0006 (5)
C70.0388 (6)0.0453 (7)0.0451 (7)0.0081 (5)0.0042 (5)0.0005 (5)
C80.0375 (6)0.0468 (7)0.0413 (6)0.0053 (5)0.0096 (5)0.0049 (5)
Geometric parameters (Å, °) top
N1—C11.3183 (17)C3—C41.3842 (16)
N1—C21.3468 (19)C3—C81.3851 (16)
N2—C21.3134 (18)C4—C51.3821 (17)
N2—N31.3587 (14)C4—H4A0.9300
N3—C11.3332 (16)C5—C61.3957 (17)
N3—C31.4284 (14)C5—H5A0.9300
N4—C61.3758 (16)C6—C71.3987 (17)
N4—H2N40.871 (18)C7—C81.3755 (16)
N4—H1N40.87 (2)C7—H7A0.9300
C1—H1A0.9300C8—H8A0.9300
C2—H2A0.9300
C1—N1—C2102.04 (11)C8—C3—N3119.62 (10)
C2—N2—N3102.11 (11)C5—C4—C3119.72 (11)
C1—N3—N2109.16 (10)C5—C4—H4A120.1
C1—N3—C3128.78 (10)C3—C4—H4A120.1
N2—N3—C3122.06 (10)C4—C5—C6121.17 (11)
C6—N4—H2N4121.5 (11)C4—C5—H5A119.4
C6—N4—H1N4118.2 (12)C6—C5—H5A119.4
H2N4—N4—H1N4120.1 (16)N4—C6—C5121.27 (12)
N1—C1—N3111.01 (12)N4—C6—C7120.72 (12)
N1—C1—H1A124.5C5—C6—C7118.00 (11)
N3—C1—H1A124.5C8—C7—C6120.95 (11)
N2—C2—N1115.69 (12)C8—C7—H7A119.5
N2—C2—H2A122.2C6—C7—H7A119.5
N1—C2—H2A122.2C7—C8—C3120.16 (11)
C4—C3—C8120.00 (11)C7—C8—H8A119.9
C4—C3—N3120.38 (10)C3—C8—H8A119.9
C2—N2—N3—C10.42 (15)C8—C3—C4—C50.32 (19)
C2—N2—N3—C3178.65 (11)N3—C3—C4—C5179.64 (11)
C2—N1—C1—N30.25 (16)C3—C4—C5—C60.0 (2)
N2—N3—C1—N10.44 (16)C4—C5—C6—N4178.34 (13)
C3—N3—C1—N1178.55 (12)C4—C5—C6—C70.26 (19)
N3—N2—C2—N10.29 (17)N4—C6—C7—C8178.50 (13)
C1—N1—C2—N20.04 (18)C5—C6—C7—C80.11 (19)
C1—N3—C3—C4146.03 (13)C6—C7—C8—C30.3 (2)
N2—N3—C3—C435.09 (17)C4—C3—C8—C70.48 (19)
C1—N3—C3—C833.93 (19)N3—C3—C8—C7179.49 (11)
N2—N3—C3—C8144.95 (12)
Hydrogen-bond geometry (Å, °) top
Cg2 is the centroid of the C3–C8 phenyl ring.
D—H···AD—HH···AD···AD—H···A
N4—H2N4···N1i0.871 (16)2.208 (16)3.0709 (18)171.1 (15)
C1—H1A···N2ii0.932.503.4035 (16)166
N4—H1N4···Cg2iii0.87 (2)2.58 (2)3.3929 (16)156.0 (17)
Symmetry codes: (i) x, −y+1/2, z−1/2; (ii) x−1, y, z; (iii) −x, y+1/2, −z+3/2.
Table 1
Hydrogen-bond geometry (Å, °)
top
Cg2 is the centroid of the C3–C8 phenyl ring.
D—H···AD—HH···AD···AD—H···A
N4—H2N4···N1i0.871 (16)2.208 (16)3.0709 (18)171.1 (15)
C1—H1A···N2ii0.932.503.4035 (16)166
N4—H1N4···Cg2iii0.87 (2)2.58 (2)3.3929 (16)156.0 (17)
Symmetry codes: (i) x, −y+1/2, z−1/2; (ii) x−1, y, z; (iii) −x, y+1/2, −z+3/2.
Acknowledgements top

HKF and CKQ thank Universiti Sains Malaysia (USM) for the Research University Grant (No. 1001/PFIZIK/811160). CKQ also thanks USM for the award of a USM fellowship. AMI thankful to the Director of the National Institute of Technology for providing research facilities and also thanks the Board for Research in Nuclear Sciences, Department of Atomic Energy, Government of India, for a Young Scientist Award.

references
References top

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