2-(Naphthalen-1-yl)-4-(thio­phen-2-yl­methyl­idene)-1,3-oxazol-5(4H)-one

Cevher Gündoğdu; Serap Alp; Yavuz Ergün; Barış Tercan; Tuncer Hökelek

doi:10.1107/S1600536811016151

. 2011 May 7;67(Pt 6):o1321–o1322. doi: 10.1107/S1600536811016151

2-(Naphthalen-1-yl)-4-(thiophen-2-ylmethylidene)-1,3-oxazol-5(4H)-one

Cevher Gündoğdu ^a, Serap Alp ^a, Yavuz Ergün ^a, Barış Tercan ^b, Tuncer Hökelek ^c,^*

PMCID: PMC3120366 PMID: 21754719

Abstract

The asymmetric unit of the title compound, C₁₈H₁₁NO₂S, contains two crystallographically independent molecules. In one molecule, the oxazole and thiophene rings are oriented at dihedral angles of 17.40 (9) and 18.18 (7)° with respect to the naphthalene ring system, while the oxazole and thiophene rings are oriented to each other at a dihedral angle of 0.86 (9)°. In the other molecule, the corresponding angles are 3.05 (8), 9.62 (6) and 7.02 (8)°, respectively. In each molecule, a weak intramolecular C—H⋯N hydrogen bond links the oxazole N atom to the naphthalene group. Weak intermolecular C—H⋯O hydrogen bonding is present in the crystal structure. π–π stacking between the oxazole and thiophene rings, between the thiophene and naphthalene rings, and between the oxaozole and naphthalene rings, [centroid–centroid distances = 3.811 (2), 3.889 (2), 3.697 (2) and 3.525 (2) Å] may further stabilize the crystal structure.

Related literature

For potential applications of the title compound, such as organic light-emitting diodes (OLEDs), organic thin-film transistors (OTFTs), and organic photovoltaics (OPVs) of various aromatic ring-based conjugated polymers, see: Liu et al. (2007 ▶); Allard et al. (2008 ▶); Woudenbergh et al. (2004 ▶); Zhang et al. (2007 ▶); Güneş et al. (2007 ▶); Soci et al. (2007 ▶). For the roles of thiophene-based molecules widely used in the syntheses of the charge-transporting molecules used in organic field effect transistors, organic solar cells and organic light emitting diodes, see: Mas-Torrent & Rovira (2008 ▶); Shirota & Kageyama (2007 ▶); Varis et al. (2006 ▶). For bond-length data, see: Allen et al. (1987 ▶).

Experimental

Crystal data

C₁₈H₁₁NO₂S
M _r = 305.35
Monoclinic,
a = 11.1509 (3) Å
b = 7.0871 (2) Å
c = 35.2592 (5) Å
β = 97.914 (4)°
V = 2759.91 (12) Å³
Z = 8
Mo Kα radiation
μ = 0.24 mm⁻¹
T = 294 K
0.35 × 0.22 × 0.20 mm

Data collection

Bruker Kappa APEXII CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2005 ▶) T _min = 0.921, T _max = 0.953
25128 measured reflections
6899 independent reflections
3925 reflections with I > 2σ(I)
R _int = 0.061

Refinement

R[F ² > 2σ(F ²)] = 0.054
wR(F ²) = 0.133
S = 1.01
6899 reflections
405 parameters
2 restraints
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.44 e Å⁻³
Δρ_min = −0.44 e Å⁻³

Data collection: APEX2 (Bruker, 2007 ▶); cell refinement: SAINT (Bruker, 2007 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997 ▶); software used to prepare material for publication: WinGX (Farrugia, 1999 ▶) and PLATON (Spek, 2009 ▶).

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536811016151/xu5202sup1.cif

e-67-o1321-sup1.cif^{(26.6KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536811016151/xu5202Isup2.hkl

e-67-o1321-Isup2.hkl^{(330.8KB, hkl)}

Supplementary material file. DOI: 10.1107/S1600536811016151/xu5202Isup3.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
C3—H3⋯N1	0.93	2.27	2.924 (3)	127
C3′—H3′⋯N1′	0.93	2.29	2.946 (3)	127
C6—H6⋯O2ⁱ	0.93	2.59	3.483 (3)	160
C9′—H9′⋯O2ⁱⁱ	0.93	2.46	3.310 (3)	152
C16′—H16′⋯O2′ⁱⁱⁱ	0.93	2.50	3.329 (3)	149

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

Acknowledgments

The authors are indebted to Anadolu University and the Medicinal Plants and Medicine Research Centre of Anadolu University, Eskişehir, Turkey, for the use of X-ray diffractometer. This study was supported by TUBITAK (grant No. 107T817).

supplementary crystallographic information

Comment

The design and syntheses of new conjugated polymers are a significant part of the conducting polymers research and have attracted great attention. Various aromatic ring-based conjugated polymers have been developed for use in potential applications, such as organic light-emitting diodes (OLEDs) (Liu et al., 2007; Allard et al., 2008), organic thin-film transistors (OTFTs) (Woudenbergh et al., 2004; Zhang et al., 2007), and organic photovoltaics (OPVs) (Güneş et al., 2007; Soci et al., 2007). Among conducting polymers, polythiophene and its derivatives have become a subject of considerable interest as electrochromic materials, due to their chemical stabilities. Thiophene based molecules are widely used in the sytheses of the charge transporting molecules used in organic field effect transistors, organic solar cells and organic light emitting diodes (Mas-Torrent & Rovira, 2008; Shirota & Kageyama, 2007; Varis et al., 2006). The present study was undertaken to ascertain the crystal structure of the title compound.

The asymmetric unit of the title compound contains two crystallographically independent molecules. Each molecule consists of an oxazol ring, a thiophene ring and a naphthalene group (Fig. 1), where the bond lengths are close to standard values (Allen et al., 1987). In each molecule, the intramolecular C-H···N hydrogen bonds link the oxazol nitrogen atoms to the naphthalene groups (Table 1 and Fig. 1).

An examination of the deviations from the least-squares planes through individual rings shows that rings A (C2—C7), B (C1/C2/C7—C10), C (O1/N1/C11—C13), D (S1/C15—C18) and A' (C2'—C7'), B' (C1'/C2'/C7'—C10'), C' (O1'/N1'/C11'—C13'), D' (S1'/C15'—C18') are planar. The naphthalene groups, containing the rings A, B and A', B' are also nearly planar [with maximum deviations of -0.032 (3) Å for atom C3 and 0.028 (3) Å for atom C4'] with dihedral angles of A/B = 2.28 (8) and A'/B' = 1.65 (8) °. In each molecule, rings C, D and C', D' are oriented with respect to the planar naphthalene groups at dihedral angles of 17.40 (9), 18.18 (7) ° and 3.05 (8), 9.62 (6) °, while the oxazole and thiophene rings are oriented at dihedral angles of 0.86 (9) and 7.02 (8) °,respectively.

In the crystal, intermolecular C'—H'···O' hydrogen bonds link the molecules into centrosymmetric dimers, in which they are also linked through C'-H'···O and C-H···O hydrogen bonds to form a three dimensional network (Table 1 and Fig. 2). The π–π contacts between the oxazol and thiophene rings, between the thiophene and naphthalene rings and between the oxaozole and naphthalene rings Cg3—Cg4ⁱ, Cg6—Cg8ⁱⁱ, Cg6—Cg7ⁱⁱⁱ and Cg5—Cg7ⁱⁱⁱ [symmetry codes: (i) -x, 1/2 + y, 1/2 - z, (ii) -x, 2 - y, -z, (iii) -x, 1 - y, -z, where Cg3, Cg4, Cg5, Cg6, Cg7 and Cg8 are centroids of the rings C (O1/N1/C11—C13), D (S1/C15—C18), A' (C2'—C7'), B' (C1'/C2'/C7'—C10'), C' (O1'/N1'/C11'—C13') and D' (S1'/C15'—C18'), respectively] may further stabilize the structure, with centroid-centroid distances of 3.811 (2), 3.889 (2), 3.697 (2) and 3.525 (2) Å, respectively.

Experimental

For the preparation of the title compound, (I), thiophene-2-carbaldehyde (0.46 g, 5 mmol), naphthalen-1-yl glycine (1.14 g, 5 mmol), acetic anhydride (2.49 ml, 12 mmol) and sodium acetate (0.41 g, 5 mmol) were heated until the mixture just liquefied, and then heating was continued for a further 2 h at 353 K. After completion of the reaction, ethanol (25 ml) was added and the mixture was kept at room temperature for 18 h. The solid product obtained was purified by washing with cold ethanol, hot water and a small amount of hexane, respectively. It was crystallized from hot ethanol (yield; 0.23 g, 49%, m.p. 460 K).