Crystal structure of (1Z,2E)-cinnamaldehyde oxime

Bernhard Bugenhagen; Nuha Al Soom; Yosef Al Jasem; Thies Thiemann

doi:10.1107/S2056989015023853

. 2015 Dec 16;71(Pt 12):o1063–o1064. doi: 10.1107/S2056989015023853

Crystal structure of (1Z,2E)-cinnamaldehyde oxime

Bernhard Bugenhagen ^a, Nuha Al Soom ^b, Yosef Al Jasem ^c, Thies Thiemann ^b,^*

PMCID: PMC4719980 PMID: 26870499

Abstract

The title compound, C₉H₉NO, crystallized with two independent molecules (A and B) in the asymmetric unit. The conformation of the two molecules differs slightly with the phenyl ring in molecule A, forming a dihedral angle of 15.38 (12)° with the oxime group (O—N=C), compared to the corresponding angle of 26.29 (11)° in molecule B. In the crystal, the A and B molecules are linked head-to-head by O—H⋯N hydrogen bonds, forming –A–B–A–B– zigzag chains along [010]. Within the chains and between neighbouring chains there are C—H⋯π interactions present, forming a three-dimensional structure.

Keywords: crystal structure, cinnamaldehyde, oxime, conformers, O—H⋯N hydrogen bonding, C—H⋯π interactions

Related literature

For the other methods of preparation of the title compound, see: Mirjafari et al. (2011 ▸); Kitahara et al. (2008 ▸). For the uses of a such compound, see: Narsaiah & Nagaiah (2004 ▸); Jasem et al. (2014 ▸); Garton et al. (2010 ▸); Patil et al. (2012 ▸); Kaur et al. (2006 ▸); Boruah & Konwar (2012 ▸). graphic file with name e-71-o1063-scheme1.jpg

Experimental

Crystal data

C₉H₉NO
M _r = 147.17
Orthorhombic,
a = 10.231 (5) Å
b = 7.584 (3) Å
c = 41.816 (18) Å
V = 3245 (2) Å³
Z = 16
Mo Kα radiation
μ = 0.08 mm⁻¹
T = 100 K
0.2 × 0.2 × 0.1 mm

Data collection

Bruker APEXII CCD diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2013 ▸) T _min = 0.666, T _max = 0.746
34431 measured reflections
3944 independent reflections
3724 reflections with I > 2σ(I)
R _int = 0.022

Refinement

R[F ² > 2σ(F ²)] = 0.043
wR(F ²) = 0.113
S = 1.10
3944 reflections
207 parameters
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.45 e Å⁻³
Δρ_min = −0.19 e Å⁻³

Data collection: APEX2 (Bruker, 2013 ▸); cell refinement: SAINT (Bruker, 2013 ▸); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▸); program(s) used to refine structure: SHELXL2014 (Sheldrick, 2015 ▸); molecular graphics: PLATON (Spek, 2009 ▸) and Mercury (Macrae et al., 2008 ▸); software used to prepare material for publication: OLEX2 (Dolomanov et al., 2009 ▸).

Supplementary Material

Crystal structure: contains datablock(s) I. DOI: 10.1107/S2056989015023853/su5260sup1.cif

e-71-o1063-sup1.cif^{(1.1MB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S2056989015023853/su5260Isup2.hkl

e-71-o1063-Isup2.hkl^{(314.8KB, hkl)}

Click here for additional data file.^{(3KB, cml)}

Supporting information file. DOI: 10.1107/S2056989015023853/su5260Isup3.cml

Click here for additional data file.^{(952.2KB, tif)}

A B . DOI: 10.1107/S2056989015023853/su5260fig1.tif

A view of the molecular structure of the two independent molecules (A and B) of the title compound, with atom labelling. Displacement ellipsoids are drawn at the 50% probability level.

Click here for additional data file.^{(1.2MB, tif)}

a . DOI: 10.1107/S2056989015023853/su5260fig2.tif

A partial view along the a axis of the crystal packing of the title compound. The O—H⋯N hydrogen bonds, and the C—H⋯π contacts between adjacent molecules are shown as dashed lines (see Table 1).

Click here for additional data file.^{(1.2MB, tif)}

b b . DOI: 10.1107/S2056989015023853/su5260fig3.tif

A view along the b axis of three stacked molecular motifs made of A (blue) and B (green) interconnected molecules forming chains along the b axis. The hydrogen bonds and C—H⋯π interactions are shown as dashed lines (see Table 1).

CCDC reference: 1441984

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

Table 1. Hydrogen-bond geometry (Å, °).

Cg1 and Cg2 are the centroids of rings C1A–C6A and C1B–C6B, respectively.

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O1A—H1A⋯N1B ⁱ	0.91 (2)	1.85 (2)	2.755 (2)	174 (2)
O1B—H1B⋯N1A ⁱⁱ	0.92 (2)	1.95 (2)	2.853 (2)	170 (2)
C2A—H2A⋯Cg1ⁱⁱⁱ	0.95	2.70	3.563 (2)	151
C5B—H5B⋯Cg2^iv	0.95	2.80	3.508 (2)	132
C9B—H9B⋯Cg2^v	0.95	2.82	3.717 (2)	159

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

supplementary crystallographic information

S1. Structural commentary

Many uses of cinnamaldehyde oxime have been reported, such as the conversion to cinnamonitrile (Narsaiah & Nagaiah 2004; Jasem et al. 2014), conversion to cinnamide (Garton et al. 2010), and as a starting material for N-heterocycles: tetrazole (Patil et al. 2012), isoxazoline (Kaur et al. 2006), and izoxazoline (Boruah & Konwar 2012).

The title compound, crystallized with two independent molecules A and B in the asymmetric unit (Fig. 1). The aromatic ring in molecule A (C1A—C6A) forms a dihedral angle of 15.38 (12)° with the oxime group (C9A/N1A/O1A), compared to a corresponding angle of 26.29 (11)° in molecule B. This conformational difference between molecules A and B is due to bond rotation, not only about bonds (C1—C7) and (C8—C9) but also of that of (C7—C8), where in molecule A the torsion angle C1—C7—C8—C9 is −174.32 (11)° while in molecule B the corresponding angle is −179.24 (11) °. The bond lengths, C7—C8, of molecules A and B are similar.

In the crystal, the A molecules align opposite B molecules, and they are linked via O—H···N hydrogen bonds forming –A—B—A—B– zigzag chains propagating along the b axis (Table 1 and Fig. 2). Adjacent molecules of the same type are tilted against each other, with the aromatic rings (C1—C6) being inclined to one another by 77.64 (2) and 59.04 (2)° for molecules A and B, respectively. In addition, adjacent molecules of the same type exhibit weak C—H..π (C2A—H2A···Cg1 and C5B—H5B···Cg2) contacts along the b axis direction (Table 1 and Fig. 2). Along the c axis, inversion related dimers stack with an offset of 11.47 (2) Å and connected via a weak C—H..π (C9B—H9B···Cg2) contact (Fig. 3 and Table 1).

S2. Synthesis and crystallization

To a solution of cinnamaldehyde (1.32 g, 10 mmol) in ethanol (20 ml) was added drop wise a solution of hydroxylamine hydrochloride (2.74 g, 39.7 mmol) in water (7.5 ml), and the resulting mixture was stirred at 60 ^oC for 3 h. Thereafter, about half of the solvent was removed in vacuo, and the remaining reaction mixture was poured into water (50 ml) and extracted with CHCl₃ (3 × 20 ml). The combined organic layer was dried over anhydrous MgSO₄ and concentrated in vacuo. The residue was subjected to column chromatography (eluant: CH₂Cl₂) to yield the title compound as colourless needles (yield: 956 mg, 65%; m.p. 348 – 349 K). IR (ν_max, KBr, cm⁻¹) 3356, 1630, 1444, 1291, 987, 976, 955, 747, 691; ¹H NMR (400 MHz, CDCl₃, δ_H) 6.84 (1H, d, ³J = 5.6 Hz), 7.28 – 7.55 (6H, m), 7.94 (1H, t, ³J = 4.8 Hz); δ_C (100.5 MHz, CDCl₃) 121.5 (CH), 127.0 (2 C, CH), 128.8 (2 C, CH), 129.0 (CH), 135.7 (C_quat), 139.2 (CH), 152.0 (CH). Crystals for X-ray analysis were grown from a solution in CH₂Cl₂/hexane (1:1, v/v) by slow evaporation of the solvents.

S3. Refinement

Crystal data, data collection and structure refinement details are summarized in Table 2. The OH H atoms were located in a difference Fourier map and freely refined. The C-bound H atoms were fixed geometrically (C—H = 0.95 Å) and allowed to ride on their parent atoms with U_iso(H) = 1.2U_eq(C).