3-(2-Formyl­phen­oxy)propanoic acid

Alain Collas; Christophe M L Vande Velde; Frank Blockhuys

doi:10.1107/S1600536810038079

. 2010 Sep 30;66(Pt 10):o2662. doi: 10.1107/S1600536810038079

3-(2-Formylphenoxy)propanoic acid

Alain Collas ^a, Christophe M L Vande Velde ^a,^‡, Frank Blockhuys ^a,^*

PMCID: PMC2983121 PMID: 21587633

Abstract

In the structure of the title compound, C₁₀H₁₀O₄, the carboxyl group forms a catemer motif in the [100] direction instead of the expected dimeric structures. The carboxylic acid group is found in the syn conformation and the three-dimensional organization in the crystal is based on C—H⋯O and O—H⋯O interactions.

Related literature

For the synthesis, see: Zawadowska (1963 ▶); Jarvest et al. (2005 ▶). For related structures, see: Gresham et al. (1949 ▶); Leiserowitz (1976 ▶); Borthwick (1980 ▶); Kennard et al. (1982 ▶); Shockravi et al. (2004 ▶); Gao & Ng (2006 ▶). For applications of poly(p-phenylene vinylene) oligomers (PPVs), see: Chemla (1987 ▶); Bandyopadhyay & Pal (2003 ▶). For hydrogen bonding and crystal engineering, see: Desiraju (1997 ▶); Steiner (2002 ▶).

Experimental

Crystal data

C₁₀H₁₀O₄
M _r = 194.18
Orthorhombic,
a = 15.269 (4) Å
b = 7.167 (2) Å
c = 17.136 (5) Å
V = 1875.2 (9) Å³
Z = 8
Mo Kα radiation
μ = 0.11 mm⁻¹
T = 293 K
0.42 × 0.21 × 0.15 mm

Data collection

Enraf–Nonius CAD-4 diffractometer
1718 measured reflections
1718 independent reflections
964 reflections with I > 2σ(I)
3 standard reflections every 60 min intensity decay: 1%

Refinement

R[F ² > 2σ(F ²)] = 0.047
wR(F ²) = 0.119
S = 1.02
1718 reflections
167 parameters
All H-atom parameters refined
Δρ_max = 0.17 e Å⁻³
Δρ_min = −0.21 e Å⁻³

Data collection: CAD-4 EXPRESS (Enraf–Nonius, 1994 ▶); cell refinement: CAD-4 EXPRESS; data reduction: XCAD4 (Harms & Wocadlo, 1995 ▶); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: ORTEP-3 (Farrugia, 1997 ▶) and PLATON (Spek, 2009 ▶); software used to prepare material for publication: WinGX (Farrugia, 1999 ▶).

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536810038079/zl2308sup1.cif

e-66-o2662-sup1.cif^{(15.7KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536810038079/zl2308Isup2.hkl

e-66-o2662-Isup2.hkl^{(83KB, hkl)}

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Table 1. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O3—H41⋯O4ⁱ	0.94 (4)	1.72 (4)	2.618 (3)	158 (3)
C21—H21a⋯O1ⁱⁱ	1.00 (3)	2.64 (3)	3.409 (4)	134.5 (2)
C22—H22b⋯O1ⁱⁱⁱ	0.96 (3)	2.46 (3)	3.187 (4)	132 (2)
C21—H21a⋯O3^iv	1.00 (3)	2.60 (2)	3.456 (3)	144 (2)
C3—H3⋯O4^v	0.96 (2)	2.71 (2)	3.536 (4)	144.9 (2)

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Symmetry codes: (i) Inline graphic ; (ii) ; (iii) ; (iv) ; (v) .

Acknowledgments

CVV thanks the Fund for Scientific Research (FWO Vlaanderen) for a grant as a research assistant. AC wishes to thank the Institute for the Promotion of Innovation by Science and Technology in Flanders (IWT) for a predoctoral grant.

supplementary crystallographic information

Comment

The title compound was synthesized as a precursor for asymmetric PPV-type [poly(p-phenylene vinylene)] oligomers. These compounds are promising candidates as the active materials in organic memories (Bandyopadhyay & Pal, 2003) and as non-linear optical (NLO) materials with a high first-order hyperpolarizability (Chemla, 1987). Besides the condition that these oligomers should bear donor and acceptor substituents connected by a π-system, it is of critical importance for their usefulness as an NLO material and as a bistable organic memory material that the crystal packing is non-centrosymmetric. In particular, the compound should crystallize in a polar space group. To influence the crystal packing by means of the crystal engineering methodology in order to meet this criterion, it is necessary to introduce certain statistically well chosen synthons (Desiraju, 1997). Therefore, we opted for carboxylic acid functional groups (powerful hydrogen bond donors) in the basic structure of the organic semiconductor. To combine the electronic (A-π-D) and the structural (non-centrosymmetric space group) requirements, we used the Williamson ether synthesis to prepare the title compound as a building block for a PPV-based semiconductor bearing a carboxylic acid moiety.

The geometry of the aldehyde contains no surprises. The methylene fragments are in synclinal conformation and the torsion angle is 65.9 (3)°. As a result and due to the repulsion between the lone pairs of oxygen atoms O2 and O3, the carboxylic acid group, found in the syn conformation, is twisted out of the plane of the phenyl ring. The O2···O3 distance is 3.034 (3) Å and this is the only contact of the ether oxygen atom. The distances in the carboxylic acid moiety are in accordance with the expected values for non-disordered carboxylic acids (Leiserowitz, 1976): the carbonyl (C=O) bond length C23—O4 is 1.209 (3) Å and the C—O single bond length C23—O3 is 1.306 (3) Å. The angles of the carboxyl moiety contain no surprises (Borthwick, 1980): C23—O3—H31 is 110 (2)° and O4—C23—O3 is 121.9 (2)°.

Two intramolecular CH···O hydrogen bonds involving the aldehyde group can be identified: the relevant parameters of C6—H6···O1 and C11—H1···O2 are given in Table 1, entries 1 and 2. The incorporation of a carboxylic acid group was expected to yield the corresponding dimer synthon, but the crystal structure of the title compound reveals a catemer motif in the [1 0 0] direction (Fig. 2), consisting of an infinite chain of hydrogen bonds. The O3···O4 distance is 2.618 (3) Å (Table 1, entry 3) which is not surprising for a hydrogen bond of moderate strength (Steiner, 2002). The chains are intertwined through O1···Cg contacts in which the aldehyde oxygen atom contacts the center of the aromatic ring [O1···Cgⁱ 3.508 (3) Å, C11—O1···Cgⁱ 78.47 (17)°, symm. code i = 1-x, -y, -z]. O1 is also involved in weak CH···O hydrogen bonds with H21a (Table 1, entry 4) and H22b (Table 1, entry 5); the latter links the infinite hydrogen bonded chains in the [0 0 1] direction (Fig. 3). Two additional hydrogen bonds can be observed: H21a contacts O3 and H3 contacts O4 (Table 1, entries 6 and 7, respectively).

Experimental

Salicylic aldehyde and 3-chloropropanoic acid were obtained from ACROS and used as received. The general procedure of Gresham was followed (Gresham et al., 1949). 8 g of NaOH in 20 ml of distilled water were added to a stirred solution of 12.2 g (0.1 mol) of salicylic aldehyde and 10.9 g (0.1 mol) of 3-chloropropanoic acid in 80 ml of distilled water. After heating under reflux for 4 h, the mixture was acidified with 19.5 ml of conc. HCl. Unreacted salicylic aldehyde was removed by steam distillation and the resulting mixture was placed in the refrigerator. The resulting tan-coloured needles were collected by filtration in a 20% yield. M.p. 381 K (uncorrected). Crystals suitable for the diffraction experiment were grown by slow evaporation of a 50:50 chloroform:toluene solvent mixture, analogous with the experiments of Kennard (Kennard et al., 1981). ¹H NMR (CD₃OD, 400 MHz, TMS): δ 2.84 (t, 2H, 6.00 Hz, H22), 4.39 (t, 2H, 6.00 Hz, H21), 7.05 (td, 1H, 7.44 and 0.88 Hz, H5), 7.18 (d, 1H, 8.10 Hz, H3), 7.61 (td, 1H, 7.32 and 1.88 Hz, H4), 7.75 (dd, 1H, 7.72 and 1.80 Hz, H6), 10.39 (d, 1H, 0.80 Hz, H21b); the proton of the carboxylic acid can not be seen. ¹³C NMR (CDCl₃, 100 MHz, TMS): δ 34.17 (C22), 63.83 (C21), 112.66 (C3), 121.33 (C5), 125.08 (C1), 128.61 (C6), 135.99 (C4), 160.75 (C2), 175.97 (C11), 189.79 (C23).