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

Esen Nur Kantar; Yavuz Köysal; Sümeyye Gümüş; Erbil Ağar; Mustafa Serkan Soylu

doi:10.1107/S160053681201882X

. 2012 May 2;68(Pt 6):o1587. doi: 10.1107/S160053681201882X

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

Esen Nur Kantar ^a, Yavuz Köysal ^b,^*, Sümeyye Gümüş ^c, Erbil Ağar ^c, Mustafa Serkan Soylu ^d

PMCID: PMC3379200 PMID: 22719398

Abstract

The title Schiff base, C₁₉H₂₄N₂O₃, exists in the crystal structure in the phenol–imine tautomeric form with an intramolecular O—H⋯N hydrogen bond. The planes of the aromatic rings form a dihedral angle of 36.8 (8)°. The crystal packing is characterized by C—H⋯O hydrogen bonds and π–π stacking interactions [centroid–centroid distance = 3.478 (4)Å].

Related literature

Schiff bases of salicylaldehyde may exhibit thermochromism or photochromism, depending on the planarity or non-planarity, respectively, of the molecule, see: Amimoto & Kawato (2005 ▶); Schmidt & Cohen (1964 ▶). For similar structures, see: Ha (2011 ▶); Asiri et al. (2010 ▶). For hydrogen-bond motifs, see: Bernstein et al. (1995 ▶). graphic file with name e-68-o1587-scheme1.jpg

Experimental

Crystal data

C₁₉H₂₄N₂O₃
M _r = 328.40
Monoclinic,
a = 7.2028 (3) Å
b = 9.4423 (5) Å
c = 26.050 (2) Å
β = 91.742 (7)°
V = 1770.9 (2) Å³
Z = 4
Mo Kα radiation
μ = 0.08 mm⁻¹
T = 293 K
0.22 × 0.15 × 0.10 mm

Data collection

Oxford Diffraction SuperNova (single source at offset) Eos diffractometer
Absorption correction: multi-scan (CrysAlis PRO; Oxford Diffraction, 2007 ▶) T _min = 0.933, T _max = 1.000
8031 measured reflections
4165 independent reflections
1959 reflections with I > 2σ(I)
R _int = 0.036

Refinement

R[F ² > 2σ(F ²)] = 0.064
wR(F ²) = 0.164
S = 1.06
4165 reflections
226 parameters
1 restraint
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.16 e Å⁻³
Δρ_min = −0.15 e Å⁻³

Data collection: CrysAlis PRO (Oxford Diffraction, 2007 ▶); cell refinement: CrysAlis PRO; data reduction: CrysAlis PRO; 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 datablock(s) I, global. DOI: 10.1107/S160053681201882X/ld2055sup1.cif

e-68-o1587-sup1.cif^{(20.6KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S160053681201882X/ld2055Isup2.hkl

e-68-o1587-Isup2.hkl^{(200KB, hkl)}

Supplementary material file. DOI: 10.1107/S160053681201882X/ld2055Isup3.cml

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⋯N1	0.84 (2)	1.79 (2)	2.575 (3)	153 (4)
C16—H16B⋯O1ⁱ	0.97	2.53	3.491 (4)	172

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Symmetry code: (i) Inline graphic .

Acknowledgments

The authors acknowledge the Faculty of Arts and Sciences, Giresun University, Turkey, for the use of the diffractometer.

supplementary crystallographic information

Comment

We have studied a Schiff base derived from 4-(diethylamino)-2-hydroxybenzaldehyde. It is known that Schiff bases of salicylaldehyde may exhibit thermochromism or photochromism, depending on planarity or non-planarity of the molecule, respectively (Schmidt & Cohen, 1964; Amimoto & Kawato, 2005).

The C10-C9-N1-C5 torsion angle is -169.8 (2)°, that contributes to the general non-planarity of the molecule. The C15-O1 [1.352 (3)Å] bond length is similar to the corresponding distance in 4-Bromo-2- {[(pyridin-3-ylmethyl)imino]-methyl}phenol, [1.352 (4)Å; Ha, 2011] and in the monoclinic modification of 2-[(1,3-benzothiazol-2-yl)iminomethyl]phenol [1.345 (3)Å; Asiri et al., 2010).

Depending on the tautomers, two types of intramolecular hydrogen bonds are observed in Schiff bases: O-H···N in phenol-imine and N-H···O in keto-amine tautomers. Our X-ray investigation shows that the title compound exists in the phenol-imine form. The title compound forms intermolecular C-H···O and a strong intramolecular O-H···N hydrogen bonds, namely C16-H16B···O1 [symmetry code: (i) x-1,y,z] and O1-H1A···N1. The intramolecular hydrogen bonds generates a six membered ring, producing S(6) ring motif (Bernstein, et al., 1995). Weak π-π stacking interactions are observed which may influence crystal stability – the distance between centroids Cg1(C2-C7 ring) to Cg1ⁱⁱ [symmetry code: (ii) 1-x,-y,1-z] is 3.478 (4)Å.

Experimental

The 2-{(E)-[(2,4-dimethoxyphenyl)imino]methyl}-5- (pentan-3-yl)phenol was prepared by refluxing a mixture of 4-(diethylamino)-2-hydroxybenzaldehyde (0.011 g 0.057 mmol) in 20 ml of ethanol and 2,4-dimethoxyaniline (0.009 g 0.057 mmol) in 20 ml of ethanol. The mixture was stirred for 1 h under reflux. The crystals of the 2-{(E)-[(2,4-dimethoxyphenyl)imino]methyl}-5-(pentan-3-yl)phenol suitable for X-ray analysis were obtained from ethyl alcohol by slow evaporation (yield %72; m.p. 371–373 °K).