6,7-Di-chloro-2,3-bis(pyridin-2-yl)quinox-aline.

The title compound, C18H10Cl2N4, synthesized by the condensation reaction between 4,5-di-chloro-benzene-1,2-di-amine and 1,2-di(pyridin-2-yl)ethane-1,2-dione in boiling acetic acid, has a nearly planar quinoxaline moiety [maximum deviation = 0.070 (1) Å] whose mean plane makes dihedral angles of 40.51 (2) and 39.29 (3)° with the pyridine rings. Within the unit cell, there are no classical hydrogen bonds. Molecules in the structure pack with π-π stacking contacts between the quinoxaline units and nearby pyridine rings with an intercentroid distance of 3.7676 (9) Å.

Related literature

For the synthesis of the title compound, see: Imeri et al. (2013 ▸). For the structures of similar compounds, see: Woźniak (1991 ▸); Rasmussen et al. (1990 ▸); Crundwell et al. (2010 ▸, 2014 ▸); Jaso et al. (2005 ▸); Bu et al. (2001 ▸); Cantalupo et al. (2010 ▸); Crundwell (2013 ▸).

Experimental

Crystal data

C18H10Cl2N4

M = 353.20

Orthorhombic,

a = 7.1921 (5) Å

b = 18.072 (3) Å

c = 24.093 (4) Å

V = 3131.6 (8) Å3

Z = 8

Mo Kα radiation

μ = 0.42 mm−1

T = 110 K

0.23 × 0.12 × 0.09 mm

Data collection

Oxford Diffraction Xcalibur, Sapphire3 diffractometer

Absorption correction: multi-scan (CrysAlis RED; Oxford Diffraction, 2009 ▸) T min = 0.971, T max = 1.000

24047 measured reflections

6227 independent reflections

3818 reflections with I > 2σ(I)

R int = 0.031

Refinement

R[F 2 > 2σ(F 2)] = 0.034

wR(F 2) = 0.086

S = 0.90

6227 reflections

217 parameters

H-atom parameters constrained

Δρmax = 0.45 e Å−3

Δρmin = −0.24 e Å−3

Data collection: CrysAlis CCD (Oxford Diffraction, 2009 ▸); cell refinement: CrysAlis RED (Oxford Diffraction, 2009 ▸); data reduction: CrysAlis RED; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▸); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▸); molecular graphics: PLATON (Spek, 2009 ▸); software used to prepare material for publication: SHELXTL (Sheldrick, 2008 ▸).

Crystal structure: contains datablock(s) I, New_Global_Publ_Block. DOI: 10.1107/S2056989015000055/hg5423sup1.cif

Structure factors: contains datablock(s) I. DOI: 10.1107/S2056989015000055/hg5423Isup2.hkl

Click here for additional data file.

Supporting information file. DOI: 10.1107/S2056989015000055/hg5423Isup3.cml

Click here for additional data file.

. DOI: 10.1107/S2056989015000055/hg5423fig1.tif

A view of the title compound (Spek, 2009). Displacement ellipsoids are drawn at the 50% probability level.

CCDC reference: 1041827

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

C18H10Cl2N4	Dx = 1.498 Mg m−3
Mr = 353.20	Melting point: 468 K
Orthorhombic, Pbca	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ac 2ab	Cell parameters from 9283 reflections
a = 7.1921 (5) Å	θ = 3.8–34.6°
b = 18.072 (3) Å	µ = 0.42 mm−1
c = 24.093 (4) Å	T = 110 K
V = 3131.6 (8) Å3	Needle, brown
Z = 8	0.23 × 0.12 × 0.09 mm
F(000) = 1440

Oxford Diffraction Xcalibur, Sapphire3 diffractometer	6227 independent reflections
Radiation source: fine-focus sealed tube	3818 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.031
Detector resolution: 16.1790 pixels mm-1	θmax = 34.7°, θmin = 4.0°
ω scans	h = −10→11
Absorption correction: multi-scan (CrysAlis RED; Oxford Diffraction, 2009)	k = −27→27
Tmin = 0.971, Tmax = 1.000	l = −36→12
24047 measured reflections

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)] = 0.034	Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.086	H-atom parameters constrained
S = 0.90	w = 1/[σ2(Fo2) + (0.0479P)2] where P = (Fo2 + 2Fc2)/3
6227 reflections	(Δ/σ)max = 0.002
217 parameters	Δρmax = 0.45 e Å−3
0 restraints	Δρmin = −0.24 e Å−3

Experimental. Carbon-bound H-atoms were placed in calculated positions (C—H = 0.93 Å) and were included in the refinement in the riding model approximation, with Uiso(H) = 1.2Ueq(C).

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 > 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
Cl2	0.32732 (4)	0.426900 (14)	1.127570 (12)	0.02132 (7)
Cl1	0.47814 (4)	0.573896 (15)	1.184200 (12)	0.02235 (7)
N1	0.40209 (13)	0.70156 (5)	0.99845 (4)	0.01556 (18)
C6	0.41314 (16)	0.57361 (6)	1.11493 (5)	0.0160 (2)
N2	0.22634 (13)	0.57626 (5)	0.95171 (4)	0.01546 (18)
C14	0.15721 (15)	0.64197 (6)	0.86826 (5)	0.0142 (2)
N4	0.06670 (13)	0.70481 (5)	0.85634 (4)	0.0180 (2)
N3	0.45961 (14)	0.75394 (5)	0.86134 (4)	0.0178 (2)
C3	0.29491 (15)	0.57490 (5)	1.00477 (5)	0.0144 (2)
C5	0.34195 (15)	0.50820 (6)	1.09007 (5)	0.0160 (2)
C15	0.16747 (16)	0.58249 (6)	0.83174 (5)	0.0174 (2)
H15	0.2258	0.5387	0.8422	0.021*
C1	0.34541 (15)	0.70080 (5)	0.94668 (5)	0.0143 (2)
C2	0.24614 (15)	0.63859 (5)	0.92372 (5)	0.0144 (2)
C7	0.42943 (15)	0.63766 (6)	1.08503 (5)	0.0162 (2)
H7	0.4772	0.6801	1.1015	0.019*
C9	0.39540 (15)	0.76674 (5)	0.91270 (5)	0.0146 (2)
C4	0.28220 (15)	0.50930 (6)	1.03626 (5)	0.0166 (2)
H4	0.2330	0.4667	1.0204	0.020*
C18	−0.01188 (17)	0.70972 (6)	0.80610 (5)	0.0210 (2)
H18	−0.0776	0.7526	0.7976	0.025*
C8	0.37327 (15)	0.63874 (6)	1.02907 (5)	0.0149 (2)
C11	0.41978 (16)	0.89793 (6)	0.90239 (5)	0.0188 (2)
H11	0.4055	0.9458	0.9159	0.023*
C10	0.37737 (16)	0.83738 (5)	0.93523 (5)	0.0169 (2)
H10	0.3376	0.8437	0.9716	0.020*
C16	0.08919 (17)	0.58966 (6)	0.77953 (5)	0.0211 (2)
H16	0.0971	0.5513	0.7539	0.025*
C13	0.50436 (16)	0.81321 (6)	0.83081 (5)	0.0198 (2)
H13	0.5518	0.8054	0.7954	0.024*
C12	0.48406 (16)	0.88553 (6)	0.84893 (5)	0.0196 (2)
H12	0.5130	0.9250	0.8257	0.024*
C17	−0.00125 (16)	0.65502 (6)	0.76609 (5)	0.0222 (2)
H17	−0.0533	0.6619	0.7311	0.027*

	U11	U22	U33	U12	U13	U23
Cl2	0.02666 (15)	0.01669 (12)	0.02059 (14)	−0.00209 (10)	−0.00040 (11)	0.00626 (11)
Cl1	0.03104 (16)	0.02148 (13)	0.01452 (13)	−0.00167 (11)	−0.00438 (11)	0.00270 (11)
N1	0.0188 (5)	0.0130 (4)	0.0149 (5)	−0.0012 (3)	0.0003 (4)	−0.0006 (3)
C6	0.0167 (5)	0.0180 (5)	0.0132 (5)	0.0002 (4)	−0.0012 (4)	0.0006 (4)
N2	0.0191 (4)	0.0133 (4)	0.0140 (4)	−0.0002 (3)	−0.0001 (4)	−0.0006 (3)
C14	0.0160 (5)	0.0131 (4)	0.0136 (5)	−0.0023 (4)	0.0001 (4)	−0.0005 (4)
N4	0.0206 (5)	0.0163 (4)	0.0170 (5)	0.0008 (4)	−0.0022 (4)	−0.0002 (4)
N3	0.0221 (5)	0.0158 (4)	0.0157 (5)	−0.0014 (4)	0.0004 (4)	−0.0007 (4)
C3	0.0161 (5)	0.0133 (4)	0.0138 (5)	−0.0004 (4)	0.0004 (4)	−0.0007 (4)
C5	0.0168 (5)	0.0138 (5)	0.0174 (5)	0.0016 (4)	0.0020 (4)	0.0027 (4)
C15	0.0207 (5)	0.0145 (5)	0.0169 (5)	−0.0035 (4)	0.0017 (4)	−0.0011 (4)
C1	0.0167 (5)	0.0115 (4)	0.0148 (5)	0.0007 (4)	0.0008 (4)	−0.0011 (4)
C2	0.0169 (5)	0.0132 (4)	0.0133 (5)	−0.0001 (4)	0.0018 (4)	−0.0016 (4)
C7	0.0178 (5)	0.0155 (5)	0.0154 (5)	−0.0018 (4)	−0.0002 (4)	−0.0017 (4)
C9	0.0161 (5)	0.0129 (4)	0.0148 (5)	−0.0005 (4)	−0.0019 (4)	0.0004 (4)
C4	0.0195 (5)	0.0131 (5)	0.0172 (6)	−0.0013 (4)	0.0001 (4)	−0.0014 (4)
C18	0.0218 (6)	0.0210 (5)	0.0203 (6)	0.0008 (5)	−0.0029 (5)	0.0020 (5)
C8	0.0169 (5)	0.0134 (4)	0.0143 (5)	−0.0001 (4)	0.0005 (4)	−0.0003 (4)
C11	0.0194 (6)	0.0126 (5)	0.0245 (6)	−0.0005 (4)	−0.0029 (5)	0.0000 (4)
C10	0.0190 (5)	0.0149 (5)	0.0167 (6)	−0.0006 (4)	−0.0009 (4)	−0.0022 (4)
C16	0.0263 (6)	0.0211 (5)	0.0158 (6)	−0.0070 (5)	0.0019 (5)	−0.0050 (4)
C13	0.0232 (6)	0.0202 (5)	0.0160 (6)	−0.0021 (4)	0.0005 (5)	0.0021 (4)
C12	0.0215 (6)	0.0165 (5)	0.0208 (6)	−0.0029 (4)	−0.0020 (5)	0.0050 (4)
C17	0.0235 (6)	0.0275 (6)	0.0155 (6)	−0.0074 (5)	−0.0045 (5)	0.0012 (5)

Cl2—C5	1.7281 (11)	C1—C2	1.4420 (15)
Cl1—C6	1.7332 (12)	C1—C9	1.4897 (15)
N1—C1	1.3124 (14)	C7—C8	1.4075 (15)
N1—C8	1.3697 (14)	C7—H7	0.9300
C6—C7	1.3685 (15)	C9—C10	1.3934 (14)
C6—C5	1.4207 (15)	C4—H4	0.9300
N2—C2	1.3206 (13)	C18—C17	1.3828 (17)
N2—C3	1.3703 (15)	C18—H18	0.9300
C14—N4	1.3402 (13)	C11—C10	1.3843 (15)
C14—C15	1.3912 (15)	C11—C12	1.3869 (17)
C14—C2	1.4826 (16)	C11—H11	0.9300
N4—C18	1.3390 (15)	C10—H10	0.9300
N3—C13	1.3386 (14)	C16—C17	1.3869 (17)
N3—C9	1.3411 (15)	C16—H16	0.9300
C3—C8	1.4112 (14)	C13—C12	1.3856 (16)
C3—C4	1.4107 (15)	C13—H13	0.9300
C5—C4	1.3658 (16)	C12—H12	0.9300
C15—C16	1.3841 (17)	C17—H17	0.9300
C15—H15	0.9300
C1—N1—C8	117.15 (9)	N3—C9—C1	116.88 (9)
C7—C6—C5	120.84 (11)	C10—C9—C1	119.77 (10)
C7—C6—Cl1	118.78 (8)	C5—C4—C3	120.16 (10)
C5—C6—Cl1	120.38 (8)	C5—C4—H4	119.9
C2—N2—C3	116.93 (9)	C3—C4—H4	119.9
N4—C14—C15	123.03 (10)	N4—C18—C17	124.02 (11)
N4—C14—C2	115.94 (9)	N4—C18—H18	118.0
C15—C14—C2	121.03 (10)	C17—C18—H18	118.0
C18—N4—C14	117.06 (10)	N1—C8—C3	120.97 (10)
C13—N3—C9	116.86 (9)	N1—C8—C7	118.94 (10)
N2—C3—C8	121.07 (9)	C3—C8—C7	120.05 (10)
N2—C3—C4	119.58 (9)	C10—C11—C12	118.46 (10)
C8—C3—C4	119.33 (10)	C10—C11—H11	120.8
C4—C5—C6	120.10 (10)	C12—C11—H11	120.8
C4—C5—Cl2	119.30 (8)	C11—C10—C9	118.77 (11)
C6—C5—Cl2	120.59 (9)	C11—C10—H10	120.6
C16—C15—C14	118.74 (10)	C9—C10—H10	120.6
C16—C15—H15	120.6	C15—C16—C17	118.86 (11)
C14—C15—H15	120.6	C15—C16—H16	120.6
N1—C1—C2	121.77 (9)	C17—C16—H16	120.6
N1—C1—C9	116.03 (9)	N3—C13—C12	123.81 (11)
C2—C1—C9	122.16 (10)	N3—C13—H13	118.1
N2—C2—C1	121.50 (10)	C12—C13—H13	118.1
N2—C2—C14	116.67 (9)	C13—C12—C11	118.69 (10)
C1—C2—C14	121.82 (9)	C13—C12—H12	120.7
C6—C7—C8	119.43 (10)	C11—C12—H12	120.7
C6—C7—H7	120.3	C18—C17—C16	118.17 (11)
C8—C7—H7	120.3	C18—C17—H17	120.9
N3—C9—C10	123.33 (10)	C16—C17—H17	120.9
C15—C14—N4—C18	−1.81 (16)	N1—C1—C9—N3	135.70 (11)
C2—C14—N4—C18	178.80 (10)	C2—C1—C9—N3	−42.28 (15)
C2—N2—C3—C8	3.50 (15)	N1—C1—C9—C10	−43.17 (15)
C2—N2—C3—C4	−178.38 (10)	C2—C1—C9—C10	138.85 (11)
C7—C6—C5—C4	−2.44 (17)	C6—C5—C4—C3	1.47 (17)
Cl1—C6—C5—C4	176.69 (9)	Cl2—C5—C4—C3	−179.29 (8)
C7—C6—C5—Cl2	178.33 (9)	N2—C3—C4—C5	−176.88 (10)
Cl1—C6—C5—Cl2	−2.54 (13)	C8—C3—C4—C5	1.27 (16)
N4—C14—C15—C16	3.48 (17)	C14—N4—C18—C17	−1.49 (17)
C2—C14—C15—C16	−177.17 (10)	C1—N1—C8—C3	3.28 (15)
C8—N1—C1—C2	3.95 (15)	C1—N1—C8—C7	−179.04 (10)
C8—N1—C1—C9	−174.03 (9)	N2—C3—C8—N1	−7.34 (16)
C3—N2—C2—C1	3.71 (15)	C4—C3—C8—N1	174.53 (10)
C3—N2—C2—C14	−174.77 (9)	N2—C3—C8—C7	175.00 (10)
N1—C1—C2—N2	−7.87 (16)	C4—C3—C8—C7	−3.13 (16)
C9—C1—C2—N2	169.99 (10)	C6—C7—C8—N1	−175.51 (10)
N1—C1—C2—C14	170.53 (10)	C6—C7—C8—C3	2.19 (17)
C9—C1—C2—C14	−11.61 (15)	C12—C11—C10—C9	−1.98 (17)
N4—C14—C2—N2	136.57 (10)	N3—C9—C10—C11	2.96 (17)
C15—C14—C2—N2	−42.83 (15)	C1—C9—C10—C11	−178.25 (10)
N4—C14—C2—C1	−41.91 (14)	C14—C15—C16—C17	−1.84 (17)
C15—C14—C2—C1	138.69 (11)	C9—N3—C13—C12	−1.45 (17)
C5—C6—C7—C8	0.57 (17)	N3—C13—C12—C11	2.30 (18)
Cl1—C6—C7—C8	−178.57 (9)	C10—C11—C12—C13	−0.46 (17)
C13—N3—C9—C10	−1.23 (17)	N4—C18—C17—C16	2.97 (18)
C13—N3—C9—C1	179.95 (10)	C15—C16—C17—C18	−1.16 (17)