2-[(E)-(5-Amino-2,3-diphenyl­quinoxalin-6-yl)imino­meth­yl]-4-chloro­phenol

Hoong-Kun Fun; Reza Kia; Paul R Raithby

doi:10.1107/S1600536808020023

. 2008 Jul 5;64(Pt 8):o1411–o1412. doi: 10.1107/S1600536808020023

2-[(E)-(5-Amino-2,3-diphenylquinoxalin-6-yl)iminomethyl]-4-chlorophenol

Hoong-Kun Fun ^a,^*, Reza Kia ^a,^‡, Paul R Raithby ^b,^§

PMCID: PMC2962046 PMID: 21203131

Abstract

The title Schiff base compound, C₂₇H₁₉ClN₄O, features two intramolecular O—H⋯N and N—H⋯N hydrogen bonds involving the hydroxy and amino groups to generate S(6) and S(5) ring motifs, respectively. In the crystal structure, weak intermolecular N—H⋯O and C—H⋯N interactions, together with π–π contacts [centroid–centroid distances = 3.6294 (11)–3.6881 (11) Å], link neighboring molecules.

Related literature

For related literature on hydrogen-bond motifs, see: Bernstein et al. (1995 ▶). For related structures, see: Corden et al. (1996 ▶); Fun et al. (2008 ▶); Govindasamy et al. (1999 ▶). For applications and bioactivities, see: Anderson et al. (1997 ▶); Cohen & Schmidt (1964 ▶); Granovski et al. (1993 ▶); Li & Chang (1991 ▶); Shahrokhian et al. (2000 ▶); Unaleroglu & Hökelek (2002 ▶).

Experimental

Crystal data

C₂₇H₁₉ClN₄O
M _r = 450.91
Monoclinic,
a = 22.8728 (11) Å
b = 7.3068 (4) Å
c = 12.5632 (6) Å
β = 92.037 (2)°
V = 2098.32 (18) Å³
Z = 4
Mo Kα radiation
μ = 0.21 mm⁻¹
T = 100.0 (1) K
0.55 × 0.09 × 0.07 mm

Data collection

Bruker SMART APEXII CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2005 ▶) T _min = 0.843, T _max = 0.985
25593 measured reflections
6180 independent reflections
4118 reflections with I > 2σ(I)
R _int = 0.062

Refinement

R[F ² > 2σ(F ²)] = 0.052
wR(F ²) = 0.159
S = 1.01
6180 reflections
310 parameters
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.40 e Å⁻³
Δρ_min = −0.41 e Å⁻³

Data collection: APEX2 (Bruker, 2005 ▶); cell refinement: APEX2; data reduction: SAINT (Bruker, 2005 ▶); 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, 2003 ▶).

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536808020023/tk2279sup1.cif

e-64-o1411-sup1.cif^{(23.2KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536808020023/tk2279Isup2.hkl

e-64-o1411-Isup2.hkl^{(302.5KB, 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—H1O1⋯N1	0.93 (3)	1.72 (3)	2.584 (2)	153 (2)
N4—H1N4⋯O1ⁱ	1.01 (3)	2.47 (3)	3.099 (2)	120.4 (18)
N4—H2N4⋯N2	1.04 (3)	2.31 (3)	2.750 (2)	104.3 (17)
C27—H27A⋯N3ⁱⁱ	0.93	2.62	3.373 (2)	138

Open in a new tab

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

Acknowledgments

HKF and RK thank the Malaysian Government and Universiti Sains Malaysia for Science Fund grant No. 305/PFIZIK/613312. RK thanks the Universiti Sains Malaysia and the University of Bath for post-doctoral research fellowships.

supplementary crystallographic information

Comment

Schiff bases are one of the most prevalent mixed-donor ligand types in coordination chemistry. The biologically activities of their complexes have been studied extensively over the last decades (Anderson et al., 1997; Corden et al., 1996; Govindasamy et al., 1999; Granovski et al., 1993; Li & Chang, 1991; Shahrokhian et al., 2000). 2-Hydroxy Schiff base ligands are of additional interest mainly due to the existence of O—H···N and O···H—N type hydrogen bonds and tautomerization between the phenol-imine and keto-amine forms (Unaleroglu & Hokelek, 2002; Fun et al., 2008). This type of tautomerism plays an important role for distinguishing their photochromic and thermochromic properties (Cohen & Schmidt, 1964). Knowing the solution and solid-state structures of free Schiff bases is important in view of the intramolecular hydrogen bonding and comparing conformation with that in the structures of Schiff base complexes. In view of the importance of these organic ligands, the title compound (I) was synthesized and its crystal structure is reported herein.

Compound (I, Fig. 1), features intramolecular O—H···N and N—H···N hydrogen bonds to form six- and five-membered rings, producing S(6) and S(5) ring motifs, respectively (Bernstein et al., 1995). The two phenyl substituents on the quinoxaline unit are inclined at an angle of 61.14 (9)° to one another. They also form dihedral angles of 43.38 (9) and 39.50 (9)°, respectively, with the ten–membered quinoxaline ring. In the crystal packing (Table 1 & Fig. 2), molecules are stacked when viewed down the b axis, being consolidated by π–π interactions with Cg2···Cg3 distances ranging from 3.6294 (11) – 3.6881 (11) Å; symmetry codes 1 - x, -1/2 + y, 3/2 - z and 1 - x, 1/2 + y, 3/2 - z, and Cg2 and Cg3 are the centroids of the C1–C6 and C8/C9/C10/C11/C14/C15 phenyl rings, respectively. The crystal structure is also stabilized by intramolecular O—H···N and N—H···N contacts.

Experimental

The synthetic method used for the preparation of (I) has been described earlier (Fun et al., 2008). Single crystals suitable for X-ray diffraction were obtained by evaporation of a mixed dichloromethane-ethanol (3/1) solution of (I), held at room temperature.