(E)-4-(4-Fluoro­styr­yl)benzoic acid

The title compound, C₁₅H₁₁FO₂, is an important inter­mediate in the synthesis of side-chain ligands for polymeric liquid crystals. The vinyl group is almost coplanar with both the aromatic rings. The crystal structure is stabilized by inter­molecular O—H...O hydrogen bonding.

Key indicators

• Single-crystal X-ray study
• T = 123 K
• Mean [sigma](C-C) = 0.003 Å
• R factor = 0.065
• wR factor = 0.155
• Data-to-parameter ratio = 15.5

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT222_ALERT_3_C Large Non-Solvent    H     Ueq(max)/Ueq(min) ...       3.42 Ratio
PLAT355_ALERT_3_C Long    O-H Bond (0.82A)   O2     -   H2     ...       1.04 Ang.

   0 ALERT level A = In general: serious problem
   0 ALERT level B = Potentially serious problem
   2 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
   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

Carboxylic acids constitute an important class of organic compounds and have been used by the medicinal industry as important drugs (Ribeiro et al., 2008; Frazee & Foraker 2008; Hameed & Rama 2004). The carboxylic acids have also found applications as intermediates in the synthesis of an enormous number of organic compounds, in general (Hussain et al., 2005; Ahmad et al., 2003), and in the synthesis of side chain ligands for polymeric liquid crystals, in particular (Wang et al., 2008; Nazir et al., 2008). The liquid crystalline molecules containing substituents at 4-position behave as well ordered calamitic ligands as a side chain group (Collings & Hird, 1997) in side chain polymeric liquid crysrtals (SCPLCs). The derivatives of 4-(4-substituted styryl)benzoic acids have found applications as side chain groups in SCPLCs (Wang et al., 2008). As a part of a project to synthesize ligands for SCPLCs, the title compound, (E)-4-(4-fluorostyryl)benzoic acid (I), was synthesized by reacting 4-fluorobenzaldehyde with methyl [4-(methoxycarbonyl)benzyl]triphenylphosphonium bromide (Nazir et al., 2008) followed by hydrolysis. In the present article, the crystal structure of (I) is being reported. Bond lengths and angles are within the normal ranges as given for vinylbenzoic acid (Yasuda et al., 2000). The C(1)—O(1) and C(1)—O(2) bond lengths are 1.252 (2) and 1.291 (2) respectively,clearly indicating the partial double bond character of the carboxylate group. The carboxylic acid group subtends a dihedral angle[13.72 (16)°] with the phenyl ring C(2)/C(3)/C(4)/C(5)/C(6)/C(7).The vinyl group is almost coplanar with both the phenyl rings. The torsion angles between the phenyl rings and vinyl group fulfill the condition of coplanarity[near to 0° or 180 °]. Two molecules related by an inversion center form a dimer via two hydrogen bonds composed of two carboxyl groups as shown in Fig. 2.

Related literature

For related literature, see: Ahmad et al. (2003); Collings & Hird (1997); Frazee & Foraker (2008); Hameed & Rama (2004); Hussain et al. (2005); Nazir et al. (2008); Ribeiro et al. (2008); Wang et al. (2008); Higashi (1999); Yasuda et al. (2000).

S2. Experimental

Methyl 4-(4-fluorostyryl)benzoate 0.8g (0.0031moles) and sodium hydroxide 0.126g (0.0031 moles) were dissolved in a mixture of 10 ml of methanol and 30 ml of water, and the mixture refluxed for 3 hours. The reaction mixture was cooled to room temperature and acidified with 6M HCl. The precipitated solid was filtered and recrystallized from hot ethanol. Yield: 76%, m.p: 240-252°C, R_f = 0.22 (n-hexane : ethyl acetate 7 : 3). IR (ν_max, KBr, cm^-1): 3300-2500, 1715, 1620, 1600, 1580, 1188, 1119, 965,834. ¹H-NMR (300 MHz,DMSO-d₆): δ 7.25 (2H, d, J = 9.0 Hz),7.28 (1H, d, J= 16.2 Hz), 7.42 (1H, d, J = 16.2 Hz), 7.71-7.67 (4H, m),7.95 (2H, d, J = 8.1 Hz), 12.93 (1H, s). ¹³C-NMR (75 MHz, DMSO-d₆): δ 116.16 (d, J= 23 Hz), 126.90, 127.77, 129.23, 130.08 (d, J = 8 Hz), 131.95, 132.49, 133.71 (d, J = 3 Hz), 141.83, 162.42 (d, J = 246 Hz), 167.54.

S3. Refinement

The O-bound H atom was refined isotropically. All the other H atoms were placed in idealized positions and treated as riding atoms with C—H distance in the range 0.95–0.99 Å and U_iso(H) = 1.2U_eq(C) or 1.5U_eq(C).

Computing details

Data collection: CrystalClear (MSC/Rigaku, 2001); cell refinement: CrystalClear (MSC/Rigaku, 2001); data reduction: TEXSAN (MSC/Rigaku , 2004); program(s) used to solve structure: SIR97 (Altomare et al., 1999); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEPII (Johnson, 1976); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008) and TEXSAN (MSC/Rigaku, 2004).

Figures

	Fig. 1. Molecular structure of (I) showing atom-labelling scheme and displacement ellipsoids at the 30% probability level.
	Fig. 2. Showing hydrogen bonded molecules through N—H···O.

(E)-4-(4-Fluorostyryl)benzoic acid

Crystal data

C15H11FO2	F(000) = 504
Mr = 242.24	Dx = 1.408 Mg m^−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71070 Å
Hall symbol: -P 2ybc	Cell parameters from 3252 reflections
a = 6.261 (4) Å	θ = 3.1–27.5°
b = 23.096 (15) Å	µ = 0.10 mm^−1
c = 8.269 (5) Å	T = 123 K
β = 107.072 (8)°	Needle, colourless
V = 1143.1 (13) Å^3	0.45 × 0.30 × 0.18 mm
Z = 4

Data collection

Rigaku/MSC Mercury CCD diffractometer	2399 reflections with I > 2σ(I)
Radiation source: Rotating anode	Rint = 0.036
Graphite monochromator	θmax = 27.5°, θmin = 3.1°
ω scans	h = −8→6
9111 measured reflections	k = −25→29
2589 independent reflections	l = −10→9

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)] = 0.065	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.155	H atoms treated by a mixture of independent and constrained refinement
S = 1.16	w = 1/[σ^2(Fo^2) + (0.0616P)^2 + 0.7669P] where P = (Fo^2 + 2Fc^2)/3
2589 reflections	(Δ/σ)max < 0.001
167 parameters	Δρmax = 0.55 e Å^−3
0 restraints	Δρmin = −0.28 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. 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 (Ų)

	x	y	z	Uiso*/Ueq
C1	0.7742 (3)	0.03235 (7)	0.8139 (2)	0.0188 (4)
O1	0.9748 (2)	0.04569 (6)	0.83715 (16)	0.0268 (3)
O2	0.7095 (2)	−0.00358 (6)	0.90952 (16)	0.0258 (3)
H2	0.843 (6)	−0.0202 (16)	1.006 (5)	0.089 (12)*
C2	0.5982 (3)	0.05820 (7)	0.6720 (2)	0.0188 (4)
C3	0.6547 (3)	0.10173 (8)	0.5755 (2)	0.0221 (4)
H3	0.8054	0.1143	0.6002	0.027*
C4	0.4916 (3)	0.12671 (8)	0.4437 (2)	0.0246 (4)
H4	0.5313	0.1568	0.3796	0.030*
C5	0.2699 (3)	0.10851 (8)	0.4031 (2)	0.0231 (4)
C6	0.2149 (3)	0.06476 (8)	0.5012 (2)	0.0232 (4)
H6	0.0645	0.0519	0.4756	0.028*
C7	0.3771 (3)	0.03999 (8)	0.6354 (2)	0.0213 (4)
H7	0.3374	0.0107	0.7020	0.026*
C8	0.1067 (3)	0.13727 (8)	0.2605 (2)	0.0250 (4)
H8	0.1586	0.1694	0.2111	0.030*
C9	−0.1064 (3)	0.12250 (8)	0.1943 (2)	0.0246 (4)
H9	−0.1587	0.0904	0.2436	0.030*
C10	−0.2687 (3)	0.15134 (8)	0.0517 (2)	0.0224 (4)
C11	−0.2127 (3)	0.19609 (8)	−0.0431 (2)	0.0250 (4)
H11	−0.0628	0.2094	−0.0148	0.030*
C12	−0.3734 (3)	0.22120 (8)	−0.1778 (2)	0.0273 (4)
H12	−0.3353	0.2514	−0.2424	0.033*
C13	−0.5900 (3)	0.20104 (8)	−0.2150 (2)	0.0262 (4)
C14	−0.6531 (3)	0.15774 (8)	−0.1256 (2)	0.0257 (4)
H14	−0.8040	0.1451	−0.1539	0.031*
C15	−0.4898 (3)	0.13277 (8)	0.0075 (2)	0.0241 (4)
H15	−0.5300	0.1023	0.0700	0.029*
F1	−0.7470 (2)	0.22525 (6)	−0.34838 (15)	0.0419 (4)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
C1	0.0185 (8)	0.0204 (8)	0.0175 (8)	0.0011 (6)	0.0052 (6)	−0.0007 (6)
O1	0.0173 (6)	0.0346 (8)	0.0269 (7)	0.0001 (5)	0.0040 (5)	0.0061 (5)
O2	0.0227 (6)	0.0285 (7)	0.0251 (6)	0.0005 (5)	0.0053 (5)	0.0084 (5)
C2	0.0190 (8)	0.0200 (8)	0.0165 (8)	0.0030 (6)	0.0038 (6)	−0.0018 (6)
C3	0.0213 (8)	0.0251 (9)	0.0195 (8)	0.0016 (7)	0.0054 (6)	−0.0001 (6)
C4	0.0267 (9)	0.0253 (9)	0.0219 (8)	0.0031 (7)	0.0073 (7)	0.0034 (7)
C5	0.0246 (9)	0.0249 (9)	0.0175 (8)	0.0057 (7)	0.0029 (7)	−0.0022 (6)
C6	0.0175 (8)	0.0265 (9)	0.0237 (8)	0.0019 (7)	0.0032 (7)	−0.0034 (7)
C7	0.0196 (8)	0.0226 (9)	0.0211 (8)	0.0012 (7)	0.0052 (6)	−0.0003 (6)
C8	0.0238 (9)	0.0262 (9)	0.0234 (8)	0.0025 (7)	0.0045 (7)	0.0031 (7)
C9	0.0264 (9)	0.0248 (9)	0.0221 (8)	0.0011 (7)	0.0062 (7)	0.0004 (7)
C10	0.0220 (9)	0.0243 (9)	0.0187 (8)	0.0044 (7)	0.0028 (6)	−0.0041 (6)
C11	0.0216 (9)	0.0259 (10)	0.0265 (9)	−0.0002 (7)	0.0055 (7)	−0.0057 (7)
C12	0.0347 (10)	0.0217 (9)	0.0265 (9)	0.0025 (8)	0.0104 (8)	0.0006 (7)
C13	0.0280 (9)	0.0233 (9)	0.0215 (8)	0.0116 (7)	−0.0018 (7)	−0.0012 (7)
C14	0.0188 (8)	0.0273 (9)	0.0290 (9)	0.0019 (7)	0.0038 (7)	−0.0072 (7)
C15	0.0260 (9)	0.0229 (9)	0.0232 (8)	0.0013 (7)	0.0067 (7)	−0.0006 (7)
F1	0.0413 (7)	0.0402 (8)	0.0330 (7)	0.0202 (6)	−0.0063 (5)	0.0036 (5)

Geometric parameters (Å, º)

C1—O1	1.252 (2)	C8—C9	1.330 (3)
C1—O2	1.291 (2)	C8—H8	0.9500
C1—C2	1.479 (2)	C9—C10	1.471 (2)
O2—H2	1.04 (4)	C9—H9	0.9500
C2—C3	1.392 (3)	C10—C15	1.392 (3)
C2—C7	1.393 (3)	C10—C11	1.402 (3)
C3—C4	1.382 (2)	C11—C12	1.390 (3)
C3—H3	0.9500	C11—H11	0.9500
C4—C5	1.394 (3)	C12—C13	1.380 (3)
C4—H4	0.9500	C12—H12	0.9500
C5—C6	1.401 (3)	C13—F1	1.363 (2)
C5—C8	1.473 (2)	C13—C14	1.369 (3)
C6—C7	1.389 (2)	C14—C15	1.389 (3)
C6—H6	0.9500	C14—H14	0.9500
C7—H7	0.9500	C15—H15	0.9500
O1—C1—O2	123.07 (15)	C9—C8—H8	116.9
O1—C1—C2	120.16 (15)	C5—C8—H8	116.9
O2—C1—C2	116.78 (15)	C8—C9—C10	125.99 (18)
C1—O2—H2	112 (2)	C8—C9—H9	117.0
C3—C2—C7	119.79 (15)	C10—C9—H9	117.0
C3—C2—C1	119.41 (16)	C15—C10—C11	118.25 (16)
C7—C2—C1	120.80 (16)	C15—C10—C9	118.07 (17)
C4—C3—C2	120.05 (17)	C11—C10—C9	123.68 (17)
C4—C3—H3	120.0	C12—C11—C10	120.96 (18)
C2—C3—H3	120.0	C12—C11—H11	119.5
C3—C4—C5	121.11 (18)	C10—C11—H11	119.5
C3—C4—H4	119.4	C13—C12—C11	118.08 (18)
C5—C4—H4	119.4	C13—C12—H12	121.0
C4—C5—C6	118.38 (16)	C11—C12—H12	121.0
C4—C5—C8	117.69 (17)	F1—C13—C14	118.85 (18)
C6—C5—C8	123.92 (17)	F1—C13—C12	118.02 (18)
C7—C6—C5	120.88 (17)	C14—C13—C12	123.12 (17)
C7—C6—H6	119.6	C13—C14—C15	118.00 (17)
C5—C6—H6	119.6	C13—C14—H14	121.0
C6—C7—C2	119.77 (17)	C15—C14—H14	121.0
C6—C7—H7	120.1	C14—C15—C10	121.58 (18)
C2—C7—H7	120.1	C14—C15—H15	119.2
C9—C8—C5	126.22 (18)	C10—C15—H15	119.2
O1—C1—C2—C3	−6.5 (2)	C6—C5—C8—C9	−7.2 (3)
O2—C1—C2—C3	173.26 (15)	C5—C8—C9—C10	−179.93 (17)
O1—C1—C2—C7	174.23 (16)	C8—C9—C10—C15	−175.06 (18)
O2—C1—C2—C7	−6.0 (2)	C8—C9—C10—C11	5.5 (3)
C7—C2—C3—C4	−0.1 (3)	C15—C10—C11—C12	−0.1 (3)
C1—C2—C3—C4	−179.31 (16)	C9—C10—C11—C12	179.26 (17)
C2—C3—C4—C5	−1.0 (3)	C10—C11—C12—C13	0.4 (3)
C3—C4—C5—C6	1.1 (3)	C11—C12—C13—F1	−179.25 (16)
C3—C4—C5—C8	−179.83 (16)	C11—C12—C13—C14	0.1 (3)
C4—C5—C6—C7	−0.2 (3)	F1—C13—C14—C15	178.64 (16)
C8—C5—C6—C7	−179.19 (17)	C12—C13—C14—C15	−0.7 (3)
C5—C6—C7—C2	−0.9 (3)	C13—C14—C15—C10	0.9 (3)
C3—C2—C7—C6	1.0 (3)	C11—C10—C15—C14	−0.5 (3)
C1—C2—C7—C6	−179.80 (15)	C9—C10—C15—C14	−179.93 (16)
C4—C5—C8—C9	173.72 (19)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O2—H2···O1^i	1.04 (4)	1.57 (4)	2.610 (2)	174 (3)

Symmetry code: (i) −x+2, −y, −z+2.