Acta Cryst. (2007). E63, o3962 [ doi:10.1107/S1600536807042481 ]
Molecules of the title compound, C4H4ClN3, are essentially planar. N-H
N hydrogen bonds link the molecules into a two-dimensional network parallel to the (100) plane. The pyridazine rings of inversion-related molecules are stacked with their centroids separated by a distance of 3.7597 (10) Å, indicating ![[pi]](http://journals.iucr.org/logos/entities/pi_rmgif.gif)
- interactions.
The title compound was prepared according to the literature method (Steck et al., 1954). Crystals suitable for X-ray analysis were obtained by slow evaporation of a isoproanol solution at room temperature (m.p. 483–485 K).
H atoms were positioned geometrically (N—H = 0.86 Å and C—H = 0.93 Å) and refined using a riding model, with Uiso(H) = 1.2–1.5Ueq(C).
Data collection: SMART (Bruker, 2002); cell refinement: SAINT (Bruker, 2002); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SHELXTL (Bruker, 2002); software used to prepare material for publication: SHELXTL.
![[Figure 1]](./ci2455fig1thm.gif)
| Fig. 1. Molecular structure of the title compound, showing 50% probability displacement ellipsoids and the atomic numbering. |
![[Figure 2]](./ci2455fig2thm.gif)
| Fig. 2. The crystal packing of the title compound, viewed down the b axis. Dashed lines indicate intermolecular hydrogen bonds. |
| C4H4ClN3 | F000 = 264 |
| Mr = 129.55 | Dx = 1.609 Mg m−3 |
| Monoclinic, P21/c | Mo Kα radiation λ = 0.71073 Å |
| Hall symbol: -P 2ybc | Cell parameters from 1227 reflections |
| a = 7.5235 (14) Å | θ = 2.8–27.6º |
| b = 6.5887 (11) Å | µ = 0.59 mm−1 |
| c = 11.1748 (19) Å | T = 125 (2) K |
| β = 105.045 (10)º | Block, colourless |
| V = 534.95 (16) Å3 | 0.50 × 0.50 × 0.40 mm |
| Z = 4 |
| Bruker SMART CCD area-detector diffractometer | 1227 independent reflections |
| Radiation source: fine-focus sealed tube | 1153 reflections with I > 2σ(I) |
| Monochromator: graphite | Rint = 0.015 |
| T = 125(2) K | θmax = 27.6º |
| φ and ω scans | θmin = 2.8º |
| Absorption correction: multi-scan (SADABS; Bruker, 2002) | h = −8→9 |
| Tmin = 0.756, Tmax = 0.794 | k = −8→8 |
| 5258 measured reflections | l = −14→12 |
| Refinement on F2 | Secondary atom site location: difference Fourier map |
| Least-squares matrix: full | Hydrogen site location: inferred from neighbouring sites |
| R[F2 > 2σ(F2)] = 0.033 | H-atom parameters constrained |
| wR(F2) = 0.088 | w = 1/[σ2(Fo2) + (0.047P)2 + 0.167P] where P = (Fo2 + 2Fc2)/3 |
| S = 1.12 | (Δ/σ)max = 0.001 |
| 1227 reflections | Δρmax = 0.25 e Å−3 |
| 73 parameters | Δρmin = −0.35 e Å−3 |
| Primary atom site location: structure-invariant direct methods | Extinction correction: none |
| C4H4ClN3 | V = 534.95 (16) Å3 |
| Mr = 129.55 | Z = 4 |
| Monoclinic, P21/c | Mo Kα |
| a = 7.5235 (14) Å | µ = 0.59 mm−1 |
| b = 6.5887 (11) Å | T = 125 (2) K |
| c = 11.1748 (19) Å | 0.50 × 0.50 × 0.40 mm |
| β = 105.045 (10)º |
| Bruker SMART CCD area-detector diffractometer | 1227 independent reflections |
| Absorption correction: multi-scan (SADABS; Bruker, 2002) | 1153 reflections with I > 2σ(I) |
| Tmin = 0.756, Tmax = 0.794 | Rint = 0.015 |
| 5258 measured reflections |
| R[F2 > 2σ(F2)] = 0.033 | 73 parameters |
| wR(F2) = 0.088 | H-atom parameters constrained |
| S = 1.12 | Δρmax = 0.25 e Å−3 |
| 1227 reflections | Δρmin = −0.35 e Å−3 |
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 > 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. |
| x | y | z | Uiso*/Ueq | ||
| Cl1 | 0.34908 (6) | 0.22748 (6) | 0.47446 (3) | 0.04506 (16) | |
| N1 | 0.19326 (16) | 0.58112 (18) | 0.46416 (10) | 0.0322 (3) | |
| C4 | 0.17199 (19) | 0.7781 (2) | 0.63301 (12) | 0.0303 (3) | |
| N3 | 0.11738 (19) | 0.9525 (2) | 0.67524 (11) | 0.0439 (3) | |
| H3A | 0.0622 | 1.0436 | 0.6238 | 0.053* | |
| H3B | 0.1377 | 0.9727 | 0.7537 | 0.053* | |
| C2 | 0.3197 (2) | 0.4557 (2) | 0.67021 (12) | 0.0353 (3) | |
| H2 | 0.3804 | 0.3520 | 0.7212 | 0.042* | |
| C3 | 0.26466 (19) | 0.6271 (2) | 0.71699 (11) | 0.0341 (3) | |
| H3 | 0.2870 | 0.6455 | 0.8021 | 0.041* | |
| C1 | 0.28026 (18) | 0.4428 (2) | 0.54031 (12) | 0.0301 (3) | |
| N2 | 0.13712 (17) | 0.75340 (18) | 0.50956 (11) | 0.0330 (3) |
| U11 | U22 | U33 | U12 | U13 | U23 | |
| Cl1 | 0.0612 (3) | 0.0370 (2) | 0.0391 (2) | 0.00197 (15) | 0.01685 (18) | −0.00858 (13) |
| N1 | 0.0413 (6) | 0.0333 (6) | 0.0217 (5) | −0.0046 (5) | 0.0078 (4) | −0.0009 (4) |
| C4 | 0.0343 (6) | 0.0328 (7) | 0.0236 (6) | −0.0024 (5) | 0.0068 (5) | 0.0002 (5) |
| N3 | 0.0626 (8) | 0.0405 (7) | 0.0262 (6) | 0.0139 (6) | 0.0073 (5) | −0.0010 (5) |
| C2 | 0.0442 (7) | 0.0359 (7) | 0.0244 (6) | 0.0042 (6) | 0.0064 (5) | 0.0048 (5) |
| C3 | 0.0428 (7) | 0.0395 (7) | 0.0187 (5) | 0.0015 (6) | 0.0056 (5) | 0.0018 (5) |
| C1 | 0.0360 (6) | 0.0301 (6) | 0.0251 (6) | −0.0046 (5) | 0.0097 (5) | −0.0026 (5) |
| N2 | 0.0429 (6) | 0.0327 (6) | 0.0218 (5) | 0.0001 (4) | 0.0057 (5) | 0.0023 (4) |
| Cl1—C1 | 1.7378 (14) | N3—H3A | 0.86 |
| N1—C1 | 1.3015 (18) | N3—H3B | 0.86 |
| N1—N2 | 1.3548 (17) | C2—C3 | 1.354 (2) |
| C4—N2 | 1.3456 (17) | C2—C1 | 1.4067 (18) |
| C4—N3 | 1.3460 (18) | C2—H2 | 0.93 |
| C4—C3 | 1.4204 (19) | C3—H3 | 0.93 |
| C1—N1—N2 | 119.64 (11) | C1—C2—H2 | 121.8 |
| N2—C4—N3 | 117.82 (12) | C2—C3—C4 | 118.44 (12) |
| N2—C4—C3 | 121.61 (12) | C2—C3—H3 | 120.8 |
| N3—C4—C3 | 120.57 (12) | C4—C3—H3 | 120.8 |
| C4—N3—H3A | 120.0 | N1—C1—C2 | 124.61 (13) |
| C4—N3—H3B | 120.0 | N1—C1—Cl1 | 116.70 (10) |
| H3A—N3—H3B | 120.0 | C2—C1—Cl1 | 118.69 (11) |
| C3—C2—C1 | 116.44 (12) | C4—N2—N1 | 119.25 (11) |
| C3—C2—H2 | 121.8 | ||
| C1—C2—C3—C4 | 0.3 (2) | C3—C2—C1—N1 | −1.2 (2) |
| N2—C4—C3—C2 | 0.6 (2) | C3—C2—C1—Cl1 | 179.46 (11) |
| N3—C4—C3—C2 | −178.90 (14) | N3—C4—N2—N1 | 178.83 (12) |
| N2—N1—C1—C2 | 1.2 (2) | C3—C4—N2—N1 | −0.6 (2) |
| N2—N1—C1—Cl1 | −179.49 (9) | C1—N1—N2—C4 | −0.20 (19) |
| D—H···A | D—H | H···A | D···A | D—H···A |
| N3—H3A···N2i | 0.86 | 2.26 | 3.1038 (18) | 168 |
| N3—H3B···N1ii | 0.86 | 2.31 | 3.1372 (17) | 162 |
| Symmetry codes: (i) −x, −y+2, −z+1; (ii) x, −y+3/2, z+1/2. |
| D—H···A | D—H | H···A | D···A | D—H···A |
| N3—H3A···N2i | 0.86 | 2.26 | 3.1038 (18) | 168 |
| N3—H3B···N1ii | 0.86 | 2.31 | 3.1372 (17) | 162 |
| Symmetry codes: (i) −x, −y+2, −z+1; (ii) x, −y+3/2, z+1/2. |
The author thanks Zhejiang Institute of Communications, People's Republic of China, for financial support.
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Pyridazines have demonstrated versatile biological activities, for example, antibacterial (Ishida et al., 1994), antidepressant (Pitarch et al., 1974) and antihypertensive (Herter et al., 1989) activities. A search of the Cambridge Structural Database (CSD, 2007 Release, Version 5.28; Allen, 2002) reveals that there are 639 crystal structures containing the pyridazine moiety. In the design of functional synthetic oligomers and ploymers, 3,6-diaminopyridazine is applied to the design of related monomeric, dimeric and trimeric duplex molecular strands (Gong et al., 2005). And in the preparation of various pyridazines, 3-amino-6-chloropyridazine is an important intermediate (Guery et al., 2001). We report here the crystal structure of the title compound.
In the title molecule (Fig. 1), the chloro and amino groups are coplanar with the pyridazine ring. Atoms N3 and Cl1 deviate from the pyridazine plane by 0.030 (1) and 0.019 (1) Å, respectively. The N1—N2 distance of 1.3548 (17) Å is slightly shorter than the N—N distance of 1.379 (2)Å reported by Gong et al. (2005).
The intermolecular N—H···N hydrogen bonds (Table 1) link the molecules into a two-dimensional network parallel to the (100) plane (Fig.2). The pyridazine rings of the inversion-related molecules at (x, y, z) and (−x, 1 − y, −z) are stacked with their centroids separated by a distance of 3.7597 (10) Å, indicating π-π interactions. In addition, C—Cl···π [Cl···pyridazine ring centroid = 3.6065 (10) Å] interactions also contribute to the stabilization of the structure.