4,4'-[Ethylenebis(nitrilomethylidyne)]dibenzonitrile.

The mol-ecule of the title Schiff base compound, C(18)H(14)N(4), lies across a crystallographic inversion centre and adopts an E configuration with respect to the azomethine (C=N) bonds. The imino groups are coplanar with the aromatic rings with a maximum deviation of 0.1574 (12) Å for the N atom. Within the mol-ecule, the planar units are parallel, but extend in opposite directions from the dimethyl-ene bridge. In the crystal structure, pairs of inter-molecular C-H⋯N hydrogen bonds link neighbouring mol-ecules into centrosymmetric dimers with R(2) (2)(10) ring motifs. An inter-esting feature of the crystal structure is the short inter-molecular C⋯C inter-action with a distance of 3.3821 (13) Å, which is shorter than the sum of the van der Waals radius of a carbon atom.

Related literature

For bond-length data, see Allen et al. (1987 ▶). For hydrogen-bond motifs, see: Bernstein et al. (1995 ▶). For related structures see, for example: Fun & Kia (2008 ▶): Fun, Kargar & Kia (2008 ▶); Fun, Kia & Kargar (2008 ▶). For information on Schiff base complexes and their applications, see, for example, Pal et al. (2005 ▶); Calligaris & Randaccio, (1987 ▶). Hou et al. (2001 ▶); Ren et al. (2002 ▶). For the stability of the temperature controller used for the data collection, see: Cosier & Glazer (1986 ▶).

Experimental

Crystal data

C18H14N4

M = 286.33

Triclinic,

a = 4.6843 (2) Å

b = 6.9872 (3) Å

c = 11.6208 (5) Å

α = 78.147 (3)°

β = 87.462 (3)°

γ = 74.081 (2)°

V = 357.94 (3) Å3

Z = 1

Mo Kα radiation

μ = 0.08 mm−1

T = 100 K

0.45 × 0.29 × 0.06 mm

Data collection

Bruker SMART APEXII CCD area-detector diffractometer

Absorption correction: multi-scan (SADABS; Bruker, 2005 ▶) T min = 0.964, T max = 0.995

7927 measured reflections

2551 independent reflections

2034 reflections with I > 2σ(I)

R int = 0.023

Refinement

R[F 2 > 2σ(F 2)] = 0.047

wR(F 2) = 0.146

S = 1.08

2551 reflections

100 parameters

H-atom parameters constrained

Δρmax = 0.44 e Å−3

Δρmin = −0.25 e Å−3

Data collection: APEX2 (Bruker, 2005 ▶); cell refinement: SAINT (Bruker, 2005 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL and PLATON (Spek, 2009).

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536809007284/at2733sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S1600536809007284/at2733Isup2.hkl

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

C18H14N4	Z = 1
Mr = 286.33	F(000) = 150
Triclinic, P1	Dx = 1.328 Mg m−3
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 4.6843 (2) Å	Cell parameters from 3276 reflections
b = 6.9872 (3) Å	θ = 3.1–36.3°
c = 11.6208 (5) Å	µ = 0.08 mm−1
α = 78.147 (3)°	T = 100 K
β = 87.462 (3)°	Plate, colourless
γ = 74.081 (2)°	0.45 × 0.29 × 0.06 mm
V = 357.94 (3) Å3

Bruker SMART APEXII CCD area-detector diffractometer	2551 independent reflections
Radiation source: fine-focus sealed tube	2034 reflections with I > 2σ(I)
graphite	Rint = 0.023
φ and ω scans	θmax = 32.5°, θmin = 3.1°
Absorption correction: multi-scan (SADABS; Bruker, 2005)	h = −6→7
Tmin = 0.964, Tmax = 0.995	k = −10→10
7927 measured reflections	l = −17→17

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)] = 0.047	Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.146	H-atom parameters constrained
S = 1.08	w = 1/[σ2(Fo2) + (0.0885P)2 + 0.0252P] where P = (Fo2 + 2Fc2)/3
2551 reflections	(Δ/σ)max < 0.001
100 parameters	Δρmax = 0.44 e Å−3
0 restraints	Δρmin = −0.25 e Å−3

Experimental. The crystal was placed in the cold stream of an Oxford Cyrosystems Cobra open-flow nitrogen cryostat (Cosier & Glazer, 1986) operating at 100.0 (1) K.

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. 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 > 2sigma(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
N1	0.59056 (17)	0.17735 (11)	0.08275 (6)	0.01615 (18)
N2	1.42099 (19)	0.74379 (12)	0.37951 (7)	0.0216 (2)
C1	0.8714 (2)	0.45474 (13)	0.15338 (7)	0.01522 (19)
H1A	0.7912	0.4927	0.0776	0.018*
C2	1.0275 (2)	0.57187 (13)	0.19178 (8)	0.01621 (19)
H2A	1.0552	0.6873	0.1416	0.019*
C3	1.14366 (19)	0.51580 (13)	0.30666 (7)	0.01489 (19)
C4	1.1063 (2)	0.34172 (13)	0.38257 (7)	0.01654 (19)
H4A	1.1845	0.3047	0.4586	0.020*
C5	0.9504 (2)	0.22467 (13)	0.34268 (8)	0.01632 (19)
H5A	0.9235	0.1088	0.3927	0.020*
C6	0.83369 (19)	0.27878 (13)	0.22843 (7)	0.01374 (18)
C7	0.67371 (19)	0.14854 (13)	0.18937 (7)	0.01451 (18)
H7A	0.6322	0.0424	0.2440	0.017*
C8	0.4324 (2)	0.03967 (13)	0.05429 (7)	0.01563 (19)
H8A	0.2243	0.1108	0.0394	0.019*
H8B	0.4460	−0.0732	0.1202	0.019*
C9	1.2999 (2)	0.64058 (13)	0.34745 (7)	0.01641 (19)

	U11	U22	U33	U12	U13	U23
N1	0.0164 (4)	0.0181 (3)	0.0170 (3)	−0.0075 (3)	−0.0010 (3)	−0.0063 (3)
N2	0.0229 (4)	0.0232 (4)	0.0216 (4)	−0.0100 (3)	−0.0030 (3)	−0.0054 (3)
C1	0.0149 (4)	0.0185 (4)	0.0139 (4)	−0.0058 (3)	−0.0021 (3)	−0.0047 (3)
C2	0.0167 (4)	0.0168 (4)	0.0169 (4)	−0.0068 (3)	−0.0011 (3)	−0.0040 (3)
C3	0.0127 (4)	0.0173 (4)	0.0168 (4)	−0.0051 (3)	−0.0004 (3)	−0.0067 (3)
C4	0.0169 (4)	0.0191 (4)	0.0151 (4)	−0.0059 (3)	−0.0028 (3)	−0.0047 (3)
C5	0.0175 (4)	0.0166 (4)	0.0159 (4)	−0.0063 (3)	−0.0015 (3)	−0.0029 (3)
C6	0.0120 (4)	0.0157 (4)	0.0149 (4)	−0.0040 (3)	−0.0001 (3)	−0.0056 (3)
C7	0.0142 (4)	0.0159 (4)	0.0153 (4)	−0.0059 (3)	0.0003 (3)	−0.0050 (3)
C8	0.0159 (4)	0.0183 (4)	0.0162 (4)	−0.0085 (3)	−0.0008 (3)	−0.0058 (3)
C9	0.0158 (4)	0.0182 (4)	0.0159 (4)	−0.0047 (3)	−0.0012 (3)	−0.0046 (3)

N1—C7	1.2745 (11)	C4—C5	1.3893 (12)
N1—C8	1.4585 (11)	C4—H4A	0.9300
N2—C9	1.1551 (11)	C5—C6	1.3962 (12)
C1—C2	1.3821 (11)	C5—H5A	0.9300
C1—C6	1.4031 (12)	C6—C7	1.4730 (11)
C1—H1A	0.9300	C7—H7A	0.9300
C2—C3	1.4017 (12)	C8—C8i	1.5246 (16)
C2—H2A	0.9300	C8—H8A	0.9700
C3—C4	1.3966 (12)	C8—H8B	0.9700
C3—C9	1.4389 (11)
C7—N1—C8	117.00 (7)	C6—C5—H5A	119.6
C2—C1—C6	120.14 (8)	C5—C6—C1	119.61 (8)
C2—C1—H1A	119.9	C5—C6—C7	118.94 (7)
C6—C1—H1A	119.9	C1—C6—C7	121.45 (8)
C1—C2—C3	119.68 (8)	N1—C7—C6	121.78 (8)
C1—C2—H2A	120.2	N1—C7—H7A	119.1
C3—C2—H2A	120.2	C6—C7—H7A	119.1
C4—C3—C2	120.80 (8)	N1—C8—C8i	109.60 (9)
C4—C3—C9	119.58 (8)	N1—C8—H8A	109.8
C2—C3—C9	119.61 (7)	C8i—C8—H8A	109.8
C5—C4—C3	118.95 (8)	N1—C8—H8B	109.8
C5—C4—H4A	120.5	C8i—C8—H8B	109.8
C3—C4—H4A	120.5	H8A—C8—H8B	108.2
C4—C5—C6	120.81 (8)	N2—C9—C3	178.76 (9)
C4—C5—H5A	119.6
C6—C1—C2—C3	−1.03 (13)	C4—C5—C6—C7	179.13 (7)
C1—C2—C3—C4	0.65 (13)	C2—C1—C6—C5	1.07 (13)
C1—C2—C3—C9	−178.50 (7)	C2—C1—C6—C7	−178.76 (7)
C2—C3—C4—C5	−0.28 (13)	C8—N1—C7—C6	−179.67 (7)
C9—C3—C4—C5	178.86 (7)	C5—C6—C7—N1	−172.24 (8)
C3—C4—C5—C6	0.32 (14)	C1—C6—C7—N1	7.59 (14)
C4—C5—C6—C1	−0.71 (14)	C7—N1—C8—C8i	−131.42 (10)

D—H···A	D—H	H···A	D···A	D—H···A
C4—H4A···N2ii	0.93	2.60	3.4702 (12)	156

Table 1

Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C4—H4A⋯N2i	0.93	2.60	3.4702 (12)	156

Symmetry code: (i) .