Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536807022714/lw2013sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S1600536807022714/lw2013Isup2.hkl |
CCDC reference: 651459
Key indicators
- Single-crystal X-ray study
- T = 120 K
- Mean (C-C) = 0.001 Å
- R factor = 0.034
- wR factor = 0.099
- Data-to-parameter ratio = 14.9
checkCIF/PLATON results
No syntax errors found
Alert level C PLAT180_ALERT_3_C Check Cell Rounding: # of Values Ending with 0 = 3
0 ALERT level A = In general: serious problem 0 ALERT level B = Potentially serious problem 1 ALERT level C = Check and explain 0 ALERT level G = General alerts; check 0 ALERT type 1 CIF construction/syntax error, inconsistent or missing data 0 ALERT type 2 Indicator that the structure model may be wrong or deficient 1 ALERT type 3 Indicator that the structure quality may be low 0 ALERT type 4 Improvement, methodology, query or suggestion 0 ALERT type 5 Informative message, check
All non-hydrogen atoms were refined by full-matrix least squares calculations with anisotropic displacement parameters. All the hydrogen atoms were allowed to ride on their attached atoms with isotropic displacement parameters 1.2 times those of the Ueq of their attached atoms. The constrained C—H distances were 0.95 Å (aromatic), 0.99 Å (methylene) and 0.84 Å (hydroxy).
4-hydroxyphenoxyacetic acid has been found in phenoxymethyl penicillin fermentations (Birner, 1972) and its molecular structure was determined to establish the hydrogen bonding patterns in the crystal. Apart from the methylene H atoms the molecule is essentially planar and the torsion angle with the greatest deviation from zero or ±180° is C7—O2—C1—C2 = 6.62 (14)°. The molecular structure is shown in Figure 1, a partial packing diagram is given in Figure 2 and selected geometric parameters are listed in Table 1. Details of the hydrogen bonding are shown in Table 2.
As is often the case for monocarboxylic acids the carboxylate groups are linked by intermolecular hydrogen bonding to form a R22(8) ring across a centre of symmetry. Weaker hydrogen bonding is also present between the 4-hydroxy groups that link an infinite chain of molecules. Taken in combination the two hydrogen motifs also form R66(44) rings involving four molecules.
Other interactions involve a C5—H5···O3 contact and one C—H···π bonding distance (Table 2) less than 3 Å (where Cg is the centre of the aryl ring).
Related structures include phenylacetic acid (Hodgson & Asplund, 1991), 4-methoxyphenoxyacetic acid (Kumar & Rao, 1982) and 2-methylphenoxyacetic acid (Cox & Hickey, 2004).
For related literature, see: Birner (1972); Cox & Hickey (2004); Hodgson & Asplund (1991); Kumar & Rao (1982).
Data collection: DENZO (Otwinowski & Minor, 1997) and COLLECT (Nonius, 1998); cell refinement: DENZO and COLLECT; data reduction: DENZO and COLLECT; program(s) used to solve structure: SIR97 (Altomare et al., 1999); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: PLATON (Spek, 2003); software used to prepare material for publication: WinGX (Farrugia, 1999).
C8H8O4 | F(000) = 352 |
Mr = 168.14 | Dx = 1.531 Mg m−3 |
Monoclinic, P21/c | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -P 2ybc | Cell parameters from 1796 reflections |
a = 8.6550 (2) Å | θ = 2.9–27.5° |
b = 5.2531 (1) Å | µ = 0.12 mm−1 |
c = 16.2401 (4) Å | T = 120 K |
β = 98.983 (1)° | Block, colourless |
V = 729.31 (3) Å3 | 0.6 × 0.45 × 0.38 mm |
Z = 4 |
Bruker Nonius KappaCCD area-detector diffractometer | 1518 reflections with I > 2σ(I) |
φ and ω scans to fill Ewald sphere | Rint = 0.022 |
Absorption correction: multi-scan (SORTAV; Blessing, 1995) | θmax = 27.5°, θmin = 3.2° |
Tmin = 0.844, Tmax = 0.954 | h = −10→11 |
9200 measured reflections | k = −5→6 |
1666 independent reflections | l = −20→18 |
Refinement on F2 | 0 restraints |
Least-squares matrix: full | H-atom parameters constrained |
R[F2 > 2σ(F2)] = 0.034 | w = 1/[σ2(Fo2) + (0.0599P)2 + 0.1898P] where P = (Fo2 + 2Fc2)/3 |
wR(F2) = 0.099 | (Δ/σ)max < 0.001 |
S = 1.07 | Δρmax = 0.35 e Å−3 |
1666 reflections | Δρmin = −0.23 e Å−3 |
112 parameters |
C8H8O4 | V = 729.31 (3) Å3 |
Mr = 168.14 | Z = 4 |
Monoclinic, P21/c | Mo Kα radiation |
a = 8.6550 (2) Å | µ = 0.12 mm−1 |
b = 5.2531 (1) Å | T = 120 K |
c = 16.2401 (4) Å | 0.6 × 0.45 × 0.38 mm |
β = 98.983 (1)° |
Bruker Nonius KappaCCD area-detector diffractometer | 1666 independent reflections |
Absorption correction: multi-scan (SORTAV; Blessing, 1995) | 1518 reflections with I > 2σ(I) |
Tmin = 0.844, Tmax = 0.954 | Rint = 0.022 |
9200 measured reflections |
R[F2 > 2σ(F2)] = 0.034 | 0 restraints |
wR(F2) = 0.099 | H-atom parameters constrained |
S = 1.07 | Δρmax = 0.35 e Å−3 |
1666 reflections | Δρmin = −0.23 e Å−3 |
112 parameters |
Experimental. Please note cell_measurement_ fields are not relevant to area detector data, the entire data set is used to refine the cell, which is indexed from all observed reflections in a 10 degree phi range. |
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. |
x | y | z | Uiso*/Ueq | ||
O1 | 0.03717 (8) | 0.18406 (14) | 0.22174 (5) | 0.0183 (2) | |
H1 | 0.0231 | 0.0486 | 0.247 | 0.022* | |
O2 | 0.58461 (8) | 0.16604 (13) | 0.08499 (4) | 0.0169 (2) | |
O3 | 0.92145 (8) | −0.20002 (14) | 0.07019 (5) | 0.0184 (2) | |
H31 | 0.9935 | −0.1832 | 0.0414 | 0.022* | |
O4 | 0.84072 (8) | 0.17346 (14) | 0.01142 (4) | 0.0188 (2) | |
C1 | 0.45139 (11) | 0.15605 (18) | 0.12213 (6) | 0.0132 (2) | |
C2 | 0.42258 (11) | −0.03065 (19) | 0.17835 (6) | 0.0150 (2) | |
H2 | 0.4964 | −0.163 | 0.1934 | 0.018* | |
C3 | 0.28426 (11) | −0.02249 (19) | 0.21258 (6) | 0.0152 (2) | |
H3 | 0.2645 | −0.1483 | 0.2516 | 0.018* | |
C4 | 0.17624 (11) | 0.16823 (18) | 0.18973 (6) | 0.0139 (2) | |
C5 | 0.20589 (11) | 0.35600 (19) | 0.13400 (6) | 0.0158 (2) | |
H5 | 0.1319 | 0.4881 | 0.119 | 0.019* | |
C6 | 0.34355 (12) | 0.35056 (18) | 0.10027 (6) | 0.0152 (2) | |
H6 | 0.3642 | 0.4793 | 0.0624 | 0.018* | |
C7 | 0.68607 (11) | −0.04464 (19) | 0.10067 (6) | 0.0153 (2) | |
H7A | 0.6296 | −0.2028 | 0.0813 | 0.018* | |
H7B | 0.7228 | −0.0601 | 0.1613 | 0.018* | |
C8 | 0.82384 (11) | −0.00948 (19) | 0.05559 (6) | 0.0145 (2) |
U11 | U22 | U33 | U12 | U13 | U23 | |
O1 | 0.0148 (4) | 0.0192 (4) | 0.0228 (4) | 0.0023 (3) | 0.0094 (3) | 0.0016 (3) |
O2 | 0.0130 (4) | 0.0179 (4) | 0.0213 (4) | 0.0040 (3) | 0.0076 (3) | 0.0050 (3) |
O3 | 0.0150 (4) | 0.0204 (4) | 0.0212 (4) | 0.0059 (3) | 0.0071 (3) | 0.0051 (3) |
O4 | 0.0168 (4) | 0.0185 (4) | 0.0223 (4) | 0.0031 (3) | 0.0069 (3) | 0.0047 (3) |
C1 | 0.0108 (5) | 0.0154 (5) | 0.0138 (4) | −0.0012 (3) | 0.0029 (3) | −0.0022 (3) |
C2 | 0.0134 (5) | 0.0146 (5) | 0.0171 (5) | 0.0019 (3) | 0.0023 (3) | 0.0008 (3) |
C3 | 0.0156 (5) | 0.0151 (5) | 0.0157 (4) | −0.0008 (3) | 0.0044 (4) | 0.0017 (3) |
C4 | 0.0113 (4) | 0.0163 (5) | 0.0147 (4) | −0.0010 (3) | 0.0034 (3) | −0.0030 (3) |
C5 | 0.0146 (5) | 0.0152 (5) | 0.0177 (5) | 0.0032 (3) | 0.0028 (4) | 0.0004 (3) |
C6 | 0.0162 (5) | 0.0141 (5) | 0.0156 (4) | 0.0004 (3) | 0.0032 (4) | 0.0015 (3) |
C7 | 0.0127 (4) | 0.0167 (5) | 0.0173 (5) | 0.0026 (4) | 0.0042 (3) | 0.0023 (4) |
C8 | 0.0126 (4) | 0.0173 (5) | 0.0136 (4) | 0.0004 (3) | 0.0020 (3) | −0.0013 (3) |
O1—C4 | 1.3861 (11) | C2—H2 | 0.95 |
O1—H1 | 0.84 | C3—C4 | 1.3810 (14) |
O2—C1 | 1.3832 (11) | C3—H3 | 0.95 |
O2—C7 | 1.4110 (12) | C4—C5 | 1.3894 (14) |
O3—C8 | 1.3074 (12) | C5—C6 | 1.3871 (13) |
O3—H31 | 0.84 | C5—H5 | 0.95 |
O4—C8 | 1.2215 (12) | C6—H6 | 0.95 |
C1—C2 | 1.3887 (14) | C7—C8 | 1.5048 (13) |
C1—C6 | 1.3920 (14) | C7—H7A | 0.99 |
C2—C3 | 1.3971 (13) | C7—H7B | 0.99 |
C4—O1—H1 | 109.5 | C6—C5—C4 | 120.00 (9) |
C1—O2—C7 | 115.42 (7) | C6—C5—H5 | 120 |
C8—O3—H31 | 109.5 | C4—C5—H5 | 120 |
O2—C1—C2 | 124.12 (9) | C5—C6—C1 | 119.83 (9) |
O2—C1—C6 | 115.61 (8) | C5—C6—H6 | 120.1 |
C2—C1—C6 | 120.27 (9) | C1—C6—H6 | 120.1 |
C1—C2—C3 | 119.53 (9) | O2—C7—C8 | 109.51 (8) |
C1—C2—H2 | 120.2 | O2—C7—H7A | 109.8 |
C3—C2—H2 | 120.2 | C8—C7—H7A | 109.8 |
C4—C3—C2 | 120.10 (9) | O2—C7—H7B | 109.8 |
C4—C3—H3 | 119.9 | C8—C7—H7B | 109.8 |
C2—C3—H3 | 119.9 | H7A—C7—H7B | 108.2 |
C3—C4—O1 | 122.26 (9) | O4—C8—O3 | 125.14 (9) |
C3—C4—C5 | 120.26 (9) | O4—C8—C7 | 123.97 (9) |
O1—C4—C5 | 117.47 (8) | O3—C8—C7 | 110.89 (8) |
C7—O2—C1—C2 | 6.62 (14) | O1—C4—C5—C6 | 179.69 (8) |
C7—O2—C1—C6 | −173.88 (8) | C4—C5—C6—C1 | 0.27 (15) |
O2—C1—C2—C3 | 179.73 (8) | O2—C1—C6—C5 | 179.67 (8) |
C6—C1—C2—C3 | 0.25 (14) | C2—C1—C6—C5 | −0.81 (15) |
C1—C2—C3—C4 | 0.84 (14) | C1—O2—C7—C8 | 179.19 (7) |
C2—C3—C4—O1 | 179.81 (8) | O2—C7—C8—O4 | −1.16 (13) |
C2—C3—C4—C5 | −1.38 (15) | O2—C7—C8—O3 | 178.87 (8) |
C3—C4—C5—C6 | 0.82 (15) |
D—H···A | D—H | H···A | D···A | D—H···A |
O1—H1···O1i | 0.84 | 2.07 | 2.8878 (6) | 165 |
O3—H31···O4ii | 0.84 | 1.78 | 2.6201 (10) | 173 |
C5—H5···O3iii | 0.95 | 2.49 | 3.4318 (12) | 174 |
C2—H2···Cgiv | 0.95 | 2.87 | 3.6190 (11) | 136 |
Symmetry codes: (i) −x, y−1/2, −z+1/2; (ii) −x+2, −y, −z; (iii) x−1, y+1, z; (iv) −x+1, y−1/2, −z+1/2. |
Experimental details
Crystal data | |
Chemical formula | C8H8O4 |
Mr | 168.14 |
Crystal system, space group | Monoclinic, P21/c |
Temperature (K) | 120 |
a, b, c (Å) | 8.6550 (2), 5.2531 (1), 16.2401 (4) |
β (°) | 98.983 (1) |
V (Å3) | 729.31 (3) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 0.12 |
Crystal size (mm) | 0.6 × 0.45 × 0.38 |
Data collection | |
Diffractometer | Bruker Nonius KappaCCD area-detector |
Absorption correction | Multi-scan (SORTAV; Blessing, 1995) |
Tmin, Tmax | 0.844, 0.954 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 9200, 1666, 1518 |
Rint | 0.022 |
(sin θ/λ)max (Å−1) | 0.649 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.034, 0.099, 1.07 |
No. of reflections | 1666 |
No. of parameters | 112 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.35, −0.23 |
Computer programs: DENZO (Otwinowski & Minor, 1997) and COLLECT (Nonius, 1998), DENZO and COLLECT, SIR97 (Altomare et al., 1999), SHELXL97 (Sheldrick, 1997), PLATON (Spek, 2003), WinGX (Farrugia, 1999).
O2—C7 | 1.4110 (12) | ||
O2—C1—C2 | 124.12 (9) | O4—C8—O3 | 125.14 (9) |
O2—C1—C6 | 115.61 (8) | O4—C8—C7 | 123.97 (9) |
C3—C4—O1 | 122.26 (9) | O3—C8—C7 | 110.89 (8) |
O1—C4—C5 | 117.47 (8) | ||
C7—O2—C1—C2 | 6.62 (14) | C7—O2—C1—C6 | −173.88 (8) |
D—H···A | D—H | H···A | D···A | D—H···A |
O1—H1···O1i | 0.84 | 2.07 | 2.8878 (6) | 165 |
O3—H31···O4ii | 0.84 | 1.78 | 2.6201 (10) | 173 |
C5—H5···O3iii | 0.95 | 2.49 | 3.4318 (12) | 174 |
C2—H2···Cgiv | 0.95 | 2.87 | 3.6190 (11) | 136 |
Symmetry codes: (i) −x, y−1/2, −z+1/2; (ii) −x+2, −y, −z; (iii) x−1, y+1, z; (iv) −x+1, y−1/2, −z+1/2. |
4-hydroxyphenoxyacetic acid has been found in phenoxymethyl penicillin fermentations (Birner, 1972) and its molecular structure was determined to establish the hydrogen bonding patterns in the crystal. Apart from the methylene H atoms the molecule is essentially planar and the torsion angle with the greatest deviation from zero or ±180° is C7—O2—C1—C2 = 6.62 (14)°. The molecular structure is shown in Figure 1, a partial packing diagram is given in Figure 2 and selected geometric parameters are listed in Table 1. Details of the hydrogen bonding are shown in Table 2.
As is often the case for monocarboxylic acids the carboxylate groups are linked by intermolecular hydrogen bonding to form a R22(8) ring across a centre of symmetry. Weaker hydrogen bonding is also present between the 4-hydroxy groups that link an infinite chain of molecules. Taken in combination the two hydrogen motifs also form R66(44) rings involving four molecules.
Other interactions involve a C5—H5···O3 contact and one C—H···π bonding distance (Table 2) less than 3 Å (where Cg is the centre of the aryl ring).
Related structures include phenylacetic acid (Hodgson & Asplund, 1991), 4-methoxyphenoxyacetic acid (Kumar & Rao, 1982) and 2-methylphenoxyacetic acid (Cox & Hickey, 2004).