2-[(E)-(2,4-Dihy­droxy­benzyl­idene)aza­nium­yl]-3-phenyl­propano­ate

Hadariah Bahron; Fatimatuzzahraa Mohd Fadzel; Karimah Kassim; Madhukar Hemamalini; Hoong-Kun Fun

doi:10.1107/S1600536811016655

. 2011 May 7;67(Pt 6):o1331–o1332. doi: 10.1107/S1600536811016655

2-[(E)-(2,4-Dihydroxybenzylidene)azaniumyl]-3-phenylpropanoate

Hadariah Bahron ^a,^‡, Fatimatuzzahraa Mohd Fadzel ^a, Karimah Kassim ^a, Madhukar Hemamalini ^b, Hoong-Kun Fun ^b,^*,^§

PMCID: PMC3120434 PMID: 21754728

Abstract

The title compound, C₁₆H₁₅NO₄, exists as a zwitterion in the solid state, with the carboxylic acid group being deprotonated and the imine N atom being protonated. The molecule adopts an E configuration about the C=N double bond. The dihedral angle between the benzene rings is 46.34 (4)°. An intramolecular N—H⋯O hydrogen bond generates an S(6) ring motif. In the crystal, adjacent molecules are connected by intermolecular O—H⋯O and C—H⋯O hydrogen bonds, forming supramolecular ribbons along the a axis.

Related literature

For details of Schiff bases and their applications, see: Dolaz et al. (2009 ▶); Kumar et al. (2010 ▶); Qiao et al. (2011 ▶); Sauri et al. (2009 ▶); Tamami & Ghasemi (2011 ▶). For related structures, see: Bahron et al. (2010 ▶); Hemamalini & Fun (2011 ▶). For the stability of the temperature controller used in the data collection, see: Cosier & Glazer (1986 ▶). For graph-set notation, see: Bernstein et al. (1995 ▶).

Experimental

Crystal data

C₁₆H₁₅NO₄
M _r = 285.29
Monoclinic,
a = 9.3943 (1) Å
b = 6.8946 (1) Å
c = 20.7251 (3) Å
β = 92.065 (1)°
V = 1341.49 (3) Å³
Z = 4
Mo Kα radiation
μ = 0.10 mm⁻¹
T = 100 K
0.34 × 0.27 × 0.17 mm

Data collection

Bruker SMART APEXII CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2009 ▶) T _min = 0.966, T _max = 0.982
22479 measured reflections
6007 independent reflections
4783 reflections with I > 2σ(I)
R _int = 0.025

Refinement

R[F ² > 2σ(F ²)] = 0.043
wR(F ²) = 0.125
S = 1.03
6007 reflections
202 parameters
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.56 e Å⁻³
Δρ_min = −0.24 e Å⁻³

Data collection: APEX2 (Bruker, 2009 ▶); cell refinement: SAINT (Bruker, 2009 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL and PLATON (Spek, 2009 ▶).

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536811016655/rz2592sup1.cif

e-67-o1331-sup1.cif^{(18.5KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536811016655/rz2592Isup2.hkl

e-67-o1331-Isup2.hkl^{(288.1KB, hkl)}

Supplementary material file. DOI: 10.1107/S1600536811016655/rz2592Isup3.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—H1O1⋯O4ⁱ	0.863 (15)	1.790 (14)	2.6302 (9)	163.9 (15)
N1—H1N1⋯O1	0.864 (14)	2.051 (15)	2.6810 (9)	129.1 (12)
O2—H1O2⋯O3ⁱⁱ	1.03 (2)	1.51 (2)	2.5310 (10)	179 (2)
C5—H5A⋯O2ⁱⁱⁱ	0.95	2.56	3.3155 (10)	137
C12—H12A⋯O2^iv	0.95	2.46	3.1781 (10)	132

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

Acknowledgments

HB, FMF and KK wish to thank both Universiti Teknologi MARA (UiTM) and Universiti Sains Malaysia (USM) for research facilities, and the Malaysian Ministry of Higher Education for the research grant FRGS UiTM 5/3/FST/(12/2008). HKF and MH thank the Malaysian Government and Universiti Sains Malaysia for the Research University grant No. 1001/PFIZIK/811160. MH also thanks Universiti Sains Malaysia for a post-doctoral research fellowship.

supplementary crystallographic information

Comment

Schiff bases have received considerable attention and remain important in the field of coordination chemistry vastly due to their simple synthesis and versatility. They are widely reported to have extensive potential applications in various biological and pharmaceutical fields (Dolaz et al., 2009) as antimicrobial (Kumar et al., 2010) and antitumor (Qiao et al., 2011) agents. They also display potential applications as corrosion inhibitors (Sauri et al., 2009) and catalysts (Tamami & Ghasemi, 2011). The title molecule, (I), is a Schiff base derived from DL-phenylalanine and 2,4-dihydroxybenzaldehyde using the procedure reported by Bahron et al. (2010). It crystallizes as a zwitterion in which the imine N is protonated. A similar zwitterionic structure was reported by Hemamalini & Fun (2011).

The asymmetric unit of the title compound is shown in Fig. 1. The molecule is a zwitterion in the crystal, with the carboxylic acid group deprotonated and the imine N atom protonated. It adopts an E configuration about the central C9═N1 double bond [1.3045 (3) Å] with the torsion angle C10-C9-N1-C8 = -175.36 (7)°. The dihedral angle between the benzene (C10–C15) and phenyl (C1–C6) rings is 46.34 (4)°.

In the crystal structure (Fig. 2), an intramolecular N1—H1N1···O1 hydrogen bond (Table 1) generates an S(6) ring motif (Bernstein et al., 1995). Furthermore, adjacent molecules are connected by intermolecular O1—H1O1···O4, O2—H1O2···O3, C5—H5A···O2 and C12—H12A···O2 (Table 1) hydrogen bonds forming supramolecular ribbons along the a axis.

Experimental

DL-phenylalanine (2 mmol, 0.330 g ) was dissolved in absolute ethanol (20 mL), into which 2,4-dihydroxybenzaldehyde (2 mmol, 0.276 g) was added, followed by refluxing for two hours. The solution was left to slowly cool to room temperature upon which pale orange crystals were produced. These were filtered off, washed with ice-cold ethanol and air dried (yield 68%). Melting point: 540–543 K. Analytical calculated for C₁₆H₁₅NO₄ (%): C, 67.36; H, 5.30; N, 4.91. Found (%): C, 67.13; H, 5.49; N, 4.89. IR (cm^-1): ν(C═N) 1642.9 (m), ν(C–OH) 1243.7 (w), ν(C═O) 1880.6 (w).