organic compounds
2,3,4-Trihydroxybenzaldehyde
aDepartment of Chemistry, University of Malaya, 50603 Kuala Lumpur, Malaysia
*Correspondence e-mail: seikweng@um.edu.my
The title compound, C7H6O4, crystallizes with two independent molecules in the In both molecules, the 2-hydroxy group is bound via intramolecular hydrogen bonds to the aldehyde group. The molecules interact through O—H⋯O hydrogen bonds to form a three-dimensional network structure; each hydroxy group serves as a donor to only one acceptor atom.
Related literature
For some references on hydroxy-substituted benzaldehydes, see: Kretz et al. (2007); Ng (2005). For the crystal structures of Schiff base derivatives of 2,3,4-trihydroxysalicylaldehyde, see: Petek et al. (2006); Sun et al. (2007).
Experimental
Crystal data
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Data collection
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Refinement
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Data collection: APEX2 (Bruker, 2007); cell SAINT (Bruker, 2007); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: X-SEED (Barbour, 2001); software used to prepare material for publication: publCIF (Westrip, 2008).
Supporting information
10.1107/S1600536808022241/bt2748sup1.cif
contains datablocks global, I. DOI:Structure factors: contains datablock I. DOI: 10.1107/S1600536808022241/bt2748Isup2.hkl
Commercially available 2,3,4-trihydroxybenzaldehyde was recrystallized from ethanol to furnished light-brown, needled-shaped crystals.
Carbon-bound H-atoms were placed in calculated positions (C—H 0.95 Å) and were included in the
in the riding model approximation, with U(H) set to 1.2Ueq(C). The hydroxy H-atoms were located in a difference Fourier map, and were refined with a distance restraint of O–H 0.84±0.01 Å; their displacement parameters were set to 1.5Ueq(O).Data collection: APEX2 (Bruker, 2007); cell
SAINT (Bruker, 2007); data reduction: SAINT (Bruker, 2007); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: X-SEED (Barbour, 2001); software used to prepare material for publication: publCIF (Westrip, 2008).Fig. 1. Plot (Barbour, 2001) of the two independent molecules of 2,3,4-trihydroxybenzaldehyde with 50% probability ellipsoids. Hydrogen atoms are drawn as spheres of arbitrary radius. |
C7H6O4 | F(000) = 640 |
Mr = 154.12 | Dx = 1.584 Mg m−3 |
Monoclinic, Cc | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: C c | Cell parameters from 446 reflections |
a = 3.6222 (3) Å | θ = 2.8–19.5° |
b = 24.006 (2) Å | µ = 0.13 mm−1 |
c = 14.8965 (9) Å | T = 100 K |
β = 93.524 (5)° | Needle, light brown |
V = 1292.9 (2) Å3 | 0.30 × 0.03 × 0.03 mm |
Z = 8 |
Bruker SMART APEX diffractometer | 1087 reflections with I > 2σ(I) |
Radiation source: fine-focus sealed tube | Rint = 0.088 |
Graphite monochromator | θmax = 27.5°, θmin = 1.7° |
ω scans | h = −4→3 |
5464 measured reflections | k = −30→30 |
1491 independent reflections | l = −19→19 |
Refinement on F2 | Secondary atom site location: difference Fourier map |
Least-squares matrix: full | Hydrogen site location: inferred from neighbouring sites |
R[F2 > 2σ(F2)] = 0.054 | H atoms treated by a mixture of independent and constrained refinement |
wR(F2) = 0.132 | w = 1/[σ2(Fo2) + (0.0467P)2 + 2.3366P] where P = (Fo2 + 2Fc2)/3 |
S = 1.01 | (Δ/σ)max = 0.001 |
1491 reflections | Δρmax = 0.30 e Å−3 |
217 parameters | Δρmin = −0.32 e Å−3 |
8 restraints | Absolute structure: Friedel pairs were merged |
Primary atom site location: structure-invariant direct methods |
C7H6O4 | V = 1292.9 (2) Å3 |
Mr = 154.12 | Z = 8 |
Monoclinic, Cc | Mo Kα radiation |
a = 3.6222 (3) Å | µ = 0.13 mm−1 |
b = 24.006 (2) Å | T = 100 K |
c = 14.8965 (9) Å | 0.30 × 0.03 × 0.03 mm |
β = 93.524 (5)° |
Bruker SMART APEX diffractometer | 1087 reflections with I > 2σ(I) |
5464 measured reflections | Rint = 0.088 |
1491 independent reflections |
R[F2 > 2σ(F2)] = 0.054 | 8 restraints |
wR(F2) = 0.132 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.01 | Δρmax = 0.30 e Å−3 |
1491 reflections | Δρmin = −0.32 e Å−3 |
217 parameters | Absolute structure: Friedel pairs were merged |
x | y | z | Uiso*/Ueq | ||
O1 | 0.5000 (11) | 0.19999 (15) | 0.5000 (3) | 0.0203 (9) | |
O2 | 0.4561 (11) | 0.18738 (14) | 0.6744 (3) | 0.0177 (9) | |
H2 | 0.432 (19) | 0.172 (2) | 0.6236 (19) | 0.027* | |
O3 | 0.2999 (11) | 0.23611 (14) | 0.8356 (2) | 0.0186 (9) | |
H3 | 0.253 (18) | 0.2022 (8) | 0.827 (4) | 0.028* | |
O4 | 0.0704 (11) | 0.34509 (15) | 0.8358 (3) | 0.0187 (9) | |
H4 | 0.046 (19) | 0.324 (2) | 0.879 (3) | 0.028* | |
O5 | 1.4505 (11) | −0.00937 (16) | 1.0289 (3) | 0.0206 (9) | |
O6 | 1.1992 (11) | 0.08512 (14) | 0.9559 (2) | 0.0195 (9) | |
H6 | 1.297 (17) | 0.062 (2) | 0.993 (3) | 0.029* | |
O7 | 0.8968 (11) | 0.13655 (14) | 0.8094 (3) | 0.0187 (9) | |
H7 | 0.801 (18) | 0.142 (2) | 0.7575 (19) | 0.028* | |
O8 | 0.7396 (10) | 0.07867 (14) | 0.6555 (2) | 0.0172 (9) | |
H8 | 0.696 (19) | 0.056 (2) | 0.613 (3) | 0.026* | |
C1 | 0.3888 (16) | 0.2489 (2) | 0.5099 (4) | 0.0182 (12) | |
H1 | 0.3571 | 0.2717 | 0.4579 | 0.022* | |
C2 | 0.3068 (15) | 0.2725 (2) | 0.5942 (4) | 0.0140 (11) | |
C3 | 0.3431 (15) | 0.2416 (2) | 0.6752 (4) | 0.0148 (11) | |
C4 | 0.2636 (16) | 0.2646 (2) | 0.7557 (4) | 0.0151 (12) | |
C5 | 0.1496 (15) | 0.3204 (2) | 0.7578 (4) | 0.0153 (11) | |
C6 | 0.1124 (15) | 0.3520 (2) | 0.6789 (4) | 0.0171 (12) | |
H6A | 0.0328 | 0.3896 | 0.6812 | 0.021* | |
C7 | 0.1914 (16) | 0.3285 (2) | 0.5982 (4) | 0.0184 (12) | |
H7A | 0.1680 | 0.3501 | 0.5448 | 0.022* | |
C8 | 1.3595 (16) | −0.0319 (2) | 0.9554 (4) | 0.0182 (12) | |
H8A | 1.4039 | −0.0707 | 0.9498 | 0.022* | |
C9 | 1.1938 (15) | −0.0035 (2) | 0.8791 (4) | 0.0146 (11) | |
C10 | 1.1232 (16) | 0.0546 (2) | 0.8814 (4) | 0.0150 (11) | |
C11 | 0.9686 (16) | 0.08085 (19) | 0.8055 (4) | 0.0142 (11) | |
C12 | 0.8902 (15) | 0.0499 (2) | 0.7274 (3) | 0.0142 (11) | |
C13 | 0.9584 (15) | −0.0072 (2) | 0.7239 (4) | 0.0160 (12) | |
H13 | 0.9043 | −0.0276 | 0.6701 | 0.019* | |
C14 | 1.1054 (15) | −0.0333 (2) | 0.7999 (4) | 0.0167 (12) | |
H14 | 1.1480 | −0.0723 | 0.7988 | 0.020* |
U11 | U22 | U33 | U12 | U13 | U23 | |
O1 | 0.023 (2) | 0.0189 (19) | 0.019 (2) | 0.0023 (16) | 0.0050 (18) | −0.0053 (15) |
O2 | 0.025 (2) | 0.0122 (17) | 0.015 (2) | 0.0033 (16) | −0.0038 (18) | −0.0012 (15) |
O3 | 0.032 (3) | 0.0111 (17) | 0.013 (2) | 0.0021 (16) | 0.0006 (18) | 0.0028 (14) |
O4 | 0.027 (2) | 0.0147 (17) | 0.015 (2) | 0.0041 (17) | 0.0023 (17) | −0.0010 (15) |
O5 | 0.023 (2) | 0.023 (2) | 0.015 (2) | 0.0024 (17) | −0.0034 (17) | 0.0012 (16) |
O6 | 0.032 (3) | 0.0147 (18) | 0.011 (2) | −0.0003 (16) | −0.0070 (18) | −0.0039 (15) |
O7 | 0.029 (3) | 0.0124 (16) | 0.0140 (18) | 0.0040 (16) | −0.0032 (17) | −0.0030 (15) |
O8 | 0.023 (2) | 0.0163 (18) | 0.011 (2) | 0.0023 (16) | −0.0065 (17) | −0.0020 (14) |
C1 | 0.017 (3) | 0.020 (3) | 0.017 (3) | 0.001 (2) | −0.005 (3) | 0.003 (2) |
C2 | 0.010 (3) | 0.018 (2) | 0.014 (3) | 0.001 (2) | 0.000 (2) | −0.003 (2) |
C3 | 0.007 (3) | 0.015 (2) | 0.022 (3) | 0.002 (2) | −0.002 (2) | −0.002 (2) |
C4 | 0.016 (3) | 0.014 (2) | 0.015 (3) | 0.001 (2) | −0.002 (2) | 0.001 (2) |
C5 | 0.011 (3) | 0.017 (3) | 0.019 (3) | −0.001 (2) | 0.003 (2) | −0.001 (2) |
C6 | 0.014 (3) | 0.012 (2) | 0.025 (3) | 0.002 (2) | 0.000 (3) | 0.000 (2) |
C7 | 0.021 (3) | 0.017 (3) | 0.017 (3) | 0.002 (2) | −0.001 (3) | 0.003 (2) |
C8 | 0.014 (3) | 0.019 (3) | 0.022 (3) | 0.000 (2) | 0.002 (2) | 0.006 (2) |
C9 | 0.012 (3) | 0.015 (2) | 0.016 (3) | 0.000 (2) | 0.001 (2) | 0.001 (2) |
C10 | 0.011 (3) | 0.021 (3) | 0.014 (3) | −0.002 (2) | 0.000 (2) | −0.004 (2) |
C11 | 0.013 (3) | 0.012 (2) | 0.017 (3) | 0.000 (2) | 0.001 (2) | −0.005 (2) |
C12 | 0.009 (3) | 0.020 (2) | 0.014 (3) | 0.000 (2) | 0.000 (2) | 0.003 (2) |
C13 | 0.013 (3) | 0.020 (3) | 0.014 (3) | 0.000 (2) | −0.002 (2) | −0.004 (2) |
C14 | 0.012 (3) | 0.014 (3) | 0.024 (3) | 0.001 (2) | −0.001 (2) | 0.000 (2) |
O1—C1 | 1.253 (6) | C9—C10 | 1.421 (7) |
O2—C3 | 1.365 (6) | C10—C11 | 1.382 (8) |
O3—C4 | 1.372 (6) | C11—C12 | 1.395 (7) |
O4—C5 | 1.351 (6) | C12—C13 | 1.394 (7) |
O5—C8 | 1.248 (7) | C13—C14 | 1.372 (7) |
O6—C10 | 1.343 (6) | O2—H2 | 0.84 (1) |
O7—C11 | 1.364 (6) | O3—H3 | 0.84 (1) |
O8—C12 | 1.361 (6) | O4—H4 | 0.84 (1) |
C1—C2 | 1.426 (7) | O6—H6 | 0.84 (1) |
C2—C7 | 1.409 (7) | O7—H7 | 0.84 (1) |
C2—C3 | 1.416 (7) | O8—H8 | 0.84 (1) |
C3—C4 | 1.367 (7) | C1—H1 | 0.9500 |
C4—C5 | 1.402 (7) | C6—H6A | 0.9500 |
C5—C6 | 1.398 (7) | C7—H7A | 0.9500 |
C6—C7 | 1.374 (7) | C8—H8A | 0.9500 |
C8—C9 | 1.425 (8) | C13—H13 | 0.9500 |
C9—C14 | 1.398 (7) | C14—H14 | 0.9500 |
C3—O2—H2 | 114 (4) | C10—C9—C8 | 121.1 (5) |
C4—O3—H3 | 110 (5) | O6—C10—C11 | 118.6 (4) |
C5—O4—H4 | 116 (5) | O6—C10—C9 | 121.9 (5) |
C10—O6—H6 | 104 (4) | C11—C10—C9 | 119.5 (5) |
C11—O7—H7 | 101 (4) | O7—C11—C10 | 118.7 (5) |
C12—O8—H8 | 108 (4) | O7—C11—C12 | 121.9 (5) |
O1—C1—C2 | 124.2 (5) | C10—C11—C12 | 119.4 (4) |
C7—C2—C3 | 118.4 (5) | O8—C12—C13 | 122.3 (5) |
C7—C2—C1 | 119.7 (5) | O8—C12—C11 | 115.9 (4) |
C3—C2—C1 | 121.9 (4) | C13—C12—C11 | 121.9 (5) |
O2—C3—C4 | 118.2 (5) | C14—C13—C12 | 118.6 (5) |
O2—C3—C2 | 120.4 (5) | C13—C14—C9 | 121.3 (5) |
C4—C3—C2 | 121.5 (4) | O1—C1—H1 | 117.9 |
C3—C4—O3 | 123.1 (4) | C2—C1—H1 | 117.9 |
C3—C4—C5 | 118.9 (5) | C7—C6—H6A | 120.1 |
O3—C4—C5 | 118.0 (5) | C5—C6—H6A | 120.1 |
O4—C5—C6 | 118.0 (5) | C6—C7—H7A | 119.8 |
O4—C5—C4 | 121.1 (5) | C2—C7—H7A | 119.8 |
C6—C5—C4 | 120.9 (5) | O5—C8—H8A | 117.6 |
C7—C6—C5 | 119.9 (5) | C9—C8—H8A | 117.6 |
C6—C7—C2 | 120.4 (5) | C14—C13—H13 | 120.7 |
O5—C8—C9 | 124.7 (5) | C12—C13—H13 | 120.7 |
C14—C9—C10 | 119.4 (5) | C13—C14—H14 | 119.3 |
C14—C9—C8 | 119.5 (5) | C9—C14—H14 | 119.3 |
D—H···A | D—H | H···A | D···A | D—H···A |
O2—H2···O1 | 0.84 (1) | 1.99 (5) | 2.631 (5) | 133 (6) |
O3—H3···O7i | 0.84 (1) | 2.04 (3) | 2.816 (5) | 153 (6) |
O4—H4···O1ii | 0.84 (1) | 1.90 (3) | 2.701 (5) | 159 (6) |
O6—H6···O5 | 0.84 (1) | 1.87 (3) | 2.653 (5) | 154 (6) |
O7—H7···O2 | 0.84 (1) | 2.02 (3) | 2.772 (5) | 149 (6) |
O8—H8···O5iii | 0.84 (1) | 1.86 (2) | 2.679 (5) | 162 (7) |
Symmetry codes: (i) x−1, y, z; (ii) x−1/2, −y+1/2, z+1/2; (iii) x−1, −y, z−1/2. |
Experimental details
Crystal data | |
Chemical formula | C7H6O4 |
Mr | 154.12 |
Crystal system, space group | Monoclinic, Cc |
Temperature (K) | 100 |
a, b, c (Å) | 3.6222 (3), 24.006 (2), 14.8965 (9) |
β (°) | 93.524 (5) |
V (Å3) | 1292.9 (2) |
Z | 8 |
Radiation type | Mo Kα |
µ (mm−1) | 0.13 |
Crystal size (mm) | 0.30 × 0.03 × 0.03 |
Data collection | |
Diffractometer | Bruker SMART APEX diffractometer |
Absorption correction | – |
No. of measured, independent and observed [I > 2σ(I)] reflections | 5464, 1491, 1087 |
Rint | 0.088 |
(sin θ/λ)max (Å−1) | 0.649 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.054, 0.132, 1.01 |
No. of reflections | 1491 |
No. of parameters | 217 |
No. of restraints | 8 |
H-atom treatment | H atoms treated by a mixture of independent and constrained refinement |
Δρmax, Δρmin (e Å−3) | 0.30, −0.32 |
Absolute structure | Friedel pairs were merged |
Computer programs: APEX2 (Bruker, 2007), SAINT (Bruker, 2007), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), X-SEED (Barbour, 2001), publCIF (Westrip, 2008).
D—H···A | D—H | H···A | D···A | D—H···A |
O2—H2···O1 | 0.84 (1) | 1.99 (5) | 2.631 (5) | 133 (6) |
O3—H3···O7i | 0.84 (1) | 2.04 (3) | 2.816 (5) | 153 (6) |
O4—H4···O1ii | 0.84 (1) | 1.90 (3) | 2.701 (5) | 159 (6) |
O6—H6···O5 | 0.84 (1) | 1.87 (3) | 2.653 (5) | 154 (6) |
O7—H7···O2 | 0.84 (1) | 2.02 (3) | 2.772 (5) | 149 (6) |
O8—H8···O5iii | 0.84 (1) | 1.86 (2) | 2.679 (5) | 162 (7) |
Symmetry codes: (i) x−1, y, z; (ii) x−1/2, −y+1/2, z+1/2; (iii) x−1, −y, z−1/2. |
Acknowledgements
I thank the University of Malaya for supporting this study through the purchase of the diffractometer.
References
Barbour, L. J. (2001). J. Supramol. Chem. 1, 189–191. CrossRef CAS Google Scholar
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2,3,4-Trihydroxybenzaldehyde condenses with primary amines to afford Schiff bases. The crystal structures of only few such Schiff bases have been reported. The 2-fluoroaniline derivative exists as a zwitterion as the hydrogen atom of the 2-hydroxy substituent is transferred to the imino nitrogen atom (Petek et al., 2006). On the other hand, the antipyrine derivative has the expected neutral structure (Sun et al., 2007). Although there are several structural studies on hydroxy-substituted benzaldehydes (Kretz et al., 2007; Ng, 2005), the structure of 2,3,4-trihydroxybenzaldehyde has not been reported.
2,3,4-Trihydroxybenzaldehyde (Scheme I) crystallizes with two independent molecules in the asymmetric unit. In both, the 2-hydroxy group is hydrogen-bonded to the aldehyde group via an intramolecular hydrogen bond (Fig. 1). The molecules interact through O–H···O hydrogen bonds to form a three-dimensional network structure; each hydroxy group serves as donor to only one acceptor atom.