Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270109047556/gd3319sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S0108270109047556/gd3319Isup2.hkl |
CCDC reference: 763605
Crystals of (I) were grown from a solution in toluene by slow evaporation of solvent at a constant temperature of 293 K.
All C-bound H atoms were included in the refinement at geometrically idealized positions, with C—H distances of 0.93 Å (aromatic) and 0.96 Å (methyl), and with Uiso(H) = 1.2Ueq(Caromatic) or Uiso(H) = 1.5Ueq(Cmethyl). The H atom of the hydroxy group was located in a difference map and refined isotropically, giving an O—H distance of 0.86 (46) Å. In the absence of significant resonant scattering, the Flack (1983) parameter was indeterminate (Flack & Bernardinelli, 2000) and the Friedel equivalent reflections were merged prior to the final refinement.
Data collection: CrysAlis CCD (Oxford Diffraction, 2008); cell refinement: CrysAlis RED (Oxford Diffraction, 2008); data reduction: CrysAlis RED (Oxford Diffraction, 2008); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: PLATON (Spek, 2009), DIAMOND (Brandenburg, 2006); software used to prepare material for publication: publCIF (Westrip, 2009).
C11H10O2 | F(000) = 184 |
Mr = 174.19 | Dx = 1.328 Mg m−3 |
Monoclinic, P21 | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: P 2yb | Cell parameters from 4896 reflections |
a = 8.5940 (4) Å | θ = 2.4–26.4° |
b = 4.7435 (2) Å | µ = 0.09 mm−1 |
c = 10.7293 (5) Å | T = 290 K |
β = 95.183 (4)° | Column, yellow-brown |
V = 435.60 (3) Å3 | 0.46 × 0.20 × 0.13 mm |
Z = 2 |
Oxford Diffraction Xcalibur3 CCD diffractometer | 994 independent reflections |
Radiation source: Enhance (Mo) X-ray Source | 865 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.024 |
ω scans | θmax = 26.4°, θmin = 3.2° |
Absorption correction: multi-scan (CrysAlis RED; Oxford Diffraction, 2008) | h = −10→10 |
Tmin = 0.966, Tmax = 1.000 | k = −5→5 |
4893 measured reflections | l = −13→13 |
Refinement on F2 | Primary atom site location: structure-invariant direct methods |
Least-squares matrix: full | Secondary atom site location: difference Fourier map |
R[F2 > 2σ(F2)] = 0.036 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.084 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.03 | w = 1/[σ2(Fo2) + (0.0485P)2 + 0.0226P] where P = (Fo2 + 2Fc2)/3 |
994 reflections | (Δ/σ)max < 0.001 |
122 parameters | Δρmax = 0.12 e Å−3 |
1 restraint | Δρmin = −0.17 e Å−3 |
C11H10O2 | V = 435.60 (3) Å3 |
Mr = 174.19 | Z = 2 |
Monoclinic, P21 | Mo Kα radiation |
a = 8.5940 (4) Å | µ = 0.09 mm−1 |
b = 4.7435 (2) Å | T = 290 K |
c = 10.7293 (5) Å | 0.46 × 0.20 × 0.13 mm |
β = 95.183 (4)° |
Oxford Diffraction Xcalibur3 CCD diffractometer | 994 independent reflections |
Absorption correction: multi-scan (CrysAlis RED; Oxford Diffraction, 2008) | 865 reflections with I > 2σ(I) |
Tmin = 0.966, Tmax = 1.000 | Rint = 0.024 |
4893 measured reflections |
R[F2 > 2σ(F2)] = 0.036 | 1 restraint |
wR(F2) = 0.084 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.03 | Δρmax = 0.12 e Å−3 |
994 reflections | Δρmin = −0.17 e Å−3 |
122 parameters |
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. |
x | y | z | Uiso*/Ueq | ||
O1 | 0.96831 (17) | −0.0348 (4) | 0.05823 (15) | 0.0542 (4) | |
H1 | 0.988 (4) | −0.186 (8) | 0.019 (3) | 0.083 (10)* | |
O2 | 0.42179 (16) | −0.1312 (5) | 0.29143 (14) | 0.0653 (5) | |
C1 | 0.8292 (2) | −0.0678 (4) | 0.11263 (17) | 0.0400 (5) | |
C2 | 0.7149 (2) | −0.2440 (4) | 0.06515 (19) | 0.0445 (5) | |
H2 | 0.7286 | −0.3478 | −0.0066 | 0.053* | |
C3 | 0.5750 (2) | −0.2709 (5) | 0.12394 (19) | 0.0462 (6) | |
H3 | 0.4974 | −0.3935 | 0.0910 | 0.055* | |
C4 | 0.5529 (2) | −0.1193 (5) | 0.22817 (18) | 0.0431 (5) | |
C5 | 0.6702 (2) | 0.0695 (4) | 0.28022 (18) | 0.0392 (5) | |
C6 | 0.6520 (2) | 0.2308 (5) | 0.38907 (19) | 0.0476 (5) | |
H6 | 0.5610 | 0.2139 | 0.4292 | 0.057* | |
C7 | 0.7662 (3) | 0.4098 (5) | 0.4352 (2) | 0.0541 (6) | |
H7 | 0.7516 | 0.5178 | 0.5056 | 0.065* | |
C8 | 0.9054 (3) | 0.4336 (5) | 0.3783 (2) | 0.0552 (6) | |
H8 | 0.9830 | 0.5561 | 0.4113 | 0.066* | |
C9 | 0.9282 (2) | 0.2786 (4) | 0.2749 (2) | 0.0479 (6) | |
H9 | 1.0222 | 0.2938 | 0.2386 | 0.057* | |
C10 | 0.8111 (2) | 0.0949 (4) | 0.22184 (18) | 0.0376 (5) | |
C11 | 0.3053 (3) | −0.3307 (8) | 0.2489 (2) | 0.0712 (8) | |
H11A | 0.2195 | −0.3190 | 0.3001 | 0.107* | |
H11B | 0.3489 | −0.5171 | 0.2544 | 0.107* | |
H11C | 0.2689 | −0.2905 | 0.1635 | 0.107* |
U11 | U22 | U33 | U12 | U13 | U23 | |
O1 | 0.0482 (8) | 0.0534 (10) | 0.0650 (10) | −0.0044 (8) | 0.0267 (7) | −0.0048 (8) |
O2 | 0.0481 (8) | 0.0863 (12) | 0.0649 (9) | −0.0226 (9) | 0.0245 (7) | −0.0171 (10) |
C1 | 0.0389 (9) | 0.0393 (12) | 0.0432 (11) | 0.0049 (11) | 0.0113 (8) | 0.0094 (11) |
C2 | 0.0474 (10) | 0.0448 (14) | 0.0419 (11) | −0.0014 (11) | 0.0069 (9) | −0.0025 (10) |
C3 | 0.0427 (10) | 0.0498 (14) | 0.0458 (11) | −0.0082 (11) | 0.0027 (9) | −0.0021 (11) |
C4 | 0.0369 (10) | 0.0499 (13) | 0.0435 (11) | −0.0064 (11) | 0.0087 (8) | 0.0039 (11) |
C5 | 0.0407 (9) | 0.0398 (12) | 0.0374 (10) | 0.0025 (9) | 0.0053 (8) | 0.0058 (10) |
C6 | 0.0495 (11) | 0.0524 (14) | 0.0425 (11) | −0.0021 (11) | 0.0125 (9) | 0.0000 (11) |
C7 | 0.0697 (13) | 0.0522 (15) | 0.0405 (11) | −0.0041 (13) | 0.0052 (10) | −0.0052 (12) |
C8 | 0.0588 (12) | 0.0531 (15) | 0.0529 (12) | −0.0157 (12) | −0.0001 (10) | −0.0021 (12) |
C9 | 0.0451 (10) | 0.0465 (14) | 0.0528 (12) | −0.0088 (11) | 0.0085 (9) | 0.0060 (11) |
C10 | 0.0365 (9) | 0.0359 (11) | 0.0404 (10) | −0.0007 (9) | 0.0046 (8) | 0.0097 (9) |
C11 | 0.0478 (12) | 0.094 (2) | 0.0737 (16) | −0.0268 (15) | 0.0156 (11) | −0.0087 (16) |
O1—C1 | 1.386 (2) | C5—C10 | 1.418 (2) |
O1—H1 | 0.86 (4) | C6—C7 | 1.357 (3) |
O2—C4 | 1.368 (2) | C6—H6 | 0.9300 |
O2—C11 | 1.422 (3) | C7—C8 | 1.396 (3) |
C1—C2 | 1.353 (3) | C7—H7 | 0.9300 |
C1—C10 | 1.423 (3) | C8—C9 | 1.360 (3) |
C2—C3 | 1.413 (3) | C8—H8 | 0.9300 |
C2—H2 | 0.9300 | C9—C10 | 1.411 (3) |
C3—C4 | 1.357 (3) | C9—H9 | 0.9300 |
C3—H3 | 0.9300 | C11—H11A | 0.9600 |
C4—C5 | 1.424 (3) | C11—H11B | 0.9600 |
C5—C6 | 1.417 (3) | C11—H11C | 0.9600 |
C1—O1—H1 | 109 (2) | C5—C6—H6 | 119.7 |
C4—O2—C11 | 117.13 (18) | C6—C7—C8 | 120.7 (2) |
C2—C1—O1 | 122.37 (18) | C6—C7—H7 | 119.6 |
C2—C1—C10 | 121.02 (16) | C8—C7—H7 | 119.6 |
O1—C1—C10 | 116.61 (17) | C9—C8—C7 | 120.4 (2) |
C1—C2—C3 | 120.36 (19) | C9—C8—H8 | 119.8 |
C1—C2—H2 | 119.8 | C7—C8—H8 | 119.8 |
C3—C2—H2 | 119.8 | C8—C9—C10 | 120.83 (18) |
C4—C3—C2 | 120.52 (19) | C8—C9—H9 | 119.6 |
C4—C3—H3 | 119.7 | C10—C9—H9 | 119.6 |
C2—C3—H3 | 119.7 | C9—C10—C5 | 118.73 (17) |
C3—C4—O2 | 124.72 (18) | C9—C10—C1 | 122.67 (16) |
C3—C4—C5 | 120.64 (16) | C5—C10—C1 | 118.60 (16) |
O2—C4—C5 | 114.64 (16) | O2—C11—H11A | 109.5 |
C6—C5—C10 | 118.73 (17) | O2—C11—H11B | 109.5 |
C6—C5—C4 | 122.41 (17) | H11A—C11—H11B | 109.5 |
C10—C5—C4 | 118.86 (16) | O2—C11—H11C | 109.5 |
C7—C6—C5 | 120.57 (18) | H11A—C11—H11C | 109.5 |
C7—C6—H6 | 119.7 | H11B—C11—H11C | 109.5 |
O1—C1—C2—C3 | 179.93 (19) | C5—C6—C7—C8 | −1.6 (3) |
C10—C1—C2—C3 | −0.3 (3) | C6—C7—C8—C9 | 0.5 (3) |
C1—C2—C3—C4 | 0.4 (3) | C7—C8—C9—C10 | 1.1 (3) |
C2—C3—C4—O2 | −180.0 (2) | C8—C9—C10—C5 | −1.5 (3) |
C2—C3—C4—C5 | 0.0 (3) | C8—C9—C10—C1 | 179.0 (2) |
C11—O2—C4—C3 | 4.2 (3) | C6—C5—C10—C9 | 0.4 (3) |
C11—O2—C4—C5 | −175.7 (2) | C4—C5—C10—C9 | −178.9 (2) |
C3—C4—C5—C6 | −179.8 (2) | C6—C5—C10—C1 | 179.90 (19) |
O2—C4—C5—C6 | 0.2 (3) | C4—C5—C10—C1 | 0.6 (2) |
C3—C4—C5—C10 | −0.5 (3) | C2—C1—C10—C9 | 179.32 (19) |
O2—C4—C5—C10 | 179.48 (18) | O1—C1—C10—C9 | −0.9 (3) |
C10—C5—C6—C7 | 1.1 (3) | C2—C1—C10—C5 | −0.2 (3) |
C4—C5—C6—C7 | −179.6 (2) | O1—C1—C10—C5 | 179.58 (16) |
D—H···A | D—H | H···A | D···A | D—H···A |
O1—H1···O1i | 0.86 (4) | 1.90 (4) | 2.758 (2) | 176 (3) |
Symmetry code: (i) −x+2, y−1/2, −z. |
Experimental details
Crystal data | |
Chemical formula | C11H10O2 |
Mr | 174.19 |
Crystal system, space group | Monoclinic, P21 |
Temperature (K) | 290 |
a, b, c (Å) | 8.5940 (4), 4.7435 (2), 10.7293 (5) |
β (°) | 95.183 (4) |
V (Å3) | 435.60 (3) |
Z | 2 |
Radiation type | Mo Kα |
µ (mm−1) | 0.09 |
Crystal size (mm) | 0.46 × 0.20 × 0.13 |
Data collection | |
Diffractometer | Oxford Diffraction Xcalibur3 CCD diffractometer |
Absorption correction | Multi-scan (CrysAlis RED; Oxford Diffraction, 2008) |
Tmin, Tmax | 0.966, 1.000 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 4893, 994, 865 |
Rint | 0.024 |
(sin θ/λ)max (Å−1) | 0.625 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.036, 0.084, 1.03 |
No. of reflections | 994 |
No. of parameters | 122 |
No. of restraints | 1 |
H-atom treatment | H atoms treated by a mixture of independent and constrained refinement |
Δρmax, Δρmin (e Å−3) | 0.12, −0.17 |
Computer programs: CrysAlis CCD (Oxford Diffraction, 2008), CrysAlis RED (Oxford Diffraction, 2008), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), PLATON (Spek, 2009), DIAMOND (Brandenburg, 2006), publCIF (Westrip, 2009).
O1—C1 | 1.386 (2) | C4—C5 | 1.424 (3) |
O2—C4 | 1.368 (2) | C5—C6 | 1.417 (3) |
O2—C11 | 1.422 (3) | C5—C10 | 1.418 (2) |
C1—C2 | 1.353 (3) | C6—C7 | 1.357 (3) |
C1—C10 | 1.423 (3) | C7—C8 | 1.396 (3) |
C2—C3 | 1.413 (3) | C8—C9 | 1.360 (3) |
C3—C4 | 1.357 (3) | C9—C10 | 1.411 (3) |
D—H···A | D—H | H···A | D···A | D—H···A |
O1—H1···O1i | 0.86 (4) | 1.90 (4) | 2.758 (2) | 176 (3) |
Symmetry code: (i) −x+2, y−1/2, −z. |
This paper is a continuation of our structural studies of 1-naphthol derivatives carrying different substituents at positions 4 or 5. In previous papers, the structures of 4-chloro-1-naphthol [CSD (Allen, 2002) refcode BOTSOT; Rozycka-Sokolowska & Marciniak, 2009a] and 5-amino-1-naphthol (Rozycka-Sokolowska & Marciniak, 2009b) have been reported, and it was found that these compounds and also several of their simple analogues, i.e. 1-naphthol (CSD refcode NAPHOL01; Rozycka-Sokolowska et al., 2004), 1,4- and 1,5-dihydroxynaphthalene [CSD refcodes NPHHQU10 (Gaultier & Hauw, 1967) and VOGRUE (Belskii et al., 1990), respectively], 1,4-dichloro- and 1,5-dibromonaphthalene [CSD refcodes DCLNAQ (Bellows et al., 1978) and DBRNAQ01 (Trotter, 1986), respectively] show π-stacking with substantial spatial overlap in the solid state. Hence they can be regarded as particularly attractive materials for the development of devices with high charge-carrier mobilities (Anthony et al., 2002; Li et al., 1998; Horowitz et al., 1996; Laquindanum et al., 1997; Chen et al., 2006).
Here we report the structure of the title compound, (I) (Fig. 1), as a further example from the group of 4- or 5-substituted 1-naphthols. This work was undertaken to check whether (I), from the viewpoint of the crystal packing, will turn out to be a promising material for applications in electronic device fabrication. We also compare the crystal structure of (I) with those of five of its simple analogues (see scheme), i.e. 1-naphthol, (II), 1,4-dihydroxynaphthalene, (III), 1,5-dihydroxynaphthalene, (IV), 4-chloro-1-naphthol, (V), and 5-amino-1-naphthol, (VI), and also with that of the isomeric 7-methoxy-2-naphthol, (VII) [CSD refcode TEBFIP (Prince et al., 1991)].
The values of bond distances (Table 1) and valence angles within the aromatic rings range from 1.353 (3) to1.424 (3) Å and from 118.6 (2) to 122.7 (2)°, respectively. From among 11 Car—Car bonds, four, i.e. C1—C2, C3—C4, C6—C7 and C8—C9 bonds, are shorter on average by 0.027 Å than the typical aromatic bond length [1.384 (13) Å] given by Allen et al. (1987), and all the other bonds are longer on average by 0.031 Å (Table 1). The C1—O1 bond length is in close agreement with the corresponding distances in the simple analogues of (I), such as (II), (III), (IV), (V) and (VI) [1.376 (1), 1.377, 1.385, 1.394 (3) and 1.379 (4) Å, respectively], and the lengths of C4—O2 and O2—C11 bonds compare well with those found in (VII) and in the methoxy derivatives of naphthalene such as 2-methoxynaphthalene [Car—O = 1.3749 (11) Å and O—Cmethyl = 1.4250 (14) Å; CSD refcode SAYRIT (Bolte & Bauch, 1998)], 1,4-dimethoxynaphthalene [Car—O = 1.37 (1) and 1.39 (1) Å, and O—Cmethyl = 1.46 (1) and 1.44 (1) Å; CSD refcode ALUJIA (Wiedenfeld et al., 1999)] and 1,8-dimethoxynaphthalene [Car—O = 1.359 (2) and 1.362 (2) Å, and O—Cmethyl = 1.425 (2) and 1.419 (2) Å; CSD refcode KEPKUL (Cosmo et al., 1990)] and with the values given by Allen & Kirby (1984). The ten-membered aromatic ring formed by atoms C1—C10 is planar, with the largest out-of-plane deviation of -0.015 (2) Å for atom C9. The deviations of hydroxyl O1 and methoxy O2 and C11 atoms from this plane are only 0.013 (2), -0.015 (2) and -0.117 (3) Å, respectively.
Each molecule of (I) is connected to two others by a strong, nearly linear O—H···O hydrogen bond (Table 2). The hydroxyl atoms O1 in the molecules at (x, y, z) and (2 - x, 1/2 + y, -z) act as hydrogen-bond donors to atoms O1 at (2 - x, -1/2 + y, -z) and (x, y, z), respectively, so forming a simple C(2) chain (Fig. 2). This chain runs parallel to the shortest crystallographic axis, i.e. axis b, and contains molecules related by the 21 screw axis. There are no interactions between adjacent C(2) chains. However, in the crystal structure of (I) there is also an intermolecular π–π stacking interaction, which involves the C1–C5/C10 (centroid Cg1) and C5–C10 (centroid Cg2) benzene rings (Fig. 2). The perpendicular distances of the ring centroids Cg1 and Cg2 from the planes containing the translation-related centroids Cg2 at (x, -1 + y, z) and Cg1 at (x, 1 + y, z), respectively, are 3.514 (1) and 3.513 (1) Å, and the Cg···Cg separation is 3.610 (1) Å. The planes of rings C1–C5/C10 and C5–C10 make an angle of only 0.437°. These aromatic π-stacking forces are an important factor in the stabilization of the one-dimensional chain in (I). Similarly, as in the cases of (II)–(VI), in order to estimate the area overlap (AO) of adjacent π-stacking molecules, the phenomenological approach proposed by Curtis et al. (2004), in combination with a simple model introduced by Janzen et al. (2004), were used. Analysis of the values of estimated parameters such as the pitch (P) and roll (R) angles, and the pitch (dp) and roll (dr) distances, and the value of AO, indicates that the solid-state packing of (I) provides a substantial overlap between molecules in the π-stack (P = 42.07° > R = 8.95°, dp = 3.18 Å > dr = 0.55 Å, AO = 27.4%). A comparison of the AO value estimated for (I) with the values given in our previous paper (Rozycka-Sokolowska & Marciniak, 2009a) for (II), (III) and (V) (AOII = 27.0%, AOIII = 31.5% and AOV = 40.7%) leads to the conclusion that [as far as the] modification of the molecular structure of (II) by replacement of one H atom at the 4-position by one hydroxy group or one Cl atom results in an increase of this overlap by 4.5 and 13.7%, respectively, then in the case of methoxy substitution, the AO value is only by 0.4% larger than that estimated for (II).
It is noteworthy that the presence of π-stacks with overlap between the adjacent molecules is not a characteristic of the herringbone packing (P < R, dp < dr) in 1,3-, 1,6- and 1,7-naphthalenediols [CSD refcodes: HEGFAB (Marciniak et al., 2006), RIGMOK (Marciniak, 2007b) and LICKEO (Marciniak, 2007a), respectively] and in 2-naphthol [CSD refcode NAPHOB03 (Marciniak et al., 2003)] and its simple derivatives such as (VII), 2,3-, 2,6- and 2,7-naphthalenediols [CSD refcodes: VOGSEP and VOGSAL (Belskii et al., 1990), and NPHLDL01 (Rozycka-Sokolowska et al., 2005), respectively], where apart from strong intermolecular O—H···O hydrogen bonds, there are also weak intermolecular hydrogen bonds of the X—H···π type. In the crystal structures of HEGFAB and LICKEO there are C—H···π hydrogen bonds (see Fig. 3 in Marciniak et al., 2006 and Fig. 4 in Marciniak et al., 2007a, respectively), while in that of RIGMOK there is an interaction of O—H···π type (see Fig.4 in Marciniak, 2007b). The interactions of the C—H···π type also stabilize the crystal structures of NAPHOB03 (Fig. 3), VOGSAL (Fig. 4) and NPHLDL01 (Fig. 5), although this was not discussed in the original reports.
In the crystal structures of (VII) and VOGSEP, however, there are both C—H···π and O—H···π hydrogen bonds (Figs. 6 and 7, respectively), although not previously discussed. Taking into account these facts and bearing in mind that (II) and its derivatives such as (I) and (III)–(VI) yield π-stacking with substantial overlap in the solid state, we may suppose that the parallel arrangement of molecules of these compounds is first of all a consequence of the presence of the substituents at position 1 of the naphthalene moiety and at positions 4 or 5. Moreover, a comparison of the AO values estimated for (II)–(VI) indicates that the overlap between adjacent molecules in the stacks is larger than that estimated for (II) when a substitution at the position 4- takes place [i.e. as in (I), (III) and (V)], while it is smaller when the substituent is at the position 5- [i.e. as in (IV) and (VI)]. Summing up, it is worth noting that in the case of monosubstituted naphthols, the parallel arrangement of the molecules depends on which positions in the naphthalene moiety carry the substituents, while the nature of the substituents, in both 4-substituted and 5-substituted 1-naphthols, determines the extent of the area overlap.
It is also noteworthy that the supramolecular aggregation in (I) is the same as that observed previously for two of its simple analogues, (V) and (II), crystallizing with Z' = 1 in the space groups Pna21 and P21/c, respectively [see Figs. 2 and 3a, respectively, in Rozycka-Sokolowska & Marciniak (2009a)] and it is the simpler than those observed in the crystal structures of three further analogues, namely (III) (Z' = 1/2, Pnma), (IV) (Z' = 1/2, P21/n) and (VI) (Z' = 1, P212121), where sheets containing R44(18) rings were identified [see Fig. 3d in Rozycka-Sokolowska & Marciniak (2009a) and Figs. 2 and 4 in Rozycka-Sokolowska & Marciniak (2009b), respectively]. By contrast with (I), in the structure of the methoxynaphthol isomer (VII) crystallizing with Z`= 1 in the space group P21/c, there are no O—H···O hydrogen bonds or π–π stacking interactions. The herringbone packing of the molecules (VII) is stabilized by three weak hydrogen bonds (Desiraju & Steiner, 1999), one O—H···π(arene) and two C—H···π(arene), although these were not discussed in the original report (Prince et al., 1991). Together these interactions generate a sheet parallel to (100) (Fig. 6).