N,N'-Bis[(E)-quinoxalin-2-ylmethyl-idene]-ethane-1,2-diamine.

In the mol-ecule of the title compound, C(20)H(16)N(6), the central C-C bond lies on a crystallographic inversion centre. The quinoxalidine ring is nearly planar, with a maximum deviation of 0.021 (2) Å from the mean plane. The crystal structure is stabilized by inter-molecular C-H⋯N inter-actions, leading to the formation of a layer-like structure, which extends along the a axis.

Related literature

For the synthesis of the Schiff base, see: Zolezzi et al. (1999 ▶). For the properties of Schiff base ligands, see: Gupta & Sutar (2008 ▶); Harmenberg et al. (1991 ▶); Mayadevi et al. (2003 ▶); Miller et al. (1999 ▶); Naylor et al. (1993 ▶); Sreekala & Yusuff (1994 ▶); Xavier et al. (2004 ▶); Yusuff & Sreekala (1991 ▶). For related structures, see: Habibi et al. (2006 ▶); Taylor & Kennard (1982 ▶).

Experimental

Crystal data

C20H16N6

M = 340.39

Triclinic,

a = 6.888 (2) Å

b = 7.381 (3) Å

c = 9.638 (4) Å

α = 101.674 (6)°

β = 96.233 (6)°

γ = 116.046 (5)°

V = 420.1 (3) Å3

Z = 1

Mo Kα radiation

μ = 0.09 mm−1

T = 298 (2) K

0.40 × 0.24 × 0.18 mm

Data collection

Bruker SMART CCD area-detector diffractometer

Absorption correction: multi-scan (SADABS; Sheldrick, 2001 ▶) T min = 0.967, T max = 0.995

3956 measured reflections

1465 independent reflections

1239 reflections with I > 2σ(I)

R int = 0.025

Refinement

R[F 2 > 2σ(F 2)] = 0.071

wR(F 2) = 0.164

S = 1.27

1465 reflections

118 parameters

H-atom parameters constrained

Δρmax = 0.13 e Å−3

Δρmin = −0.21 e Å−3

Data collection: SMART (Bruker, 2000 ▶); cell refinement: SAINT (Bruker, 2000 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: SHELXTL (Sheldrick, 2008 ▶) and/or ORTEP-3 (Farrugia, 1997 ▶); software used to prepare material for publication: SHELXL97 and PLATON (Spek, 2003 ▶).

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536809003006/fj2185sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S1600536809003006/fj2185Isup2.hkl

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

C20H16N6	Z = 1
Mr = 340.39	F(000) = 178
Triclinic, P1	Dx = 1.345 Mg m−3
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 6.888 (2) Å	Cell parameters from 1465 reflections
b = 7.381 (3) Å	θ = 2.3–25.0°
c = 9.638 (4) Å	µ = 0.09 mm−1
α = 101.674 (6)°	T = 298 K
β = 96.233 (6)°	Plate, yellow
γ = 116.046 (5)°	0.40 × 0.24 × 0.18 mm
V = 420.1 (3) Å3

Bruker SMART CCD area-detector diffractometer	1465 independent reflections
Radiation source: fine-focus sealed tube	1239 reflections with I > 2σ(I)
graphite	Rint = 0.025
φ and ω scans	θmax = 25.0°, θmin = 2.2°
Absorption correction: multi-scan (SADABS; Sheldrick, 2001)	h = −8→8
Tmin = 0.967, Tmax = 0.995	k = −8→8
3956 measured reflections	l = −11→11

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)] = 0.071	Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.164	H-atom parameters constrained
S = 1.27	w = 1/[σ2(Fo2) + (0.0542P)2 + 0.1572P] where P = (Fo2 + 2Fc2)/3
1465 reflections	(Δ/σ)max < 0.001
118 parameters	Δρmax = 0.13 e Å−3
0 restraints	Δρmin = −0.21 e Å−3

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
N1	0.4604 (3)	0.2446 (3)	0.5782 (2)	0.0439 (6)
N2	0.0673 (3)	0.2571 (3)	0.4735 (2)	0.0405 (6)
N3	0.0679 (3)	0.3587 (3)	0.8476 (2)	0.0425 (6)
C1	0.5203 (4)	0.1943 (4)	0.3355 (3)	0.0482 (7)
H1	0.6488	0.1881	0.3682	0.058*
C2	0.4561 (5)	0.1772 (4)	0.1921 (3)	0.0518 (8)
H2	0.5425	0.1608	0.1280	0.062*
C3	0.2624 (5)	0.1841 (4)	0.1406 (3)	0.0522 (8)
H3	0.2216	0.1735	0.0429	0.063*
C4	0.1338 (4)	0.2062 (4)	0.2329 (3)	0.0473 (7)
H4	0.0032	0.2070	0.1975	0.057*
C5	0.1963 (4)	0.2279 (4)	0.3820 (3)	0.0374 (6)
C6	0.3918 (4)	0.2210 (4)	0.4334 (3)	0.0381 (6)
C7	0.3349 (4)	0.2733 (4)	0.6617 (3)	0.0429 (7)
H7	0.3764	0.2897	0.7604	0.051*
C8	0.1382 (4)	0.2813 (4)	0.6116 (3)	0.0371 (6)
C9	0.0064 (4)	0.3217 (4)	0.7124 (3)	0.0419 (6)
H9	−0.1251	0.3198	0.6754	0.050*
C10	−0.0707 (4)	0.3998 (4)	0.9395 (3)	0.0438 (7)
H10A	−0.1415	0.2835	0.9804	0.053*
H10B	−0.1857	0.4133	0.8820	0.053*

	U11	U22	U33	U12	U13	U23
N1	0.0419 (12)	0.0551 (14)	0.0405 (12)	0.0272 (11)	0.0095 (10)	0.0150 (10)
N2	0.0409 (12)	0.0465 (13)	0.0350 (12)	0.0231 (11)	0.0064 (9)	0.0084 (10)
N3	0.0463 (13)	0.0504 (13)	0.0342 (12)	0.0257 (11)	0.0108 (9)	0.0113 (10)
C1	0.0440 (15)	0.0514 (17)	0.0495 (16)	0.0233 (14)	0.0136 (13)	0.0113 (13)
C2	0.0565 (18)	0.0512 (17)	0.0433 (16)	0.0210 (14)	0.0221 (13)	0.0093 (13)
C3	0.0596 (18)	0.0568 (18)	0.0332 (14)	0.0228 (15)	0.0095 (13)	0.0101 (13)
C4	0.0497 (16)	0.0554 (18)	0.0345 (14)	0.0243 (14)	0.0039 (12)	0.0122 (12)
C5	0.0375 (14)	0.0327 (13)	0.0385 (14)	0.0138 (11)	0.0077 (11)	0.0098 (11)
C6	0.0380 (13)	0.0377 (14)	0.0372 (13)	0.0173 (12)	0.0074 (11)	0.0096 (11)
C7	0.0448 (15)	0.0524 (16)	0.0313 (13)	0.0233 (13)	0.0052 (11)	0.0127 (12)
C8	0.0368 (13)	0.0367 (14)	0.0357 (14)	0.0173 (11)	0.0061 (11)	0.0071 (11)
C9	0.0414 (15)	0.0457 (16)	0.0406 (15)	0.0229 (13)	0.0076 (12)	0.0113 (12)
C10	0.0443 (15)	0.0528 (17)	0.0368 (14)	0.0235 (13)	0.0139 (11)	0.0139 (12)

N1—C7	1.298 (3)	C3—H3	0.9300
N1—C6	1.373 (3)	C4—C5	1.410 (3)
N2—C8	1.315 (3)	C4—H4	0.9300
N2—C5	1.369 (3)	C5—C6	1.409 (3)
N3—C9	1.260 (3)	C7—C8	1.418 (3)
N3—C10	1.455 (3)	C7—H7	0.9300
C1—C2	1.367 (4)	C8—C9	1.472 (3)
C1—C6	1.404 (3)	C9—H9	0.9300
C1—H1	0.9300	C10—C10i	1.512 (5)
C2—C3	1.398 (4)	C10—H10A	0.9700
C2—H2	0.9300	C10—H10B	0.9700
C3—C4	1.357 (4)
C7—N1—C6	115.8 (2)	N1—C6—C1	119.7 (2)
C8—N2—C5	116.2 (2)	N1—C6—C5	120.9 (2)
C9—N3—C10	117.9 (2)	C1—C6—C5	119.4 (2)
C2—C1—C6	119.9 (3)	N1—C7—C8	124.0 (2)
C2—C1—H1	120.1	N1—C7—H7	118.0
C6—C1—H1	120.1	C8—C7—H7	118.0
C1—C2—C3	121.0 (3)	N2—C8—C7	121.6 (2)
C1—C2—H2	119.5	N2—C8—C9	116.9 (2)
C3—C2—H2	119.5	C7—C8—C9	121.5 (2)
C4—C3—C2	120.1 (3)	N3—C9—C8	121.5 (2)
C4—C3—H3	120.0	N3—C9—H9	119.3
C2—C3—H3	120.0	C8—C9—H9	119.3
C3—C4—C5	120.7 (3)	N3—C10—C10	109.5 (3)
C3—C4—H4	119.7	N3—C10—H10A	109.8
C5—C4—H4	119.7	C10—C10—H10A	109.8
N2—C5—C6	121.6 (2)	N3—C10—H10B	109.8
N2—C5—C4	119.4 (2)	C10—C10—H10B	109.8
C6—C5—C4	119.0 (2)	H10A—C10—H10B	108.2

D—H···A	D—H	H···A	D···A	D—H···A
C1—H1···N2ii	0.93	2.73	3.647 (4)	168
C9—H9···N1iii	0.93	2.67	3.593 (3)	169

Table 1

Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C1—H1⋯N2i	0.93	2.73	3.647 (4)	168
C9—H9⋯N1ii	0.93	2.67	3.593 (3)	169

Symmetry codes: (i) ; (ii) .