1,1′-{(Hexane-1,6-di­yl)bis­[(aza­niumylyl­idene)methanylyl­idene]}bis­(naphthalen-2-olate)

Kamel Ouari; Sabrina Bendia; Moufida Merzougui; Corinne Bailly

doi:10.1107/S2056989014027236

. 2015 Jan 1;71(Pt 1):o51–o52. doi: 10.1107/S2056989014027236

1,1′-{(Hexane-1,6-diyl)bis[(azaniumylylidene)methanylylidene]}bis(naphthalen-2-olate)

Kamel Ouari ^a,^*, Sabrina Bendia ^a, Moufida Merzougui ^a, Corinne Bailly ^b

PMCID: PMC4331877 PMID: 25705504

Abstract

The whole molecule of the title Schiff base compound, C₂₈H₂₈N₂O₂, is generated by inversion symmetry. It is formed from two units of ortho-hydroxynaphthaldehyde bridged with 1,6-diaminohexane. The N atoms are protonated and, thus, the structure is a bis-zwitterionic compound in the solid state. The zwitterion shows strong intramolecular N—H⋯O hydrogen bonds between the iminium N and the naphthalenolate O atoms.

Keywords: crystal structure; 1,6-diaminohexane; 2-hydroxy-1-naphthaldehyde; hydrogen bonding; elemental analysis.

Related literature

For the synthesis of similar compounds, see: Ramos Silva et al. (2009 ▸); Li et al. (2007 ▸); Zhu et al. (2006 ▸); Sampath Kumar et al. (2010 ▸); Bhattacharjee et al. (2012 ▸). For their applications, see: Ourari et al. (2006 ▸, 2008 ▸); Ouari et al. (2010 ▸, 2015 ▸). For related crystal structures, see: Yuan & Li (2013 ▸); Paul & Kubicki (2009 ▸). For the biological activity of Schiff bases, see: Zayed et al. (2015 ▸); Abou-Hussein & Linert (2014 ▸); Sadeek et al. (2013 ▸). graphic file with name e-71-00o51-scheme1.jpg

Experimental

Crystal data

C₂₈H₂₈N₂O₂
M _r = 424.52
Orthorhombic,
a = 23.722 (1) Å
b = 8.8117 (3) Å
c = 10.3903 (5) Å
V = 2171.90 (16) Å³
Z = 4
Mo Kα radiation
μ = 0.08 mm⁻¹
T = 173 K
0.36 × 0.16 × 0.08 mm

Data collection

Nonius KappaCCD diffractometer
17177 measured reflections
2500 independent reflections
1285 reflections with I > 2σ(I)
R _int = 0.082

Refinement

R[F ² > 2σ(F ²)] = 0.054
wR(F ²) = 0.160
S = 0.99
2500 reflections
150 parameters
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.23 e Å⁻³
Δρ_min = −0.28 e Å⁻³

Data collection: COLLECT (Nonius, 1998 ▸); cell refinement: DENZO (Otwinowski & Minor, 1997 ▸); data reduction: SCALEPACK (Otwinowski & Minor, 1997 ▸); program(s) used to solve structure: SHELXS2013 (Sheldrick, 2008 ▸); program(s) used to refine structure: SHELXL2013 (Sheldrick, 200); molecular graphics: PLATON (Spek, 2009 ▸); software used to prepare material for publication: SHELXL2013.

Supplementary Material

Crystal structure: contains datablock(s) I. DOI: 10.1107/S2056989014027236/mw2128sup1.cif

e-71-00o51-sup1.cif^{(1.5MB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S2056989014027236/mw2128Isup2.hkl

e-71-00o51-Isup2.hkl^{(137.6KB, hkl)}

Click here for additional data file.^{(1MB, tif)}

. DOI: 10.1107/S2056989014027236/mw2128fig1.tif

The molecular geometry of the title compound with displacement ellipsoids drawn at the 50% probability level. H atoms are represented as small spheres of arbitrary radii. Hydrogen bonds are shown as dashed lines. Only the non-H atoms of the asymmetric unit are labelled.

Click here for additional data file.^{(1.9MB, tif)}

c . DOI: 10.1107/S2056989014027236/mw2128fig2.tif

Crystal packing of the title compound viewed along the c axis.

CCDC reference: 1032693

Additional supporting information: crystallographic information; 3D view; checkCIF report

Table 1. Hydrogen-bond geometry (, ).

DHA	DH	HA	D A	DHA
N1H1NO1	0.99(3)	1.74(3)	2.587(2)	141(2)

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Acknowledgments

The authors gratefully acknowledge financial support from the Algerian Ministry of Higher Education and Scientific Research. They also acknowledge the help of Dr Jean Weiss (CLAC) at the University of Strasbourg, France.

supplementary crystallographic information

S1. Experimental

The Schiff base ligand was prepared in 67% yield by condensation between 58 mg (0.5 mmole) of 1,6-diaminohexane and 172 mg (1 mmole) of 2-hydroxy-1-naphthaldehyde in methanol (12 mL). The mixture was refluxed and stirred under a nitrogen atmosphere for 3 hours. The precipitate obtained was filtered, washed with methanol and diethyl ether and dried in vacuum overnight. The product was recrystallized from dimethyl sulfoxide at room temperature over a period of a week. The yellow, single crystals of C₂₈H₂₈O₂N₂ obtained were of X-ray quality. Elemental analysis: calculated for C₂₈H₂₈O₂N₂: C 79.20, H 6.65, N 6.60%; found: C 78.84, H 6.63, N 6.78%.

S1.1. Refinement

The iminium H atom was located from a difference Fourier map and refined isotropically. C-bound H atoms were included in calculated positions and treated as riding atoms: C—H = 0.95 Å (CH) or 0.99 Å (CH₂) with Uiso(H) = 1.2Ueq(C—H_aromatics). .

S2. Results and discussion

The synthesis of the Schiff base is similar to those described in the literature (Ramos Silva et al., 2009; Li et al., 2007; Zhu et al., 2006; Sampath Kumar et al., 2010; Bhattacharjee et al., 2012). These ligands are also currently applied in coordination chemistry for the synthesis of Schiff base complexes of transition metals (Ouari et al., 2015; Ouari et al., 2010; Ourari et al., 2008; Ourari et al., 2006). Compounds of the type of the title molecule possess diverse biological properties such as anti-anxiety, anti-depressant (Zayed et al., 2015) and anti-tumor activities as well as antibacterial and fungicidal properties (Abou-Hussein et al., 2014; Sadeek et al., 2013). We report here the synthesis of title compound and its crystal structure.

A perspective view of the title molecule, which has crystallographically- imposed centrosymmetry, is shown in Fig. 1. The intramolecular N1—H1N···O1 hydrogen bond forces the O1–C1–C10–C11–N1 unit into near planarity (rms deviation 0.005 Å) with the consequence that the naphthalene portion is nearly co-planar with it (dihedral angle 1.20 (8)°).