4-Chloro-3-ethyl­phenol

Sean H Majer; Joseph M Tanski

doi:10.1107/S1600536814013919

. 2014 Jun 21;70(Pt 7):o801. doi: 10.1107/S1600536814013919

4-Chloro-3-ethylphenol

Sean H Majer ^a, Joseph M Tanski ^a,^*

PMCID: PMC4120563 PMID: 25161582

Abstract

The title compound, C₈H₉ClO, packs with two independent molecules in the asymmetric unit, without significant differences in corresponding bond lengths and angles, with the ethyl group in each oriented nearly perpendicular to the aromatic ring having ring-to-side chain torsion angles of 81.14 (18) and −81.06 (19)°. In the crystal, molecules form an O—H⋯O hydrogen-bonded chain extending along the b-axis direction, through the phenol groups in which the H atoms are disordered. These chains pack together in the solid state, giving a sheet lying parallel to (001), via an offset face-to-face π-stacking interaction characterized by a centroid–centroid distance of 3.580 (1) Å, together with a short intermolecular Cl⋯Cl contact [3.412 (1) Å].

Keywords: crystal structure

Related literature

For information regarding the synthesis of 4-chloro-3-ethylphenol, see the following patents: Awano et al. (1987 ▶) or Schroetter et al. (1977 ▶). For applications in biological systems, see: Gerbershagen et al. (2005 ▶); Low et al. (1997 ▶). For similar chlorinated phenols, see: Cox (1995 ▶, 2003 ▶); Oswald et al. (2005 ▶). For more information on π-stacking, see: Lueckheide et al. (2013 ▶) and on halogen–halogen interactions, see: Pedireddi et al. (1994 ▶). graphic file with name e-70-0o801-scheme1.jpg

Experimental

Crystal data

C₈H₉ClO
M _r = 156.60
Triclinic,
a = 7.5580 (7) Å
b = 8.6854 (8) Å
c = 12.2520 (11) Å
α = 78.363 (1)°
β = 78.762 (1)°
γ = 80.355 (1)°
V = 765.72 (12) Å³
Z = 4
Mo Kα radiation
μ = 0.42 mm⁻¹
T = 125 K
0.20 × 0.15 × 0.10 mm

Data collection

Bruker APEXII CCD diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2007 ▶) T _min = 0.910, T _max = 0.949
17904 measured reflections
4656 independent reflections
4176 reflections with I > 2σ(I)
R _int = 0.019

Refinement

R[F ² > 2σ(F ²)] = 0.037
wR(F ²) = 0.107
S = 1.13
4656 reflections
183 parameters
4 restraints
H-atom parameters constrained
Δρ_max = 0.48 e Å⁻³
Δρ_min = −0.26 e Å⁻³

Data collection: APEX2 (Bruker, 2007 ▶); cell refinement: SAINT (Bruker, 2007 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: SHELXTL (Sheldrick, 2008 ▶); software used to prepare material for publication: SHELXTL, OLEX2 (Dolomanov et al., 2009 ▶) and Mercury (Macrae et al., 2006 ▶).

Supplementary Material

Crystal structure: contains datablock(s) I, New_Global_Publ_Block. DOI: 10.1107/S1600536814013919/zs2303sup1.cif

e-70-0o801-sup1.cif^{(23.8KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536814013919/zs2303Isup2.hkl

e-70-0o801-Isup2.hkl^{(228.1KB, hkl)}

Click here for additional data file.^{(2.9KB, cml)}

Supporting information file. DOI: 10.1107/S1600536814013919/zs2303Isup3.cml

CCDC reference: 1008296

Additional supporting information: crystallographic information; 3D view; checkCIF report

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

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O1—H1⋯O1ⁱ	0.81	1.97	2.708 (3)	152
O1—H1A⋯O2ⁱ	0.81	1.86	2.6642 (17)	171
O2—H2⋯O1ⁱ	0.81	1.86	2.6642 (17)	168
O2—H2A⋯O2ⁱⁱ	0.82	1.91	2.704 (2)	166

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Symmetry codes: (i) Inline graphic ; (ii) .

Acknowledgments

This work was supported by Vassar College. X-ray facilities were provided by the US National Science Foundation (grant No. 0521237 to JMT).

supplementary crystallographic information

S1. Comment

4-Chloro-3-ethylphenol, the title compound, can be synthesized by chlorination of 3-ethylphenol by SO₂Cl₂ in the presence of FeCl₃ in CCl₄ (Awano et al., 1987) or by adding the hydroxyl group to 1-ethyl-2-nitrobenzene followed by an acidic workup and a Sandmeyer reaction with CuCl (Schroetter et al., 1977). The title compound has been found to be useful in multiple biological applications, including testing the contracture in malignant hypothermia skeletal tissue (Low et al., 1997) and in biological activity on Ca²⁺ deposits in muscle cells (Gerbershagen et al., 2005).

The two independent molecules of the title compound in the asymmetric unit (Fig. 1) exhibit C—Cl bond lengths of 1.7430 (15) and 1.7469 (15) Å, and C—O bond lengths of 1.3751 (18) and 1.3778 (17) Å, respectively. These are in very close agreement with analogous bond lengths in the stuctures of 4-chlorophenol (Oswald et al., 2005), 4-chloro-3-methylphenol (Cox, 2003), and 4-chloro-3,5-dimethylphenol (Cox, 1995). The ethyl group is rotated nearly perpendicular to the plane of the ring for each independent molecule, displaying very similar torsion angles of 81.14 (18)° (C4—C3—C7—C8) and -81.06 (19)° (C12—C11—C15—C16). The structure forms a one-dimensional O—H···O hydrogen-bonded chain through the phenol groups, in which the phenol protons are 50% rotationally disordered (Fig. 2). These chains run parallel to the crystallographic b-axis. Each independent molecule forms hydrogen bonds with a neighboring equivalent independent molecule, with an oxygen–oxygen distance (O1···O1ⁱ) of 2.708 (3) Å and an oxygen–oxygen distance (O2···O2ⁱⁱ) of 2.704 (2) Å [for symmetry codes (i) and (ii), see Table 1]. These pairwise dimers are hydrogen-bonded to one another resulting in a third unique hydrogen bond, (O1···O2ⁱ), with length 2.6642 (17) Å. A similar hydrogen-bonding motif is found in the ordered one-dimensional hydrogen bonding chain in the structure of 4-chloro-3-methylphenol (Cox, 2003), where the O···O distances are similar at 2.711 (2) and 2.714 (2) Å. Unlike 4-chloro-3-methylphenol, where the planes of the aromatic units on each side of the hydrogen-bonded chain are parallel, in the the title compound they form a herringbone (edge-to-face or T) motif.

Neighboring hydrogen-bonded chains pack together in the solid state to form a two-dimensional sheet parallel to the 0 0 1 plane via an offset face-to-face π-stacking interaction of one of the two independent molecules, whereas the other molecule does not engage in π-stacking (Fig. 3). The π-stacking is characterized by a centroid-to-centroid distance of 3.580 (1) Å, a plane-to-centroid distance of 3.410 (1) Å, and a ring offset or ring-slipage distance of 1.092 (3) Å (Lueckheide et al., 2013). Neighboring sheets are further linked by a short intermolecular chlorine–chlorine contact (Cl1···Cl2ⁱⁱⁱ) of 3.412 (1) Å, which is less than the sum of the van der Waals radii of 3.50 Å for chlorine–chlorine interactions (Pedireddi et al., 1994). For symmetry code (iii): -x, -y + 1, -z.

S2. Experimental

4-Chloro-3-ethylphenol was purchased from Aldrich Chemical Company, USA, and recrystallized from hexanes.