organic compounds
2-(4-Methylphenyl)-6-nitro-1,3-benzoxazole
aDipartimento di Scienze Chimiche, Università degli Studi di Napoli 'Federico II', Complesso di Monte S. Angelo, Via Cinthia, 80126 Napoli, Italy
*Correspondence e-mail: roberto.centore@unina.it
The title compound, C14H10N2O3, is a π-conjugated molecule containing a benzoxazole aromatic fused heterobicycle. The benzoxazole ring system is planar within 0.01 Å. The molecule assumes an approximately flat conformation, the benzoxazole ring system forming dihedral angles of 6.52 (12) and 7.4 (3)° with the benzene ring and the nitro group, respectively. In the crystal, molecules are connected by very weak C—H⋯O hydrogen interactions, forming chains running parallel to the a or c axes. The methyl H atoms are disordered over two sets of sites of equal occupancy rotated by 60°.
Related literature
For general information on heterocycles in organic electronics and optoelectronics, see: Dalton (2002); Heeger (2010). For heterocycle-based semiconductors, optoelectronic and piezoelectric materials, see: Carella, Centore, Sirigu et al. (2004); Centore, Ricciotti et al. (2012); Centore, Concilio et al. (2012). For structural and theoretical analysis of conjugation in heterocycle-based organic molecules, see: Carella, Centore, Fort et al. (2004); Gainsford et al. (2008). For structural and theoretical analysis of conjugation in heterocycle-based metallorganic compounds, see: Takjoo et al. (2011); Takjoo & Centore (2013). For theoretical computations on similar compounds, see: Capobianco et al. (2012, 2013). For the synthesis of related see: Bruno et al. (2002); Centore et al. (2007); Piccialli et al. (2013); Centore, Fusco, Capobianco et al. (2013). For hydrogen bonding in crystals see: Desiraju & Steiner (1999); Centore, Fusco, Jazbinsek et al. (2013).
Experimental
Crystal data
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Data collection: MACH3/PC Software (Nonius, 1996); cell CELLFITW (Centore, 2004); data reduction: XCAD4 (Harms & Wocadlo, 1995); program(s) used to solve structure: SIR97 (Altomare et al., 1999); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia, 2012) and Mercury (Macrae et al., 2006); software used to prepare material for publication: WinGX (Farrugia, 2012).
Supporting information
https://doi.org/10.1107/S1600536813008970/rz5053sup1.cif
contains datablocks global, I. DOI:Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S1600536813008970/rz5053Isup2.hkl
Supporting information file. DOI: https://doi.org/10.1107/S1600536813008970/rz5053Isup3.cml
The title compound was prepared by reaction of 2-amino-5-nitrophenol (5.00 g, 32.4 mmol) with toluic acid (4.41 g, 32.4 mmol) in polyphosphoric acid (150 g) at 150°C. The dehydration procedure is analogous to that we have already described for the synthesis of similar chromophores (Bruno et al., 2002; Centore et al., 2007). Purification of the title compound was obtained by recrystallization from ethanol. The final yield was 5.69 g (69%). M. p. 437 K. Single crystals were obtained by slow evaporation of an ethanol solution. 1H-NMR (CDCl3) δ 2.47 (s, 3H), 7.38 (d, 2H, J = 7.9 Hz), 7.82 (d, 1H, J= 8.5 Hz), 8.18 (d, 2H, J = 8.3 Hz), 8.33 (d, 1H, J= 8.7 Hz), 8.48 (d, 1H, J= 1.8 Hz).
All H atoms were generated stereochemically. In particular, the methyl group is disordered over two sets of sites of equal occupancy rotated from each other by 60°. All H atoms were refined by a riding model with C—H = 0.93-0.96 Å and with Uiso(H) = 1.2Ueq(C) or 1.5Ueq(C) for methyl hydrogen atoms.
Heterocycles are important compounds of synthetic chemistry. Besides their long standing and relevant application as drugs and bioactive compounds, aromatic heterocycles are playing a fundamental role in modern material chemistry as building blocks of conjugated active molecules in some emerging fields of organic electronics and optoelectronics: conducting polymers and organic solar cells (Heeger, 2010), organic field-effect transistors (Centore, Ricciotti et al., 2012), nonlinear optically active and piezoelectric compounds (Dalton, 2002; Carella, Centore, Sirigu et al. (2004); Centore, Concilio et al., 2012). The chemical investigation is mainly directed to the synthesis of new molecules or conjugated polymers containing heterocyclic moieties. However, also the structural investigation of the molecules is relevant, pointing towards the quantitative evaluation of the structural parameters related to the conjugation (Carella, Centore, Fort et al., 2004; Gainsford et al., 2008; Capobianco et al., 2012; Capobianco et al., 2013). Following our interest in the synthesis and characterization of new
including metal containing (Takjoo et al., 2011; Takjoo & Centore, 2013) for applications as advanced materials and bioactive compounds, and in the analysis of crystal structures controlled by the formation of H bonds (Centore, Fusco, Jazbinsek et al., 2013), we report, in the present paper, the structural investigation of the title compound, shown in Scheme 1. 2-(4-methyl)-phenyl-6-nitro-benzoxazole is an organic dye containing the 6-nitrobenzoxazole acceptor group conjugated with a 4-methylphenyl moiety. The 6-nitrobenzoxazole-2-yl moiety has been used in the synthesis of polymers showing quadratic NLO behaviour (Bruno et al., 2002).The molecular structure of the title compound is shown in Fig. 1. The phenyl and benzoxazole rings are nearly coplanar, the dihedral angle between the mean planes being 6.7 (1)°. That structural feature is in accordance with the expected π conjugation of the compound.
Molecules in the crystal form rows through very weak hydrogen interactions between methyl or aromatic C–H donors and oxygen acceptors of the nitro group (Fig. 2 and Fig. 3; Table 1). The chains, which have graph set symbol C11(14) and C11(7) are generated, respectively, by the b and a glide planes.
For general information on heterocycles in organic electronics and optoelectronics, see: Dalton (2002); Heeger (2010). For heterocycle-based semiconductors, optoelectronic and piezoelectric materials, see: Carella, Centore, Sirigu et al. (2004); Centore, Ricciotti et al. (2012); Centore, Concilio et al. (2012). For structural and theoretical analysis of conjugation in heterocycle-based organic molecules, see: Carella, Centore, Fort et al. (2004); Gainsford et al. (2008). For structural and theoretical analysis of conjugation in heterocycle-based metallorganic compounds, see: Takjoo et al. (2011); Takjoo & Centore (2013). For theoretical computations on similar compounds, see: Capobianco et al. (2012, 2013). For the synthesis of related
see: Bruno et al. (2002); Centore et al. (2007); Piccialli et al. (2013); Centore, Fusco, Capobianco et al. (2013). For hydrogen bonding in crystals see: Desiraju & Steiner (1999); Centore, Fusco, Jazbinsek et al. (2013).Data collection: MACH3/PC Software (Nonius, 1996); cell
CELLFITW (Centore, 2004); data reduction: XCAD4 (Harms & Wocadlo, 1995); program(s) used to solve structure: SIR97 (Altomare et al., 1999); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia, 2012) and Mercury (Macrae et al., 2006); software used to prepare material for publication: WinGX (Farrugia, 2012).C14H10N2O3 | F(000) = 1056 |
Mr = 254.24 | Dx = 1.388 Mg m−3 |
Orthorhombic, Pbca | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -P 2ac 2ab | Cell parameters from 25 reflections |
a = 27.251 (4) Å | θ = 12.2–12.4° |
b = 7.4457 (6) Å | µ = 0.10 mm−1 |
c = 11.990 (9) Å | T = 293 K |
V = 2432.8 (19) Å3 | Prism, brown |
Z = 8 | 0.40 × 0.20 × 0.20 mm |
Enraf–Nonius MACH3 diffractometer | Rint = 0.020 |
Radiation source: fine-focus sealed tube | θmax = 25.0°, θmin = 1.5° |
Graphite monochromator | h = −12→32 |
non–profiled ω scans | k = −3→8 |
2968 measured reflections | l = −5→14 |
2140 independent reflections | 1 standard reflections every 120 min |
970 reflections with I > 2σ(I) | intensity decay: none |
Refinement on F2 | Primary atom site location: structure-invariant direct methods |
Least-squares matrix: full | Secondary atom site location: difference Fourier map |
R[F2 > 2σ(F2)] = 0.055 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.168 | H-atom parameters constrained |
S = 1.11 | w = 1/[σ2(Fo2) + (0.0553P)2 + 0.383P] where P = (Fo2 + 2Fc2)/3 |
2140 reflections | (Δ/σ)max < 0.001 |
174 parameters | Δρmax = 0.14 e Å−3 |
0 restraints | Δρmin = −0.19 e Å−3 |
C14H10N2O3 | V = 2432.8 (19) Å3 |
Mr = 254.24 | Z = 8 |
Orthorhombic, Pbca | Mo Kα radiation |
a = 27.251 (4) Å | µ = 0.10 mm−1 |
b = 7.4457 (6) Å | T = 293 K |
c = 11.990 (9) Å | 0.40 × 0.20 × 0.20 mm |
Enraf–Nonius MACH3 diffractometer | Rint = 0.020 |
2968 measured reflections | 1 standard reflections every 120 min |
2140 independent reflections | intensity decay: none |
970 reflections with I > 2σ(I) |
R[F2 > 2σ(F2)] = 0.055 | 0 restraints |
wR(F2) = 0.168 | H-atom parameters constrained |
S = 1.11 | Δρmax = 0.14 e Å−3 |
2140 reflections | Δρmin = −0.19 e Å−3 |
174 parameters |
Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes. |
Refinement. Refinement of F2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F2, conventional R-factors R are based on F, with F set to zero for negative F2. The threshold expression of F2 > σ(F2) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F2 are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger. |
x | y | z | Uiso*/Ueq | Occ. (<1) | |
O1 | 0.05625 (9) | 0.1644 (3) | 0.0918 (2) | 0.0545 (7) | |
O2 | 0.25311 (13) | −0.0885 (6) | 0.2271 (3) | 0.1125 (14) | |
O3 | 0.19587 (12) | −0.0394 (6) | 0.3439 (3) | 0.1144 (14) | |
N1 | 0.08562 (12) | 0.1994 (4) | −0.0827 (3) | 0.0614 (10) | |
N2 | 0.21215 (15) | −0.0363 (6) | 0.2493 (4) | 0.0771 (11) | |
C1 | −0.14836 (14) | 0.4375 (6) | −0.1283 (4) | 0.0819 (15) | |
H1A | −0.1684 | 0.3329 | −0.1391 | 0.123* | 0.57 (5) |
H1B | −0.1477 | 0.5068 | −0.1958 | 0.123* | 0.57 (5) |
H1C | −0.1618 | 0.5090 | −0.0690 | 0.123* | 0.57 (5) |
H1D | −0.1502 | 0.5663 | −0.1302 | 0.123* | 0.43 (5) |
H1E | −0.1709 | 0.3923 | −0.0735 | 0.123* | 0.43 (5) |
H1F | −0.1568 | 0.3901 | −0.2002 | 0.123* | 0.43 (5) |
C2 | −0.09695 (16) | 0.3808 (5) | −0.0983 (4) | 0.0624 (12) | |
C3 | −0.05929 (17) | 0.3930 (6) | −0.1742 (4) | 0.0754 (13) | |
H3 | −0.0656 | 0.4411 | −0.2443 | 0.091* | |
C4 | −0.01233 (16) | 0.3358 (6) | −0.1496 (4) | 0.0710 (13) | |
H4 | 0.0122 | 0.3420 | −0.2035 | 0.085* | |
C5 | −0.00180 (14) | 0.2695 (5) | −0.0448 (3) | 0.0516 (10) | |
C6 | −0.03907 (14) | 0.2611 (5) | 0.0325 (3) | 0.0621 (11) | |
H6 | −0.0325 | 0.2182 | 0.1038 | 0.074* | |
C7 | −0.08606 (15) | 0.3154 (6) | 0.0058 (4) | 0.0682 (13) | |
H7 | −0.1107 | 0.3075 | 0.0592 | 0.082* | |
C8 | 0.04769 (15) | 0.2121 (5) | −0.0175 (3) | 0.0521 (10) | |
C9 | 0.12336 (14) | 0.1393 (5) | −0.0134 (3) | 0.0548 (11) | |
C10 | 0.17235 (15) | 0.1012 (6) | −0.0351 (4) | 0.0724 (13) | |
H10 | 0.1855 | 0.1146 | −0.1062 | 0.087* | |
C11 | 0.20086 (14) | 0.0426 (6) | 0.0532 (4) | 0.0718 (13) | |
H11 | 0.2337 | 0.0139 | 0.0416 | 0.086* | |
C12 | 0.18069 (14) | 0.0268 (6) | 0.1583 (4) | 0.0592 (11) | |
C13 | 0.13235 (14) | 0.0639 (5) | 0.1837 (3) | 0.0571 (11) | |
H13 | 0.1194 | 0.0525 | 0.2551 | 0.069* | |
C14 | 0.10530 (14) | 0.1191 (5) | 0.0941 (3) | 0.0509 (10) |
U11 | U22 | U33 | U12 | U13 | U23 | |
O1 | 0.0553 (17) | 0.0632 (18) | 0.0449 (16) | 0.0015 (13) | 0.0038 (13) | 0.0002 (14) |
O2 | 0.057 (2) | 0.171 (4) | 0.110 (3) | 0.020 (2) | −0.005 (2) | 0.013 (3) |
O3 | 0.086 (2) | 0.190 (4) | 0.068 (2) | 0.022 (3) | −0.004 (2) | 0.022 (3) |
N1 | 0.064 (2) | 0.073 (3) | 0.0474 (19) | −0.0022 (18) | 0.010 (2) | −0.0039 (19) |
N2 | 0.058 (2) | 0.096 (3) | 0.077 (3) | −0.006 (2) | −0.004 (2) | 0.006 (3) |
C1 | 0.073 (3) | 0.070 (3) | 0.103 (4) | 0.010 (3) | −0.024 (3) | −0.008 (3) |
C2 | 0.071 (3) | 0.051 (3) | 0.066 (3) | 0.000 (2) | −0.008 (3) | −0.011 (3) |
C3 | 0.090 (3) | 0.087 (3) | 0.049 (3) | 0.014 (3) | −0.011 (3) | 0.007 (3) |
C4 | 0.075 (3) | 0.086 (3) | 0.052 (3) | 0.009 (3) | 0.002 (2) | −0.001 (3) |
C5 | 0.060 (2) | 0.051 (3) | 0.044 (2) | 0.000 (2) | −0.002 (2) | −0.003 (2) |
C6 | 0.064 (3) | 0.073 (3) | 0.050 (2) | −0.004 (3) | 0.002 (2) | 0.004 (2) |
C7 | 0.060 (3) | 0.078 (3) | 0.067 (3) | −0.006 (2) | 0.004 (2) | 0.001 (3) |
C8 | 0.067 (3) | 0.051 (3) | 0.038 (2) | 0.000 (2) | −0.001 (2) | −0.003 (2) |
C9 | 0.058 (3) | 0.058 (3) | 0.048 (2) | −0.009 (2) | 0.008 (2) | −0.007 (2) |
C10 | 0.065 (3) | 0.093 (4) | 0.058 (3) | −0.003 (3) | 0.019 (3) | −0.001 (3) |
C11 | 0.053 (3) | 0.092 (3) | 0.070 (3) | −0.001 (3) | 0.010 (2) | −0.003 (3) |
C12 | 0.050 (2) | 0.066 (3) | 0.062 (3) | −0.003 (2) | −0.005 (2) | −0.002 (2) |
C13 | 0.059 (3) | 0.060 (3) | 0.052 (3) | −0.004 (2) | 0.005 (2) | −0.001 (2) |
C14 | 0.048 (2) | 0.051 (2) | 0.054 (3) | −0.005 (2) | 0.006 (2) | −0.005 (2) |
O1—C8 | 1.378 (4) | C3—H3 | 0.9300 |
O1—C14 | 1.379 (4) | C4—C5 | 1.380 (5) |
O2—N2 | 1.212 (4) | C4—H4 | 0.9300 |
O3—N2 | 1.218 (5) | C5—C6 | 1.376 (5) |
N1—C8 | 1.299 (4) | C5—C8 | 1.452 (5) |
N1—C9 | 1.396 (5) | C6—C7 | 1.381 (5) |
N2—C12 | 1.465 (5) | C6—H6 | 0.9300 |
C1—C2 | 1.506 (5) | C7—H7 | 0.9300 |
C1—H1A | 0.9600 | C9—C14 | 1.387 (5) |
C1—H1B | 0.9600 | C9—C10 | 1.389 (5) |
C1—H1C | 0.9600 | C10—C11 | 1.383 (6) |
C1—H1D | 0.9600 | C10—H10 | 0.9300 |
C1—H1E | 0.9600 | C11—C12 | 1.380 (5) |
C1—H1F | 0.9600 | C11—H11 | 0.9300 |
C2—C7 | 1.373 (6) | C12—C13 | 1.380 (5) |
C2—C3 | 1.375 (6) | C13—C14 | 1.366 (5) |
C3—C4 | 1.381 (6) | C13—H13 | 0.9300 |
C8—O1—C14 | 104.2 (3) | C5—C4—H4 | 120.1 |
C8—N1—C9 | 104.6 (3) | C3—C4—H4 | 120.1 |
O2—N2—O3 | 122.3 (4) | C6—C5—C4 | 118.4 (4) |
O2—N2—C12 | 118.5 (4) | C6—C5—C8 | 121.4 (4) |
O3—N2—C12 | 119.1 (4) | C4—C5—C8 | 120.2 (4) |
C2—C1—H1A | 109.5 | C5—C6—C7 | 121.0 (4) |
C2—C1—H1B | 109.5 | C5—C6—H6 | 119.5 |
H1A—C1—H1B | 109.5 | C7—C6—H6 | 119.5 |
C2—C1—H1C | 109.5 | C2—C7—C6 | 121.0 (4) |
H1A—C1—H1C | 109.5 | C2—C7—H7 | 119.5 |
H1B—C1—H1C | 109.5 | C6—C7—H7 | 119.5 |
C2—C1—H1D | 109.5 | N1—C8—O1 | 114.8 (3) |
H1A—C1—H1D | 141.1 | N1—C8—C5 | 128.7 (4) |
H1B—C1—H1D | 56.3 | O1—C8—C5 | 116.6 (3) |
H1C—C1—H1D | 56.3 | C14—C9—C10 | 119.5 (4) |
C2—C1—H1E | 109.5 | C14—C9—N1 | 109.0 (3) |
H1A—C1—H1E | 56.3 | C10—C9—N1 | 131.4 (4) |
H1B—C1—H1E | 141.1 | C11—C10—C9 | 117.4 (4) |
H1C—C1—H1E | 56.3 | C11—C10—H10 | 121.3 |
H1D—C1—H1E | 109.5 | C9—C10—H10 | 121.3 |
C2—C1—H1F | 109.5 | C12—C11—C10 | 120.1 (4) |
H1A—C1—H1F | 56.3 | C12—C11—H11 | 119.9 |
H1B—C1—H1F | 56.3 | C10—C11—H11 | 119.9 |
H1C—C1—H1F | 141.1 | C13—C12—C11 | 124.4 (4) |
H1D—C1—H1F | 109.5 | C13—C12—N2 | 117.3 (4) |
H1E—C1—H1F | 109.5 | C11—C12—N2 | 118.3 (4) |
C7—C2—C3 | 117.7 (4) | C14—C13—C12 | 113.7 (4) |
C7—C2—C1 | 121.1 (4) | C14—C13—H13 | 123.1 |
C3—C2—C1 | 121.2 (4) | C12—C13—H13 | 123.1 |
C2—C3—C4 | 122.0 (4) | C13—C14—O1 | 127.8 (4) |
C2—C3—H3 | 119.0 | C13—C14—C9 | 124.8 (4) |
C4—C3—H3 | 119.0 | O1—C14—C9 | 107.4 (4) |
C5—C4—C3 | 119.9 (4) | ||
C7—C2—C3—C4 | 2.4 (7) | N1—C9—C10—C11 | −179.9 (4) |
C1—C2—C3—C4 | −177.7 (4) | C9—C10—C11—C12 | −1.1 (7) |
C2—C3—C4—C5 | −2.1 (7) | C10—C11—C12—C13 | 0.8 (7) |
C3—C4—C5—C6 | 0.5 (7) | C10—C11—C12—N2 | 179.8 (4) |
C3—C4—C5—C8 | −178.9 (4) | O2—N2—C12—C13 | 172.0 (4) |
C4—C5—C6—C7 | 0.8 (6) | O3—N2—C12—C13 | −5.9 (7) |
C8—C5—C6—C7 | −179.8 (4) | O2—N2—C12—C11 | −7.0 (7) |
C3—C2—C7—C6 | −1.0 (6) | O3—N2—C12—C11 | 175.1 (5) |
C1—C2—C7—C6 | 179.0 (4) | C11—C12—C13—C14 | 0.0 (6) |
C5—C6—C7—C2 | −0.6 (7) | N2—C12—C13—C14 | −179.0 (4) |
C9—N1—C8—O1 | −0.3 (4) | C12—C13—C14—O1 | 179.4 (4) |
C9—N1—C8—C5 | 179.6 (4) | C12—C13—C14—C9 | −0.6 (6) |
C14—O1—C8—N1 | 0.7 (4) | C8—O1—C14—C13 | 179.2 (4) |
C14—O1—C8—C5 | −179.2 (3) | C8—O1—C14—C9 | −0.8 (4) |
C6—C5—C8—N1 | 174.5 (4) | C10—C9—C14—C13 | 0.3 (6) |
C4—C5—C8—N1 | −6.1 (7) | N1—C9—C14—C13 | −179.3 (3) |
C6—C5—C8—O1 | −5.6 (6) | C10—C9—C14—O1 | −179.7 (3) |
C4—C5—C8—O1 | 173.8 (4) | N1—C9—C14—O1 | 0.7 (4) |
C8—N1—C9—C14 | −0.2 (4) | C4—C5—C8—N1 | −6.1 (7) |
C8—N1—C9—C10 | −179.8 (4) | C4—C5—C8—O1 | 173.8 (4) |
C14—C9—C10—C11 | 0.5 (6) | C11—C12—N2—O3 | 175.1 (5) |
D—H···A | D—H | H···A | D···A | D—H···A |
C10—H10···O2i | 0.93 | 2.61 | 3.502 (6) | 160 |
C1—H1B···O2ii | 0.96 | 2.80 | 3.143 (5) | 102 |
Symmetry codes: (i) −x+1/2, −y, z−1/2; (ii) x−1/2, −y+1/2, −z. |
Experimental details
Crystal data | |
Chemical formula | C14H10N2O3 |
Mr | 254.24 |
Crystal system, space group | Orthorhombic, Pbca |
Temperature (K) | 293 |
a, b, c (Å) | 27.251 (4), 7.4457 (6), 11.990 (9) |
V (Å3) | 2432.8 (19) |
Z | 8 |
Radiation type | Mo Kα |
µ (mm−1) | 0.10 |
Crystal size (mm) | 0.40 × 0.20 × 0.20 |
Data collection | |
Diffractometer | Enraf–Nonius MACH3 |
Absorption correction | – |
No. of measured, independent and observed [I > 2σ(I)] reflections | 2968, 2140, 970 |
Rint | 0.020 |
(sin θ/λ)max (Å−1) | 0.594 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.055, 0.168, 1.11 |
No. of reflections | 2140 |
No. of parameters | 174 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.14, −0.19 |
Computer programs: MACH3/PC Software (Nonius, 1996), CELLFITW (Centore, 2004), XCAD4 (Harms & Wocadlo, 1995), SIR97 (Altomare et al., 1999), SHELXL97 (Sheldrick, 2008), ORTEP-3 for Windows (Farrugia, 2012) and Mercury (Macrae et al., 2006), WinGX (Farrugia, 2012).
D—H···A | D—H | H···A | D···A | D—H···A |
C10—H10···O2i | 0.93 | 2.61 | 3.502 (6) | 160.0 |
C1—H1B···O2ii | 0.96 | 2.80 | 3.143 (5) | 102.2 |
Symmetry codes: (i) −x+1/2, −y, z−1/2; (ii) x−1/2, −y+1/2, −z. |
Acknowledgements
The authors thank the Centro Interdipartimentale di Metodologie Chimico-Fisiche, Università degli Studi di Napoli "Federico II", for support.
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This is an open-access article distributed under the terms of the Creative Commons Attribution (CC-BY) Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are cited.
Heterocycles are important compounds of synthetic chemistry. Besides their long standing and relevant application as drugs and bioactive compounds, aromatic heterocycles are playing a fundamental role in modern material chemistry as building blocks of conjugated active molecules in some emerging fields of organic electronics and optoelectronics: conducting polymers and organic solar cells (Heeger, 2010), organic field-effect transistors (Centore, Ricciotti et al., 2012), nonlinear optically active and piezoelectric compounds (Dalton, 2002; Carella, Centore, Sirigu et al. (2004); Centore, Concilio et al., 2012). The chemical investigation is mainly directed to the synthesis of new molecules or conjugated polymers containing heterocyclic moieties. However, also the structural investigation of the molecules is relevant, pointing towards the quantitative evaluation of the structural parameters related to the conjugation (Carella, Centore, Fort et al., 2004; Gainsford et al., 2008; Capobianco et al., 2012; Capobianco et al., 2013). Following our interest in the synthesis and characterization of new heterocyclic compounds, including metal containing heterocyclic compounds (Takjoo et al., 2011; Takjoo & Centore, 2013) for applications as advanced materials and bioactive compounds, and in the analysis of crystal structures controlled by the formation of H bonds (Centore, Fusco, Jazbinsek et al., 2013), we report, in the present paper, the structural investigation of the title compound, shown in Scheme 1. 2-(4-methyl)-phenyl-6-nitro-benzoxazole is an organic dye containing the 6-nitrobenzoxazole acceptor group conjugated with a 4-methylphenyl moiety. The 6-nitrobenzoxazole-2-yl moiety has been used in the synthesis of polymers showing quadratic NLO behaviour (Bruno et al., 2002).
The molecular structure of the title compound is shown in Fig. 1. The phenyl and benzoxazole rings are nearly coplanar, the dihedral angle between the mean planes being 6.7 (1)°. That structural feature is in accordance with the expected π conjugation of the compound.
Molecules in the crystal form rows through very weak hydrogen interactions between methyl or aromatic C–H donors and oxygen acceptors of the nitro group (Fig. 2 and Fig. 3; Table 1). The chains, which have graph set symbol C11(14) and C11(7) are generated, respectively, by the b and a glide planes.