(E)-3-[(4-Butyl­phen­yl)imino­meth­yl]benzene-1,2-diol

Zeynep Keleşoğlu; Orhan Büyükgüngör; Çiğdem Albayrak; Mustafa Odabaşoğlu

doi:10.1107/S1600536809029316

. 2009 Jul 29;65(Pt 8):o2022. doi: 10.1107/S1600536809029316

(E)-3-[(4-Butylphenyl)iminomethyl]benzene-1,2-diol

Zeynep Keleşoğlu ^a, Orhan Büyükgüngör ^a,^*, Çiğdem Albayrak ^b, Mustafa Odabaşoğlu ^c

PMCID: PMC2977352 PMID: 21583691

Abstract

The title compound, C₁₇H₁₉NO₂, exists as an enol–imine tautomer. The dihedral angle between the two benzene rings is 4.6 (2)°. The molecular structure is stabilized by intramolecular O—H⋯O and O—H⋯N hydrogen bonds which generate S(5) and S(6) ring motifs, respectively. In the crystal, molecules are linked into centrosymmetric dimers by pairs of O—H⋯O hydrogen bonds. In addition, C—H⋯π interactions involving both benzene rings are observed.

Related literature

For general background to Schiff bases, see: Lozier et al. (1975 ▶); Calligaris et al. (1972 ▶); Maslen & Waters (1975 ▶); Steward & Lingafelter (1959 ▶). For the photochromic and thermochromic characteristics of Schiff base compounds, see: Hadjoudis et al. (1987 ▶); Moustakali-Mavridis et al. (1980 ▶). For graph-set motifs, see: Bernstein et al. (1995 ▶). For related structures, see: Temel et al. (2007 ▶); Koşar et al. (2005 ▶).

Experimental

Crystal data

C₁₇H₁₉NO₂
M _r = 269.33
Monoclinic,
a = 16.2774 (13) Å
b = 6.0148 (6) Å
c = 17.6166 (14) Å
β = 121.476 (5)°
V = 1471.0 (2) Å³
Z = 4
Mo Kα radiation
μ = 0.08 mm⁻¹
T = 296 K
0.50 × 0.45 × 0.03 mm

Data collection

Stoe IPDSII diffractometer
Absorption correction: integration (X-RED32; Stoe & Cie, 2002 ▶) T _min = 0.954, T _max = 0.998
8711 measured reflections
3061 independent reflections
1643 reflections with I > 2σ(I)
R _int = 0.062

Refinement

R[F ² > 2σ(F ²)] = 0.064
wR(F ²) = 0.163
S = 1.07
3061 reflections
189 parameters
2 restraints
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.15 e Å⁻³
Δρ_min = −0.15 e Å⁻³

Data collection: X-AREA (Stoe & Cie, 2002 ▶); cell refinement: X-AREA; data reduction: X-RED32 (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/S1600536809029316/ci2863sup1.cif

e-65-o2022-sup1.cif^{(18.4KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536809029316/ci2863Isup2.hkl

e-65-o2022-Isup2.hkl^{(147.2KB, 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
O2—H2⋯O1	0.86 (2)	2.21 (3)	2.728 (2)	118 (3)
O2—H2⋯O1ⁱ	0.86 (2)	2.08 (3)	2.802 (3)	141 (3)
O1—H1⋯N1	0.88 (2)	1.74 (2)	2.555 (2)	155 (3)
C6—H6⋯Cg2ⁱⁱ	0.93	2.85	3.645 (3)	144
C10—H10⋯Cg1ⁱⁱ	0.93	2.80	3.491 (3)	132

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Symmetry codes: (i) Inline graphic ; (ii) . Cg1 and Cg2 are the centroids of the C1–C6 and C8–C13 rings, respectively.

Acknowledgments

The authors acknowledge the Faculty of Arts and Sciences, Ondokuz Mayıs University, Turkey, for the use of the Stoe IPDSII diffractometer (purchased under grant F.279 of the University Research Fund).

supplementary crystallographic information

Comment

Schiff bases are widely used as ligands in the field of coordination chemistry and they play an important role in various field of chemistry due to their biological activities (Lozier et al., 1975). o-Hydroxy Schiff bases derived from the reaction of o-hydroxy aldehydes with aniline have been examined extensively (Steward & Lingafelter, 1959; Calligaris et al., 1972; Maslen & Waters, 1975). Some Schiff bases derived from salicylaldehyde have attracted the interest of chemists and physicists because they show thermochromism and photochromism in the solid state by H-atom transfer from the hydroxy O atom to the N atom (Hadjoudis, et al., 1987). It has been proposed that molecules showing thermochromism are planar while those showing photochromism are non-planar (Moustakali-Mavridis et al., 1980). There are two types of intramolecular hydrogen bonds in Schiff bases arising from the keto-amine (N—H···O) and enol-imine (N···H—O) tautomeric forms.

X-ray analysis shows that compound (I) prefers the enol-imine tautomeric form with a strong intramolecular O—H···N hydrogen bond. A H atom is located on atom O1, thus the enol-imine tautomer is favoured over the keto-amine form, as indicated by the C2—O1 [1.333 (2) Å], C7—N1 [1.297 (2) Å], C1—C7 [1.433 (2) Å] and C1—C2 [1.406 (2) Å] bond lengths (Fig. 1). The C2—O1 bond length of 1.333 (2) Å indicates a single-bond character, whereas the C7—N1 bond length of 1.297 (2) Å indicates a high degree of double-bond character. Similar results were observed for (E)-3-[(2-fluorophenylimino)methyl]benzene-1,2-diol [C—O = 1.354 (19) Å, C—N = 1.285 (2) Å; Temel et al., 2007].

The molecule of (I) is nearly planar, with a dihedral angle between the benzene rings A(C1-C6) and B(C8-C13) of 4.6 (2) Å. Intramolecular O—H···O and O—H···N hydrogen bonds generate S(5) and S(6) ring motifs, respectively (Bernstein et al., 1995) (Fig. 1). The nearly planar S(6) ring forms dihedral angles of 2.3 (4)° and 2.5 (5)° with the rings A and B, respectively.

In the crystal, molecules of (I) are linked by intermolecular O—H···O hydrogen bonds forming centrosymmetric dimers (Fig.2). In addition, C6—H6···Cg2 and C10—H10···Cg1 interactions (Cg1 and Cg2 are the centroids of the C1—C6 and C8—C13 rings, respectively) are observed (Table 1).

Experimental

Compound (I) was prepared by refluxing a mixture of 2,3-dihydroxy benzaldehyde (0.5 g, 0.0036 mol) in ethanol (20 ml) and 4-butilanilyne (0.54 g 0.0036 mol) in ethanol (20 ml). The reaction mixture was stirred for 1 h under reflux. The crystals of (I) suitable for X-ray analysis were obtained from a methanol solution by slow evaporation (yield 85%; m.p. 363–364 K).