supplementary materials


Acta Cryst. (2009). E65, o371    [ doi:10.1107/S1600536809002244 ]

N,N'-Bis[(E)-4-cyanobenzylidene]urea

D.-H. Wu and L. Hu

Abstract top

The molecule of the title compound, C17H10N4O, has crystallographically imposed C2 symmetry. The urea group and the benzene ring are nearly coplanar, the dihedral angle between them being 4.15 (7)°. The crystal packing is stabilized by aromatic [pi]-[pi] stacking interactions, with a centroid-to-centroid separation of 3.833 (4) Å.

Comment top

Nitriles are parent compounds for the preparation of various functional organic materials having imidazole, triazole, or thidiazole functionalities (Íkizler & Sancak, 1992). The Schiff-base compounds derived from the condensation of urea with alkynes are very few (Martínez-García et al., 2004) because of the low reactivity of the NH2 group of urea. Here we report the crystal structure of the title compound, which was obtained by the reaction of urea with 4-cyanobenzaldehyde in acetic acid with ammonium chloride as a catalyzer.

The molecule of the title compound (Fig. 1) possesses a crystallographically imposed C2 symmetry, with atoms C1 and O1 located on a two-fold axis. The urea group and the aromatic rings are nearly coplanar, forming a dihedral angle of 4.15 (7)°. In the crystal packing, molecules are linked along the a axis by aromatic ππ stacking interactions, with centroid-to-centroid separations of 3.833 (4) Å, perpendicular interplanar distances of 3.474 (4) Å and centroid–centroid offsets of 1.620 (3) Å.

Related literature top

For a general background on the use of nitriles as starting materials, see: Íkizler & Sancak (1992). For the products of the condensation of urea with alkynes, see: Martínez-García et al. (2004).

Experimental top

A mixture of 4-cyanobenzaldehyde (0.53 g, 4 mmol), urea (0.36 g, 6 mmol) and NH4Cl (0.10 g, 1.6 mmol) was heated with stirring at 100°C in 5 ml acetic acid for 5 h. After cooling, the reaction mixture was washed with cold water (3 × 50 ml) and the residue recrystallized from ethyl acetate/n-hexane (1:2 v/v) to afford the title compound (0.57 g, 50%). Single crystals suitable for X-ray structure analysis were obtained by the slow evaporation of an ethyl acetate solution in air.

Refinement top

All H atoms were placed in calculated positions and refined using a riding model aproximation, with C—H = 0.93 Å and with Uiso(H) = 1.2Ueq(C).

Computing details top

Data collection: CrystalClear (Rigaku, 2005); cell refinement: CrystalClear (Rigaku, 2005); data reduction: CrystalClear (Rigaku, 2005); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

Figures top
[Figure 1] Fig. 1. The molecular structure of the title compound, showing the atomic numbering scheme. Displacement ellipsoids are drawn at the 30% probability level. Unlabelled atoms are related to the labelled atoms by (-x, y, 1/2 - z).
N,N'-Bis[(E)-4-cyanobenzylidene]urea top
Crystal data top
C17H10N4OF(000) = 592
Mr = 286.29Dx = 1.283 Mg m3
Monoclinic, C2/cMo Kα radiation, λ = 0.71073 Å
Hall symbol: -C 2ycCell parameters from 1587 reflections
a = 10.552 (4) Åθ = 2.6–27.4°
b = 11.687 (5) ŵ = 0.08 mm1
c = 12.198 (3) ÅT = 291 K
β = 99.94 (4)°Block, yellow
V = 1481.7 (9) Å30.36 × 0.30 × 0.28 mm
Z = 4
Data collection top
Rigaku Mercury2
diffractometer
1423 independent reflections
Radiation source: fine-focus sealed tube1107 reflections with I > 2σ(I)
graphiteRint = 0.041
Detector resolution: 13.6612 pixels mm-1θmax = 26.0°, θmin = 2.9°
CCD profile fitting scansh = 1212
Absorption correction: multi-scan
(CrystalClear; Rigaku, 2005)
k = 1414
Tmin = 0.96, Tmax = 0.98l = 1515
6461 measured reflections
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.072Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.164H-atom parameters constrained
S = 1.06 w = 1/[σ2(Fo2) + (0.0535P)2 + 1.99P]
where P = (Fo2 + 2Fc2)/3
1423 reflections(Δ/σ)max < 0.001
102 parametersΔρmax = 0.43 e Å3
1 restraintΔρmin = 0.27 e Å3
Crystal data top
C17H10N4OV = 1481.7 (9) Å3
Mr = 286.29Z = 4
Monoclinic, C2/cMo Kα radiation
a = 10.552 (4) ŵ = 0.08 mm1
b = 11.687 (5) ÅT = 291 K
c = 12.198 (3) Å0.36 × 0.30 × 0.28 mm
β = 99.94 (4)°
Data collection top
Rigaku Mercury2
diffractometer
1423 independent reflections
Absorption correction: multi-scan
(CrystalClear; Rigaku, 2005)
1107 reflections with I > 2σ(I)
Tmin = 0.96, Tmax = 0.98Rint = 0.041
6461 measured reflectionsθmax = 26.0°
Refinement top
R[F2 > 2σ(F2)] = 0.072H-atom parameters constrained
wR(F2) = 0.164Δρmax = 0.43 e Å3
S = 1.06Δρmin = 0.27 e Å3
1423 reflectionsAbsolute structure: ?
102 parametersFlack parameter: ?
1 restraintRogers parameter: ?
Special details top

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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
C10.00000.1727 (3)0.25000.0459 (8)
C20.0655 (2)0.1864 (2)0.45184 (18)0.0476 (6)
H2A0.06450.10680.44910.057*
C30.1028 (2)0.2366 (2)0.56187 (18)0.0419 (6)
C40.1265 (2)0.1659 (2)0.65419 (19)0.0505 (6)
H4A0.11740.08720.64450.061*
C50.1636 (2)0.2094 (2)0.7610 (2)0.0526 (7)
H5A0.17900.16050.82200.063*
C60.1773 (2)0.3265 (2)0.77534 (19)0.0484 (6)
C70.2135 (3)0.3729 (2)0.8858 (2)0.0564 (7)
C80.1546 (2)0.3991 (2)0.6841 (2)0.0544 (7)
H8A0.16400.47770.69420.065*
C90.1181 (2)0.3551 (2)0.5786 (2)0.0525 (7)
H9A0.10340.40430.51790.063*
N10.0325 (2)0.2397 (2)0.35441 (17)0.0643 (7)
N20.2416 (3)0.4101 (2)0.9729 (2)0.0772 (8)
O10.00000.0683 (2)0.25000.0655 (8)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
C10.0458 (18)0.055 (2)0.0363 (17)0.0000.0039 (13)0.000
C20.0485 (13)0.0509 (14)0.0428 (12)0.0062 (10)0.0065 (10)0.0032 (9)
C30.0412 (12)0.0466 (13)0.0384 (12)0.0019 (9)0.0081 (9)0.0009 (9)
C40.0628 (15)0.0472 (14)0.0412 (13)0.0034 (11)0.0085 (10)0.0011 (10)
C50.0608 (16)0.0575 (16)0.0394 (12)0.0015 (12)0.0087 (11)0.0065 (11)
C60.0449 (13)0.0595 (15)0.0404 (13)0.0016 (11)0.0058 (10)0.0095 (11)
C70.0638 (16)0.0577 (16)0.0468 (15)0.0041 (12)0.0073 (12)0.0036 (12)
C80.0626 (16)0.0484 (14)0.0509 (14)0.0036 (11)0.0063 (11)0.0025 (11)
C90.0604 (15)0.0522 (14)0.0435 (13)0.0021 (12)0.0049 (11)0.0055 (11)
N10.0696 (15)0.0745 (17)0.0472 (12)0.0003 (12)0.0055 (10)0.0023 (10)
N20.106 (2)0.0707 (17)0.0511 (14)0.0061 (14)0.0034 (13)0.0151 (12)
O10.098 (2)0.0506 (16)0.0442 (14)0.0000.0009 (13)0.000
Geometric parameters (Å, °) top
C1—O11.221 (4)C4—H4A0.9300
C1—N11.484 (3)C5—C61.384 (4)
C1—N1i1.484 (3)C5—H5A0.9300
C2—N11.334 (3)C6—C81.387 (4)
C2—C31.455 (3)C6—C71.442 (3)
C2—H2A0.9300C7—N21.138 (3)
C3—C41.384 (3)C8—C91.377 (3)
C3—C91.405 (3)C8—H8A0.9300
C4—C51.390 (3)C9—H9A0.9300
O1—C1—N1121.83 (16)C6—C5—H5A120.5
O1—C1—N1i121.83 (16)C4—C5—H5A120.5
N1—C1—N1i116.3 (3)C5—C6—C8120.2 (2)
N1—C2—C3128.4 (2)C5—C6—C7119.7 (2)
N1—C2—H2A115.8C8—C6—C7120.1 (2)
C3—C2—H2A115.8N2—C7—C6179.5 (3)
C4—C3—C9118.0 (2)C9—C8—C6120.2 (2)
C4—C3—C2119.5 (2)C9—C8—H8A119.9
C9—C3—C2122.5 (2)C6—C8—H8A119.9
C3—C4—C5121.8 (2)C8—C9—C3120.7 (2)
C3—C4—H4A119.1C8—C9—H9A119.7
C5—C4—H4A119.1C3—C9—H9A119.7
C6—C5—C4119.1 (2)C2—N1—C1120.3 (3)
Symmetry codes: (i) −x, y, −z+1/2.
Acknowledgements top

The authors thank the Jiangsu Planned Projects for Postdoctoral Research Funds (grant No. 0802003B) and Professor Dr Rengen Xiong.

references
References top

Íkizler, A. A. & Sancak, K. (1992). Monatsh. Chem. 123, 257–263.

Martínez-García, A., Ortiz, M., Martínez, R., Ortiz, P. & Reguera, E. (2004). Ind. Crops Prod. 19, 99–106.

Rigaku (2005). CrystalClear. Rigaku Corporation, Tokyo, Japan.

Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122.