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The crystal structure of the title compound, C8H8O4, is characterized by extensive hydrogen-bonding interactions to yield centrosymmetrically related dimers linked to each other by intermolecular interactions between the hydroxy groups and between the hydroxy and methyl groups.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536803007347/bt6260sup1.cif
Contains datablocks global, I

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S1600536803007347/bt6260Isup2.hkl
Contains datablock I

CCDC reference: 214606

Key indicators

  • Single-crystal X-ray study
  • T = 295 K
  • Mean [sigma](C-C) = 0.002 Å
  • R factor = 0.044
  • wR factor = 0.140
  • Data-to-parameter ratio = 16.2

checkCIF results

No syntax errors found

ADDSYM reports no extra symmetry








Comment top

The title compound, (I), was prepared as a prototype receptor with multiple functionality for coordination to analytes. The structure of (I) shows the molecules to be planar (Fig. 1) with bond lengths and angles in accord with conventional values (Allen et al., 1987). Pairs of centrosymmetrically related molecules are associated through bifurcated intra- and intermolecular hydrogen-bonding interactions between the α-hydroxy group and carbonyl O atoms to form a carboxylic acid dimer motif. Further hydrogen-bonding is observed between the 2- and 5-hydroxy groups on adjacent molecules (Fig. 2). In addition, the structure is stabilized through weak C—H····O hydrogen-bonding interactions between the ester methyl group and 5-hydroxy groups on adjacent molecules.

Experimental top

2,5-Dihydroxybenzoic acid (24.6 g, 159.5 mmol) was dissolved in methanol (500 ml). Sulfuric acid (98%, 10 ml) was added dropwise and the mixture stirred under reflux for 72 h. Removal of the solvent under reduced pressure yielded a yellow oil that was partitioned between chloroform (200 ml) and deionized water (100 ml). The organic layer was dried (magnesium sulfate) and condensed to yield the title compound as a crystalline white solid. Yield 24.5 g, 80.0%; m.p. 357–359 K (literature: 357–359 K; Malcolm, 1981). Crystals suitable for X-ray diffraction studies were prepared by slow evaporation at room temperature of a solution of 30 mg of (I) in a solution of diethyl ether (2 ml) and hexane (5 ml).

Refinement top

H atoms were located at calculated positions with C—H set to 0.95 Å. Hydroxy H atoms were located from difference Fourier maps and the O—H bond length set to 0.85 Å. Uiso values for the H atoms were set at 1.2Ueq of the parent atom.

Computing details top

Data collection: MSC/AFC7 Diffractometer Control Software for Windows (Molecular Structure Corporation, 1999); cell refinement: MSC/AFC7 Diffractometer Control Software for Windows; data reduction: TEXSAN for Windows (Molecular Structure Corporation, 1997-2001); program(s) used to solve structure: TEXSAN for Windows; program(s) used to refine structure: TEXSAN for Windows and SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 (Farrugia, 1997); software used to prepare material for publication: TEXSAN for Windows and PLATON (Spek, 1980-2001).

Figures top
[Figure 1] Fig. 1. ORTEP-3 (Farrugia, 1997) plot showing the atomic numbering scheme for (I). Displacement ellipsoids are drawn at the 30% probability level for non-H atoms.
[Figure 2] Fig. 2. The hydrogen-bonding scheme for (I).
Methyl 2,5-dihydroxybenzoate top
Crystal data top
C8H8O4F(000) = 352
Mr = 168.14Dx = 1.440 Mg m3
Monoclinic, P21/nMo Kα radiation, λ = 0.71069 Å
Hall symbol: -P 2ynCell parameters from 25 reflections
a = 12.316 (2) Åθ = 12.6–17.2°
b = 12.986 (2) ŵ = 0.12 mm1
c = 4.8795 (6) ÅT = 295 K
β = 96.406 (12)°Prismatic, colorless
V = 775.5 (2) Å30.40 × 0.30 × 0.30 mm
Z = 4
Data collection top
Rigaku AFC-7R
diffractometer
Rint = 0.029
Radiation source: Rigaku rotating anodeθmax = 27.5°, θmin = 3.1°
Graphite monochromatorh = 715
ω–2θ scansk = 016
2012 measured reflectionsl = 66
1784 independent reflections3 standard reflections every 150 reflections
1353 reflections with I > 2σ(I) intensity decay: 0.5%
Refinement top
Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.044H-atom parameters not refined
wR(F2) = 0.140 w = 1/[σ2(Fo2) + (0.092P)2 + 0.1P]
where P = (Fo2 + 2Fc2)/3
S = 1.03(Δ/σ)max < 0.001
1784 reflectionsΔρmax = 0.23 e Å3
110 parametersΔρmin = 0.19 e Å3
0 restraintsExtinction correction: SHELXL97, FC*=KFC[1+0.001XFC2Λ3/SIN(2Θ)]-1/4
Primary atom site location: structure-invariant direct methodsExtinction coefficient: 0.033 (9)
Crystal data top
C8H8O4V = 775.5 (2) Å3
Mr = 168.14Z = 4
Monoclinic, P21/nMo Kα radiation
a = 12.316 (2) ŵ = 0.12 mm1
b = 12.986 (2) ÅT = 295 K
c = 4.8795 (6) Å0.40 × 0.30 × 0.30 mm
β = 96.406 (12)°
Data collection top
Rigaku AFC-7R
diffractometer
Rint = 0.029
2012 measured reflections3 standard reflections every 150 reflections
1784 independent reflections intensity decay: 0.5%
1353 reflections with I > 2σ(I)
Refinement top
R[F2 > 2σ(F2)] = 0.0440 restraints
wR(F2) = 0.140H-atom parameters not refined
S = 1.03Δρmax = 0.23 e Å3
1784 reflectionsΔρmin = 0.19 e Å3
110 parameters
Special details top

Experimental. The scan width was (1.84 + 0.30tanθ)° with an ω scan speed of 16° per minute (up to 4 scans to achieve I/σ(I) > 10). Stationary background counts were recorded at each end of the scan, and the scan time:background time ratio was 2:1.

Geometry. Bond distances, angles etc. have been calculated using the rounded fractional coordinates. All e.s.d.'s are estimated from the variances of the (full) variance-covariance matrix. The cell e.s.d.'s are taken into account in the estimation of distances, angles and torsion angles

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 (Å2) top
xyzUiso*/Ueq
O210.05155 (9)0.61114 (10)0.3442 (3)0.0536 (4)
O510.23480 (9)0.86979 (10)0.9592 (3)0.0512 (4)
O710.11486 (9)0.53975 (9)0.1116 (2)0.0511 (4)
O720.28205 (8)0.60082 (8)0.2479 (2)0.0448 (3)
C10.13566 (11)0.67001 (11)0.4560 (3)0.0360 (4)
C20.02443 (11)0.67113 (12)0.4920 (3)0.0404 (4)
C30.01199 (12)0.73664 (14)0.6876 (3)0.0483 (5)
C40.05920 (13)0.80102 (13)0.8406 (3)0.0464 (5)
C50.16959 (12)0.80239 (11)0.8026 (3)0.0389 (4)
C60.20744 (11)0.73648 (11)0.6123 (3)0.0371 (4)
C70.17441 (12)0.59739 (11)0.2548 (3)0.0378 (4)
C80.32540 (15)0.52997 (14)0.0596 (4)0.0532 (5)
H30.087100.736700.716500.0580*
H40.032900.845200.974000.0560*
H60.282800.736200.587400.0440*
H8A0.297500.546900.124300.0640*
H8B0.304300.461800.099900.0640*
H8C0.402800.534700.079100.0640*
H210.022100.580300.216800.0640*
H510.298600.869400.906700.0610*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
O210.0335 (6)0.0668 (8)0.0614 (7)0.0041 (5)0.0093 (5)0.0160 (6)
O510.0422 (6)0.0575 (7)0.0549 (7)0.0028 (5)0.0105 (5)0.0157 (5)
O710.0438 (6)0.0540 (7)0.0562 (7)0.0041 (5)0.0083 (5)0.0130 (5)
O720.0373 (6)0.0459 (6)0.0538 (6)0.0008 (4)0.0163 (5)0.0093 (5)
C10.0334 (7)0.0378 (7)0.0382 (7)0.0029 (5)0.0096 (5)0.0054 (6)
C20.0317 (7)0.0471 (8)0.0430 (7)0.0014 (6)0.0068 (6)0.0023 (6)
C30.0329 (7)0.0616 (10)0.0522 (9)0.0042 (7)0.0125 (6)0.0048 (8)
C40.0406 (8)0.0534 (9)0.0471 (8)0.0075 (7)0.0137 (6)0.0061 (7)
C50.0378 (7)0.0398 (7)0.0398 (7)0.0027 (6)0.0072 (6)0.0013 (6)
C60.0315 (7)0.0406 (7)0.0406 (7)0.0024 (5)0.0106 (5)0.0029 (6)
C70.0359 (7)0.0379 (7)0.0407 (7)0.0015 (6)0.0098 (6)0.0039 (6)
C80.0533 (9)0.0500 (9)0.0604 (10)0.0048 (7)0.0243 (8)0.0092 (8)
Geometric parameters (Å, º) top
O21—C21.361 (2)C2—C31.390 (2)
O51—C51.363 (2)C3—C41.371 (2)
O71—C71.2133 (18)C4—C51.393 (2)
O72—C71.3306 (18)C5—C61.382 (2)
O72—C81.444 (2)C3—H30.9512
O21—H210.8536C4—H40.9512
O51—H510.8532C6—H60.9494
C1—C71.478 (2)C8—H8A0.9502
C1—C21.4005 (19)C8—H8B0.9494
C1—C61.399 (2)C8—H8C0.9494
O21···O712.6205 (17)C8···O51x3.283 (2)
O21···O71i3.0012 (18)C2···H51ii2.8156
O21···O51ii2.7622 (17)C3···H51ii2.9160
O51···C8iii3.283 (2)C4···H8Cviii3.0563
O51···C7iii3.404 (2)C5···H8Biv2.8960
O51···C8iv3.296 (2)C6···H8Aix2.9368
O51···O21v2.7622 (17)C7···H212.4168
O71···O71i3.0934 (16)H3···O51ii2.7723
O71···O21i3.0012 (18)H3···O72viii2.6698
O71···O212.6205 (17)H3···H6viii2.5717
O72···C3vi3.338 (2)H3···H51ii2.3854
O21···H51ii1.9206H6···O722.4149
O51···H8Aiv2.8237H6···H512.3216
O51···H3v2.7723H6···H3vi2.5717
O51···H8Biii2.5533H8A···O712.6403
O71···H211.8919H8A···C6vii2.9368
O71···H8B2.5497H8A···O51xi2.8237
O71···H21i2.4279H8B···O712.5497
O71···H8A2.6403H8B···O51x2.5533
O72···H62.4149H8B···C5xi2.8960
O72···H3vi2.6698H8C···C4vi3.0563
C1···C4vii3.488 (2)H21···O711.8919
C3···O72viii3.338 (2)H21···C72.4168
C4···C1ix3.488 (2)H21···O71i2.4279
C4···C7ix3.529 (2)H21···H51ii2.5726
C5···C8iv3.448 (2)H51···H62.3216
C5···C7ix3.454 (2)H51···O21v1.9206
C7···C5vii3.454 (2)H51···C2v2.8156
C7···C4vii3.529 (2)H51···C3v2.9160
C7···O51x3.404 (2)H51···H3v2.3854
C8···C5xi3.448 (2)H51···H21v2.5726
C8···O51xi3.296 (2)
C7—O72—C8115.78 (12)O72—C7—C1113.07 (12)
C2—O21—H21109.36O71—C7—O72123.09 (13)
C5—O51—H51109.43O71—C7—C1123.84 (14)
C6—C1—C7121.62 (13)C2—C3—H3119.74
C2—C1—C7118.86 (13)C4—C3—H3119.49
C2—C1—C6119.51 (13)C3—C4—H4119.64
O21—C2—C3117.31 (13)C5—C4—H4119.70
O21—C2—C1123.50 (13)C1—C6—H6119.68
C1—C2—C3119.19 (14)C5—C6—H6119.76
C2—C3—C4120.77 (14)O72—C8—H8A109.45
C3—C4—C5120.66 (14)O72—C8—H8B109.46
C4—C5—C6119.29 (14)O72—C8—H8C109.48
O51—C5—C4117.16 (13)H8A—C8—H8B109.44
O51—C5—C6123.55 (13)H8A—C8—H8C109.45
C1—C6—C5120.56 (13)H8B—C8—H8C109.55
C8—O72—C7—O710.8 (2)C2—C1—C7—O72177.40 (13)
C8—O72—C7—C1178.67 (13)C6—C1—C7—O71178.64 (14)
C6—C1—C2—O21178.27 (14)O21—C2—C3—C4178.62 (15)
C6—C1—C2—C31.6 (2)C1—C2—C3—C41.2 (2)
C6—C1—C7—O721.9 (2)C2—C3—C4—C50.2 (2)
C7—C1—C2—O212.4 (2)C3—C4—C5—O51178.89 (15)
C7—C1—C2—C3177.78 (14)C3—C4—C5—C61.3 (2)
C2—C1—C6—C50.5 (2)O51—C5—C6—C1179.26 (14)
C7—C1—C6—C5178.84 (14)C4—C5—C6—C10.9 (2)
C2—C1—C7—O712.0 (2)
Symmetry codes: (i) x, y+1, z; (ii) x1/2, y+3/2, z1/2; (iii) x+1/2, y+1/2, z+3/2; (iv) x+1/2, y+1/2, z+1/2; (v) x+1/2, y+3/2, z+1/2; (vi) x+1/2, y+3/2, z1/2; (vii) x, y, z1; (viii) x1/2, y+3/2, z+1/2; (ix) x, y, z+1; (x) x+1/2, y1/2, z+3/2; (xi) x+1/2, y1/2, z+1/2.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O21—H21···O710.851.892.6205 (17)142
O21—H21···O71i0.852.433.0012 (18)125
O51—H51···O21v0.851.922.7622 (17)169
C8—H8B···O51x0.952.553.283 (2)134
Symmetry codes: (i) x, y+1, z; (v) x+1/2, y+3/2, z+1/2; (x) x+1/2, y1/2, z+3/2.

Experimental details

Crystal data
Chemical formulaC8H8O4
Mr168.14
Crystal system, space groupMonoclinic, P21/n
Temperature (K)295
a, b, c (Å)12.316 (2), 12.986 (2), 4.8795 (6)
β (°) 96.406 (12)
V3)775.5 (2)
Z4
Radiation typeMo Kα
µ (mm1)0.12
Crystal size (mm)0.40 × 0.30 × 0.30
Data collection
DiffractometerRigaku AFC-7R
diffractometer
Absorption correction
No. of measured, independent and
observed [I > 2σ(I)] reflections
2012, 1784, 1353
Rint0.029
(sin θ/λ)max1)0.650
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.044, 0.140, 1.03
No. of reflections1784
No. of parameters110
H-atom treatmentH-atom parameters not refined
Δρmax, Δρmin (e Å3)0.23, 0.19

Computer programs: MSC/AFC7 Diffractometer Control Software for Windows (Molecular Structure Corporation, 1999), MSC/AFC7 Diffractometer Control Software for Windows, TEXSAN for Windows (Molecular Structure Corporation, 1997-2001), TEXSAN for Windows and SHELXL97 (Sheldrick, 1997), ORTEP-3 (Farrugia, 1997), TEXSAN for Windows and PLATON (Spek, 1980-2001).

Selected geometric parameters (Å, º) top
O21—C21.361 (2)O72—C71.3306 (18)
O51—C51.363 (2)O72—C81.444 (2)
O71—C71.2133 (18)
C7—O72—C8115.78 (12)O51—C5—C6123.55 (13)
O21—C2—C3117.31 (13)O72—C7—C1113.07 (12)
O21—C2—C1123.50 (13)O71—C7—O72123.09 (13)
O51—C5—C4117.16 (13)O71—C7—C1123.84 (14)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O21—H21···O710.851.892.6205 (17)142
O21—H21···O71i0.852.433.0012 (18)125
O51—H51···O21ii0.851.922.7622 (17)169
C8—H8B···O51iii0.952.553.283 (2)134
Symmetry codes: (i) x, y+1, z; (ii) x+1/2, y+3/2, z+1/2; (iii) x+1/2, y1/2, z+3/2.
 

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