(S)-(+)-1-(1-Naphth­yl)-1-(2-thienylmethyl­ene)ethyl­amine

Armando Espinosa Leija; Guadalupe Hernández; Roberto Portillo; René Gutiérrez; Sylvain Bernès

doi:10.1107/S1600536809022375

. 2009 Jun 20;65(Pt 7):o1651. doi: 10.1107/S1600536809022375

(S)-(+)-1-(1-Naphthyl)-1-(2-thienylmethylene)ethylamine

Armando Espinosa Leija ^a, Guadalupe Hernández ^b, Roberto Portillo ^b, René Gutiérrez ^b, Sylvain Bernès ^c,^*

PMCID: PMC2969493 PMID: 21582915

Abstract

The title chiral imine, C₁₇H₁₅NS, has been obtained via a direct synthesis route. The imine group displays the common E configuration, and is almost coplanar with the thiophene heterocycle; the dihedral angle between the C=N—C group and the thiophene ring is 5.1 (8)°. In contrast, the naphthyl group makes an angle of 83.79 (13)° with the thiophene ring. The observed solid-state molecular conformation is suitable for the use of this molecule as an N,S-bidentate Schiff base ligand. The molecular packing features double C—H⋯π interactions between naphthyl groups of neighboring molecules, which form chains in the [100] direction. The crystal structure is further stabilized by a short C—H⋯π contact involving the methyl group and one ring of a naphthyl group. The resulting two-dimensional network is completed by a weak intermolecular C—H(imine)⋯π(thiophene) interaction.

Related literature

For background to direct synthesis, see: Tanaka & Toda (2000 ▶); Jeon et al. (2005 ▶); Tovar et al. (2007 ▶). For the configuration and conformation of imines derived from thiophene, see: Arjona et al. (1986 ▶).

Experimental

Crystal data

C₁₇H₁₅NS
M _r = 265.36
Orthorhombic,
a = 5.5274 (14) Å
b = 7.990 (2) Å
c = 31.517 (8) Å
V = 1392.0 (6) Å³
Z = 4
Mo Kα radiation
μ = 0.22 mm⁻¹
T = 298 K
0.50 × 0.36 × 0.04 mm

Data collection

Siemens P4 diffractometer
Absorption correction: ψ scan (XSCANS; Siemens, 1996 ▶) T _min = 0.802, T _max = 0.991
4462 measured reflections
2446 independent reflections
1280 reflections with I > 2σ(I)
R _int = 0.045
2 standard reflections every 48 reflections intensity decay: 1.8%

Refinement

R[F ² > 2σ(F ²)] = 0.059
wR(F ²) = 0.174
S = 1.56
2446 reflections
174 parameters
H-atom parameters constrained
Δρ_max = 0.31 e Å⁻³
Δρ_min = −0.39 e Å⁻³
Absolute structure: Flack (1983 ▶), 946 Friedel pairs
Flack parameter: 0.2 (2)

Data collection: XSCANS (Siemens, 1996 ▶); cell refinement: XSCANS; data reduction: XSCANS; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: Mercury (Macrae et al., 2006 ▶); software used to prepare material for publication: SHELXL97.

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536809022375/wn2331sup1.cif

e-65-o1651-sup1.cif^{(17.9KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536809022375/wn2331Isup2.hkl

e-65-o1651-Isup2.hkl^{(120.2KB, 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
C9—H9B⋯CgAⁱ	0.96	2.85	3.682 (6)	145
C6—H6A⋯CgBⁱⁱ	0.93	3.03	3.891 (5)	155
C13—H13A⋯CgCⁱⁱⁱ	0.93	3.54	4.399 (6)	155
C15—H15A⋯CgAⁱⁱⁱ	0.93	3.22	4.030 (6)	147

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Symmetry codes: (i) Inline graphic ; (ii) ; (iii) . CgA is the centroid of ring C10–C14/C19, CgB is the centroid of the thiophene ring and CgC is the centroid of ring C14–C19.

Acknowledgments

Partial support from VIEP-UAP (GUPJ-NAT08-G) is acknowledged.

supplementary crystallographic information

Comment

Nowadays, there is an increasing interest in the use of environmentally benign reagents and conditions, leading particularly to solvent-free procedures. Avoiding organic solvents during the reactions in organic synthesis affords clean, efficient and economical features: safety is largely increased, working is considerably simplified, cost is reduced, increased amounts of reactants can be used, etc. (Tanaka & Toda, 2000; Jeon et al., 2005).

On the other hand, imines continue to attract much attention, mainly due to their versatile coordination behavior and the interesting properties of their metal complexes. Continuing our work on the synthesis of chiral imines (Tovar et al., 2007), we synthesized the title compound under solvent-free conditions (see Experimental) and report here its X-ray crystal structure.

The molecule is stabilized in the solid state as an E-trans aldimine (Fig. 1), which has been shown to be the preferred configuration for imine systems derived from thiophene (Arjona et al., 1986). By conjugation, the imine group C6/N7/C8 is almost coplanar with the thiophene ring S1/C2/C3/C4/C5, with a dihedral angle of 5.1 (8)°. In contrast, the naphthyl group is almost normal to the thiophene ring, at 83.79 (13)°. The crystal packing features a number of intermolecular C—H···π contacts (Fig. 2), the strongest involving the methyl group and a naphthyl group of a symmetry-related molecule. Naphthyl systems aggregate through double C—H···π interactions, forming chains along the [100] direction. The set of contacts results in a two-dimensional framework of efficiently stacked molecules.

Experimental

Under solvent-free conditions, (S)-(-)-(1-naphthyl)ethylamine (213 mg, 1.24 mmol) and 2-thiophenecarboxaldehyde (139 mg, 1.24 mmol) were mixed at 298 K, giving a white solid. The crude product was recrystallized from CH₂Cl₂, affording colorless crystals of the title compound. Yield 87%; m.p. 345 K. Analytical data are in agreement with the structure determined by X-ray diffraction (see archived CIF).