4-(4-Ethyl­phenyl­diazen­yl)phenol

Joost de Wit; Gert O R Alberda van Ekenstein; Gerrit ten Brinke; Auke Meetsma

doi:10.1107/S160053680801338X

. 2008 May 10;64(Pt 6):o1048. doi: 10.1107/S160053680801338X

4-(4-Ethylphenyldiazenyl)phenol

Joost de Wit ^a, Gert O R Alberda van Ekenstein ^a, Gerrit ten Brinke ^a, Auke Meetsma ^b,^*

PMCID: PMC2961569 PMID: 21202567

Abstract

The crystal structure of the title compound, C₁₄H₁₄N₂O, determined at 100 K, shows that the molecules are not planar in the solid state, in contrast to other diazene (azobenzene) derivatives. The dihedral angle between the planes of the two aromatic rings is 42.32 (7)°. The molecules are linked by intermolecular O—H⋯N hydrogen bonds, forming an infinite one-dimensional chain.

Related literature

For related literature, see: Bowes et al. (2003 ▶); Brown et al. (1971 ▶); Burger & Ramberger (1979 ▶); Enkelmann et al. (1978 ▶); Kageyama et al. (1982 ▶, 1985 ▶, 1986 ▶); Kashino et al. (1979 ▶); Kocaokutgen et al. (2003 ▶); McWilliam et al. (2001 ▶); Okamoto et al. (1983 ▶); Okamoto & Nakano (1994 ▶); Ruokolainen et al. (1996 ▶, 1998 ▶, 1999 ▶); Shibaev et al. (2003 ▶); Soylu et al. (2004 ▶); Zhang et al. (1998 ▶).

Experimental

Crystal data

C₁₄H₁₄N₂O
M _r = 226.28
Monoclinic,
a = 7.5261 (9) Å
b = 13.4298 (15) Å
c = 11.6412 (13) Å
β = 97.4001 (15)°
V = 1166.8 (2) Å³
Z = 4
Mo Kα radiation
μ = 0.08 mm⁻¹
T = 100 (1) K
0.42 × 0.33 × 0.22 mm

Data collection

Bruker SMART APEX CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2007 ▶) T _min = 0.956, T _max = 0.982
8700 measured reflections
2276 independent reflections
1848 reflections with I > 2σ(I)
R _int = 0.028

Refinement

R[F ² > 2σ(F ²)] = 0.040
wR(F ²) = 0.107
S = 1.04
2276 reflections
210 parameters
All H-atom parameters refined
Δρ_max = 0.17 e Å⁻³
Δρ_min = −0.24 e Å⁻³

Data collection: SMART (Bruker, 2007 ▶); cell refinement: SAINT-Plus (Bruker, 2007 ▶); data reduction: SAINT-Plus; program(s) used to solve structure: SIR2004 (Burla et al., 2005 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: PLATON (Spek, 2003 ▶) and PLUTO (Meetsma, 2007 ▶); software used to prepare material for publication: PLATON.

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S160053680801338X/bg2174sup1.cif

e-64-o1048-sup1.cif^{(20.4KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S160053680801338X/bg2174Isup2.hkl

e-64-o1048-Isup2.hkl^{(111.9KB, hkl)}

Additional supplementary materials: 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⋯N1ⁱ	0.91 (2)	1.98 (2)	2.8316 (15)	154.7 (17)
C3—H3⋯O1ⁱⁱ	0.987 (15)	2.585 (15)	3.3541 (17)	134.7 (11)

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

Acknowledgments

Albert Kiewiet is acknowledged for performing the MS analysis.

supplementary crystallographic information

Comment

Azobenzenes are widely used as dyes, but also as photochemical switch using photo-isomerization by UV light to induce a conformational change from trans to cis and back. This principle has been explored extensively in order to exploit the isomerization for several applications. (Shibaev et al., 2003) The presence of the phenolic moiety makes it possible to form complexes with e.g. poly (4-vinylpyridine) homopolymer or with poly (4-vinylpyridine) containing block copolymers. These supramolecular comb-like polymeric structures give rise to hierarchical structure-in-structure morphologies comparable with the systems with poly (4-vinylpyridine) containing block co-polymers complexed with nona- or pentadecylphenol. (Ruokolainen et al., 1998, 1999) The molecular geometry of (I) and the adopted atom-numbering scheme are shown in the perspective view in Figure 1. The crystal structure is similar to several other azo compounds, (Kocaokutgen et al. 2003; Soylu et al. 2004; Zhang et al., 1998) The –N1=N2- bond length is 1.2636 (16) Å, indicating a double-bond character. Regarding the azo double bond the rings are in a trans configuration. In contrast to many other azocompounds the benzene rings of EPAP are not coplanar.

Experimental

To a vigorously stirred solution of 1.21 g of ethylaniline (0.01 mol) in 3 ml of water and 3 ml of concentrated hydrochloric acid, a solution of 2.8 g sodiumnitrite in 20 ml water was added drop wise while maintaining the temperature during the reaction at 0 °C. The resulting pale yellow mixture was added drop wise to a phenolate ion solution which was prepared by dissolving 0.94 g phenol (0.01 mol) and 0.84 g potassium hydroxide (0.015 mol) in 20 ml of methanol. Dichloromethane was used to extract the product from the aquatic reaction mixture, followed by 5 times washing with water. The solvent was then removed by evaporation. Subsequently the crude product was purified over a silica gel column using a dichloromethane / n-hexane mixture (3:1 v/v). The final solution was evaporated to dryness and dried further overnight in vacuum at 40°C. The yield of the bright orange crystalline solid was 61%. Single crystals of (I) suitable for the x-ray analysis were grown by slow evaporation from a dichloromethane solution at room temperature in air.

Analysis Differential Scanning Calorimetry (DSC, Q1000 TA instruments; 10°C/min): melting point (onset) 120°C. H-NMR (Varian VXR 300 MHz, CDCl₃): δ p.p.m. = 7.85 (d, 2H, H-3 and H-5), 7.79 p.p.m. (d, 2H, H-3' and H-5'), 7.31 p.p.m. (d, 2H, H-2' and H-6'), 6.92 p.p.m. (d, 2H, H-2 and H-6), 5.09 p.p.m. (s, 1H, –OH), 2.67 p.p.m. (t, 2H, H_A), 1.57 p.p.m. (m, 2H, –CH2-)), 1.26 p.p.m. (t, 3H, CH₃—CH₂). Mass (Jeol JMS 600H EI+ 70 eV): m/z = 226 (calculated: 226.3)