3-Carb­oxy-2-methoxy­phenyl­boronic acid

Sergiusz Luliński

doi:10.1107/S1600536808029504

. 2008 Sep 20;64(Pt 10):o1963. doi: 10.1107/S1600536808029504

3-Carboxy-2-methoxyphenylboronic acid

Sergiusz Luliński ^a,^*

PMCID: PMC2959364 PMID: 21201164

Abstract

The molecular structure of the title compound, 3-COOH-2-CH₃O—C₆H₃B(OH)₂ or C₈H₉BO₅, is stabilized in part due to the presence of an intramolecular O—H⋯O hydrogen bond. In the crystal structure, molecules are linked by intermolecular O—H⋯O hydrogen bonds, generating a two-dimensional sheet structure aligned parallel to the (11 Inline graphic ) plane.

Related literature

For structures of other carboxyphenylboronic acids, see: SeethaLekshmi & Pedireddi (2007 ▶); Soundararajan et al. (1993 ▶). For the application of carboxyphenylboronic acids in crystal engineering, see: (Aakeröy et al., 2005 ▶; SeethaLekshmi & Pedireddi, 2006 ▶). For structural characterization of related ortho-alkoxy arylboronic acids, see: Dabrowski et al. (2006 ▶); Dąbrowski et al. (2008 ▶); Yang et al. (2005 ▶). For the synthesis of the title compound, see: (Kurach et al., 2008 ▶).

Experimental

Crystal data

C₈H₉BO₅
M _r = 195.96
Triclinic,
a = 4.8451 (5) Å
b = 7.7564 (7) Å
c = 12.1064 (9) Å
α = 79.476 (7)°
β = 79.575 (7)°
γ = 76.125 (8)°
V = 429.75 (7) Å³
Z = 2
Mo Kα radiation
μ = 0.12 mm⁻¹
T = 100 (2) K
0.32 × 0.20 × 0.14 mm

Data collection

Kuma KM4 CCD diffractometer
Absorption correction: multi-scan (CrysAlis RED; Oxford Diffraction 2005 ▶) T _min = 0.95, T _max = 0.98
12229 measured reflections
2106 independent reflections
1526 reflections with I > 2σ(I)
R _int = 0.018

Refinement

R[F ² > 2σ(F ²)] = 0.035
wR(F ²) = 0.101
S = 1.05
2106 reflections
163 parameters
All H-atom parameters refined
Δρ_max = 0.35 e Å⁻³
Δρ_min = −0.26 e Å⁻³

Data collection: CrysAlis CCD (Oxford Diffraction (2005 ▶); cell refinement: CrysAlis RED (Oxford Diffraction (2005 ▶); data reduction: CrysAlis RED; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: DIAMOND (Brandenburg, 1999 ▶); software used to prepare material for publication: SHELXTL (Sheldrick, 2008 ▶).

Supplementary Material

Crystal structure: contains datablocks I. DOI: 10.1107/S1600536808029504/tk2303sup1.cif

e-64-o1963-sup1.cif^{(15.4KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536808029504/tk2303Isup2.hkl

e-64-o1963-Isup2.hkl^{(103.5KB, hkl)}

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

Table 1. Selected geometric parameters (Å, °).

B1—O2	1.3443 (15)
B1—O3	1.3461 (16)
B1—C9	1.5661 (17)
C6—O8	1.2607 (13)
C6—O7	1.3044 (14)

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O2—B1—C9—C14	18.65 (16)
C5—O4—C10—C9	93.35 (12)
O8—C6—C11—C10	177.57 (10)

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Table 2. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O2—H2⋯O3ⁱ	0.802 (19)	1.96 (2)	2.7572 (13)	172.6 (18)
O3—H3⋯O4	0.84 (2)	2.06 (2)	2.7283 (12)	136.8 (19)
O3—H3⋯O2ⁱⁱ	0.84 (2)	2.45 (2)	3.0538 (14)	130.2 (19)
O7—H8⋯O8ⁱⁱⁱ	1.03 (2)	1.60 (2)	2.6255 (11)	177.0 (16)

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Symmetry codes: (i) Inline graphic ; (ii) ; (iii) .

Acknowledgments

The X-ray measurements were undertaken in the Crystallographic Unit of the Physical Chemistry Laboratory at the Chemistry Department of the University of Warsaw. This work was supported by the Warsaw University of Technology and by the Polish Ministry of Science and Higher Education (grant No. N N205 055633).

supplementary crystallographic information

Comment

The presence of a carboxyl group in a molecule of arylboronic acid provides an increased potential for extended supramolecular organization (SeethaLekshmi & Pedireddi, 2007). The promising properties of carboxyphenylboronic acids in crystal engineering (Aakeröy et al., 2005; SeethaLekshmi & Pedireddi, 2006) prompted us to determine the structure of the title compound, (I).

The molecular structure of (I) shows the boronic groups possesses an exo-endo conformation and is slightly twisted with respect to the benzene ring (Table 1). The methoxy group is twisted almost perpendicularly with respect to the aromatic ring. The endo-oriented OH group is engaged in an intramolecular O—H···O hydrogen bonds with the methoxy O atom, resulting in the formation of a six-membered ring. This motif is generally typical of structures of ortho-alkoxyarylboronic acids (Yang et al., 2005; Dąbrowski et al., 2006). The carboxyl group is almost coplanar with respect to the benzene ring. The molecules are linked via almost linear O—H···O bridges in a "head-to-head, tail-to-tail" fashion, i.e., equivalent groups interact with each other forming two alternate centrosymmetric dimeric motifs, Table 2. As a result, an infinite, zigzag chain is formed (Fig. 2). The chain structure resembles the situation found for the related 2-methoxy-1,3-phenylenediboronic acid (Dąbrowski et al., 2008), where single molecules are linked via homomeric (SeethaLekshmi & Pedireddi, 2007) hydrogen-bonding interactions of non-equivalent boronic groups.

The 1D supramolecular architecture extends through cross-linking weak O—H···O bonds between twisted boronic groups. As a result a 2D array is formed, aligned parallel to the (11–2) plane. In conclusion, the intermolecular hydrogen-bonding interactions of boronic and carboxyl groups result in the formation of the infinite chain structure. Chains are interconnected by means of weaker hydrogen-bonds, thus forming the layer structure.

Experimental

The compund was prepared according to the published procedure (Kurach et al., 2008). Crystals suitable for single-crystal X-ray diffraction analysis were grown by slow evaporation of a solution of the acid (0.15 g) in ethyl acetate/acetone (10 ml, 1:1).