Ethyl 4-[(3,5-di-tert-butyl-2-hy­droxy­benzyl­idene)­amino]­benzoate

Raied Mustafa Shakir; Azhar Ariffin; Seik Weng Ng

doi:10.1107/S1600536810041383

. 2010 Oct 23;66(Pt 11):o2915. doi: 10.1107/S1600536810041383

Ethyl 4-[(3,5-di-tert-butyl-2-hydroxybenzylidene)amino]benzoate

Raied Mustafa Shakir ^a, Azhar Ariffin ^a, Seik Weng Ng ^a,^*

PMCID: PMC3009105 PMID: 21589089

Abstract

The title compound, a Schiff base, C₂₄H₃₁NO₃, has a substituted aromatic ring at both ends of the azomethine linkage and these make a dihedral angle of 24.9 (1)°. There is an intramolecular hydrogen bond between the hydroxy group (donor) and the N atom of themazomethine linkage.

Related literature

For the use of the methyl ester analog of the title compound as a second-harmonic generation material, see: Sliwa et al. (2008 ▶).

Experimental

Crystal data

C₂₄H₃₁NO₃
M _r = 381.50
Monoclinic,
a = 18.4789 (18) Å
b = 10.7194 (11) Å
c = 10.7768 (10) Å
β = 97.437 (2)°
V = 2116.7 (4) Å³
Z = 4
Mo Kα radiation
μ = 0.08 mm⁻¹
T = 100 K
0.30 × 0.05 × 0.05 mm

Data collection

Bruker SMART APEX diffractometer
19941 measured reflections
4855 independent reflections
3123 reflections with I > 2σ(I)
R _int = 0.065

Refinement

R[F ² > 2σ(F ²)] = 0.053
wR(F ²) = 0.142
S = 1.01
4855 reflections
257 parameters
1 restraint
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.64 e Å⁻³
Δρ_min = −0.26 e Å⁻³

Data collection: APEX2 (Bruker, 2009 ▶); cell refinement: SAINT (Bruker, 2009 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: X-SEED (Barbour, 2001 ▶); software used to prepare material for publication: publCIF (Westrip, 2010 ▶).

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536810041383/fl2320sup1.cif

e-66-o2915-sup1.cif^{(20.9KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536810041383/fl2320Isup2.hkl

e-66-o2915-Isup2.hkl^{(237.8KB, 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⋯N1	0.87 (1)	1.80 (2)	2.609 (2)	154 (3)

Open in a new tab

Acknowledgments

We thank the University of Malaya for supporting this study.

supplementary crystallographic information

Comment

The Schiff base, methyl 4-(di-3,5-tert-butyl-2-hydroxybenzylideneamino)benzoate, is a material suitable for second-harmonic generation as it has electron-donating and electron-withdrawing components that are critical for the manifestation of a permanent dipole (Sliwa et al., 2008). Replacing the methyl group with an ethyl moiety leads to (I), an intensely orange-colored compound (Scheme I, Fig. 1) that crystallizes in a centric space group and is, therefore, not suitable as an SHG material. The azomethine bond has an E-configuration; the two aromatic rings are aligned at 24.9 (1) °. The compound is neutral as the hydroxy group bears a hydrogen atom which is a donor in an intra-molecular H bond to the azomethine nitrogen atom (Table 1). There are no important intermolecular contacts; on the other hand, the compound appears to pack in such a way as to accomodate the bulky t-butyl groups as far as possible (Fig. 2).

Experimental

Ethyl 4-aminobenzoate (0.35 g) dissolved in ethanol (5 ml) was added to 3,5-di-tert-butyl-2-hydroxybenzaldehyde (0.5 g) dissolved in ethanol (20 ml). Several drops of acetic acid were added. The solution was heated for 3 h. The solvent was evaporated and the product recrystallized from ethanol to yield orange prisms in 80% yield that were suitable for data collection.