5-Diethyl­amino-2-[(E)-(4-eth­oxy­phen­yl)imino­meth­yl]phenol

Erkan Soydemir; Orhan Büyükgüngör; Çiğdem Albayrak; Mustafa Odabaşoğlu

doi:10.1107/S1600536811004533

. 2011 Feb 12;67(Pt 3):o599–o600. doi: 10.1107/S1600536811004533

5-Diethylamino-2-[(E)-(4-ethoxyphenyl)iminomethyl]phenol

Erkan Soydemir ^a, Orhan Büyükgüngör ^a,^*, Çiğdem Albayrak ^b, Mustafa Odabaşoğlu ^c

PMCID: PMC3051950 PMID: 21522358

Abstract

The title compound, C₁₉H₂₄N₂O₂, adopts the phenol–imine tautomeric form. An intramolecular O—H⋯N hydrogen bond results in the formation of a six-membered ring. The aromatic rings are oriented at a dihedral angle of 17.33 (16)°. Intermolecular C—H⋯π interactions occur in the crystal.

Related literature

For general background to Schiff bases, see: Hadjoudis et al. (1987 ▶); Hodnett & Dunn (1970 ▶); Misra et al. (1981 ▶); Agarwal et al. (1983 ▶); Varma et al. (1986 ▶); Singh & Dash (1988 ▶); Pandeya et al. (1999 ▶); El-Masry et al. (2000 ▶); Cohen et al. (1964 ▶); Moustakali-Mavridis et al. (1978 ▶) Kaitner & Pavlovic (1996 ▶); Yıldız et al. (1998 ▶). For related structures, see: Odabaşoğlu et al. (2003 ▶); Hökelek et al. (2000 ▶); Bingöl Alpaslan et al. (2010 ▶).

Experimental

Crystal data

C₁₉H₂₄N₂O₂
M _r = 312.40
Monoclinic,
a = 29.4936 (13) Å
b = 7.8546 (2) Å
c = 16.7146 (7) Å
β = 115.093 (3)°
V = 3506.7 (2) Å³
Z = 8
Mo Kα radiation
μ = 0.08 mm⁻¹
T = 296 K
0.76 × 0.59 × 0.28 mm

Data collection

Stoe IPDS 2 diffractometer
Absorption correction: integration (X-RED32; Stoe & Cie, 2002 ▶) T _min = 0.944, T _max = 0.979
22701 measured reflections
3625 independent reflections
2383 reflections with I > 2σ(I)
R _int = 0.073

Refinement

R[F ² > 2σ(F ²)] = 0.080
wR(F ²) = 0.260
S = 1.10
3625 reflections
208 parameters
4 restraints
H-atom parameters constrained
Δρ_max = 0.56 e Å⁻³
Δρ_min = −0.28 e Å⁻³

Data collection: X-AREA (Stoe & Cie, 2002 ▶); cell refinement: X-AREA; data reduction: X-RED (Stoe & Cie, 2002 ▶); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997 ▶); software used to prepare material for publication: WinGX (Farrugia, 1999 ▶).

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536811004533/fj2390sup1.cif

e-67-0o599-sup1.cif^{(19.8KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536811004533/fj2390Isup2.hkl

e-67-0o599-Isup2.hkl^{(174.2KB, hkl)}

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

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

Cg1 is the centroid of C8–C13 ring.

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O1—H1⋯N1	0.82	1.88	2.610 (3)	148
C2—H2⋯Cg1ⁱ	0.93	2.85	3.681 (4)	149
C17—H17A⋯Cg1ⁱⁱ	0.96	2.97	3.763 (6)	140

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

Acknowledgments

The authors wish to acknowledge the Faculty of Arts and Sciences, Ondokuz Mayıs University, Turkey, for the use of the Stoe IPDS 2 diffractometer (purchased under grant No. F279 of the University Research Fund).

supplementary crystallographic information

Comment

Schiff bases are used as substrates in the preparation of number of industrial and biologically active compounds via ring closure, cycloaddition and replacement reactions. Some Schiff base derivatives are also known to have biological activities such as antimicrobial (El-Masry et al., 2000; Pandeya et al., 1999); antifungal (Singh & Dash 1988; Varma et al., 1986) and antitumor (Hodnett & Dunn 1970; Misra et al., 1981; Agarwal et al., 1983). There are two characteristic properties of Schiff bases, viz. photochromism and thermochromism (Cohen et al., 1964; Moustakali-Mavridis et al., 1978). Schiff bases display two possible tautomeric form, namely the phenol-imine (O—H···N) and keto-amine (N—H···O) forms. In the solid state, the keto-amine tautomer has been found in naphthaldimines (Hökelek et al., 2000; Odabaşoğlu et al., 2003), while the phenol-imine form exists in salicylaldimine Schiff bases (Kaitner & Pavlovic, 1996; Yıldız et al., 1998).

In the title compound, (I), the phenol-imine tautomer is favoured over the keto-amine form, and there is an intramolecular O—H···N hydrogen bond (Fig. 1 and Table 1). It is known that Schiff bases may exhibit thermochromism or photochromism, depending on the planarity or non-planarity of the molecule, respectively. This planarity of the molecule allows the H atom to be transferred through the hydrogen bond in the ground state with a low energy requirement (Hadjoudis et al., 1987). Therefore, one can expect thermochromic properties in (I) caused by planarity of the molecule: the dihedral angle between rings A (C1—C6) and B (C8—C13) is 17.33 (16)° (Fig. 1). In (I), the C8—C7, C4—N1, C7=N1 and O1—C13 bond lengths of 1.441 (4), 1.417 (3), 1.263 (3) and 1.338 (3) Å, respectively are in good agreement with those observed in (E)-2[(3-Fluoropheng)iminomethy]-4-(trifluoromethoxy)phenol [1.447 (4), 1.420 (3), 1.268 (3) and 1.343 (3) Å, Bingöl Alpaslan et al., 2010]. The C5—C4—N1=C7 and N1=C7—C8—C13 torsion angles are -19.0 (5)° and 1.2 (5)°, respectively. In crystal packing, the interactions [C2—H2···Cg1(x, 1 - y, z - 1/2)] and [C17—H17A···Cg1(1/2 - x, 1/2 + y, 3/2 - z)] are effective (Table 1 and Fig. 2.)

Experimental

The title compound was prepared by refluxing a mixture of a solution containing 5-(diethylamino)-2-hydroxybenzaldehyde (0.5 g, 2.59 mmol) in 20 ml e thanol and a solution containing 4-ethoxyaniline (0.4 g, 2.59 mmol) in 20 ml e thanol. The reaction mixture was stirred for 1 h under reflux. The crystals of (E)-5-(diethylamino)-2-[(4-ethoxyphenylimino)methyl]phenol suitable for x-ray analysis were obtained by slow evaporation from ethyl alcohol (yield % 82;).