Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270106012297/jz3006sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S0108270106012297/jz3006Isup2.hkl |
CCDC reference: 609554
Compound (I) was obtained from Aldrich. Crystals of (I) suitable for for single-crystal X-ray diffraction analysis were grown by slow evaporation of a saturated solution in ethyl acetate/toluene (1:1) (m.p. 375–377 K).
All H atoms were located in difference syntheses and refined freely [C—H = 0.931 (19)–0.996 (14) Å.
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, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: DIAMOND (Brandenburg, 1999); software used to prepare material for publication: SHELXTL97.
C8H9BO4 | Dx = 1.389 Mg m−3 |
Mr = 179.96 | Melting point = 375–377 K |
Monoclinic, P21/m | Mo Kα radiation, λ = 0.71073 Å |
a = 8.2764 (2) Å | Cell parameters from 18642 reflections |
b = 19.7124 (6) Å | θ = 2.6–29.0° |
c = 8.7321 (3) Å | µ = 0.11 mm−1 |
β = 115.007 (3)° | T = 100 K |
V = 1291.07 (7) Å3 | Prism, colourless |
Z = 6 | 0.46 × 0.32 × 0.21 mm |
F(000) = 564 |
Oxford Diffraction KM-4 CCD diffractometer | 3268 independent reflections |
Radiation source: fine-focus sealed tube | 2797 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.012 |
Detector resolution: 8.6479 pixels mm-1 | θmax = 28.6°, θmin = 2.8° |
ω scans | h = −11→11 |
Absorption correction: multi-scan (CrysAlis RED; Oxford Diffraction, 2005) | k = −26→26 |
Tmin = 0.96, Tmax = 0.98 | l = −11→11 |
23407 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)] = 0.033 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.094 | All H-atom parameters refined |
S = 1.12 | w = 1/[σ2(Fo2) + (0.0537P)2 + 0.2342P] where P = (Fo2 + 2Fc2)/3 |
3268 reflections | (Δ/σ)max = 0.001 |
252 parameters | Δρmax = 0.53 e Å−3 |
0 restraints | Δρmin = −0.26 e Å−3 |
C8H9BO4 | V = 1291.07 (7) Å3 |
Mr = 179.96 | Z = 6 |
Monoclinic, P21/m | Mo Kα radiation |
a = 8.2764 (2) Å | µ = 0.11 mm−1 |
b = 19.7124 (6) Å | T = 100 K |
c = 8.7321 (3) Å | 0.46 × 0.32 × 0.21 mm |
β = 115.007 (3)° |
Oxford Diffraction KM-4 CCD diffractometer | 3268 independent reflections |
Absorption correction: multi-scan (CrysAlis RED; Oxford Diffraction, 2005) | 2797 reflections with I > 2σ(I) |
Tmin = 0.96, Tmax = 0.98 | Rint = 0.012 |
23407 measured reflections |
R[F2 > 2σ(F2)] = 0.033 | 0 restraints |
wR(F2) = 0.094 | All H-atom parameters refined |
S = 1.12 | Δρmax = 0.53 e Å−3 |
3268 reflections | Δρmin = −0.26 e Å−3 |
252 parameters |
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 | ||
B1A | 0.7560 (2) | 0.2500 | 0.10927 (19) | 0.0147 (3) | |
O2A | 0.84020 (9) | 0.19131 (4) | 0.10383 (10) | 0.01859 (17) | |
C4A | 0.58490 (18) | 0.2500 | 0.14853 (18) | 0.0135 (3) | |
C5A | 0.40914 (18) | 0.2500 | 0.02271 (17) | 0.0135 (3) | |
C6A | 0.26290 (19) | 0.2500 | 0.06308 (18) | 0.0155 (3) | |
C7A | 0.28900 (19) | 0.2500 | 0.23082 (18) | 0.0164 (3) | |
C8A | 0.46185 (19) | 0.2500 | 0.35780 (18) | 0.0154 (3) | |
C9A | 0.60694 (19) | 0.2500 | 0.31652 (18) | 0.0153 (3) | |
C10A | 0.38300 (18) | 0.2500 | −0.15829 (18) | 0.0151 (3) | |
O11A | 0.50296 (14) | 0.2500 | −0.20031 (13) | 0.0217 (2) | |
O12A | 0.21027 (13) | 0.2500 | −0.26413 (13) | 0.0189 (2) | |
C13A | 0.1733 (2) | 0.2500 | −0.44150 (18) | 0.0205 (3) | |
H2A | 0.778 (2) | 0.1552 (9) | 0.106 (2) | 0.040 (4)* | |
H6A | 0.146 (2) | 0.2500 | −0.024 (2) | 0.018 (4)* | |
H7A | 0.186 (3) | 0.2500 | 0.257 (2) | 0.020 (4)* | |
H8A | 0.485 (2) | 0.2500 | 0.472 (2) | 0.017 (4)* | |
H9A | 0.727 (3) | 0.2500 | 0.410 (2) | 0.019 (4)* | |
H13B | 0.2218 (17) | 0.2909 (7) | −0.4699 (16) | 0.022 (3)* | |
H13A | 0.043 (3) | 0.2500 | −0.502 (2) | 0.022 (5)* | |
B1B | 0.64335 (15) | 0.03990 (6) | 0.23390 (14) | 0.0160 (2) | |
O2B | 0.63920 (11) | 0.07786 (4) | 0.10208 (10) | 0.02110 (18) | |
O3B | 0.59072 (10) | −0.02644 (4) | 0.20533 (9) | 0.01729 (17) | |
C4B | 0.72656 (13) | 0.07235 (5) | 0.41676 (12) | 0.0148 (2) | |
C5B | 0.62241 (13) | 0.09238 (5) | 0.50140 (12) | 0.0144 (2) | |
C6B | 0.69903 (14) | 0.12175 (5) | 0.66217 (13) | 0.0168 (2) | |
C7B | 0.88173 (14) | 0.13109 (5) | 0.74235 (13) | 0.0195 (2) | |
C8B | 0.98774 (14) | 0.11072 (6) | 0.66255 (14) | 0.0205 (2) | |
C9B | 0.91089 (14) | 0.08231 (5) | 0.50166 (14) | 0.0183 (2) | |
C10B | 0.42559 (13) | 0.08558 (5) | 0.42013 (13) | 0.0151 (2) | |
O11B | 0.32945 (10) | 0.08921 (4) | 0.49407 (9) | 0.01926 (17) | |
O12B | 0.36270 (9) | 0.07474 (4) | 0.25489 (9) | 0.01917 (17) | |
C13B | 0.17208 (15) | 0.06358 (7) | 0.16598 (15) | 0.0253 (2) | |
H2B | 0.574 (2) | 0.0605 (9) | 0.002 (2) | 0.045 (5)* | |
H3B | 0.609 (2) | −0.0490 (10) | 0.295 (2) | 0.051 (5)* | |
H6B | 0.6238 (16) | 0.1378 (6) | 0.7136 (16) | 0.017 (3)* | |
H7B | 0.9340 (18) | 0.1523 (7) | 0.8526 (18) | 0.025 (3)* | |
H8B | 1.1197 (19) | 0.1161 (7) | 0.7198 (18) | 0.028 (4)* | |
H9B | 0.9892 (19) | 0.0696 (7) | 0.4494 (18) | 0.027 (3)* | |
H13D | 0.152 (2) | 0.0539 (8) | 0.050 (2) | 0.032 (4)* | |
H13E | 0.1379 (19) | 0.0251 (8) | 0.2171 (18) | 0.029 (4)* | |
H13F | 0.1087 (19) | 0.1045 (8) | 0.1705 (19) | 0.030 (4)* |
U11 | U22 | U33 | U12 | U13 | U23 | |
B1A | 0.0128 (7) | 0.0176 (7) | 0.0133 (7) | 0.000 | 0.0053 (6) | 0.000 |
O2A | 0.0168 (4) | 0.0159 (4) | 0.0263 (4) | 0.0009 (3) | 0.0123 (3) | 0.0005 (3) |
C4A | 0.0141 (6) | 0.0107 (6) | 0.0167 (6) | 0.000 | 0.0076 (5) | 0.000 |
C5A | 0.0147 (6) | 0.0115 (6) | 0.0152 (7) | 0.000 | 0.0073 (5) | 0.000 |
C6A | 0.0129 (6) | 0.0171 (7) | 0.0160 (7) | 0.000 | 0.0056 (5) | 0.000 |
C7A | 0.0155 (7) | 0.0171 (7) | 0.0193 (7) | 0.000 | 0.0100 (6) | 0.000 |
C8A | 0.0190 (7) | 0.0151 (6) | 0.0135 (6) | 0.000 | 0.0081 (5) | 0.000 |
C9A | 0.0144 (6) | 0.0155 (7) | 0.0152 (6) | 0.000 | 0.0056 (5) | 0.000 |
C10A | 0.0113 (6) | 0.0100 (6) | 0.0211 (7) | 0.000 | 0.0041 (5) | 0.000 |
O11A | 0.0197 (5) | 0.0297 (6) | 0.0180 (5) | 0.000 | 0.0103 (4) | 0.000 |
O12A | 0.0152 (5) | 0.0292 (6) | 0.0125 (5) | 0.000 | 0.0059 (4) | 0.000 |
C13A | 0.0192 (7) | 0.0301 (8) | 0.0125 (7) | 0.000 | 0.0071 (6) | 0.000 |
B1B | 0.0158 (5) | 0.0175 (6) | 0.0161 (5) | −0.0005 (4) | 0.0081 (4) | −0.0016 (4) |
O2B | 0.0294 (4) | 0.0190 (4) | 0.0156 (4) | −0.0077 (3) | 0.0102 (3) | −0.0021 (3) |
O3B | 0.0227 (4) | 0.0154 (4) | 0.0142 (3) | −0.0021 (3) | 0.0082 (3) | −0.0007 (3) |
C4B | 0.0173 (5) | 0.0121 (4) | 0.0152 (4) | −0.0007 (3) | 0.0071 (4) | 0.0004 (3) |
C5B | 0.0155 (5) | 0.0124 (4) | 0.0146 (5) | 0.0003 (3) | 0.0057 (4) | 0.0017 (3) |
C6B | 0.0209 (5) | 0.0149 (5) | 0.0151 (5) | 0.0012 (4) | 0.0080 (4) | 0.0001 (4) |
C7B | 0.0219 (5) | 0.0179 (5) | 0.0149 (5) | −0.0019 (4) | 0.0041 (4) | −0.0019 (4) |
C8B | 0.0158 (5) | 0.0197 (5) | 0.0224 (5) | −0.0027 (4) | 0.0045 (4) | −0.0011 (4) |
C9B | 0.0178 (5) | 0.0175 (5) | 0.0215 (5) | −0.0005 (4) | 0.0100 (4) | −0.0011 (4) |
C10B | 0.0180 (5) | 0.0115 (4) | 0.0151 (5) | 0.0015 (4) | 0.0065 (4) | 0.0015 (3) |
O11B | 0.0182 (4) | 0.0214 (4) | 0.0198 (4) | 0.0018 (3) | 0.0097 (3) | 0.0031 (3) |
O12B | 0.0149 (4) | 0.0253 (4) | 0.0145 (3) | 0.0011 (3) | 0.0035 (3) | −0.0017 (3) |
C13B | 0.0160 (5) | 0.0303 (6) | 0.0217 (6) | 0.0000 (4) | 0.0003 (4) | −0.0020 (5) |
B1A—O2Ai | 1.3616 (11) | B1B—O3B | 1.3677 (14) |
B1A—O2A | 1.3616 (11) | B1B—C4B | 1.5823 (15) |
B1A—C4A | 1.592 (2) | O2B—H2B | 0.880 (19) |
O2A—H2A | 0.883 (17) | O3B—H3B | 0.858 (19) |
C4A—C9A | 1.3997 (19) | C4B—C9B | 1.3998 (14) |
C4A—C5A | 1.4042 (19) | C4B—C5B | 1.4083 (14) |
C5A—C6A | 1.3963 (19) | C5B—C6B | 1.3984 (14) |
C5A—C10A | 1.502 (2) | C5B—C10B | 1.4825 (14) |
C6A—C7A | 1.387 (2) | C6B—C7B | 1.3840 (15) |
C6A—H6A | 0.945 (18) | C6B—H6B | 0.962 (12) |
C7A—C8A | 1.392 (2) | C7B—C8B | 1.3906 (16) |
C7A—H7A | 0.973 (19) | C7B—H7B | 0.968 (14) |
C8A—C9A | 1.392 (2) | C8B—C9B | 1.3915 (15) |
C8A—H8A | 0.931 (19) | C8B—H8B | 0.996 (14) |
C9A—H9A | 0.983 (19) | C9B—H9B | 0.970 (14) |
C10A—O11A | 1.1951 (17) | C10B—O11B | 1.2204 (12) |
C10A—O12A | 1.3344 (17) | C10B—O12B | 1.3280 (12) |
O12A—C13A | 1.4462 (17) | O12B—C13B | 1.4507 (13) |
C13A—H13B | 0.978 (13) | C13B—H13D | 0.969 (15) |
C13A—H13A | 0.976 (19) | C13B—H13E | 0.981 (15) |
B1B—O2B | 1.3610 (13) | C13B—H13F | 0.972 (16) |
O2Ai—B1A—O2A | 116.34 (12) | O3B—B1B—C4B | 122.67 (9) |
O2Ai—B1A—C4A | 121.50 (6) | B1B—O2B—H2B | 114.3 (11) |
O2A—B1A—C4A | 121.50 (6) | B1B—O3B—H3B | 114.1 (13) |
B1A—O2A—H2A | 112.0 (10) | C9B—C4B—C5B | 117.04 (9) |
C9A—C4A—C5A | 116.93 (12) | C9B—C4B—B1B | 120.21 (9) |
C9A—C4A—B1A | 119.48 (12) | C5B—C4B—B1B | 122.76 (9) |
C5A—C4A—B1A | 123.59 (12) | C6B—C5B—C4B | 121.63 (9) |
C6A—C5A—C4A | 121.62 (13) | C6B—C5B—C10B | 117.27 (9) |
C6A—C5A—C10A | 120.73 (12) | C4B—C5B—C10B | 121.05 (9) |
C4A—C5A—C10A | 117.65 (12) | C7B—C6B—C5B | 119.85 (10) |
C7A—C6A—C5A | 120.12 (13) | C7B—C6B—H6B | 120.3 (7) |
C7A—C6A—H6A | 119.8 (11) | C5B—C6B—H6B | 119.8 (7) |
C5A—C6A—H6A | 120.1 (11) | C6B—C7B—C8B | 119.60 (10) |
C6A—C7A—C8A | 119.36 (13) | C6B—C7B—H7B | 119.6 (8) |
C6A—C7A—H7A | 119.0 (11) | C8B—C7B—H7B | 120.8 (8) |
C8A—C7A—H7A | 121.6 (11) | C7B—C8B—C9B | 120.41 (10) |
C7A—C8A—C9A | 120.18 (13) | C7B—C8B—H8B | 120.5 (8) |
C7A—C8A—H8A | 121.9 (11) | C9B—C8B—H8B | 119.1 (8) |
C9A—C8A—H8A | 118.0 (11) | C8B—C9B—C4B | 121.46 (10) |
C8A—C9A—C4A | 121.80 (13) | C8B—C9B—H9B | 117.9 (9) |
C8A—C9A—H9A | 117.5 (11) | C4B—C9B—H9B | 120.6 (9) |
C4A—C9A—H9A | 120.7 (11) | O11B—C10B—O12B | 122.72 (9) |
O11A—C10A—O12A | 124.97 (14) | O11B—C10B—C5B | 124.87 (9) |
O11A—C10A—C5A | 123.66 (13) | O12B—C10B—C5B | 112.42 (8) |
O12A—C10A—C5A | 111.37 (12) | C10B—O12B—C13B | 116.35 (8) |
C10A—O12A—C13A | 114.93 (11) | O12B—C13B—H13D | 104.9 (9) |
O12A—C13A—H13B | 110.3 (8) | O12B—C13B—H13E | 109.3 (8) |
O12A—C13A—H13A | 105.2 (11) | H13D—C13B—H13E | 111.4 (13) |
H13B—C13A—H13A | 109.9 (9) | O12B—C13B—H13F | 109.6 (9) |
O2B—B1B—O3B | 118.63 (9) | H13D—C13B—H13F | 110.3 (13) |
O2B—B1B—C4B | 118.41 (9) | H13E—C13B—H13F | 111.1 (12) |
O2Ai—B1A—C4A—C9A | −85.18 (12) | O2B—B1B—C4B—C9B | −71.88 (13) |
O2A—B1A—C4A—C9A | 85.18 (12) | O3B—B1B—C4B—C9B | 101.97 (12) |
O2Ai—B1A—C4A—C5A | 94.82 (12) | O2B—B1B—C4B—C5B | 108.12 (11) |
O2A—B1A—C4A—C5A | −94.82 (12) | O3B—B1B—C4B—C5B | −78.04 (13) |
C9A—C4A—C5A—C6A | 0.0 | C9B—C4B—C5B—C6B | 0.83 (14) |
B1A—C4A—C5A—C6A | 180.0 | B1B—C4B—C5B—C6B | −179.17 (9) |
C9A—C4A—C5A—C10A | 180.0 | C9B—C4B—C5B—C10B | 178.36 (9) |
B1A—C4A—C5A—C10A | 0.0 | B1B—C4B—C5B—C10B | −1.63 (15) |
C4A—C5A—C6A—C7A | 0.0 | C4B—C5B—C6B—C7B | −0.63 (15) |
C10A—C5A—C6A—C7A | 180.0 | C10B—C5B—C6B—C7B | −178.26 (9) |
C5A—C6A—C7A—C8A | 0.0 | C5B—C6B—C7B—C8B | −0.43 (16) |
C6A—C7A—C8A—C9A | 0.0 | C6B—C7B—C8B—C9B | 1.27 (16) |
C7A—C8A—C9A—C4A | 0.0 | C7B—C8B—C9B—C4B | −1.07 (16) |
C5A—C4A—C9A—C8A | 0.0 | C5B—C4B—C9B—C8B | 0.02 (15) |
B1A—C4A—C9A—C8A | 180.0 | B1B—C4B—C9B—C8B | −179.98 (10) |
C6A—C5A—C10A—O11A | 180.0 | C6B—C5B—C10B—O11B | −17.14 (15) |
C4A—C5A—C10A—O11A | 0.0 | C4B—C5B—C10B—O11B | 165.22 (10) |
C6A—C5A—C10A—O12A | 0.0 | C6B—C5B—C10B—O12B | 163.00 (9) |
C4A—C5A—C10A—O12A | 180.0 | C4B—C5B—C10B—O12B | −14.64 (13) |
O11A—C10A—O12A—C13A | 0.0 | O11B—C10B—O12B—C13B | −3.24 (14) |
C5A—C10A—O12A—C13A | 180.0 | C5B—C10B—O12B—C13B | 176.62 (9) |
Symmetry code: (i) x, −y+1/2, z. |
D—H···A | D—H | H···A | D···A | D—H···A |
O2A—H2A···O2B | 0.883 (17) | 1.901 (17) | 2.7835 (11) | 177.8 (16) |
O2B—H2B···O3Bii | 0.880 (19) | 1.870 (19) | 2.7451 (11) | 172.8 (16) |
O3B—H3B···O11Biii | 0.858 (19) | 1.87 (2) | 2.7187 (11) | 172.6 (18) |
Symmetry codes: (ii) −x+1, −y, −z; (iii) −x+1, −y, −z+1. |
Experimental details
Crystal data | |
Chemical formula | C8H9BO4 |
Mr | 179.96 |
Crystal system, space group | Monoclinic, P21/m |
Temperature (K) | 100 |
a, b, c (Å) | 8.2764 (2), 19.7124 (6), 8.7321 (3) |
β (°) | 115.007 (3) |
V (Å3) | 1291.07 (7) |
Z | 6 |
Radiation type | Mo Kα |
µ (mm−1) | 0.11 |
Crystal size (mm) | 0.46 × 0.32 × 0.21 |
Data collection | |
Diffractometer | Oxford Diffraction KM-4 CCD diffractometer |
Absorption correction | Multi-scan (CrysAlis RED; Oxford Diffraction, 2005) |
Tmin, Tmax | 0.96, 0.98 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 23407, 3268, 2797 |
Rint | 0.012 |
(sin θ/λ)max (Å−1) | 0.674 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.033, 0.094, 1.12 |
No. of reflections | 3268 |
No. of parameters | 252 |
H-atom treatment | All H-atom parameters refined |
Δρmax, Δρmin (e Å−3) | 0.53, −0.26 |
Computer programs: CrysAlis CCD (Oxford Diffraction, 2005), CrysAlis RED (Oxford Diffraction, 2005), CrysAlis RED, SHELXS97 (Sheldrick, 1990), SHELXL97 (Sheldrick, 1997), DIAMOND (Brandenburg, 1999), SHELXTL97.
B1A—O2Ai | 1.3616 (11) | B1B—O3B | 1.3677 (14) |
B1A—C4A | 1.592 (2) | B1B—C4B | 1.5823 (15) |
C5A—C10A | 1.502 (2) | C5B—C10B | 1.4825 (14) |
C10A—O11A | 1.1951 (17) | C10B—O11B | 1.2204 (12) |
C10A—O12A | 1.3344 (17) | C10B—O12B | 1.3280 (12) |
B1B—O2B | 1.3610 (13) | ||
O2Ai—B1A—O2A | 116.34 (12) | O2B—B1B—O3B | 118.63 (9) |
O2Ai—B1A—C4A | 121.50 (6) | O2B—B1B—C4B | 118.41 (9) |
C9A—C4A—B1A | 119.48 (12) | O3B—B1B—C4B | 122.67 (9) |
C5A—C4A—B1A | 123.59 (12) | C5B—C4B—B1B | 122.76 (9) |
C6A—C5A—C10A | 120.73 (12) | C6B—C5B—C10B | 117.27 (9) |
C4A—C5A—C10A | 117.65 (12) | C4B—C5B—C10B | 121.05 (9) |
O11A—C10A—O12A | 124.97 (14) | O11B—C10B—O12B | 122.72 (9) |
O11A—C10A—C5A | 123.66 (13) | O11B—C10B—C5B | 124.87 (9) |
O12A—C10A—C5A | 111.37 (12) | O12B—C10B—C5B | 112.42 (8) |
O2A—B1A—C4A—C9A | 85.18 (12) | C4B—C5B—C10B—O11B | 165.22 (10) |
O2Ai—B1A—C4A—C5A | 94.82 (12) | C6B—C5B—C10B—O12B | 163.00 (9) |
B1B—C4B—C5B—C10B | −1.63 (15) | O11B—C10B—O12B—C13B | −3.24 (14) |
C6B—C5B—C10B—O11B | −17.14 (15) |
Symmetry code: (i) x, −y+1/2, z. |
D—H···A | D—H | H···A | D···A | D—H···A |
O2A—H2A···O2B | 0.883 (17) | 1.901 (17) | 2.7835 (11) | 177.8 (16) |
O2B—H2B···O3Bii | 0.880 (19) | 1.870 (19) | 2.7451 (11) | 172.8 (16) |
O3B—H3B···O11Biii | 0.858 (19) | 1.87 (2) | 2.7187 (11) | 172.6 (18) |
Symmetry codes: (ii) −x+1, −y, −z; (iii) −x+1, −y, −z+1. |
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The use of arylboronic acids in supramolecular assembly is potentially promising (Fournier et al., 2003; Davis et al., 2001) but still relatively unexplored. Arylboronic acids with carbonyl substituents are interesting as they may be able to support supramolecular organization via hydrogen-bonding interactions. For this reason we have determined the structure of the title compound, (I), for crystal structures of related arylboronic acids (see Fronczek et al., 2001; Ganguly et al., 2003; Scouten et al., 1994; Zarychta et al., 2004).
The structure of (I) is unusual in that it displays conformational isomerism, in contrast to the related compounds cited above. It contains two independent molecules (Fig. 1), one of which (A) lies with all non-H atoms except atom O2A in a crystallographic mirror plane, while the other (B) occupies a general position. In molecule A, the methoxycarbonyl group is coplanar by symmetry with the ring. The carbonyl group in molecule A is syn-directed with respect to the boronic acid group, which resembles the situation in 2-acetylphenylboronic acid monohydrate (Ganguly et al., 2003). In contrast, the carbonyl group in molecule B is anti with respect to the boronic acid group. The methoxycarbonyl group in molecule B is not strictly coplanar with the benzene ring; the C4B—C5B—C10B—O11B torsion angle is 165.22 (10)°, which may reflect steric repulsion between functional groups. Some variation of bond lengths and angles is also observed. The C10—O11 bond in molecule B [1.2204 (12) Å] is longer than the corresponding bond in A [1.1951 (17) Å]. Presumably, this effect can be rationalized in terms of hydrogen-bonding interaction between the carbonyl O atom and an OH group from a neighboring molecule B (Fig. 2), which slightly decreases the C10B—O11B bond order. The C4—C5—C10 bond angles are 117.65 (12) and 121.05 (9)°, whereas the C6—C5—C10 bond angles are 120.73 (12) and 117.27 (9)° for molecules A and B, respectively. The situation in molecule A is similar to that observed in 2-acetylphenylboronic acid (Ganguly et al., 2003). It is plausible that a weak boron–oxygen interaction [B1A···O11A = 2.628 (s.u.?) Å], resulting from a partial overlap of an empty 2p orbital of the B atom with the lone pair of the carbonyl O atom, decreases the C4—C5—C10 angle. In molecule B, such an interaction is not possible, and the C4—C5—C10 angle is larger. The conformational isomerism is also reflected in the behaviour of the boronic acid groups. In molecule A, the boronic acid group is rotated more with respect to the ring, as seen from the O2A—B1A—C4A—C5A torsion angle [94.82 (12)°]. In 1B the boronic moiety displays a corresponding O2B—B1B—C4B—C9B torsion angle of −71.88 (13)°. Such flexible behaviour of a boronic acid group was found in other ortho-substituted arylboronic acids (Gainsford et al., 1995; Ganguly et al., 2003) but not for the closely related 2-formylphenylboronic acid (Scouten et al., 1994), where the planar conformation is stabilized by an intramolecular hydrogen bond. Another difference is the conformation within B(OH)2 groups, reflecting a specific crystal packing imposed by intermolecular hydrogen bonding. In molecule A, both OH bonds are syn directed with respect to the ring, whereas in B they exhibit a syn-anti orientation.
A crystal packing diagram for (I), showing the effect of mirror symmetry, is depicted in Fig. 2. There are three classical O—H···O hydrogen bonds (Table 2); the strongest hydrogen bonds, O3B—H3B···O11B, are formed between molecules B (motif a in Fig. 2) (Etter, 1990; Bernstein et al., 1995), producing a centrosymmetric dimer [R22(14) graph set descriptor]. Furthermore, molecules B are linked with one another by O2B—H2B···O3B hydrogen bonds between B(OH)2 groups (motif b), to form centrosymmetric dimers [R22(8) ring] typical of arylboronic acids (Rettig & Trotter, 1977). Molecules A are linked to boronic acid O atoms of two adjacent molecules B by an O2A—H2A···O2B bridge [motif c, D22(7) graph-set descriptor]. The second-level motif N2(ab) = C22(9)[R44(20)] depicts a characteristic infinite chain of alternating fused rings. Other chains are represented by binary motifs N2(ac) = C33(15) and N2(bc) = C33(10). The hydrogen-bond network produces an infinite two-dimensional structure, where a larger ring depicted by the third-level graph-set descriptor N3(abc) = C44(15)[R88(30)] can be distinguished.