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Acta Crystallogr Sect E Struct Rep Online. 2009 February 1; 65(Pt 2): o435.
Published online 2009 January 31. doi:  10.1107/S1600536809003006
PMCID: PMC2968406

N,N′-Bis[(E)-quinoxalin-2-ylmethyl­idene]­ethane-1,2-diamine

Abstract

In the mol­ecule of the title compound, C20H16N6, 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 inter­molecular C—H(...)N inter­actions, 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 [triangle]). For the properties of Schiff base ligands, see: Gupta & Sutar (2008 [triangle]); Harmenberg et al. (1991 [triangle]); Mayadevi et al. (2003 [triangle]); Miller et al. (1999 [triangle]); Naylor et al. (1993 [triangle]); Sreekala & Yusuff (1994 [triangle]); Xavier et al. (2004 [triangle]); Yusuff & Sreekala (1991 [triangle]). For related structures, see: Habibi et al. (2006 [triangle]); Taylor & Kennard (1982 [triangle]).

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Object name is e-65-0o435-scheme1.jpg

Experimental

Crystal data

  • C20H16N6
  • M r = 340.39
  • Triclinic, An external file that holds a picture, illustration, etc.
Object name is e-65-0o435-efi1.jpg
  • 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 [triangle]) 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 [triangle]); cell refinement: SAINT (Bruker, 2000 [triangle]); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 [triangle]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 [triangle]); molecular graphics: SHELXTL (Sheldrick, 2008 [triangle]) and/or ORTEP-3 (Farrugia, 1997 [triangle]); software used to prepare material for publication: SHELXL97 and PLATON (Spek, 2003 [triangle]).

Table 1
Hydrogen-bond geometry (Å, °)

Supplementary Material

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

Acknowledgments

The authors thank Professor M. V. Rajasekharan, School of Chemistry, University of Hyderabad, for kind help and useful discussions. The X-ray data were collected on the diffractometer facilities at the University of Hyderabad provided by the Department of Science and Technology. DV gratefully acknowledges financial support from the Council of Scientific and Industrial Research (CSIR), India. MS thanks KSCSTE, Trivandrum, Kerala, for financial assistance.

supplementary crystallographic information

Comment

Schiff bases derived from aldehydes and diamines constitute one of the most relevant synthetic ligand systems. They find application in a broad range of transition metal catalyzed reactions including lactide polymerization, epoxidation of olefins, hydroxylation and asymmetric ring opening of epoxides (Gupta & Sutar, 2008). Many drug candidates bearing quinoxaline core structures are in clinical trials in antiviral (Harmenberg et al., 1991), anticancer and central nervous system therapeutic areas (Naylor et al., 1993). Catalytic and antibacterial activities have been observed for the Schiff base complexes derived from Quinoxaline-2-carboxaldehyde (Yusuff & Sreekala, 1991; Sreekala & Yusuff, 1994; Mayadevi et al., 2003). Ethylenediamine groups appear to be of importance for various transition metal catalysis (Miller et al., 1999; Xavier et al., 2004). We have recently prepared the title compound (1), and report here its structure.

The single-crystal X-ray structure determination of (1) was carried out at 298 (2) K. The structure analysis showed that the compound to form in triclinic space group P-1 with a =6.888 (2) A°, b=7.381 (3) A°, c=9.638 (4) A° and α = 101.674 (6)°, β = 96.233 (6)°, γ = 116.046 (5)° with z=1. A perspective drawing is depicted in figure 1 with the atomic numbering scheme. The C10—N3—C9, N3—C9—C8 angles are 117.9 (2)° and 121.5 (2)° respectively. The N3—C10 and N3—C9 bond lengths are 1.455 (3) A° and 1.260 (3) A° respectively. In this compound (1), the short (C–)H···N contacts are responsible for the stability of layer structure (figure 3) which extends along the a axis (Taylor & Kennard, 1982). The (C–)H···N distances and C—H—N angles are given in table 1.

Experimental

A hot solution of ethylenediamine (1 mmol) in methanol (25 ml) was slowly added over a hot solution of quinoxaline-2-carboxaldehyde (2 mmol) in the same solvent (50 ml). The resulting mixture on cooling yielded the crude product. The precipitated diimine was filtered off and washed with cold methanol. Light yellow single crystals of (1) were obtained from a solution of dichloromethane by slow evaporation.

Refinement

H atoms were positioned geometrically with, C—H = 0.93 A° and refined in riding mode with Uiso (H) = 1.2Ueq(C).

Figures

Fig. 1.
An ORTEP-3 (Farrugia, 1997) plot of the (I) compound, with the atomic labelling scheme. The shapes of the ellipsoids correspond to 50% probability contours of atomic displacement.
Fig. 2.
Unit cell packing diagram of N,N'-bis[(E)-quinoxalin-2-ylmethylidene]ethane-1,2-diamine.
Fig. 3.
Pairs of (C–)H···N interactions lead to a layer structure along the a axis.

Crystal data

C20H16N6Z = 1
Mr = 340.39F(000) = 178
Triclinic, P1Dx = 1.345 Mg m3
Hall symbol: -P 1Mo Kα radiation, λ = 0.71073 Å
a = 6.888 (2) ÅCell parameters from 1465 reflections
b = 7.381 (3) Åθ = 2.3–25.0°
c = 9.638 (4) ŵ = 0.09 mm1
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

Data collection

Bruker SMART CCD area-detector diffractometer1465 independent reflections
Radiation source: fine-focus sealed tube1239 reflections with I > 2σ(I)
graphiteRint = 0.025
[var phi] and ω scansθmax = 25.0°, θmin = 2.2°
Absorption correction: multi-scan (SADABS; Sheldrick, 2001)h = −8→8
Tmin = 0.967, Tmax = 0.995k = −8→8
3956 measured reflectionsl = −11→11

Refinement

Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.071Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.164H-atom parameters constrained
S = 1.27w = 1/[σ2(Fo2) + (0.0542P)2 + 0.1572P] where P = (Fo2 + 2Fc2)/3
1465 reflections(Δ/σ)max < 0.001
118 parametersΔρmax = 0.13 e Å3
0 restraintsΔρmin = −0.21 e Å3

Special details

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)

xyzUiso*/Ueq
N10.4604 (3)0.2446 (3)0.5782 (2)0.0439 (6)
N20.0673 (3)0.2571 (3)0.4735 (2)0.0405 (6)
N30.0679 (3)0.3587 (3)0.8476 (2)0.0425 (6)
C10.5203 (4)0.1943 (4)0.3355 (3)0.0482 (7)
H10.64880.18810.36820.058*
C20.4561 (5)0.1772 (4)0.1921 (3)0.0518 (8)
H20.54250.16080.12800.062*
C30.2624 (5)0.1841 (4)0.1406 (3)0.0522 (8)
H30.22160.17350.04290.063*
C40.1338 (4)0.2062 (4)0.2329 (3)0.0473 (7)
H40.00320.20700.19750.057*
C50.1963 (4)0.2279 (4)0.3820 (3)0.0374 (6)
C60.3918 (4)0.2210 (4)0.4334 (3)0.0381 (6)
C70.3349 (4)0.2733 (4)0.6617 (3)0.0429 (7)
H70.37640.28970.76040.051*
C80.1382 (4)0.2813 (4)0.6116 (3)0.0371 (6)
C90.0064 (4)0.3217 (4)0.7124 (3)0.0419 (6)
H9−0.12510.31980.67540.050*
C10−0.0707 (4)0.3998 (4)0.9395 (3)0.0438 (7)
H10A−0.14150.28350.98040.053*
H10B−0.18570.41330.88200.053*

Atomic displacement parameters (Å2)

U11U22U33U12U13U23
N10.0419 (12)0.0551 (14)0.0405 (12)0.0272 (11)0.0095 (10)0.0150 (10)
N20.0409 (12)0.0465 (13)0.0350 (12)0.0231 (11)0.0064 (9)0.0084 (10)
N30.0463 (13)0.0504 (13)0.0342 (12)0.0257 (11)0.0108 (9)0.0113 (10)
C10.0440 (15)0.0514 (17)0.0495 (16)0.0233 (14)0.0136 (13)0.0113 (13)
C20.0565 (18)0.0512 (17)0.0433 (16)0.0210 (14)0.0221 (13)0.0093 (13)
C30.0596 (18)0.0568 (18)0.0332 (14)0.0228 (15)0.0095 (13)0.0101 (13)
C40.0497 (16)0.0554 (18)0.0345 (14)0.0243 (14)0.0039 (12)0.0122 (12)
C50.0375 (14)0.0327 (13)0.0385 (14)0.0138 (11)0.0077 (11)0.0098 (11)
C60.0380 (13)0.0377 (14)0.0372 (13)0.0173 (12)0.0074 (11)0.0096 (11)
C70.0448 (15)0.0524 (16)0.0313 (13)0.0233 (13)0.0052 (11)0.0127 (12)
C80.0368 (13)0.0367 (14)0.0357 (14)0.0173 (11)0.0061 (11)0.0071 (11)
C90.0414 (15)0.0457 (16)0.0406 (15)0.0229 (13)0.0076 (12)0.0113 (12)
C100.0443 (15)0.0528 (17)0.0368 (14)0.0235 (13)0.0139 (11)0.0139 (12)

Geometric parameters (Å, °)

N1—C71.298 (3)C3—H30.9300
N1—C61.373 (3)C4—C51.410 (3)
N2—C81.315 (3)C4—H40.9300
N2—C51.369 (3)C5—C61.409 (3)
N3—C91.260 (3)C7—C81.418 (3)
N3—C101.455 (3)C7—H70.9300
C1—C21.367 (4)C8—C91.472 (3)
C1—C61.404 (3)C9—H90.9300
C1—H10.9300C10—C10i1.512 (5)
C2—C31.398 (4)C10—H10A0.9700
C2—H20.9300C10—H10B0.9700
C3—C41.357 (4)
C7—N1—C6115.8 (2)N1—C6—C1119.7 (2)
C8—N2—C5116.2 (2)N1—C6—C5120.9 (2)
C9—N3—C10117.9 (2)C1—C6—C5119.4 (2)
C2—C1—C6119.9 (3)N1—C7—C8124.0 (2)
C2—C1—H1120.1N1—C7—H7118.0
C6—C1—H1120.1C8—C7—H7118.0
C1—C2—C3121.0 (3)N2—C8—C7121.6 (2)
C1—C2—H2119.5N2—C8—C9116.9 (2)
C3—C2—H2119.5C7—C8—C9121.5 (2)
C4—C3—C2120.1 (3)N3—C9—C8121.5 (2)
C4—C3—H3120.0N3—C9—H9119.3
C2—C3—H3120.0C8—C9—H9119.3
C3—C4—C5120.7 (3)N3—C10—C10109.5 (3)
C3—C4—H4119.7N3—C10—H10A109.8
C5—C4—H4119.7C10—C10—H10A109.8
N2—C5—C6121.6 (2)N3—C10—H10B109.8
N2—C5—C4119.4 (2)C10—C10—H10B109.8
C6—C5—C4119.0 (2)H10A—C10—H10B108.2

Symmetry codes: (i) −x, −y+1, −z+2.

Hydrogen-bond geometry (Å, °)

D—H···AD—HH···AD···AD—H···A
C1—H1···N2ii0.932.733.647 (4)168
C9—H9···N1iii0.932.673.593 (3)169

Symmetry codes: (ii) x+1, y, z; (iii) x−1, y, z.

Footnotes

Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: FJ2185).

References

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