2,4-Difluoro-phenyl-boronic acid.

The mol-ecular structure of the title compound, C(6)H(5)BF(2)O(2), is essentially planar (mean deviation = 0.019 Å), indicating electronic delocalization between the dihydroxy-boryl group and the aromatic ring. In the crystal structure, inversion dimers linked by two O-H⋯O hydrogen bonds arise. An intra-molecular O-H⋯F hydrogen bond reinforces the conformation and the same H atom is also involved in an inter-molecular O-H⋯F link, leading to mol-ecular sheets in the crystal.

Related literature

For general backround to boronic acids, see: Hall (2005 ▶); Höpfl (2002 ▶); Fujita et al. (2008 ▶); Soloway et al. (1998 ▶). For hydrogen-bond motifs, see: Bernstein et al. (1995 ▶); Desiraju (2002 ▶). For related structures, see: Wu et al. (2006 ▶); Bradley et al. (1996 ▶); Horton et al. (2004 ▶). For crystal engineering, see: Fournier et al. (2003 ▶); Rodríguez-Cuamatzi et al. (2004 ▶, 2005 ▶).

Experimental

Crystal data

C6H5BF2O2

M = 157.91

Monoclinic,

a = 3.7617 (11) Å

b = 12.347 (4) Å

c = 14.620 (4) Å

β = 95.450 (5)°

V = 676.0 (3) Å3

Z = 4

Mo Kα radiation

μ = 0.15 mm−1

T = 293 (2) K

0.37 × 0.35 × 0.22 mm

Data collection

Bruker SMART APEX CCD area-detector diffractometer

Absorption correction: multi-scan (SADABS; Sheldrick, 1996 ▶) T min = 0.947, T max = 0.968

3196 measured reflections

1190 independent reflections

1012 reflections with I > 2σ(I)

R int = 0.028

Refinement

R[F 2 > 2σ(F 2)] = 0.056

wR(F 2) = 0.127

S = 1.15

1190 reflections

106 parameters

2 restraints

H atoms treated by a mixture of independent and constrained refinement

Δρmax = 0.14 e Å−3

Δρmin = −0.18 e Å−3

Data collection: SMART (Bruker, 2000 ▶); cell refinement: SAINT-Plus-NT (Bruker, 2001 ▶); data reduction: SAINT-Plus-NT; program(s) used to solve structure: SHELXTL-NT (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXTL-NT; molecular graphics: CAMERON (Watkin et al., 1996 ▶); software used to prepare material for publication: PLATON (Spek, 2003 ▶) and publCIF (Westrip, 2009 ▶).

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536808040646/hb2865sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S1600536808040646/hb2865Isup2.hkl

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

C6H5BF2O2	F(000) = 320
Mr = 157.91	Dx = 1.552 Mg m−3
Monoclinic, P21/n	Melting point = 521–522 K
Hall symbol: -P 2yn	Mo Kα radiation, λ = 0.71073 Å
a = 3.7617 (11) Å	Cell parameters from 1052 reflections
b = 12.347 (4) Å	θ = 2.3–26.2°
c = 14.620 (4) Å	µ = 0.15 mm−1
β = 95.450 (5)°	T = 293 K
V = 676.0 (3) Å3	Block, colorless
Z = 4	0.37 × 0.35 × 0.22 mm

Bruker SMART APEX CCD area-detector diffractometer	1190 independent reflections
Radiation source: fine-focus sealed tube	1012 reflections with I > 2σ(I)
graphite	Rint = 0.028
Detector resolution: 8.3 pixels mm-1	θmax = 25.0°, θmin = 2.2°
φ and ω scans	h = −3→4
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	k = −14→12
Tmin = 0.947, Tmax = 0.968	l = −17→17
3196 measured reflections

Refinement on F2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.056	Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.127	H atoms treated by a mixture of independent and constrained refinement
S = 1.15	w = 1/[σ2(Fo2) + (0.0442P)2 + 0.2673P] where P = (Fo2 + 2Fc2)/3
1190 reflections	(Δ/σ)max < 0.001
106 parameters	Δρmax = 0.14 e Å−3
2 restraints	Δρmin = −0.18 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 > 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.

	x	y	z	Uiso*/Ueq
B1	0.7704 (8)	0.4548 (2)	0.62567 (18)	0.0452 (7)
O1	0.6825 (6)	0.38623 (15)	0.55419 (13)	0.0695 (6)
H1	0.748 (9)	0.3215 (9)	0.562 (2)	0.104*
O2	0.6880 (6)	0.55977 (14)	0.61557 (12)	0.0630 (6)
H2	0.593 (8)	0.577 (3)	0.5632 (10)	0.094*
F1	1.0385 (5)	0.23728 (11)	0.67473 (11)	0.0768 (6)
F2	1.4329 (5)	0.33016 (14)	0.97634 (10)	0.0822 (6)
C1	0.9591 (6)	0.41789 (18)	0.72069 (15)	0.0424 (6)
C2	1.0796 (7)	0.31430 (18)	0.74175 (16)	0.0470 (6)
C3	1.2380 (7)	0.2819 (2)	0.82553 (17)	0.0539 (7)
H3	1.3138	0.2109	0.8363	0.065*
C4	1.2785 (7)	0.3593 (2)	0.89223 (17)	0.0547 (7)
C5	1.1696 (8)	0.4640 (2)	0.87828 (17)	0.0586 (7)
H5	1.2013	0.5150	0.9251	0.070*
C6	1.0119 (7)	0.49169 (19)	0.79282 (16)	0.0498 (6)
H6	0.9371	0.5628	0.7827	0.060*

	U11	U22	U33	U12	U13	U23
B1	0.0451 (16)	0.0425 (15)	0.0471 (16)	−0.0009 (12)	−0.0005 (12)	0.0033 (12)
O1	0.1000 (17)	0.0484 (11)	0.0540 (11)	0.0158 (10)	−0.0241 (10)	−0.0009 (9)
O2	0.0850 (15)	0.0441 (10)	0.0552 (11)	0.0087 (9)	−0.0172 (10)	0.0048 (8)
F1	0.1192 (15)	0.0456 (9)	0.0602 (10)	0.0151 (9)	−0.0187 (9)	−0.0046 (7)
F2	0.1070 (14)	0.0804 (12)	0.0527 (10)	−0.0120 (10)	−0.0262 (9)	0.0181 (8)
C1	0.0383 (13)	0.0412 (13)	0.0473 (13)	−0.0039 (10)	0.0019 (10)	0.0048 (10)
C2	0.0523 (16)	0.0410 (13)	0.0467 (13)	−0.0017 (11)	0.0001 (11)	0.0008 (10)
C3	0.0584 (17)	0.0449 (14)	0.0564 (15)	0.0002 (12)	−0.0053 (13)	0.0124 (12)
C4	0.0579 (17)	0.0613 (17)	0.0426 (13)	−0.0099 (13)	−0.0075 (12)	0.0135 (12)
C5	0.0696 (19)	0.0552 (16)	0.0489 (14)	−0.0109 (13)	−0.0058 (13)	−0.0020 (12)
C6	0.0559 (16)	0.0399 (13)	0.0522 (14)	−0.0011 (11)	−0.0011 (12)	0.0029 (11)

B1—O2	1.338 (3)	C1—C6	1.394 (3)
B1—O1	1.361 (3)	C2—C3	1.370 (3)
B1—C1	1.566 (3)	C3—C4	1.363 (4)
O1—H1	0.841 (15)	C3—H3	0.93
O2—H2	0.841 (15)	C4—C5	1.366 (4)
F1—C2	1.364 (3)	C5—C6	1.374 (3)
F2—C4	1.358 (3)	C5—H5	0.93
C1—C2	1.382 (3)	C6—H6	0.93
O2—B1—O1	118.7 (2)	C4—C3—H3	121.8
O2—B1—C1	117.4 (2)	C2—C3—H3	121.8
O1—B1—C1	123.8 (2)	F2—C4—C3	118.1 (2)
B1—O1—H1	116 (2)	F2—C4—C5	118.8 (2)
B1—O2—H2	115 (2)	C3—C4—C5	123.0 (2)
C2—C1—C6	114.6 (2)	C4—C5—C6	117.9 (2)
C2—C1—B1	125.3 (2)	C4—C5—H5	121.0
C6—C1—B1	120.1 (2)	C6—C5—H5	121.0
F1—C2—C3	116.7 (2)	C5—C6—C1	122.9 (2)
F1—C2—C1	118.2 (2)	C5—C6—H6	118.5
C3—C2—C1	125.1 (2)	C1—C6—H6	118.5
C4—C3—C2	116.4 (2)
O2—B1—C1—C2	−176.5 (2)	C1—C2—C3—C4	−0.3 (4)
O1—B1—C1—C2	4.5 (4)	C2—C3—C4—F2	179.7 (2)
O2—B1—C1—C6	4.6 (4)	C2—C3—C4—C5	0.0 (4)
O1—B1—C1—C6	−174.5 (2)	F2—C4—C5—C6	−179.6 (2)
C6—C1—C2—F1	−179.9 (2)	C3—C4—C5—C6	0.1 (4)
B1—C1—C2—F1	1.1 (4)	C4—C5—C6—C1	0.0 (4)
C6—C1—C2—C3	0.4 (4)	C2—C1—C6—C5	−0.3 (4)
B1—C1—C2—C3	−178.6 (2)	B1—C1—C6—C5	178.8 (2)
F1—C2—C3—C4	180.0 (2)

D—H···A	D—H	H···A	D···A	D—H···A
O1—H1···F1	0.84 (2)	2.16 (3)	2.799 (3)	133 (2)
O1—H1···F2i	0.84 (2)	2.39 (2)	3.086 (3)	140 (3)
O2—H2···O1ii	0.84 (2)	1.97 (2)	2.809 (3)	174 (3)

Table 1

Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O1—H1⋯F1	0.841 (15)	2.16 (3)	2.799 (3)	133 (2)
O1—H1⋯F2i	0.841 (15)	2.39 (2)	3.086 (3)	140 (3)
O2—H2⋯O1ii	0.841 (19)	1.97 (2)	2.809 (3)	174 (3)

Symmetry codes: (i) ; (ii) .