2,4-Difluoro­benzohydroxamic acid

In the title compound, C₇H₅F₂NO₂, the hydroxyl group is trans to the difluoro­phenyl group with respect to the C—N bond. The mol­ecules are linked into chains of rings parallel to [100] by a combination of O—H...O and N—H...O hydrogen bonds.

Key indicators

• Single-crystal X-ray study
• T = 292 K
• Mean [sigma](C-C)= 0.002 Å
• R factor = 0.046
• wR factor = 0.126
• Data-to-parameter ratio = 14.3

checkCIF/PLATON results

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Computing details

Data collection: SMART (Bruker, 2003); cell refinement: SMART; data reduction: SAINT (Bruker, 2003); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SHELXTL (Bruker, 1997); software used to prepare material for publication: SHELXTL.

2,4-Difluorobenzohydroxamic acid

Crystal data

C7H5F2NO2	F(000) = 352
Mr = 173.12	Dx = 1.653 Mg m^−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 1339 reflections
a = 6.9266 (10) Å	θ = 2.7–26.2°
b = 15.358 (2) Å	µ = 0.16 mm^−1
c = 7.0430 (11) Å	T = 292 K
β = 111.795 (3)°	Block, colourless
V = 695.68 (18) Å^3	0.30 × 0.20 × 0.15 mm
Z = 4

Data collection

Bruker SMART CCD area-detector diffractometer	1564 independent reflections
Radiation source: fine-focus sealed tube	1091 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.044
φ and ω scans	θmax = 27.4°, θmin = 2.7°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	h = −8→7
Tmin = 0.955, Tmax = 0.970	k = −19→19
4297 measured reflections	l = −9→8

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)] = 0.046	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.126	H-atom parameters constrained
S = 1.04	w = 1/[σ^2(Fo^2) + (0.0664P)^2] where P = (Fo^2 + 2Fc^2)/3
1564 reflections	(Δ/σ)max < 0.001
109 parameters	Δρmax = 0.24 e Å^−3
0 restraints	Δρmin = −0.20 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
C1	0.7887 (2)	0.28126 (10)	0.5190 (2)	0.0408 (4)
C2	0.5910 (2)	0.24563 (10)	0.4534 (2)	0.0466 (4)
C3	0.5514 (3)	0.15762 (11)	0.4337 (3)	0.0554 (5)
H3	0.4165	0.1359	0.3881	0.066*
C4	0.7200 (3)	0.10372 (10)	0.4844 (3)	0.0551 (5)
C5	0.9192 (3)	0.13384 (12)	0.5522 (3)	0.0593 (5)
H5	1.0308	0.0954	0.5874	0.071*
C6	0.9516 (3)	0.22264 (11)	0.5674 (2)	0.0513 (4)
H6	1.0870	0.2437	0.6116	0.062*
C7	0.8437 (2)	0.37584 (10)	0.5462 (2)	0.0446 (4)
F1	0.6865 (2)	0.01699 (6)	0.4639 (2)	0.0845 (4)
F2	0.42360 (14)	0.29886 (6)	0.40470 (18)	0.0734 (4)
N1	0.6894 (2)	0.43291 (8)	0.4884 (2)	0.0532 (4)
O1	1.02750 (17)	0.39864 (8)	0.61625 (19)	0.0630 (4)
O2	0.7298 (2)	0.52064 (7)	0.5350 (2)	0.0687 (4)
H1	0.5617	0.4178	0.4454	0.082*
H2A	0.8208	0.5334	0.4828	0.103*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
C1	0.0378 (8)	0.0452 (9)	0.0394 (8)	0.0000 (6)	0.0145 (7)	0.0005 (6)
C2	0.0380 (9)	0.0437 (9)	0.0557 (10)	0.0031 (7)	0.0146 (7)	−0.0010 (7)
C3	0.0485 (10)	0.0455 (10)	0.0721 (12)	−0.0060 (8)	0.0222 (9)	−0.0043 (8)
C4	0.0672 (12)	0.0384 (9)	0.0656 (11)	0.0031 (8)	0.0316 (9)	0.0025 (8)
C5	0.0550 (11)	0.0569 (11)	0.0666 (12)	0.0187 (9)	0.0232 (9)	0.0098 (8)
C6	0.0389 (9)	0.0551 (11)	0.0577 (11)	0.0042 (7)	0.0152 (8)	0.0028 (7)
C7	0.0410 (9)	0.0488 (9)	0.0469 (9)	−0.0057 (7)	0.0197 (7)	−0.0008 (7)
F1	0.0966 (10)	0.0402 (6)	0.1274 (10)	0.0024 (6)	0.0542 (8)	0.0012 (6)
F2	0.0357 (6)	0.0464 (6)	0.1245 (10)	0.0014 (4)	0.0141 (6)	−0.0076 (5)
N1	0.0434 (8)	0.0377 (8)	0.0784 (10)	−0.0059 (6)	0.0226 (7)	−0.0045 (6)
O1	0.0398 (7)	0.0615 (8)	0.0863 (9)	−0.0122 (6)	0.0216 (6)	0.0019 (6)
O2	0.0650 (9)	0.0392 (7)	0.1169 (12)	−0.0108 (6)	0.0514 (8)	−0.0105 (6)

Geometric parameters (Å, º)

C1—C6	1.383 (2)	C5—C6	1.380 (2)
C1—C2	1.386 (2)	C5—H5	0.9300
C1—C7	1.496 (2)	C6—H6	0.9300
C2—F2	1.3544 (18)	C7—O1	1.2331 (17)
C2—C3	1.376 (2)	C7—N1	1.324 (2)
C3—C4	1.366 (2)	N1—O2	1.3903 (17)
C3—H3	0.9300	N1—H1	0.8539
C4—F1	1.3505 (18)	O2—H2A	0.8619
C4—C5	1.363 (2)
C6—C1—C2	116.10 (15)	C4—C5—H5	120.8
C6—C1—C7	117.07 (14)	C6—C5—H5	120.8
C2—C1—C7	126.82 (14)	C5—C6—C1	122.01 (16)
F2—C2—C3	116.61 (14)	C5—C6—H6	119.0
F2—C2—C1	119.56 (14)	C1—C6—H6	119.0
C3—C2—C1	123.83 (15)	O1—C7—N1	122.05 (14)
C4—C3—C2	116.76 (16)	O1—C7—C1	120.19 (14)
C4—C3—H3	121.6	N1—C7—C1	117.74 (13)
C2—C3—H3	121.6	C7—N1—O2	120.01 (13)
F1—C4—C5	118.90 (16)	C7—N1—H1	122.8
F1—C4—C3	118.29 (16)	O2—N1—H1	116.0
C5—C4—C3	122.81 (16)	N1—O2—H2A	103.5
C4—C5—C6	118.49 (15)
C6—C1—C2—F2	179.48 (14)	C4—C5—C6—C1	1.0 (3)
C7—C1—C2—F2	0.7 (2)	C2—C1—C6—C5	−0.2 (2)
C6—C1—C2—C3	−0.6 (2)	C7—C1—C6—C5	178.64 (15)
C7—C1—C2—C3	−179.30 (15)	C6—C1—C7—O1	−2.6 (2)
F2—C2—C3—C4	−179.47 (14)	C2—C1—C7—O1	176.13 (15)
C1—C2—C3—C4	0.6 (2)	C6—C1—C7—N1	175.87 (14)
C2—C3—C4—F1	−179.05 (15)	C2—C1—C7—N1	−5.4 (2)
C2—C3—C4—C5	0.2 (2)	O1—C7—N1—O2	−10.1 (2)
F1—C4—C5—C6	178.30 (15)	C1—C7—N1—O2	171.44 (13)
C3—C4—C5—C6	−1.0 (3)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1···F2	0.85	2.03	2.6776 (17)	132
O2—H2A···O1^i	0.86	1.80	2.6129 (19)	158
N1—H1···O2^ii	0.85	2.28	2.935 (2)	134

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