4-Chloro­benzohydrazide

The crystal structure of the title compound, C₇H₇N₂OCl, has been determined in the monoclinic space group P2₁/c at room temperature. The structure is stabilized by intermolecular N—H...O and N—H...N hydrogen bonds.

Key indicators

• Single-crystal X-ray study
• T = 293 K
• Mean [sigma](C-C) = 0.004 Å
• R factor = 0.061
• wR factor = 0.143
• Data-to-parameter ratio = 12.3

checkCIF results

No syntax errors found

ADDSYM reports no extra symmetry

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S1. Comment

The title compound, (I), was tested for its activity against tuberculosis `in vitro' (Bew-Hol et al., 1952), and was found to be inactive at a concentration of 10 µg ml⁻¹ of the culture medium. Compound (I) was also used as a starting material for the synthesis of α-methyl-substituted or unsubstituted [(4-phenyl/ethyl-5-p-chlorophenyl-4H-1,2,4-triazol-3-yl)thio]acetic acids which have been found to possess good anti-inflammatory activity (Sung & Lee, 1992).

The orientations of the carbonyl and hydrazide groups with respect to the aromatic ring are defined by the torsion angles C5—C4—C7—O1 31.9 (4)° and C5—C4—C7—N1 − 148.3 (3)°. The crystal structure is held together by two intermolecular hydrogen bonds, N1—H1···N2ⁱ and N2—H2N···O1ⁱⁱ (symmetry codes as in Table 1).

S2. Experimental

The title compound was synthesized from 4-chlorobenzoic acid by refluxing it with anhydrous ethanol and concentrated sulfuric acid for 3 h to obtain ethyl 4-chlorobenzoate. This, on further reaction with hydrazine hydrate in ethanol under reflux conditions for 6 h, yielded 4-chlorobenzohydrazide. Crystallization from ethanol yielded colorless crystals (Saikachi et al., 1955).

S3. Refinement

The H atoms on N2, viz. H1N and H2N, were located in a difference Fourier map and refined freely. All other atoms were positioned geometrically and allowed to ride on their parent atoms, with U_iso(H) = U_eq of the parent atom.

Computing details

Data collection: SMART (Bruker, 1998); cell refinement: SMART; data reduction: SAINT (Bruker, 1998); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997) and CAMERON (Watkin et al., 1996); software used to prepare material for publication: PLATON (Spek, 1990).

Figures

	Fig. 1. View of the title compound with the atom-numbering scheme. Displacement ellipsoids for non-H atoms are drawn at the 50% probability level. H atoms are shown as spheres of arbitrary radii.
	Fig. 2. Packing diagram of the title compound, viewed down the b axis. N—H···O and N—H···N hydrogen bonds are shown as dotted lines.

'4-chlorobenzohydrazide'

Crystal data

C7H7ClN2O	F(000) = 352
Mr = 170.60	Dx = 1.513 Mg m^−3
Monoclinic, P21/c	Melting point: 435 K
Hall symbol: -P 2ybc	Mo Kα radiation, λ = 0.71073 Å
a = 15.945 (7) Å	Cell parameters from 2013 reflections
b = 3.8449 (16) Å	θ = 2.6–27.9°
c = 12.389 (5) Å	µ = 0.45 mm^−1
β = 99.664 (7)°	T = 293 K
V = 748.7 (5) Å^3	Rod, colorless
Z = 4	0.2 × 0.18 × 0.05 mm

Data collection

Bruker SMART CCD area-detector diffractometer	981 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.049
Graphite monochromator	θmax = 25.0°, θmin = 2.6°
ϕ and ω scans	h = −18→18
4456 measured reflections	k = −4→4
1329 independent reflections	l = −13→14

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)] = 0.061	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.143	H atoms treated by a mixture of independent and constrained refinement
S = 1.03	w = 1/[σ^2(Fo^2) + (0.1534P)^2 + 0.0248P] where P = (Fo^2 + 2Fc^2)/3
1329 reflections	(Δ/σ)max = 0.010
108 parameters	Δρmax = 0.38 e Å^−3
0 restraints	Δρmin = −0.35 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
Cl1	0.45824 (5)	0.7728 (2)	0.37421 (8)	0.0713 (4)
C7	0.12270 (16)	0.3411 (6)	0.1246 (2)	0.0308 (6)
N1	0.05582 (12)	0.3817 (6)	0.17382 (17)	0.0368 (6)
H1	0.0623	0.4934	0.2348	0.044*
N2	−0.02547 (15)	0.2501 (8)	0.13093 (18)	0.0362 (6)
H2N	−0.0566 (19)	0.400 (8)	0.091 (3)	0.048 (9)*
H1N	−0.0179 (18)	0.074 (8)	0.093 (3)	0.050 (10)*
C5	0.26727 (16)	0.5765 (7)	0.1344 (2)	0.0407 (7)
H5	0.2561	0.5962	0.0585	0.049*
C1	0.36096 (17)	0.6420 (7)	0.3013 (3)	0.0436 (7)
C4	0.20523 (15)	0.4470 (6)	0.18823 (19)	0.0314 (6)
C3	0.22348 (16)	0.4105 (7)	0.3013 (2)	0.0389 (7)
H3	0.1827	0.3207	0.3392	0.047*
C2	0.30190 (18)	0.5071 (7)	0.3571 (2)	0.0454 (8)
H2	0.3145	0.4805	0.4327	0.054*
O1	0.11599 (11)	0.2207 (5)	0.03092 (14)	0.0417 (5)
C6	0.34545 (18)	0.6774 (8)	0.1900 (3)	0.0474 (8)
H6	0.3867	0.7674	0.1529	0.057*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Cl1	0.0433 (5)	0.0794 (7)	0.0797 (8)	−0.0065 (4)	−0.0230 (4)	−0.0099 (5)
C7	0.0346 (13)	0.0402 (14)	0.0170 (12)	0.0014 (11)	0.0023 (10)	0.0027 (11)
N1	0.0308 (12)	0.0617 (14)	0.0171 (11)	−0.0058 (10)	0.0011 (9)	−0.0083 (10)
N2	0.0333 (12)	0.0570 (16)	0.0167 (11)	−0.0041 (12)	−0.0007 (10)	0.0000 (11)
C5	0.0378 (15)	0.0584 (18)	0.0254 (14)	−0.0015 (13)	0.0038 (12)	0.0038 (13)
C1	0.0328 (14)	0.0470 (16)	0.0458 (18)	0.0030 (13)	−0.0085 (13)	−0.0077 (14)
C4	0.0327 (13)	0.0419 (14)	0.0187 (13)	0.0027 (11)	0.0017 (10)	−0.0023 (11)
C3	0.0381 (15)	0.0583 (17)	0.0198 (13)	0.0030 (13)	0.0032 (11)	0.0006 (12)
C2	0.0450 (16)	0.0627 (19)	0.0240 (14)	0.0064 (14)	−0.0069 (13)	−0.0052 (13)
O1	0.0399 (11)	0.0668 (13)	0.0176 (10)	−0.0004 (9)	0.0029 (8)	−0.0082 (8)
C6	0.0353 (15)	0.0597 (18)	0.0470 (19)	−0.0034 (13)	0.0061 (14)	0.0048 (15)

Geometric parameters (Å, º)

Cl1—C1	1.733 (3)	C5—C4	1.376 (4)
C7—O1	1.237 (3)	C5—H5	0.9300
C7—N1	1.324 (3)	C1—C2	1.361 (4)
C7—C4	1.473 (4)	C1—C6	1.366 (4)
N1—N2	1.410 (3)	C4—C3	1.389 (4)
N1—H1	0.8600	C3—C2	1.374 (4)
N2—H2N	0.86 (3)	C3—H3	0.9300
N2—H1N	0.85 (3)	C2—H2	0.9300
C5—C6	1.375 (4)	C6—H6	0.9300
O1—C7—N1	121.8 (2)	C6—C1—Cl1	119.4 (2)
O1—C7—C4	122.3 (2)	C5—C4—C3	118.7 (2)
N1—C7—C4	115.9 (2)	C5—C4—C7	119.4 (2)
C7—N1—N2	123.0 (2)	C3—C4—C7	121.9 (2)
C7—N1—H1	118.5	C2—C3—C4	119.9 (3)
N2—N1—H1	118.5	C2—C3—H3	120.0
N1—N2—H2N	112 (2)	C4—C3—H3	120.0
N1—N2—H1N	107 (2)	C1—C2—C3	119.8 (3)
H2N—N2—H1N	110 (3)	C1—C2—H2	120.1
C6—C5—C4	121.6 (3)	C3—C2—H2	120.1
C6—C5—H5	119.2	C1—C6—C5	118.2 (3)
C4—C5—H5	119.2	C1—C6—H6	120.9
C2—C1—C6	121.8 (3)	C5—C6—H6	120.9
C2—C1—Cl1	118.8 (2)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1···N2^i	0.86	2.10	2.911 (4)	157
N2—H2N···O1^ii	0.86 (3)	2.22 (4)	3.046 (4)	168 (3)

Symmetry codes: (i) −x, y+1/2, −z+1/2; (ii) −x, −y+1, −z.