2,4-Bis(α,α-di­methyl­benzyl)­phenol

The structure of the title compound, 2,4-bis(1-methyl-1-phenylethyl)phenol, C₂₄H₂₆O, was found to have a torsion angle of 129.95 (13)° for the C—C bond that connects the benzyl carbon to the phenol ring ortho to the OH group. A value of ∼50° was expected from molecular mechanics calculations. Intermolecular interactions, in particular O—H...O and edge–face π bonding, may contribute to this discrepancy. Intramolecular O—H...π bonding is also observed.

S1. Comment

As part of our investigation into the extraction of caesium by 2-benzylphenol and its derivatives (Bryan et al., 1999; Delmau et al., 2000), we wished to examine the structural effects of alkyl substitution on the benzyl carbon atom. Molecular mechanics (MM) calculations suggest that metal ion selectivity may be affected by the rotational potential energy surface for the C—C bond that connects the benzyl carbon to the phenol ring ortho to the OH group (Delmau et al., 2000). In other words, the value for this torsion angle (referred to here as ψ) varies in MM minimizations depending on the alkali metal ion complexed, from 100° for Cs⁺ to 126° for Li⁺ (Bryan et al., 1999). Varying the steric environment at the ortho benzyl carbon atom will affect the potential energy surface, and therefore also affect selectivity.

We previously reported the structure of 2-benzylphenol, which exhibited a ψ value of 11.1 (2)°. This unusually low value was attributed to intermolecular O—H···O hydrogen bonding and edge-to-face arene interactions (Bryan et al., 1999), and to the relatively low conformational energies calculated for 2-benzylphenol by MM at low ψ (Delmau et al., 2000). The only published structure of a 2-benzylphenol derivative containing alkyl substitution at the benzyl carbon is 2,4,6-tris(α,α-dimethylbenzyl)phenol, which exhibits ψ values of 122.3 (3) and −124.4 (3)° for the two benzyl groups ortho to the hydroxyl group (Kurashev et al., 1986). We sought to investigate the structure of the title compound, (I), because of its commercial availability and because MM calculations predicted a minimum conformational energy for ψ of \sim50° for methyl substitution on the benzyl carbon (2-α-methylbenzylphenol; Delmau et al., 2000). \sch

The structure of (I) (Figure 1) is dramatically different from 2-benzylphenol (Bryan et al., 1999), but is quite similar to the more closely related 2,4,6-tris(α,α-dimethylbenzyl)phenol (Kurashev et al., 1986). Specifically, the ψ angle (C3—C2—C7—C11) is 129.95 (13)° in (I), almost identical to those reported for 2,4,6-tris(α,α-dimethylbenzyl)phenol. These results suggest that the MM calculations performed for 2-α-methylbenzylphenol do not correlate well to structures determined containing the 2-α,α-dimethylbenzylphenol fragment, possibly due to intermolecular forces in the crystal structure.

The hydroxyl H atom in (I) was determined to be disordered over two sites (50:50) by examination of an electron-density difference map. One position (H1) is oriented outwards from the molecule, and forms an intermolecular hydrogen bond to Oⁱ [symmetry code (i) −x, 1 − y, 1 − z]. The other location (H2) is oriented inwards, forming an O—H···π interaction (Steiner et al., 1996; Bakshi, et al., 1994) with the phenyl group (Table 2).

The three arene rings in this structure are each planar within 0.016 Å, and are all roughly orthogonal to each other. The interarene angles are A1—A2 = 80.36 (7)°, A1—A3 = 71.43 (8)°, and A2—A3 = 71.88 (8)°, where A1 = C1–C6, A2 = C11–C16, and A3 = C21–C26. No π–π ring stacking is observed, but two edge-face arene interactions are detected, which are illustrated in Figure 2. These interactions are further quantified in Table 2 where metrical parameters for the two C—H···π-centroid interactions are listed. The centroids are represented as CgX, where X corresponds to the appropriate arene (AX) ring. Taken together, the hydrogen bonds of the hydroxyl group and the edge-face interactions of the arene groups, a three-dimensional network is formed.

S2. Experimental

The title compound was obtained from a commercial source (Aldrich) and was recrystallized from 2,2,2-trifluorethanol.

S3. Refinement

A 1.1 mm collimator was used. All carbon-bound H atoms were placed in calculated positions, refined using a riding model, and given an isotropic displacement parameter equal to 1.2 (CH) or 1.5 (CH₃) times the equivalent isotropic displacement parameter of the atom to which they were attached. The C—H distances used depend on the type of C atom: C_aromatic—H = 0.95, C_methyl—H = 0.98 Å. Methyl H atoms were allowed to rotate about the adjacent C—C bond. The hydroxyl H atom was found to be disordered over two sites (50:50). The positional parameters of the hydroxyl H atom were allowed to refine, and they were given an isotropic displacement parameter equal to 1.5 times the equivalent isotropic displacement parameter of O.

Computing details

Data collection: CAD-4-PC (Nonius, 1993); cell refinement: CAD-4-PC; data reduction: XCAD4 (Harms, 1995); program(s) used to solve structure: SHELXS86 (Sheldrick, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SHELXTL (Siemens, 1994); software used to prepare material for publication: PLATON (Spek, 1999).

Figures

	Fig. 1. The molecular structure of (I) showing 50% probability displacement ellipsoids.
	Fig. 2. Packing diagram illustrating the edge-face π and O—H···O interactions of (I). For clarity, all atoms are represented as circles and H atoms are omitted [symmetry codes: (i) −x, 1 − y, 1 − z; (ii) x − 1, y − 1, z; (iii) 1 − x, 1 − y, −z] where Cg2 represents the centroid for C11–16.

(I)

Crystal data

C24H26O	Z = 2
Mr = 330.4	F(000) = 356
Triclinic, P1	Dx = 1.17 Mg m^−3
Hall symbol: -P 1	Melting point = 63–65 K
a = 6.1716 (9) Å	Mo Kα radiation, λ = 0.71073 Å
b = 11.7924 (14) Å	Cell parameters from 25 reflections
c = 13.2197 (14) Å	θ = 10.0–17.6°
α = 97.731 (10)°	µ = 0.07 mm^−1
β = 97.109 (12)°	T = 173 K
γ = 97.353 (12)°	Plate, colourless
V = 935.7 (2) Å^3	0.71 × 0.47 × 0.13 mm

Data collection

Nonius CAD-4 diffractometer	Rint = 0.028
Radiation source: fine-focus sealed tube	θmax = 25.0°, θmin = 2.1°
Graphite monochromator	h = −7→7
ω–scans	k = −14→0
3458 measured reflections	l = −15→15
3282 independent reflections	3 standard reflections every 120 min
2656 reflections with I > 2σI	intensity decay: 1%

Refinement

Refinement on F^2	0 restraints
Least-squares matrix: full	H atoms treated by a mixture of independent and constrained refinement
R[F^2 > 2σ(F^2)] = 0.040	w = 1/[σ^2(Fo^2) + (0.0631P)^2 + 0.2606P] where P = (Fo^2 + 2Fc^2)/3
wR(F^2) = 0.110	(Δ/σ)max < 0.001
S = 1.07	Δρmax = 0.21 e Å^−3
3282 reflections	Δρmin = −0.23 e Å^−3
236 parameters

Special details

Geometry. Bond distances, angles etc. have been calculated using the rounded fractional coordinates. All e.s.d.'s are estimated from the variances of the (full) variance-covariance matrix. The cell e.s.d.'s are taken into account in the estimation of distances, angles and torsion angles

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

	x	y	z	Uiso*/Ueq	Occ. (<1)
O	0.0934 (2)	0.45563 (10)	0.40796 (9)	0.0371 (4)
C1	0.2585 (2)	0.53809 (12)	0.39012 (11)	0.0267 (4)
C2	0.3097 (2)	0.54428 (12)	0.29059 (11)	0.0235 (4)
C3	0.4705 (2)	0.63486 (12)	0.27953 (11)	0.0235 (4)
C4	0.5773 (2)	0.71780 (12)	0.36163 (11)	0.0257 (4)
C5	0.5253 (3)	0.70564 (13)	0.45935 (12)	0.0312 (5)
C6	0.3689 (3)	0.61682 (14)	0.47360 (12)	0.0317 (5)
C7	0.1845 (2)	0.45797 (12)	0.19757 (11)	0.0256 (4)
C8	−0.0524 (3)	0.48571 (14)	0.17804 (13)	0.0347 (5)
C9	0.2889 (3)	0.46927 (13)	0.09881 (11)	0.0335 (5)
C11	0.1919 (2)	0.33335 (12)	0.21881 (10)	0.0244 (4)
C12	0.0048 (2)	0.24976 (13)	0.20398 (12)	0.0301 (5)
C13	0.0203 (3)	0.13785 (13)	0.22261 (13)	0.0357 (5)
C14	0.2219 (3)	0.10721 (13)	0.25672 (13)	0.0352 (5)
C15	0.4100 (3)	0.18852 (13)	0.27083 (12)	0.0323 (5)
C16	0.3940 (2)	0.30020 (13)	0.25193 (11)	0.0272 (5)
C17	0.7545 (2)	0.81724 (12)	0.34845 (12)	0.0280 (4)
C18	0.7123 (3)	0.93286 (14)	0.40797 (13)	0.0392 (5)
C19	0.9791 (3)	0.7918 (2)	0.39688 (14)	0.0405 (6)
C21	0.7518 (2)	0.83103 (12)	0.23504 (12)	0.0267 (4)
C22	0.5684 (3)	0.86590 (13)	0.18112 (12)	0.0323 (5)
C23	0.5614 (3)	0.88164 (15)	0.07913 (14)	0.0426 (6)
C24	0.7379 (3)	0.8622 (2)	0.02727 (14)	0.0470 (6)
C25	0.9186 (3)	0.82708 (15)	0.07850 (14)	0.0442 (6)
C26	0.9260 (3)	0.81138 (13)	0.18067 (13)	0.0339 (5)
H1	0.052 (7)	0.467 (4)	0.475 (3)	0.056*	0.500
H2	0.093 (7)	0.380 (4)	0.361 (3)	0.056*	0.500
H3	0.5088	0.64014	0.21272	0.028*
H5	0.5986	0.75936	0.51725	0.037*
H6	0.3366	0.60960	0.54107	0.038*
H8A	−0.0484	0.5654	0.1639	0.052*
H8B	−0.1245	0.4772	0.2392	0.052*
H8C	−0.1353	0.4323	0.1186	0.052*
H9A	0.4439	0.4578	0.1107	0.050*
H9B	0.2801	0.5465	0.0805	0.050*
H9C	0.2091	0.4107	0.0423	0.050*
H12	−0.1353	0.26971	0.18080	0.036*
H13	−0.1088	0.08194	0.21179	0.043*
H14	0.2316	0.03084	0.27043	0.042*
H15	0.5498	0.16786	0.29343	0.039*
H16	0.5241	0.35538	0.26184	0.033*
H18A	0.7279	0.9286	0.4820	0.059*
H18B	0.5626	0.9469	0.3843	0.059*
H18C	0.8197	0.9963	0.3953	0.059*
H19A	0.9746	0.7843	0.4696	0.061*
H19B	1.0944	0.8553	0.3920	0.061*
H19C	1.0115	0.7195	0.3600	0.061*
H22	0.4456	0.87910	0.21551	0.039*
H23	0.4351	0.90587	0.04451	0.051*
H24	0.7340	0.8730	−0.04283	0.056*
H25	1.0403	0.81338	0.04341	0.053*
H26	1.0527	0.78665	0.21441	0.041*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O	0.0391 (7)	0.0342 (6)	0.0376 (6)	−0.0047 (5)	0.0146 (5)	0.0056 (5)
C1	0.0267 (8)	0.0242 (7)	0.0298 (8)	0.0024 (6)	0.0051 (6)	0.0071 (6)
C2	0.0241 (7)	0.0193 (7)	0.0266 (7)	0.0036 (6)	0.0009 (6)	0.0041 (6)
C3	0.0239 (7)	0.0220 (7)	0.0242 (7)	0.0032 (6)	0.0022 (6)	0.0039 (6)
C4	0.0236 (7)	0.0231 (7)	0.0290 (8)	0.0036 (6)	−0.0010 (6)	0.0027 (6)
C5	0.0339 (8)	0.0293 (8)	0.0262 (8)	0.0007 (6)	−0.0018 (6)	−0.0011 (6)
C6	0.0361 (9)	0.0354 (9)	0.0231 (7)	0.0022 (7)	0.0037 (6)	0.0059 (6)
C7	0.0264 (8)	0.0216 (7)	0.0265 (7)	−0.0017 (6)	−0.0007 (6)	0.0047 (6)
C8	0.0305 (8)	0.0275 (8)	0.0428 (9)	0.0019 (6)	−0.0070 (7)	0.0070 (7)
C9	0.0442 (9)	0.0262 (8)	0.0251 (8)	−0.0071 (7)	−0.0002 (7)	0.0021 (6)
C11	0.0269 (8)	0.0227 (7)	0.0220 (7)	0.0002 (6)	0.0039 (6)	0.0011 (6)
C12	0.0264 (8)	0.0242 (8)	0.0378 (9)	−0.0008 (6)	0.0051 (6)	0.0021 (6)
C13	0.0355 (9)	0.0241 (8)	0.0461 (10)	−0.0044 (7)	0.0119 (7)	0.0036 (7)
C14	0.0459 (10)	0.0227 (8)	0.0393 (9)	0.0069 (7)	0.0114 (7)	0.0064 (7)
C15	0.0343 (9)	0.0315 (8)	0.0321 (8)	0.0092 (7)	0.0040 (7)	0.0049 (6)
C16	0.0267 (8)	0.0261 (8)	0.0269 (8)	−0.0010 (6)	0.0033 (6)	0.0026 (6)
C17	0.0236 (7)	0.0233 (7)	0.0336 (8)	0.0000 (6)	−0.0004 (6)	−0.0011 (6)
C18	0.0458 (10)	0.0255 (8)	0.0421 (10)	−0.0017 (7)	0.0074 (8)	−0.0045 (7)
C19	0.0297 (9)	0.0408 (10)	0.0457 (10)	−0.0010 (7)	−0.0067 (7)	0.0043 (8)
C21	0.0245 (7)	0.0154 (7)	0.0369 (8)	−0.0040 (5)	0.0034 (6)	0.0002 (6)
C22	0.0272 (8)	0.0264 (8)	0.0430 (9)	0.0002 (6)	0.0055 (7)	0.0074 (7)
C23	0.0412 (10)	0.0373 (9)	0.0466 (10)	−0.0039 (8)	−0.0030 (8)	0.0142 (8)
C24	0.0575 (12)	0.0429 (10)	0.0362 (10)	−0.0114 (9)	0.0100 (9)	0.0052 (8)
C25	0.0442 (10)	0.0383 (10)	0.0473 (11)	−0.0056 (8)	0.0194 (8)	−0.0044 (8)
C26	0.0293 (8)	0.0229 (8)	0.0465 (10)	−0.0013 (6)	0.0075 (7)	−0.0020 (7)

Geometric parameters (Å, º)

O—C1	1.3809 (18)	C24—C25	1.371 (3)
O—H1	0.95 (4)	C25—C26	1.384 (2)
O—H2	1.02 (4)	C3—H3	0.95
C1—C2	1.400 (2)	C5—H5	0.95
C1—C6	1.386 (2)	C6—H6	0.95
C2—C7	1.540 (2)	C8—H8A	0.98
C2—C3	1.3978 (19)	C8—H8B	0.98
C3—C4	1.393 (2)	C8—H8C	0.98
C4—C17	1.5412 (19)	C9—H9A	0.98
C4—C5	1.390 (2)	C9—H9B	0.98
C5—C6	1.380 (2)	C9—H9C	0.98
C7—C11	1.538 (2)	C12—H12	0.95
C7—C8	1.537 (2)	C13—H13	0.95
C7—C9	1.540 (2)	C14—H14	0.95
C11—C16	1.3914 (18)	C15—H15	0.95
C11—C12	1.394 (2)	C16—H16	0.95
C12—C13	1.388 (2)	C18—H18A	0.98
C13—C14	1.379 (3)	C18—H18B	0.98
C14—C15	1.384 (2)	C18—H18C	0.98
C15—C16	1.386 (2)	C19—H19A	0.98
C17—C19	1.536 (2)	C19—H19B	0.98
C17—C18	1.549 (2)	C19—H19C	0.98
C17—C21	1.528 (2)	C22—H22	0.95
C21—C26	1.392 (2)	C23—H23	0.95
C21—C22	1.399 (2)	C24—H24	0.95
C22—C23	1.382 (2)	C25—H25	0.95
C23—C24	1.384 (3)	C26—H26	0.95
C1—O—H1	115 (3)	C16—C11—C7	119.30 (12)
C1—O—H2	110 (2)	C12—C11—C7	123.02 (13)
O—C1—C6	117.94 (13)	C13—C12—C11	120.92 (15)
O—C1—C2	121.30 (13)	C14—C13—C12	120.48 (15)
C6—C1—C2	120.73 (13)	C13—C14—C15	119.52 (14)
C3—C2—C1	117.04 (13)	C14—C15—C16	119.85 (15)
C3—C2—C7	122.15 (12)	C15—C16—C11	121.56 (14)
C1—C2—C7	120.74 (13)	C21—C17—C19	111.92 (13)
C4—C3—C2	123.25 (13)	C21—C17—C4	111.34 (12)
C5—C4—C3	117.38 (13)	C19—C17—C4	107.73 (12)
C5—C4—C17	119.81 (13)	C21—C17—C18	108.09 (12)
C3—C4—C17	122.76 (13)	C19—C17—C18	107.57 (13)
C6—C5—C4	121.08 (14)	C4—C17—C18	110.13 (12)
C5—C6—C1	120.43 (14)	C26—C21—C22	116.81 (15)
C8—C7—C11	112.59 (12)	C26—C21—C17	123.29 (14)
C8—C7—C9	107.63 (12)	C22—C21—C17	119.90 (13)
C11—C7—C9	106.96 (12)	C23—C22—C21	121.7 (2)
C8—C7—C2	107.91 (12)	C22—C23—C24	120.1 (2)
C11—C7—C2	109.86 (11)	C25—C24—C23	119.1 (2)
C9—C7—C2	111.93 (12)	C24—C25—C26	120.8 (2)
C16—C11—C12	117.66 (13)	C25—C26—C21	121.4 (2)
H1—O—C1—C2	−169 (3)	C8—C7—C11—C12	10.53 (19)
H1—O—C1—C6	10 (3)	C9—C7—C11—C16	70.84 (16)
H2—O—C1—C2	37 (3)	C8—C7—C11—C16	−171.14 (13)
H2—O—C1—C6	−144 (3)	C9—C7—C11—C12	−107.50 (15)
O—C1—C6—C5	−175.78 (15)	C2—C7—C11—C16	−50.85 (16)
C2—C1—C6—C5	2.6 (2)	C2—C7—C11—C12	130.81 (14)
C6—C1—C2—C3	−2.0 (2)	C7—C11—C12—C13	178.93 (13)
O—C1—C2—C3	176.37 (12)	C16—C11—C12—C13	0.6 (2)
O—C1—C2—C7	−0.7 (2)	C7—C11—C16—C15	−179.14 (13)
C6—C1—C2—C7	−179.03 (14)	C12—C11—C16—C15	−0.7 (2)
C1—C2—C3—C4	−0.7 (2)	C11—C12—C13—C14	0.3 (2)
C3—C2—C7—C8	−106.97 (15)	C12—C13—C14—C15	−1.0 (3)
C3—C2—C7—C9	11.28 (18)	C13—C14—C15—C16	0.8 (2)
C3—C2—C7—C11	129.95 (13)	C14—C15—C16—C11	0.0 (2)
C1—C2—C7—C9	−171.82 (13)	C18—C17—C21—C26	124.14 (15)
C7—C2—C3—C4	176.33 (12)	C19—C17—C21—C26	5.9 (2)
C1—C2—C7—C8	69.94 (16)	C4—C17—C21—C26	−114.81 (15)
C1—C2—C7—C11	−53.15 (16)	C19—C17—C21—C22	−173.61 (15)
C2—C3—C4—C5	2.6 (2)	C4—C17—C21—C22	65.71 (17)
C2—C3—C4—C17	180.0 (3)	C18—C17—C21—C22	−55.33 (17)
C3—C4—C17—C21	14.92 (18)	C17—C21—C22—C23	178.66 (14)
C5—C4—C17—C18	−47.97 (18)	C26—C21—C22—C23	−0.8 (2)
C3—C4—C17—C19	−108.19 (16)	C17—C21—C26—C25	−178.71 (15)
C3—C4—C5—C6	−2.0 (2)	C22—C21—C26—C25	0.8 (2)
C17—C4—C5—C6	−179.38 (15)	C21—C22—C23—C24	0.4 (3)
C3—C4—C17—C18	134.77 (14)	C22—C23—C24—C25	0.1 (3)
C5—C4—C17—C21	−167.81 (13)	C23—C24—C25—C26	−0.2 (3)
C5—C4—C17—C19	69.08 (17)	C24—C25—C26—C21	−0.3 (3)
C4—C5—C6—C1	−0.6 (3)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O—H1···O^i	0.95 (4)	2.05 (4)	2.944 (2)	156 (4)
O—H2···Cg2	1.02 (4)	2.56	3.54	162
C8—H8B···O	0.98	2.52	3.141 (2)	121
C13—H13···Cg3^ii	0.95	2.83	3.61	141
C24—H24···Cg2^iii	0.95	2.74	3.57	146

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