research communications
H-naphtho[1,2-e][1,3]oxazine): a prospective raw material for polybenzoxazines
of 2,2′-(ethane-1,2-diyl)bis(2,3-dihydro-1aUniversidad Nacional de Colombia, Sede Bogotá, Facultad de Ciencias, Departamento de Química, Cra 30 No. 45-03, Bogotá, Código Postal 111321, Colombia, and bInstitut für Anorganische Chemie, J. W. Goethe-Universität Frankfurt, Max-von Laue-Strasse 7, 60438 Frankfurt/Main, Germany
*Correspondence e-mail: ariverau@unal.edu.co
In the title compound, C26H24N2O2, the oxazine moiety is fused to a naphthalene ring system. The consists of one half of the molecule, which lies about an inversion centre. The C atoms of the ethylene spacer group adopt an antiperiplanar arrangement. The oxazine ring adopts a half-chair conformation. In the crystal, supramolecular chains running along the b axis are formed via short C—H⋯π contacts. The crystal studied was a non-merohedral twin with a fractional contribution of 0.168 (2) of the minor twin component.
Keywords: crystal structure; short contacts; benzoxazines; phenolic resins.
CCDC reference: 1547729
1. Chemical context
The oxazine moiety is well known as a building block for high-performance phenolic resins, which are of great interest in industry due to their superior mechanical and physical properties together with unusually high ). Recently, because of their high flexibility in molecular design and performance-to-cost ratio, these monomers have gained attention for the preparation of cured thermosetting resins (Song et al., 2014; Yeganeh & Jangi, 2010). Benzoxazines and naphthoxazines, originally proposed by Holly & Cope (1944) and subsequently elaborated by Burke and co-workers (Burke et al., 1952), are obtained by Mannich-type condensation–cyclization reactions of or naphthols with formaldehyde and primary in a 1:2:1 ratio (Deck et al., 2014). Interest in the synthesis of polybenzoxazines and polynaphthoxazines has greatly increased during the past few years as they have a great deal of molecular design flexibility compared to ordinary phenolics (Yildirim et al., 2006). The title bisnapthoxazine, 2,2′-(ethane-1,2-diyl)bis(2,3-dihydro-1H-naphtho[1,2-e][1,3]oxazine), C26H24N2O2, was prepared by condensation of 2-naphthol with ethylenediamine and formaldehyde in a 2:1:4 molar ratio at room temperature for 15 min in methanol solution. Evaporation at room temperature afforded the title compound in 73% yield after recrystallization.
(Kiskan & Yagci, 20052. Structural commentary
In general terms, the structure of the title compound (Fig. 1) is similar to those of other naphthoxazine derivatives that have been reported in that the oxazine moiety adopts a half-chair conformation (Yang et al., 2007; Rivera et al., 2015), with puckering parameters Q = 0.478 (3) Å, θ = 51.5 (4)°, φ = 86.6 (4)°, and the ethylene spacer group adopts an antiperiplanar arrangement as observed in 3,3′-(ethane-1,2-diyl)bis(3,4-dihydro-2H-1,3-benzoxazine) (Rivera et al., 2012), with a N1—C13—C13i—N1i torsion angle of 180.0° [symmetry code: (i) 1 − x, 1 − y, 1 − z]. However, unlike the related structures, which crystallized in monoclinic space groups with one molecule in the (Yang et al., 2007; Rivera et al., 2012, 2015), the title compound (I) crystallizes with just half a molecule in the in the P21/c, utilizing the crystallographic inversion centre in the molecular symmetry. The other half of the molecule is generated by the (1 − x, 1 − y, 1 − z).
The aromatic C—C bonds of naphthalene ring system have a narrow range of distances [from 1.365 (5) to 1.431 (4) Å]. The central C5—C10 bond at 1.415 (4) Å is, however, shorter by 0.014 Å than those in related structures (Yang et al., 2007; Rivera et al., 2015). The N1—C1 and O1—C1 bond lengths are normal and comparable to the corresponding values observed in these related structures.
3. Supramolecular features
In the crystal, the packing of the title compound is dominated by short contacts (Table 1), as indicated by a PLATON (Spek, 2009) analysis. These contacts result from short C12—H12B⋯C2 and C12—H12B⋯C3 separations, which at 2.75 Å are both 0.15 Å shorter than the sum of the van der Waals radii, while the C—H⋯Cg1 contact to the mid-point of the C2–-C3 bond is even shorter at approximately 2.65 Å. These contacts are also much shorter than the C—H⋯Cg2 contact to the centroid of the C2–C4/C11/C12 ring (Fig. 2). The molecules are by these short C—H⋯π contacts linked into chains propagating along the b-axis direction (Fig. 3).
4. Database survey
The title compound is the first example of two naphtho-oxazine moieties linked by an ethylene bridge.
5. Synthesis and crystallization
The title compound was prepared as described by Rivera et al. (2006). Crystals were obtained by slow evaporation of the reaction solution at ambient temperature and were isolated from the solution before complete evaporation of the solvent mixture.
6. details
Crystal data, data collection and structure . All H atoms were located in the difference electron-density map. C-bound H atoms were fixed geometrically (C—H = 0.95 or 0.99 Å) and refined using a riding-model approximation, with Uiso(H) set to 1.2Ueq of the parent atom. The crystal was a non-merohedral twin with a fractional contribution of 0.168 (2) of the minor twin component.
details are summarized in Table 2Supporting information
CCDC reference: 1547729
https://doi.org/10.1107/S2056989017006673/sj5529sup1.cif
contains datablock I. DOI:Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S2056989017006673/sj5529Isup2.hkl
Supporting information file. DOI: https://doi.org/10.1107/S2056989017006673/sj5529Isup3.cml
Data collection: X-AREA (Stoe & Cie, 2001); cell
X-AREA (Stoe & Cie, 2001); data reduction: X-AREA (Stoe & Cie, 2001); program(s) used to solve structure: SHELXT (Sheldrick, 2015a); program(s) used to refine structure: SHELXL2016 (Sheldrick, 2015b); molecular graphics: XP in SHELXTL-Plus (Sheldrick, 2008); software used to prepare material for publication: SHELXL2016 (Sheldrick, 2015b) and publCIF (Westrip, 2010).C26H24N2O2 | F(000) = 420 |
Mr = 396.47 | Dx = 1.347 Mg m−3 |
Monoclinic, P21/c | Mo Kα radiation, λ = 0.71073 Å |
a = 9.8658 (10) Å | Cell parameters from 9056 reflections |
b = 5.0979 (4) Å | θ = 2.8–26.4° |
c = 19.551 (2) Å | µ = 0.09 mm−1 |
β = 96.033 (8)° | T = 173 K |
V = 977.87 (16) Å3 | Needle, colourless |
Z = 2 | 0.27 × 0.11 × 0.04 mm |
Stoe IPDS II two-circle diffractometer | 9335 independent reflections |
Radiation source: Genix 3D IµS microfocus X-ray source | 5706 reflections with I > 2σ(I) |
ω scans | θmax = 26.4°, θmin = 2.8° |
Absorption correction: multi-scan (X-AREA; Stoe & Cie, 2001) | h = −12→12 |
Tmin = 0.443, Tmax = 1.000 | k = −6→6 |
9335 measured reflections | l = −24→24 |
Refinement on F2 | 0 restraints |
Least-squares matrix: full | Hydrogen site location: inferred from neighbouring sites |
R[F2 > 2σ(F2)] = 0.063 | H-atom parameters constrained |
wR(F2) = 0.130 | w = 1/[σ2(Fo2) + (0.050P)2] where P = (Fo2 + 2Fc2)/3 |
S = 0.94 | (Δ/σ)max < 0.001 |
9335 reflections | Δρmax = 0.53 e Å−3 |
137 parameters | Δρmin = −0.34 e Å−3 |
Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes. |
Refinement. Refined as a 2-component twin |
x | y | z | Uiso*/Ueq | ||
N1 | 0.3328 (2) | 0.3467 (5) | 0.51587 (12) | 0.0291 (6) | |
O1 | 0.14340 (19) | 0.6404 (5) | 0.52587 (10) | 0.0346 (5) | |
C1 | 0.1935 (3) | 0.4104 (7) | 0.49256 (16) | 0.0351 (8) | |
H1A | 0.135064 | 0.258586 | 0.501152 | 0.042* | |
H1B | 0.185528 | 0.440900 | 0.442290 | 0.042* | |
C2 | 0.1675 (3) | 0.6281 (6) | 0.59661 (15) | 0.0302 (7) | |
C3 | 0.0926 (3) | 0.8089 (6) | 0.63272 (17) | 0.0350 (8) | |
H3 | 0.029986 | 0.925542 | 0.608217 | 0.042* | |
C4 | 0.1107 (3) | 0.8150 (7) | 0.70288 (17) | 0.0370 (8) | |
H4 | 0.061911 | 0.939265 | 0.726968 | 0.044* | |
C5 | 0.2015 (3) | 0.6382 (7) | 0.74028 (15) | 0.0319 (7) | |
C6 | 0.2182 (3) | 0.6366 (7) | 0.81341 (16) | 0.0397 (8) | |
H6 | 0.169242 | 0.759116 | 0.837964 | 0.048* | |
C7 | 0.3039 (3) | 0.4611 (7) | 0.84895 (16) | 0.0419 (9) | |
H7 | 0.313599 | 0.460117 | 0.897805 | 0.050* | |
C8 | 0.3771 (3) | 0.2834 (7) | 0.81263 (17) | 0.0421 (9) | |
H8 | 0.436829 | 0.162438 | 0.837424 | 0.051* | |
C9 | 0.3648 (3) | 0.2792 (7) | 0.74225 (15) | 0.0355 (8) | |
H9 | 0.415732 | 0.155997 | 0.718946 | 0.043* | |
C10 | 0.2761 (3) | 0.4585 (6) | 0.70373 (15) | 0.0295 (7) | |
C11 | 0.2593 (3) | 0.4567 (6) | 0.63016 (15) | 0.0276 (7) | |
C12 | 0.3413 (3) | 0.2746 (6) | 0.58900 (14) | 0.0288 (7) | |
H12A | 0.437938 | 0.278593 | 0.608671 | 0.035* | |
H12B | 0.307562 | 0.092959 | 0.593092 | 0.035* | |
C13 | 0.4289 (2) | 0.5552 (6) | 0.50126 (15) | 0.0290 (7) | |
H13A | 0.430945 | 0.691415 | 0.537435 | 0.035* | |
H13B | 0.397638 | 0.638414 | 0.456628 | 0.035* |
U11 | U22 | U33 | U12 | U13 | U23 | |
N1 | 0.0234 (11) | 0.0348 (16) | 0.0294 (13) | −0.0034 (11) | 0.0031 (9) | 0.0008 (11) |
O1 | 0.0264 (10) | 0.0434 (14) | 0.0335 (12) | 0.0053 (9) | 0.0002 (8) | 0.0001 (10) |
C1 | 0.0240 (14) | 0.047 (2) | 0.0339 (16) | −0.0011 (13) | 0.0013 (12) | −0.0078 (15) |
C2 | 0.0194 (13) | 0.0348 (18) | 0.0365 (17) | −0.0036 (13) | 0.0034 (12) | −0.0013 (14) |
C3 | 0.0233 (13) | 0.035 (2) | 0.047 (2) | 0.0023 (13) | 0.0047 (13) | −0.0013 (15) |
C4 | 0.0284 (14) | 0.033 (2) | 0.051 (2) | −0.0017 (13) | 0.0120 (14) | −0.0119 (15) |
C5 | 0.0270 (14) | 0.0336 (18) | 0.0358 (18) | −0.0090 (13) | 0.0070 (12) | −0.0041 (14) |
C6 | 0.0412 (17) | 0.040 (2) | 0.0398 (19) | −0.0157 (16) | 0.0151 (14) | −0.0116 (16) |
C7 | 0.0501 (19) | 0.048 (2) | 0.0286 (17) | −0.0210 (17) | 0.0061 (14) | 0.0037 (15) |
C8 | 0.0444 (17) | 0.043 (2) | 0.038 (2) | −0.0089 (16) | −0.0002 (15) | 0.0075 (16) |
C9 | 0.0355 (15) | 0.034 (2) | 0.0377 (19) | −0.0048 (14) | 0.0057 (13) | 0.0047 (15) |
C10 | 0.0244 (13) | 0.0273 (17) | 0.0374 (17) | −0.0071 (12) | 0.0067 (12) | −0.0008 (13) |
C11 | 0.0232 (12) | 0.0280 (17) | 0.0322 (16) | −0.0049 (12) | 0.0058 (11) | −0.0010 (13) |
C12 | 0.0266 (13) | 0.0287 (17) | 0.0319 (16) | 0.0005 (12) | 0.0067 (12) | 0.0002 (13) |
C13 | 0.0250 (13) | 0.0322 (18) | 0.0302 (15) | 0.0019 (12) | 0.0047 (12) | 0.0014 (14) |
N1—C1 | 1.439 (3) | C6—C7 | 1.369 (5) |
N1—C13 | 1.472 (4) | C6—H6 | 0.9500 |
N1—C12 | 1.470 (4) | C7—C8 | 1.398 (5) |
O1—C2 | 1.380 (4) | C7—H7 | 0.9500 |
O1—C1 | 1.453 (4) | C8—C9 | 1.369 (4) |
C1—H1A | 0.9900 | C8—H8 | 0.9500 |
C1—H1B | 0.9900 | C9—C10 | 1.425 (4) |
C2—C11 | 1.375 (4) | C9—H9 | 0.9500 |
C2—C3 | 1.415 (4) | C10—C11 | 1.431 (4) |
C3—C4 | 1.365 (5) | C11—C12 | 1.517 (4) |
C3—H3 | 0.9500 | C12—H12A | 0.9900 |
C4—C5 | 1.418 (4) | C12—H12B | 0.9900 |
C4—H4 | 0.9500 | C13—C13i | 1.518 (5) |
C5—C10 | 1.415 (4) | C13—H13A | 0.9900 |
C5—C6 | 1.422 (4) | C13—H13B | 0.9900 |
C1—N1—C13 | 112.9 (2) | C6—C7—H7 | 120.3 |
C1—N1—C12 | 108.6 (2) | C8—C7—H7 | 120.3 |
C13—N1—C12 | 113.4 (2) | C9—C8—C7 | 121.7 (3) |
C2—O1—C1 | 112.5 (2) | C9—C8—H8 | 119.2 |
N1—C1—O1 | 113.5 (2) | C7—C8—H8 | 119.2 |
N1—C1—H1A | 108.9 | C8—C9—C10 | 120.4 (3) |
O1—C1—H1A | 108.9 | C8—C9—H9 | 119.8 |
N1—C1—H1B | 108.9 | C10—C9—H9 | 119.8 |
O1—C1—H1B | 108.9 | C5—C10—C9 | 118.1 (3) |
H1A—C1—H1B | 107.7 | C5—C10—C11 | 120.0 (3) |
C11—C2—O1 | 122.9 (3) | C9—C10—C11 | 121.8 (3) |
C11—C2—C3 | 121.9 (3) | C2—C11—C10 | 118.5 (3) |
O1—C2—C3 | 115.2 (3) | C2—C11—C12 | 119.8 (3) |
C4—C3—C2 | 119.7 (3) | C10—C11—C12 | 121.7 (3) |
C4—C3—H3 | 120.1 | N1—C12—C11 | 112.6 (2) |
C2—C3—H3 | 120.1 | N1—C12—H12A | 109.1 |
C3—C4—C5 | 120.8 (3) | C11—C12—H12A | 109.1 |
C3—C4—H4 | 119.6 | N1—C12—H12B | 109.1 |
C5—C4—H4 | 119.6 | C11—C12—H12B | 109.1 |
C10—C5—C4 | 119.0 (3) | H12A—C12—H12B | 107.8 |
C10—C5—C6 | 119.5 (3) | N1—C13—C13i | 110.8 (3) |
C4—C5—C6 | 121.5 (3) | N1—C13—H13A | 109.5 |
C7—C6—C5 | 120.9 (3) | C13i—C13—H13A | 109.5 |
C7—C6—H6 | 119.5 | N1—C13—H13B | 109.5 |
C5—C6—H6 | 119.5 | C13i—C13—H13B | 109.5 |
C6—C7—C8 | 119.4 (3) | H13A—C13—H13B | 108.1 |
C13—N1—C1—O1 | −62.2 (3) | C6—C5—C10—C11 | 179.5 (3) |
C12—N1—C1—O1 | 64.5 (3) | C8—C9—C10—C5 | −0.3 (4) |
C2—O1—C1—N1 | −50.6 (3) | C8—C9—C10—C11 | −179.0 (3) |
C1—O1—C2—C11 | 16.5 (4) | O1—C2—C11—C10 | −179.6 (3) |
C1—O1—C2—C3 | −164.7 (2) | C3—C2—C11—C10 | 1.6 (4) |
C11—C2—C3—C4 | −0.2 (5) | O1—C2—C11—C12 | 1.3 (4) |
O1—C2—C3—C4 | −179.0 (3) | C3—C2—C11—C12 | −177.5 (3) |
C2—C3—C4—C5 | −1.5 (5) | C5—C10—C11—C2 | −1.4 (4) |
C3—C4—C5—C10 | 1.6 (4) | C9—C10—C11—C2 | 177.2 (3) |
C3—C4—C5—C6 | −178.0 (3) | C5—C10—C11—C12 | 177.6 (3) |
C10—C5—C6—C7 | −1.0 (5) | C9—C10—C11—C12 | −3.7 (4) |
C4—C5—C6—C7 | 178.6 (3) | C1—N1—C12—C11 | −43.2 (3) |
C5—C6—C7—C8 | 0.8 (5) | C13—N1—C12—C11 | 83.2 (3) |
C6—C7—C8—C9 | −0.3 (5) | C2—C11—C12—N1 | 12.7 (4) |
C7—C8—C9—C10 | 0.1 (5) | C10—C11—C12—N1 | −166.3 (3) |
C4—C5—C10—C9 | −178.8 (3) | C1—N1—C13—C13i | −156.7 (3) |
C6—C5—C10—C9 | 0.8 (4) | C12—N1—C13—C13i | 79.2 (4) |
C4—C5—C10—C11 | −0.1 (4) |
Symmetry code: (i) −x+1, −y+1, −z+1. |
Cg1 is the mid-point of the C2—C3 bond and Cg2 is the centroid of the C2–C4/C11/C12 ring. |
C—H···C | H···C | C—H···C |
C12—H12B···C2i | 2.75 | 169 |
C12—H12B···C3i | 2.75 | 142 |
C12–H12B···Cg1 | 2.654 | 157 |
C12–H12B···Cg2 | 3.073 | 155 |
Symmetry code: (i) x, -1 + y, z. |
Acknowledgements
We acknowledge the Dirección de Investigaciones, Sede Bogotá (DIB) de la Universidad Nacional de Colombia for financial support of this work (research project No. 35816).
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