Redetermination of 2-(naphthalen-2-yl­oxy)­ethano­ic acid

The redetermination of the title compound, C₁₂H₁₀O₃, agrees completely with the results previously reported by Pattabhi, Ragnuthan & Chacko [Acta Cryst. (1973), B34, 3118–3120], but with improved precision. In addition, now reported are intermolecular π–π, C—H...π and aryl C—H...O interactions.

Key indicators

• Single-crystal X-ray study
• T = 295 K
• Mean [sigma](C-C) = 0.002 Å
• R factor = 0.049
• wR factor = 0.126
• Data-to-parameter ratio = 25.5

checkCIF results

No syntax errors found

ADDSYM reports no extra symmetry


 Alert Level C:



ABSMU_01  Alert C The ratio of given/expected absorption coefficient lies
          outside the range 0.99 <> 1.01
          Calculated value of mu =     0.097
          Value of mu given      =     0.100

ABSTM_02  Alert C The ratio of expected to reported Tmax/Tmin(RR') is < 0.90
          Tmin and Tmax reported:      0.782     0.997
          Tmin' and Tmax expected:      0.941     0.997
          RR' =      0.831
          Please check that your absorption correction is appropriate.


 0 Alert Level A = Potentially serious problem

 0 Alert Level B = Potential problem

 2 Alert Level C = Please check

---

S1. Comment

A search of the Cambridge Structural Database (Allen & Kennard, 1993) at the Chemical database service of the EPSRC (Fletcher et al., 1996) reveals that the structure of the title compound, (I), was first reported (NAPXAC10; Pattabhi et al., 1973) with R = 0.083 for 1623 reflections. The redetermination reported here with current refinement software and a more extensive set of intensity data yields a model of greater precision and improved R. Allowing for the different choice of unit cell (P2₁/n for P2₁/c) and atom-labelling scheme (Fig. 1), the results of the redetermination (Table 1) agree in all respects with those of Pattabhi et al. (1973).

A feature unremarked on in the original determination but replicated here was the variation in C—C bond lengths within the naphthalene ring system of the molecule. The bonds C1—C2, C4—C5, C6—C7 and C9—C10 at the corners of the ring system are in the range 1.3568 (19)–1.362 (2) Å (Table 1). The remainder are longer, ranging from 1.392 (2) to 1.4197 (18) Å. The difference between the bond lengths of the two groups is at least 0.03 Å and no less than 15 times the s.u.'s, and therefore significant and clearly of the type described elsewhere, e.g. for naphthalene (Brock & Dunitz, 1982).

The planarity of the molecule as a whole also merits comment. In addition to the undoubted planarity of the naphthalene group [maximum out of plane distance 0.0079 (13) Å for C7], the dihedral angles at the C11—C12 bond are clearly indicative of comparable planarity for the group comprising C11, C12 and O1 to O3 [maximum out of plane distance 0.0066 (9) for C11]. It is tempting then to estimate the angle between these planar entities by means of the dihedral angles at the C1—O1 bond which yield an average value of 5.88 (12)°. This, however, overestimates the value of 4.13 (5)° from mean-plane calculation because it fails to take account of the effect of the C1—O1—C11—C12 torsion angle which accounts for the difference. The departure from planarity is not in any case large.

As shown in Fig. 2, in which the essentially planar molecules are seen edge-on, the molecules are packed face-to-face to form layers parallel to (001) at z = 0 and 1/2. Three significant intermolecular contacts arise within the layers. The first of these is the previously reported centrosymmetrically hydrogen-bonded pair-wise association of the molecules (Fig. 1 and Table 2). The others, elucidated by PLATON (Spek, 1990), both involve the π system of the C3–C8 ring (with centroid Cg) of the naphthalene group. In one of these, the rings are found in centrosymmetrically related pairs and are then by definition parallel to one another within the pair (Fig. 3). This interaction is characterized by the perpendicular distance between the parallel planes (3.604 Å), the distance between their centroids [Cg···Cgⁱ 4.028 Å; symmetry code: (i) 1 - x, 1 - y, -z] and the angle between these vectors (26.52°). Finally, there is an interaction of the form C11—H11B···Cgⁱⁱ [symmetry code: (ii) x, y - 1, z]. This is characterized by five parameters as: (I) the distance between H and the centroid of the π system (H..-Cgⁱⁱ 2.792 Å); (ii) the perpendicular distance from H to the plane of the aryl ring (H–perp 2.747 Å); (iii) the angle between these vectors (γ 10.28°); (iv) the angle C11—H11B.·Cgⁱⁱ (137.29°); and (v) the C11.·Cgⁱⁱ distance (3.56 Å).

As noted above, the crystallographic centres of symmetry are involved in relationships between molecules within the layers. The layers themselves are related instead by the operation of the crystallographic n-glides, and equivalently by the crystallographic twofold screw axes. he tilt of the molecules relative to (010) therefore alternates from one layer to the next to yield a crisscross effect overall. The only interaction of any significance between the layers is the weak hydrogen-bond-type contact C5—H5.·O2 (Table 2).

S2. Experimental

As reported by Fries (1921), basic hydrolysis of methyl 2-naphthalenyloxyethanoate prepared by reaction of 2-naphthol and methyl bromoethanoate yielded (I), which was recrystallized from 1% aqueous hydrochloric acid solution [m.p. 432–433 K (literature value 428 K)].

S3. Refinement

Aryl and methylene H atoms were placed in calculated positions with C—H = 0.93 and 0.97 Å, respectively, and refined with a riding model with U_iso equal to 1.2U_eq of the C atomto which they are attached. The hydroxy H (H3A) atom was found in a difference map and refined isotropically in the usual manner.

Computing details

Data collection: SMART (Bruker, 1999); cell refinement: SAINT (Bruker, 1999); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 (Farrugia, 1997); software used to prepare material for publication: SHELXL97.

Figures

	Fig. 1. The centrosymmetric hydrogen-bonded dimer of (I). All non-H of the asymmetric unit and selected non-H atoms of the symmetry related molecule [symmetry code: (i) -x + 2, -y - 1, -z] are labelled. Non-H atoms are shown as 50% probability ellipsoids and H atoms are shown as open circles. Dashed lines represent H···O contacts.
	Fig. 2. Part of a layer of molecules of (I) parallel to (001). The representation of the atoms is the same as in Fig. 1 and dashed lines represent intermolecular contacts (see text).
	Fig. 3. A π–π stacked pair of molecules of (I). The representation of the atoms is the same as in Figs. 1 and 2, and selected atoms are labelled [symmetry code: (i) 1 - x, 1 - y, -z].

2-Naphthalenyloxyethanoic acid

Crystal data

C12H10O3	F(000) = 424
Mr = 202.20	Dx = 1.354 Mg m^−3
Monoclinic, P21/n	Mo Kα radiation, λ = 0.71073 Å
a = 12.3112 (10) Å	Cell parameters from 1594 reflections
b = 6.8401 (5) Å	θ = 3.0–25.5°
c = 13.1658 (10) Å	µ = 0.10 mm^−1
β = 116.507 (2)°	T = 295 K
V = 992.14 (13) Å^3	Needle, colourless
Z = 4	0.60 × 0.10 × 0.03 mm

Data collection

Bruker SMART 1000 CCD diffractometer	3577 independent reflections
Radiation source: fine-focus sealed tube	1511 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.043
ϕ and ω scans	θmax = 32.5°, θmin = 3.0°
Absorption correction: multi-scan (SADABS; Bruker, 1999)	h = −18→15
Tmin = 0.782, Tmax = 0.997	k = −10→9
9994 measured reflections	l = −19→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)] = 0.049	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.126	H atoms treated by a mixture of independent and constrained refinement
S = 0.82	w = 1/[σ^2(Fo^2) + (0.059P)^2] where P = (Fo^2 + 2Fc^2)/3
3577 reflections	(Δ/σ)max < 0.001
140 parameters	Δρmax = 0.18 e Å^−3
0 restraints	Δρmin = −0.20 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.

H of C—H in calculated positions and refined with a riding model. Hydroxyl found in difference map and refined isotropically in the usual manner.

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

	x	y	z	Uiso*/Ueq
C1	0.79229 (12)	0.19222 (19)	0.02361 (12)	0.0404 (3)
C2	0.71463 (13)	0.27454 (19)	−0.07653 (11)	0.0413 (3)
H2	0.7021	0.2159	−0.1446	0.050*
C3	0.65258 (12)	0.44997 (19)	−0.07742 (11)	0.0365 (3)
C4	0.57137 (13)	0.5404 (2)	−0.17977 (12)	0.0444 (4)
H4	0.5581	0.4842	−0.2487	0.053*
C5	0.51216 (14)	0.7081 (2)	−0.17937 (13)	0.0542 (4)
H5	0.4585	0.7649	−0.2476	0.065*
C6	0.53180 (16)	0.7949 (2)	−0.07700 (14)	0.0621 (5)
H6	0.4911	0.9096	−0.0772	0.074*
C7	0.61011 (14)	0.7133 (2)	0.02353 (13)	0.0547 (4)
H7	0.6226	0.7737	0.0912	0.066*
C8	0.67273 (12)	0.53836 (19)	0.02683 (11)	0.0401 (3)
C9	0.75357 (13)	0.4456 (2)	0.12874 (12)	0.0463 (4)
H9	0.7670	0.5009	0.1979	0.056*
C10	0.81189 (13)	0.2779 (2)	0.12773 (12)	0.0462 (4)
H10	0.8648	0.2195	0.1957	0.055*
O1	0.85899 (9)	0.02366 (14)	0.03510 (8)	0.0512 (3)
C11	0.83497 (13)	−0.07882 (19)	−0.06582 (12)	0.0442 (4)
H11A	0.8549	0.0023	−0.1156	0.053*
H11B	0.7496	−0.1125	−0.1052	0.053*
C12	0.91077 (13)	−0.2611 (2)	−0.03524 (12)	0.0408 (3)
O2	0.97923 (10)	−0.30728 (14)	0.06142 (9)	0.0534 (3)
O3	0.89432 (10)	−0.36239 (16)	−0.12538 (9)	0.0535 (3)
H3A	0.9313 (17)	−0.474 (3)	−0.1063 (14)	0.082 (6)*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
C1	0.0427 (8)	0.0345 (7)	0.0431 (8)	0.0062 (6)	0.0183 (7)	−0.0015 (6)
C2	0.0468 (9)	0.0393 (8)	0.0367 (8)	0.0031 (6)	0.0176 (6)	−0.0057 (6)
C3	0.0360 (8)	0.0359 (7)	0.0368 (8)	−0.0003 (6)	0.0156 (6)	−0.0009 (6)
C4	0.0426 (9)	0.0493 (9)	0.0382 (8)	0.0038 (7)	0.0152 (7)	−0.0018 (6)
C5	0.0525 (10)	0.0589 (10)	0.0456 (9)	0.0187 (8)	0.0168 (7)	0.0071 (8)
C6	0.0688 (11)	0.0550 (10)	0.0602 (11)	0.0270 (8)	0.0268 (9)	0.0015 (8)
C7	0.0633 (11)	0.0528 (9)	0.0463 (9)	0.0142 (8)	0.0228 (8)	−0.0078 (7)
C8	0.0412 (8)	0.0389 (8)	0.0402 (8)	0.0023 (6)	0.0182 (6)	−0.0038 (6)
C9	0.0506 (9)	0.0513 (9)	0.0343 (8)	0.0061 (7)	0.0164 (7)	−0.0073 (7)
C10	0.0496 (9)	0.0481 (9)	0.0359 (8)	0.0095 (7)	0.0147 (7)	0.0011 (6)
O1	0.0616 (7)	0.0423 (6)	0.0417 (6)	0.0171 (5)	0.0160 (5)	−0.0024 (4)
C11	0.0495 (9)	0.0382 (8)	0.0432 (8)	0.0070 (6)	0.0192 (7)	−0.0029 (6)
C12	0.0445 (8)	0.0347 (7)	0.0455 (9)	0.0007 (6)	0.0221 (7)	−0.0012 (7)
O2	0.0659 (7)	0.0442 (6)	0.0445 (6)	0.0159 (5)	0.0197 (6)	0.0005 (5)
O3	0.0696 (8)	0.0418 (6)	0.0450 (6)	0.0141 (5)	0.0218 (5)	−0.0027 (5)

Geometric parameters (Å, º)

C1—C2	1.3580 (19)	C7—C8	1.4135 (19)
C1—O1	1.3840 (16)	C7—H7	0.930
C1—C10	1.4091 (18)	C8—C9	1.4146 (19)
C2—C3	1.4197 (18)	C9—C10	1.3568 (19)
C2—H2	0.930	C9—H9	0.930
C3—C4	1.4125 (18)	C10—H10	0.930
C3—C8	1.4167 (17)	O1—C11	1.4118 (15)
C4—C5	1.361 (2)	C11—C12	1.5005 (19)
C4—H4	0.930	C11—H11A	0.970
C5—C6	1.392 (2)	C11—H11B	0.970
C5—H5	0.930	C12—O2	1.2134 (15)
C6—C7	1.362 (2)	C12—O3	1.3097 (16)
C6—H6	0.930	O3—H3A	0.87 (2)
C2—C1—O1	125.30 (12)	C7—C8—C9	123.49 (12)
C2—C1—C10	120.84 (12)	C7—C8—C3	118.31 (12)
O1—C1—C10	113.86 (12)	C9—C8—C3	118.19 (12)
C1—C2—C3	120.10 (12)	C10—C9—C8	121.41 (12)
C1—C2—H2	119.9	C10—C9—H9	119.3
C3—C2—H2	119.9	C8—C9—H9	119.3
C4—C3—C8	118.73 (12)	C9—C10—C1	119.98 (13)
C4—C3—C2	121.80 (12)	C9—C10—H10	120.0
C8—C3—C2	119.46 (12)	C1—C10—H10	120.0
C5—C4—C3	121.18 (13)	C1—O1—C11	116.48 (10)
C5—C4—H4	119.4	O1—C11—C12	108.42 (11)
C3—C4—H4	119.4	O1—C11—H11A	110.0
C4—C5—C6	120.11 (14)	C12—C11—H11A	110.0
C4—C5—H5	119.9	O1—C11—H11B	110.0
C6—C5—H5	119.9	C12—C11—H11B	110.0
C7—C6—C5	120.54 (14)	H11A—C11—H11B	108.4
C7—C6—H6	119.7	O2—C12—O3	124.52 (13)
C5—C6—H6	119.7	O2—C12—C11	123.74 (12)
C6—C7—C8	121.12 (13)	O3—C12—C11	111.74 (13)
C6—C7—H7	119.4	C12—O3—H3A	110.8 (11)
C8—C7—H7	119.4
O1—C1—C2—C3	−179.00 (12)	C4—C3—C8—C9	179.54 (12)
C10—C1—C2—C3	0.5 (2)	C2—C3—C8—C9	−0.84 (19)
C1—C2—C3—C4	179.82 (13)	C7—C8—C9—C10	−179.87 (14)
C1—C2—C3—C8	0.2 (2)	C3—C8—C9—C10	0.8 (2)
C8—C3—C4—C5	−0.6 (2)	C8—C9—C10—C1	−0.1 (2)
C2—C3—C4—C5	179.76 (14)	C2—C1—C10—C9	−0.5 (2)
C3—C4—C5—C6	0.6 (2)	O1—C1—C10—C9	179.00 (13)
C4—C5—C6—C7	0.0 (3)	C2—C1—O1—C11	−6.1 (2)
C5—C6—C7—C8	−0.4 (3)	C10—C1—O1—C11	174.35 (12)
C6—C7—C8—C9	−178.97 (15)	C1—O1—C11—C12	−177.02 (11)
C6—C7—C8—C3	0.4 (2)	O1—C11—C12—O2	0.55 (19)
C4—C3—C8—C7	0.2 (2)	O1—C11—C12—O3	−179.07 (11)
C2—C3—C8—C7	179.79 (13)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O3—H3A···O2^i	0.87 (2)	1.79 (2)	2.6586 (14)	174.6 (18)
C5—H5···O2^ii	0.93	2.65	3.3220 (19)	129

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