3-(5-tert-Butyl-2-hydroxy­benzoyl)­propanoic acid

The title compound, C₁₂H₁₈O₄, was synthesized as a part of an investigation into corrosion inhibitors, as it is structurally related to the commercial reagent Ircagor 419. The mol­ecules form centrosymmetric dimers due to hydrogen bonding involving the carboxyl groups, typical for the crystal structures of carboxylic acids. There is also an intra­molecular hydrogen bond between the phenol hydroxyl group and the ortho keto O atom. π–π inter­actions between benzene rings link the mol­ecules into stacks running along the a axis (distances between the planes of adjacent mol­ecules are 3.305 and 3.389 Å). Inter­molecular hydrogen bonds, together with the stacking inter­actions, give rise to infinite sheets parallel to the ac plane of the crystal structure.

Key indicators

• Single-crystal X-ray study
• T = 150 K
• Mean [sigma](C-C) = 0.002 Å
• R factor = 0.052
• wR factor = 0.142
• Data-to-parameter ratio = 23.4

checkCIF/PLATON results

No syntax errors found



Alert level C
ABSTM02_ALERT_3_C  The ratio of expected to reported Tmax/Tmin(RR') is < 0.90
            Tmin and Tmax reported:      0.807     0.990
            Tmin(prime) and Tmax expected:      0.969     0.987
            RR(prime) =      0.830
            Please check that your absorption correction is appropriate.
PLAT061_ALERT_3_C Tmax/Tmin Range Test RR' too Large .............       0.83
PLAT094_ALERT_2_C Ratio of Maximum / Minimum Residual Density ....       2.39
PLAT154_ALERT_1_C The su's on the Cell Angles are Equal  (x 10000)        200 Deg.

   0 ALERT level A = In general: serious problem
   0 ALERT level B = Potentially serious problem
   4 ALERT level C = Check and explain
   0 ALERT level G = General alerts; check

   1 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   1 ALERT type 2 Indicator that the structure model may be wrong or deficient
   2 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

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S1. Comment

The title compound was synthesized as a potential corrosion inhibitor as it has a structure similar to that of successful reagent Ircagor 419^TM (Frey et al., 2000) and, in addition, includes a phenolic hydroxyl group which may coordinate to a metal or form hydrogen bonds to the surface. The molecules in the crystal structure form dimers via H-bonding between two adjacent carboxylate moieties (O4—H4···O3 = 2.642 (1) Å; Figure 1) which is typical for carboxylate structures. An intramolecular hydrogen bond is also formed between the phenolic hydroxyl group and the ortho keto oxygen (O1···O29 = 2.578 (1) Å).

Each molecule is involved in π–π stacking interactions with one molecule above and one below, in the direction of the a axis. The distances between the planes of the molecules are 3.305 Å and 3.389 Å. An isotactic arrangement of these π–π stacked chains occurs, with each chain linked to the next one through the carboxylate H-bonds described above, thus forming two-dimensional sheets parallel to the ac plane (Figure 2).

Related literature

Similar 4-keto acids based on 3-benzoylpropionic acid, which does not contain the phenolic hydroxyl group, have been characterized crystallographically. These include two polymorphs of 3-benzoylpropionic acid (Selladurai et al., 1990; Thompson et al., 1991), 4-(4-biphenyl)-4-oxobutyric acid (Kim et al., 1988), 3-[4-(methylsulfonyl)benzoyl]propionic acid (Lynch & McClenaghan, 2002) and 3-(4-methylbenzoyl)propionic acid (Ircagor 419; Frey et al., 2000), which is used as a corrosion inhibitor for mild steel. All structures contain the dimeric carboxylate hydrogen bonding seen in the title compound.

S2. Experimental

4-tert-Butylanisole (3.001 g, 18.2 mmol) and succinic anhydride (1.832 g, 18.3 mmol) were dissolved in nitrobenzene and aluminium chloride (5.1 g, 38.2 mmol) was added in portions over ice. The mixture was heated to 60 °C for 4 h and then treated with aqueous HCl (100 ml, 1 M). Extraction into chloroform (100 ml) and removal of solvent yielded a solid which was dissolved in NaOH (1 M, 100 ml). The pH was adjusted to 2 with conc HCl and the precipitate collected and recrystallized from hexane/chloroform to yield the title compound (2.350 g, 9.4 mmol, 52%). Colourless rods suitable for XRD analysis were grown by slow evaporation of a hexane/chloroform solution.

S3. Refinement

Hydroxyl H atoms were found in a Fourier difference map and their positional and isotropic displacement parameters refined [O1—H1 0.86 (2) Å; O4—H4 0.87 (2) Å]. The H atoms bound to carbon were placed in idealized positions and allowed to ride on their parent atoms with bond lengths of 0.95–0.99 Å and U_iso values set at 1.2U_eq of the corresponding carrier atom (1.5U_eq for methyl H atoms).

Computing details

Data collection: SMART (Siemens, 1993); cell refinement: SAINT; data reduction: SAINT (Siemens, 1995); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: DIAMOND (Brandenburg, 2004); software used to prepare material for publication: PLATON (Spek, 2003).

Figures

	Fig. 1. The molecular structure of (I) showing atom labels and 50% probability displacement ellipsoids for non-H atoms. The H-atoms are shown as dashed lines. The unlabelled atoms are related to corresponding labelled atoms by an inversion centre (-x, 1 - y, 1 - z).
	Fig. 2. Crystal packing of (I) as viewed along the b axis, showing the formation of two-dimensional sheets via combination of H-bonding and π–π stacking interactions. H-bonds are shown as dotted lines.

3-(5-tert-Butyl-2-hydroxybenzoyl)propanoic acid

Crystal data

C14H18O4	Z = 2
Mr = 250.28	F(000) = 268
Triclinic, P1	Dx = 1.228 Mg m^−3
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 7.0938 (2) Å	Cell parameters from 3804 reflections
b = 8.5918 (3) Å	θ = 30.5–2.4°
c = 11.4966 (3) Å	µ = 0.09 mm^−1
α = 76.917 (2)°	T = 150 K
β = 85.205 (2)°	Block, colourless
γ = 83.318 (2)°	0.34 × 0.26 × 0.15 mm
V = 676.69 (4) Å^3

Data collection

Bruker SMART APEX CCD area-detector diffractometer	3998 independent reflections
Radiation source: fine-focus sealed tube	2956 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.034
ω and φ scans	θmax = 30.6°, θmin = 2.4°
Absorption correction: multi-scan (SADABS; Sheldrick, 2004)	h = −10→9
Tmin = 0.807, Tmax = 0.990	k = −12→12
14490 measured reflections	l = −16→16

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.052	Hydrogen site location: difference Fourier map
wR(F^2) = 0.142	H atoms treated by a mixture of independent and constrained refinement
S = 1.03	w = 1/[σ^2(Fo^2) + (0.0764P)^2 + 0.0859P] where P = (Fo^2 + 2Fc^2)/3
3998 reflections	(Δ/σ)max < 0.001
171 parameters	Δρmax = 0.43 e Å^−3
0 restraints	Δρmin = −0.18 e Å^−3

Special details

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. Checkcif output:

912_ALERT_3_B # Missing FCF Reflections Above STH/L=0.6 ······ 159 910_ALERT_3_C # Missing FCF Reflections Below TH(Min) ······.. 1 911_ALERT_3_C # Missing FCF Refl Between THmin & STh/l= 0.600 1

The data collection strategy used aimed to achieve a complete data set to 2θ = 53 °. Some higher angle data were collected in the process and these have been included in the refinement. Please refer to the completeness statistics below

================================================================================ Resolution & Completeness Statistics (Cumulative) ================================================================================ Theta sin(th)/Lambda Complete Expected Measured Missing ——————————————————————————– 20.82 0.500 0.999 1418 1417 1 23.01 0.550 0.999 1883 1882 1 25.24 0.600 0.999 2457 2455 2 ———————————————————— ACTA Min. Res. —- 27.51 0.650 0.997 3116 3108 8 29.84 0.700 0.977 3877 3787 90 30.57 0.716 0.961 4159 3998 161

061_ALERT_3_C Tmax/Tmin Range Test RR' too Large ············. 0.83

SADABS corrects for all systematic errors that lead to disparities in the intensities of symmetry-equivalent data. These may include absorption by the mount, crystal decay etc. The crystal was a rather irregular shape, having been cleaved from a larger block; this precluded integration methods for correcting for absorption.

094_ALERT_2_C Ratio of Maximum / Minimum Residual Density ···. 2.37

Highest peak = 0.43 Deepest Hole = -0.18 These are not unreasonable. They are localized in the region of an aromatic ring

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
O1	0.25675 (15)	0.27572 (10)	0.04192 (9)	0.0344 (2)
C1	0.23777 (17)	0.42613 (13)	−0.02693 (10)	0.0256 (2)
C2	0.26835 (17)	0.56259 (13)	0.01488 (10)	0.0235 (2)
O3	0.04561 (13)	0.62039 (11)	0.37232 (8)	0.0318 (2)
C3	0.25301 (18)	0.71372 (13)	−0.06456 (10)	0.0249 (2)
H3A	0.2753	0.8056	−0.0367	0.030*
C4	0.20655 (18)	0.73325 (14)	−0.18182 (10)	0.0261 (3)
O4	0.25919 (15)	0.47532 (13)	0.49478 (8)	0.0392 (3)
H4	0.157 (3)	0.443 (2)	0.5352 (19)	0.059 (6)*
C5	0.16996 (19)	0.59523 (15)	−0.21840 (10)	0.0281 (3)
H5A	0.1331	0.6057	−0.2976	0.034*
C6	0.18548 (18)	0.44515 (14)	−0.14380 (11)	0.0280 (3)
H6A	0.1605	0.3543	−0.1720	0.034*
C21	0.31001 (17)	0.54528 (14)	0.14063 (10)	0.0260 (2)
C22	0.33448 (19)	0.69232 (15)	0.18742 (10)	0.0285 (3)
H22A	0.2174	0.7676	0.1762	0.034*
H22B	0.4408	0.7476	0.1411	0.034*
C23	0.3750 (2)	0.64759 (17)	0.31958 (11)	0.0332 (3)
H23A	0.4881	0.5677	0.3312	0.040*
H23B	0.4046	0.7444	0.3449	0.040*
C24	0.21078 (19)	0.57950 (15)	0.39652 (10)	0.0280 (3)
O29	0.32127 (14)	0.41288 (11)	0.21016 (8)	0.0333 (2)
C41	0.1914 (2)	0.89572 (15)	−0.27057 (11)	0.0334 (3)
C42	−0.0136 (3)	0.93891 (19)	−0.30816 (15)	0.0495 (4)
H42A	−0.0987	0.9467	−0.2376	0.074*
H42B	−0.0502	0.8554	−0.3450	0.074*
H42C	−0.0229	1.0422	−0.3659	0.074*
C43	0.3241 (3)	0.8850 (2)	−0.38152 (14)	0.0554 (5)
H43A	0.3144	0.9889	−0.4386	0.083*
H43B	0.2872	0.8022	−0.4189	0.083*
H43C	0.4555	0.8571	−0.3578	0.083*
C44	0.2471 (3)	1.02985 (17)	−0.21712 (15)	0.0532 (5)
H44A	0.1630	1.0390	−0.1464	0.080*
H44B	0.2350	1.1316	−0.2766	0.080*
H44C	0.3790	1.0051	−0.1941	0.080*
H1	0.284 (3)	0.287 (3)	0.1107 (19)	0.065 (6)*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O1	0.0409 (6)	0.0241 (4)	0.0364 (5)	−0.0035 (4)	−0.0020 (4)	−0.0029 (3)
C1	0.0223 (6)	0.0244 (5)	0.0290 (5)	−0.0017 (4)	0.0019 (5)	−0.0054 (4)
C2	0.0204 (6)	0.0262 (5)	0.0236 (5)	−0.0012 (4)	0.0004 (4)	−0.0058 (4)
O3	0.0267 (5)	0.0390 (5)	0.0274 (4)	−0.0007 (4)	−0.0024 (4)	−0.0035 (3)
C3	0.0260 (6)	0.0248 (5)	0.0245 (5)	−0.0020 (4)	0.0000 (4)	−0.0074 (4)
C4	0.0282 (7)	0.0260 (5)	0.0234 (5)	−0.0016 (4)	−0.0005 (5)	−0.0049 (4)
O4	0.0284 (6)	0.0598 (6)	0.0245 (4)	−0.0027 (5)	−0.0047 (4)	0.0009 (4)
C5	0.0285 (7)	0.0329 (6)	0.0247 (5)	−0.0023 (5)	−0.0024 (5)	−0.0099 (4)
C6	0.0279 (7)	0.0273 (5)	0.0314 (6)	−0.0033 (5)	−0.0002 (5)	−0.0125 (4)
C21	0.0205 (6)	0.0331 (6)	0.0233 (5)	−0.0007 (4)	0.0009 (4)	−0.0055 (4)
C22	0.0293 (7)	0.0352 (6)	0.0215 (5)	−0.0039 (5)	−0.0009 (5)	−0.0073 (4)
C23	0.0289 (7)	0.0478 (7)	0.0243 (5)	−0.0071 (5)	−0.0030 (5)	−0.0086 (5)
C24	0.0297 (7)	0.0353 (6)	0.0213 (5)	−0.0030 (5)	−0.0029 (5)	−0.0108 (4)
O29	0.0366 (6)	0.0332 (4)	0.0267 (4)	−0.0013 (4)	−0.0023 (4)	−0.0007 (3)
C41	0.0438 (8)	0.0282 (6)	0.0266 (5)	−0.0041 (5)	−0.0044 (5)	−0.0017 (4)
C42	0.0538 (11)	0.0377 (7)	0.0515 (9)	0.0022 (7)	−0.0158 (8)	0.0028 (6)
C43	0.0701 (13)	0.0504 (9)	0.0362 (7)	−0.0051 (8)	0.0119 (8)	0.0044 (6)
C44	0.0850 (14)	0.0297 (6)	0.0452 (8)	−0.0146 (7)	−0.0201 (9)	0.0016 (6)

Geometric parameters (Å, º)

O1—C1	1.3524 (14)	C22—C23	1.5238 (16)
O1—H1	0.86 (2)	C22—H22A	0.99
C1—C6	1.3925 (17)	C22—H22B	0.99
C1—C2	1.4087 (16)	C23—C24	1.4945 (19)
C2—C3	1.4067 (15)	C23—H23A	0.99
C2—C21	1.4709 (16)	C23—H23B	0.99
O3—C24	1.2199 (15)	C41—C44	1.526 (2)
C3—C4	1.3832 (16)	C41—C42	1.532 (2)
C3—H3A	0.95	C41—C43	1.534 (2)
C4—C5	1.4022 (17)	C42—H42A	0.98
C4—C41	1.5296 (16)	C42—H42B	0.98
O4—C24	1.3156 (14)	C42—H42C	0.98
O4—H4	0.87 (2)	C43—H43A	0.98
C5—C6	1.3757 (17)	C43—H43B	0.98
C5—H5A	0.95	C43—H43C	0.98
C6—H6A	0.95	C44—H44A	0.98
C21—O29	1.2318 (14)	C44—H44B	0.98
C21—C22	1.5131 (17)	C44—H44C	0.98
C1—O1—H1	105.5 (14)	C22—C23—H23A	109.2
O1—C1—C6	117.98 (10)	C24—C23—H23B	109.2
O1—C1—C2	122.74 (11)	C22—C23—H23B	109.2
C6—C1—C2	119.28 (10)	H23A—C23—H23B	107.9
C3—C2—C1	118.83 (10)	O3—C24—O4	122.72 (12)
C3—C2—C21	121.44 (10)	O3—C24—C23	123.00 (11)
C1—C2—C21	119.71 (10)	O4—C24—C23	114.24 (11)
C4—C3—C2	122.29 (10)	C44—C41—C4	112.10 (11)
C4—C3—H3A	118.9	C44—C41—C42	108.46 (13)
C2—C3—H3A	118.9	C4—C41—C42	109.44 (12)
C3—C4—C5	117.00 (10)	C44—C41—C43	108.31 (14)
C3—C4—C41	123.41 (10)	C4—C41—C43	109.30 (11)
C5—C4—C41	119.59 (10)	C42—C41—C43	109.19 (13)
C24—O4—H4	108.8 (13)	C41—C42—H42A	109.5
C6—C5—C4	122.40 (11)	C41—C42—H42B	109.5
C6—C5—H5A	118.8	H42A—C42—H42B	109.5
C4—C5—H5A	118.8	C41—C42—H42C	109.5
C5—C6—C1	120.12 (10)	H42A—C42—H42C	109.5
C5—C6—H6A	119.9	H42B—C42—H42C	109.5
C1—C6—H6A	119.9	C41—C43—H43A	109.5
O29—C21—C2	121.18 (11)	C41—C43—H43B	109.5
O29—C21—C22	118.85 (10)	H43A—C43—H43B	109.5
C2—C21—C22	119.95 (10)	C41—C43—H43C	109.5
C21—C22—C23	111.33 (10)	H43A—C43—H43C	109.5
C21—C22—H22A	109.4	H43B—C43—H43C	109.5
C23—C22—H22A	109.4	C41—C44—H44A	109.5
C21—C22—H22B	109.4	C41—C44—H44B	109.5
C23—C22—H22B	109.4	H44A—C44—H44B	109.5
H22A—C22—H22B	108.0	C41—C44—H44C	109.5
C24—C23—C22	112.24 (11)	H44A—C44—H44C	109.5
C24—C23—H23A	109.2	H44B—C44—H44C	109.5

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O1—H1···O29	0.86 (2)	1.80 (2)	2.5777 (14)	150 (2)
O4—H4···O3^i	0.87 (2)	1.78 (2)	2.6417 (15)	175.8 (19)

Symmetry code: (i) −x, −y+1, −z+1.