Ethyl 2-(2-formyl­phen­oxy)ethano­ate–ethyl 2-(2-carboxy­phen­oxy)ethano­ate [0.682 (7)/0.318 (7)]

Williamson, C.; Storey, J.M.D.; Harrison, W.T.A.

doi:10.1107/S1600536807007738

organic compounds

CRYSTALLOGRAPHIC
COMMUNICATIONS

ISSN: 2056-9890

Volume 63| Part 3| March 2007| Pages o1426-o1427

https://doi.org/10.1107/S1600536807007738

Ethyl 2-(2-formylphenoxy)ethanoate–ethyl 2-(2-carboxyphenoxy)ethanoate [0.682 (7)/0.318 (7)]

Craig Williamson,^a John M. D. Storey ^a and William T. A. Harrison ^a ^*

^aDepartment of Chemistry, University of Aberdeen, Meston Walk, Aberdeen AB24 3UE, Scotland
^*Correspondence e-mail: w.harrison@abdn.ac.uk

(Received 14 February 2007; accepted 15 February 2007; online 23 February 2007)

In the title cocrystal, 0.682C₁₁H₁₂O₄.0.318C₁₁H₁₂O₅, the carboxylic acid constituent shows an intramolecular O—H⋯(O,O) hydrogen bond.

Comment

The title compound, (I)/(II) (Fig. 1), is a cocrystal of a substituted benzaldehyde and benzoic acid that arose unexpectedly during our studies of novel cyclization reactions (Williamson et al., 2005 ). Auto-oxidation reactions of benzaldehydes, probably proceeding via a radical mechanism, have been known for many years (Mulcahy & Watt, 1952 ).

Except for the aldehyde –H and carboxylic acid –OH groups, all the atoms in (I)/(II) are equivalent and overlap in the cocrystal, and the geometric parameters for (I)/(II) may be regarded as normal (Allen et al., 1987 ). Compound (II) displays a bifurcated intramolecular O—H⋯(O,O) bond (Table 1). The fact that (II) prefers (or is forced) to form this intramolecular interaction may help to explain why the aldehyde and acid are able to crystallize together.

Two short intermolecular C—H⋯O interactions occur in the cocrystal (Table 1). For the C6—H6⋯O1ⁱ bond (see Table 1 for symmetry code), the O atom of the aldehyde/carboxylic acid C=O group serves as one of the acceptors. Thus, regardless of the identity of an individual molecule (aldehyde or acid), an infinite (along [010]) C(6) chain (Bernstein et al., 1995 ) generated by the 2₁ screw axis is established. There are no π–π stacking interactions observed in this cocrystal; the minimum separation of the centroids of the benzene rings of nearby molecules is greater than 4.8 Å.

Figure 1
The structures of two molecules in the cocrystal, with one represented as the acid, (II), and one as the aldehyde, (I)

. Displacement ellipsoids are drawn at the 50% probability level and H atoms are shown as small spheres of arbitrary radius. Hydrogen bonds are indicated by double-dashed lines. Only one disorder component of the C11 methyl group is shown. (Symmetry code as in Table 1

Experimental

A dry two-necked flask was charged with NaH (0.360 g, 15 mmol), which had been washed with dry petrol (3 × 1 ml). Dry dimethylformamide (40 ml) was added and the suspension cooled to 273 K. Salicylaldehyde (1.220 g, 1.06 ml, 10 mmol) was added, and the solution stirred for 20 min. Ethyl bromoacetate (2.12 g, 1.20 ml, 11 mmol) was added in one portion. The solution was allowed to warm to room temperature and was then stirred for 1 h. H₂O (60 ml) was added, followed by extraction with Et₂O (3 × 50 ml). The organic fractions were combined, washed with saturated brine (75 ml) and dried over MgSO₄, and the solvent was removed in vacuo. Chromatography, eluting with 20% EtOAc in hexane, collecting the fraction with R_f = 0.22, yielded the desired product as an oil, which crystallized slowly at room temperature (1.90 g, 91%; m.p. 333–337 K). Analysis: C₁₁H₁₂O₄ requires: C 63.45, H 5.81%; found C 61.80, H, 5.72%. IR (KBr, ν_max, cm⁻¹): 2954.0 (Ar), 2843.3 [C=O (aldehyde)], 1740.3 [C=O (ester)], 1695.9 [C=O (aldehyde)].

Recrystallization from EtOH did not succeed immediately. However, colourless needles were obtained upon slow (7 d) evaporation of an ethanol solution. It is likely that auto-oxidation occurred at this stage to yield the final cocrystal of (I)/(II).

Crystal data

0.682C₁₁H₁₂O₄·0.318C₁₁H₁₂O₅
M_r = 213.29
Orthorhombic, P 2₁ 2₁ 2₁
a = 4.8119 (2) Å
b = 13.8528 (6) Å
c = 15.6831 (7) Å
V = 1045.41 (8) Å³
Z = 4
Mo Kα radiation
μ = 0.11 mm⁻¹
T = 120 (2) K
0.42 × 0.25 × 0.08 mm

Data collection

Nonius KappaCCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2003 ) T_min = 0.957, T_max = 0.993
9977 measured reflections
1419 independent reflections
1129 reflections with I > 2σ(I)
R_int = 0.046

Refinement

R[F² > 2σ(F²)] = 0.039
wR(F²) = 0.098
S = 1.06
1419 reflections
157 parameters
H-atom parameters constrained
Δρ_max = 0.19 e Å⁻³
Δρ_min = −0.23 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O2—H2⋯O3	0.99	1.70	2.497 (5)	134
O2—H2⋯O4	0.99	2.50	3.395 (5)	151
C6—H6⋯O1ⁱ	0.95	2.56	3.504 (3)	174
C8—H8B⋯O4ⁱⁱ	0.99	2.43	3.354 (3)	155
Symmetry codes: (i) $[-x, y-{\script{1\over 2}}, -z+{\script{3\over 2}}]$ ; (ii) x-1, y, z.

Anomalous dispersion was negligible and Friedel pairs were merged before refinement. The molecules of (I) and (II) are achiral, and thus the observed non-centrosymmetric space group must arise from a packing effect. After initial modelling as the expected aldehyde [compound (I)], very high residuals (wR > 0.40) and a large difference peak near atom C1 resulted. Modelling the crystal structure as compound (II) also resulted in very high residuals, and unreasonable U^ij values for atom O2. Refinement as a cocrystal of (I) + (II) (occupancies of the –O2—H2 and –H1 groups/atoms attached to atom C1 refined with their sum constrained to unity) rapidly converged to a physically plausible result with low residuals.

The C11 methyl group is disordered over two positions of equal occupancy [refined value for the first component = 0.50 (3)]. The O-bound H atom was located in a difference map and refined as riding, with U_iso(H) = 1.2U_eq(O). All C-bound H atoms were placed in calculated positions, with C—H = 0.95–0.99 Å, and refined as riding, with U_iso(H) = 1.2U_eq(C) or 1.5U_eq(methyl C).

Data collection: COLLECT (Nonius, 1998 ); cell refinement: SCALEPACK (Otwinowski & Minor, 1997 ); data reduction: SCALEPACK and DENZO (Otwinowski & Minor, 1997), and SORTAV (Blessing, 1995 ); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997 ); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 (Farrugia, 1997 ); software used to prepare material for publication: SHELXL97.

Supporting information

Crystal structure: contains datablocks I, global. DOI: https://doi.org/10.1107/S1600536807007738/bt2273sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S1600536807007738/bt2273Isup2.hkl

Computing details top

Data collection: COLLECT (Nonius, 1998); cell refinement: SCALEPACK (Otwinowski & Minor, 1997); data reduction: SCALEPACK and DENZO (Otwinowski & Minor, 1997), and SORTAV (Blessing, 1995); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 (Farrugia, 1997); software used to prepare material for publication: SHELXL97.

Ethyl 2-(2-formylphenoxy)ethanoate–ethyl 2-(2-carboxyphenoxy)ethanoate [0.682 (7)/0.318 (7)] top

Crystal data top

0.682C₁₁H₁₂O₄·0.318C₁₁H₁₂O₅	F(000) = 450
M_r = 213.29	D_x = 1.355 Mg m⁻³
Orthorhombic, P2₁2₁2₁	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 2ac 2ab	Cell parameters from 1430 reflections
a = 4.8119 (2) Å	θ = 2.9–27.5°
b = 13.8528 (6) Å	µ = 0.11 mm⁻¹
c = 15.6831 (7) Å	T = 120 K
V = 1045.41 (8) Å³	Slab, colourless
Z = 4	0.42 × 0.25 × 0.08 mm

Data collection top

Nonius KappaCCD area-detector diffractometer	1419 independent reflections
Radiation source: fine-focus sealed tube	1129 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.046
ω and φ scans	θ_max = 27.5°, θ_min = 3.9°
Absorption correction: multi-scan (SADABS; Bruker, 2003)	h = −6→5
T_min = 0.957, T_max = 0.993	k = −17→13
9977 measured reflections	l = −20→20

Refinement top

Refinement on F²	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: difmap and geom
R[F² > 2σ(F²)] = 0.039	H-atom parameters constrained
wR(F²) = 0.098	w = 1/[σ²(F_o²) + (0.0559P)² + 0.0632P] where P = (F_o² + 2F_c²)/3
S = 1.06	(Δ/σ)_max < 0.001
1419 reflections	Δρ_max = 0.19 e Å⁻³
157 parameters	Δρ_min = −0.23 e Å⁻³
0 restraints	Extinction correction: SHELXL97 (Sheldrick, 1997), Fc^*=kFc[1+0.001xFc²λ³/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.031 (6)

Special details top

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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq	Occ. (<1)
C1	0.3059 (5)	0.92120 (16)	0.70792 (15)	0.0331 (5)
H1	0.4298	0.9021	0.7520	0.040*	0.682 (7)
C2	0.0918 (5)	0.85223 (14)	0.67935 (13)	0.0279 (5)
C3	−0.0628 (5)	0.87175 (16)	0.60610 (14)	0.0326 (5)
H3	−0.0302	0.9299	0.5756	0.039*
C4	−0.2616 (5)	0.80823 (17)	0.57725 (15)	0.0342 (6)
H4	−0.3644	0.8221	0.5270	0.041*
C5	−0.3106 (5)	0.72371 (17)	0.62229 (14)	0.0325 (5)
H5	−0.4472	0.6796	0.6023	0.039*
C6	−0.1631 (5)	0.70251 (15)	0.69608 (13)	0.0279 (5)
H6	−0.2014	0.6452	0.7272	0.033*
C7	0.0399 (4)	0.76560 (15)	0.72365 (13)	0.0257 (5)
C8	0.1580 (5)	0.66534 (15)	0.84300 (13)	0.0276 (5)
H8A	0.1944	0.6077	0.8074	0.033*
H8B	−0.0354	0.6621	0.8643	0.033*
C9	0.3585 (4)	0.66947 (15)	0.91613 (13)	0.0276 (5)
C10	0.4839 (6)	0.5919 (2)	1.04427 (16)	0.0456 (7)
H10A	0.5094	0.6564	1.0703	0.055*
H10B	0.6683	0.5650	1.0294	0.055*
C11A	0.324 (3)	0.5233 (10)	1.1055 (6)	0.046 (2)	0.50 (3)
H11A	0.4306	0.5151	1.1582	0.068*	0.50 (3)
H11B	0.2988	0.4604	1.0780	0.068*	0.50 (3)
H11C	0.1419	0.5512	1.1188	0.068*	0.50 (3)
C11B	0.449 (6)	0.5058 (10)	1.0888 (11)	0.065 (5)	0.50 (3)
H11D	0.5727	0.5053	1.1385	0.098*	0.50 (3)
H11E	0.4948	0.4514	1.0514	0.098*	0.50 (3)
H11F	0.2559	0.5003	1.1078	0.098*	0.50 (3)
O1	0.3320 (3)	1.00164 (11)	0.67838 (12)	0.0434 (5)
O2	0.4619 (10)	0.9054 (4)	0.7772 (3)	0.037 (2)	0.318 (7)
H2	0.4288	0.8436	0.8074	0.045*	0.318 (7)
O3	0.1994 (3)	0.75114 (10)	0.79483 (9)	0.0306 (4)
O4	0.5400 (3)	0.72816 (12)	0.92481 (11)	0.0384 (4)
O5	0.3060 (3)	0.59732 (10)	0.96963 (9)	0.0321 (4)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
C1	0.0332 (12)	0.0300 (12)	0.0360 (12)	0.0012 (10)	0.0098 (11)	−0.0001 (10)
C2	0.0286 (11)	0.0231 (10)	0.0319 (11)	0.0051 (9)	0.0095 (9)	−0.0015 (10)
C3	0.0343 (12)	0.0319 (12)	0.0316 (12)	0.0089 (10)	0.0067 (10)	0.0057 (10)
C4	0.0314 (12)	0.0395 (13)	0.0316 (11)	0.0059 (11)	0.0005 (10)	0.0045 (10)
C5	0.0274 (11)	0.0344 (12)	0.0357 (12)	−0.0015 (11)	−0.0010 (10)	−0.0042 (10)
C6	0.0271 (11)	0.0235 (10)	0.0330 (11)	−0.0008 (9)	0.0027 (10)	0.0001 (9)
C7	0.0261 (11)	0.0240 (11)	0.0271 (11)	0.0053 (9)	0.0039 (9)	−0.0013 (9)
C8	0.0277 (11)	0.0257 (11)	0.0296 (11)	0.0018 (10)	0.0022 (9)	0.0016 (9)
C9	0.0235 (10)	0.0280 (11)	0.0314 (11)	0.0047 (10)	0.0017 (10)	−0.0015 (9)
C10	0.0481 (15)	0.0493 (15)	0.0395 (14)	0.0060 (13)	−0.0176 (12)	0.0030 (13)
C11A	0.043 (5)	0.061 (5)	0.033 (3)	−0.003 (4)	−0.007 (4)	0.009 (3)
C11B	0.089 (12)	0.050 (5)	0.057 (6)	−0.013 (6)	−0.040 (7)	0.016 (4)
O1	0.0448 (10)	0.0260 (8)	0.0595 (11)	−0.0027 (8)	0.0151 (10)	0.0015 (8)
O2	0.033 (3)	0.034 (3)	0.045 (4)	−0.008 (2)	−0.002 (2)	0.008 (2)
O3	0.0330 (9)	0.0288 (8)	0.0300 (8)	−0.0045 (7)	−0.0035 (7)	0.0051 (6)
O4	0.0288 (9)	0.0407 (9)	0.0456 (9)	−0.0056 (8)	−0.0043 (8)	0.0014 (8)
O5	0.0359 (9)	0.0298 (8)	0.0306 (8)	0.0015 (7)	−0.0069 (7)	0.0017 (7)

Geometric parameters (Å, º) top

C1—O1	1.213 (3)	C8—H8A	0.9900
C1—O2	1.339 (5)	C8—H8B	0.9900
C1—C2	1.475 (3)	C9—O4	1.201 (3)
C1—H1	0.9500	C9—O5	1.329 (3)
C2—C3	1.395 (3)	C10—C11B	1.392 (11)
C2—C7	1.409 (3)	C10—O5	1.452 (3)
C3—C4	1.377 (3)	C10—C11A	1.555 (10)
C3—H3	0.9500	C10—H10A	0.9900
C4—C5	1.388 (3)	C10—H10B	0.9900
C4—H4	0.9500	C11A—H11A	0.9800
C5—C6	1.389 (3)	C11A—H11B	0.9800
C5—H5	0.9500	C11A—H11C	0.9800
C6—C7	1.380 (3)	C11B—H11D	0.9800
C6—H6	0.9500	C11B—H11E	0.9800
C7—O3	1.369 (3)	C11B—H11F	0.9800
C8—O3	1.422 (2)	O2—H2	0.9903
C8—C9	1.500 (3)

O1—C1—O2	113.7 (3)	O4—C9—O5	125.2 (2)
O1—C1—C2	123.5 (2)	O4—C9—C8	125.47 (19)
O2—C1—C2	122.2 (3)	O5—C9—C8	109.36 (17)
O1—C1—H1	117.9	C11B—C10—O5	112.2 (5)
C2—C1—H1	118.6	C11B—C10—C11A	26.8 (9)
C3—C2—C7	118.5 (2)	O5—C10—C11A	103.7 (4)
C3—C2—C1	119.8 (2)	C11B—C10—H10A	125.6
C7—C2—C1	121.7 (2)	O5—C10—H10A	111.0
C4—C3—C2	121.2 (2)	C11A—C10—H10A	111.0
C4—C3—H3	119.4	C11B—C10—H10B	84.4
C2—C3—H3	119.4	O5—C10—H10B	111.0
C3—C4—C5	119.3 (2)	C11A—C10—H10B	111.0
C3—C4—H4	120.3	H10A—C10—H10B	109.0
C5—C4—H4	120.3	C10—C11A—H11A	109.5
C4—C5—C6	121.0 (2)	C10—C11A—H11B	109.5
C4—C5—H5	119.5	H11A—C11A—H11B	109.5
C6—C5—H5	119.5	C10—C11A—H11C	109.5
C7—C6—C5	119.3 (2)	H11A—C11A—H11C	109.5
C7—C6—H6	120.4	H11B—C11A—H11C	109.5
C5—C6—H6	120.4	C10—C11B—H11D	109.5
O3—C7—C6	124.01 (18)	C10—C11B—H11E	109.5
O3—C7—C2	115.30 (19)	H11D—C11B—H11E	109.5
C6—C7—C2	120.7 (2)	C10—C11B—H11F	109.5
O3—C8—C9	106.51 (17)	H11D—C11B—H11F	109.5
O3—C8—H8A	110.4	H11E—C11B—H11F	109.5
C9—C8—H8A	110.4	C1—O2—H2	116.0
O3—C8—H8B	110.4	C7—O3—C8	118.48 (17)
C9—C8—H8B	110.4	C9—O5—C10	115.81 (18)
H8A—C8—H8B	108.6

O1—C1—C2—C3	10.7 (3)	C1—C2—C7—O3	0.7 (3)
O2—C1—C2—C3	−179.3 (3)	C3—C2—C7—C6	−1.3 (3)
O1—C1—C2—C7	−170.1 (2)	C1—C2—C7—C6	179.48 (19)
O2—C1—C2—C7	0.0 (4)	O3—C8—C9—O4	−8.5 (3)
C7—C2—C3—C4	0.0 (3)	O3—C8—C9—O5	172.12 (16)
C1—C2—C3—C4	179.2 (2)	C6—C7—O3—C8	1.0 (3)
C2—C3—C4—C5	0.5 (3)	C2—C7—O3—C8	179.79 (18)
C3—C4—C5—C6	0.3 (3)	C9—C8—O3—C7	−179.91 (17)
C4—C5—C6—C7	−1.6 (3)	O4—C9—O5—C10	0.8 (3)
C5—C6—C7—O3	−179.22 (18)	C8—C9—O5—C10	−179.85 (18)
C5—C6—C7—C2	2.1 (3)	C11B—C10—O5—C9	−169.3 (15)
C3—C2—C7—O3	179.91 (18)	C11A—C10—O5—C9	163.9 (6)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
O2—H2···O3	0.99	1.70	2.497 (5)	134
O2—H2···O4	0.99	2.50	3.395 (5)	151
C6—H6···O1ⁱ	0.95	2.56	3.504 (3)	174
C8—H8B···O4ⁱⁱ	0.99	2.43	3.354 (3)	155

Symmetry codes: (i) −x, y−1/2, −z+3/2; (ii) x−1, y, z.

Acknowledgements

The authors thank the EPSRC National Crystallographic Service, University of Southampton, for the X-ray data collection.

References

Allen, F. H., Kennard, O., Watson, D. G., Brammer, L. Orpen, A. G. & Taylor, R. (1987). J. Chem. Soc. Perkin Trans. 2, pp. S1–19. CrossRef Google Scholar
Bernstein, J., Davis, R. E., Shimoni, L. & Chang, N.-L. (1995). Angew. Chem. Int. Ed. Engl. 34, 1555–1573. CrossRef CAS Web of Science Google Scholar
Blessing, R. H. (1995). Acta Cryst. A51, 33–38. CrossRef CAS Web of Science IUCr Journals Google Scholar
Bruker (2003). SADABS. Bruker AXS Inc., Madison, Wisconsin, USA. Google Scholar
Farrugia, L. J. (1997). J. Appl. Cryst. 30, 565. CrossRef IUCr Journals Google Scholar
Mulcahy, M. F. R. & Watt, I. C. (1952). Proc. R. Soc. London Ser. A, 211, 10–29. Google Scholar
Nonius (1998). COLLECT. Nonius BV, Delft, The Netherlands. Google Scholar
Otwinowski, Z. & Minor, W. (1997). Methods in Enzymology, Vol. 276, Macromolecular Crystallography, Part A, edited by C. W. Carter Jr & R. M. Sweet, pp. 307–326. New York: Academic Press. Google Scholar
Sheldrick, G. M. (1997). SHELXS97 and SHELXL97. University of Göttingen, Germany. Google Scholar
Williamson, C., Storey, J. M. D. & Harrison, W. T. A. (2005). Acta Cryst. E61, o1566–o1568. Web of Science CSD CrossRef IUCr Journals Google Scholar

© International Union of Crystallography. Prior permission is not required to reproduce short quotations, tables and figures from this article, provided the original authors and source are cited. For more information, click here.