(2Z,3Z)-Quinoxaline-2,3(1H,4H)-dione dioxime.

The asymmetric unit of the title compound, C(8)H(8)N(4)O(2), contains one half-mol-ecule; a twofold rotation axis bisects the molecule. An intra-molecular N-H⋯O hydrogen bond results in the formation of a five-membered ring, which displays an envelope conformation. In the crystal structure, inter-molecular O-H⋯N hydrogen bonds link the mol-ecules.

Related literature

For related literature, see: Kakanejadifard, Niknam & Zabardasti (2007 ▶); Kakanejadifard, Saniei et al. (2007 ▶); Kakanejadifard & Niknam (2006 ▶); For general background, see: Jones et al. (1961 ▶); Schrauzer & Kohnle (1964 ▶); Yari et al. (2006 ▶); Hashemi et al. (2006 ▶); Ghiasvand et al. (2004 ▶, 2005 ▶); Kakanejadifard, Niknam, Ranjbar et al. (2007 ▶); Gok & Kantekin (1997 ▶).

Experimental

Crystal data

C8H8N4O2

M = 192.18

Orthorhombic,

a = 9.831 (2) Å

b = 13.609 (3) Å

c = 24.344 (5) Å

V = 3256.9 (11) Å3

Z = 16

Mo Kα radiation

μ = 0.12 mm−1

T = 120 (2) K

0.4 × 0.2 × 0.2 mm

Data collection

Bruker SMART 1000 CCD area-detector diffractometer

Absorption correction: none

7925 measured reflections

983 independent reflections

708 reflections with I > 2σ(I)

R int = 0.065

Refinement

R[F 2 > 2σ(F 2)] = 0.060

wR(F 2) = 0.118

S = 1.01

983 reflections

67 parameters

1 restraint

H atoms treated by a mixture of independent and constrained refinement

Δρmax = 0.43 e Å−3

Δρmin = −0.25 e Å−3

Data collection: SMART (Bruker, 1998 ▶); cell refinement: SMART; data reduction: SAINT-Plus (Bruker, 1998 ▶); 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.

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536808021570/hk2493sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S1600536808021570/hk2493Isup2.hkl

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

C8H8N4O2	F000 = 1600
Mr = 192.18	Dx = 1.568 Mg m−3
Orthorhombic, Fddd	Mo Kα radiation λ = 0.71073 Å
Hall symbol: -F 2uv 2vw	Cell parameters from 744 reflections
a = 9.831 (2) Å	θ = 3–30º
b = 13.609 (3) Å	µ = 0.12 mm−1
c = 24.344 (5) Å	T = 120 (2) K
V = 3256.9 (11) Å3	Prism, light-brown
Z = 16	0.4 × 0.2 × 0.2 mm

Bruker SMART 1000 CCD area-detector diffractometer	708 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.065
Monochromator: graphite	θmax = 28.0º
T = 120(2) K	θmin = 2.7º
φ and ω scans	h = −12→12
Absorption correction: none	k = −17→17
7925 measured reflections	l = −32→31
983 independent reflections

Refinement on F2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.060	H atoms treated by a mixture of independent and constrained refinement
wR(F2) = 0.118	w = 1/[σ2(Fo2) + (0.005P)2 + 25P] where P = (Fo2 + 2Fc2)/3
S = 1.01	(Δ/σ)max < 0.001
983 reflections	Δρmax = 0.43 e Å−3
67 parameters	Δρmin = −0.25 e Å−3
1 restraint	Extinction correction: none
Primary atom site location: structure-invariant direct methods

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 > 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
O1	0.47468 (17)	−0.04564 (12)	0.43944 (6)	0.0324 (4)
H1	0.454 (3)	−0.0611 (18)	0.4723 (4)	0.039*
N1	0.54273 (19)	0.04548 (13)	0.44726 (7)	0.0261 (4)
N2	0.5691 (2)	0.03307 (14)	0.35156 (7)	0.0308 (5)
H2A	0.5385	−0.0261	0.3513	0.037*
C1	0.5867 (2)	0.07818 (15)	0.40084 (8)	0.0242 (4)
C2	0.5981 (2)	0.07776 (16)	0.30119 (8)	0.0268 (5)
C3	0.5745 (2)	0.03025 (19)	0.25164 (9)	0.0358 (6)
H3A	0.5413	−0.0337	0.2514	0.043*
C4	0.6000 (3)	0.0776 (2)	0.20291 (9)	0.0412 (6)
H4A	0.5835	0.0457	0.1698	0.049*

	U11	U22	U33	U12	U13	U23
O1	0.0423 (10)	0.0304 (8)	0.0244 (7)	−0.0098 (7)	0.0009 (7)	0.0025 (7)
N1	0.0314 (9)	0.0243 (9)	0.0226 (8)	−0.0053 (8)	0.0002 (7)	0.0004 (7)
N2	0.0447 (11)	0.0279 (9)	0.0198 (8)	−0.0126 (8)	0.0022 (8)	−0.0015 (7)
C1	0.0282 (11)	0.0261 (10)	0.0184 (9)	−0.0014 (9)	−0.0009 (8)	−0.0002 (8)
C2	0.0282 (11)	0.0334 (11)	0.0187 (9)	−0.0055 (9)	0.0016 (8)	−0.0002 (8)
C3	0.0422 (13)	0.0422 (13)	0.0230 (10)	−0.0154 (11)	0.0041 (10)	−0.0059 (10)
C4	0.0440 (14)	0.0596 (17)	0.0199 (10)	−0.0188 (13)	0.0004 (10)	−0.0054 (10)

O1—H1	0.852 (13)	C2—C2i	1.390 (4)
N1—C1	1.289 (3)	C2—C3	1.388 (3)
N1—O1	1.422 (2)	C3—C4	1.373 (3)
N2—C1	1.359 (2)	C3—H3A	0.9300
N2—C2	1.398 (3)	C4—C4i	1.380 (5)
N2—H2A	0.8600	C4—H4A	0.9300
C1—C1i	1.481 (4)
N1—O1—H1	101.8 (17)	C3—C2—N2	121.7 (2)
C1—N1—O1	109.96 (16)	C2i—C2—N2	118.68 (11)
C1—N2—C2	123.50 (18)	C4—C3—C2	120.1 (2)
C1—N2—H2A	118.3	C4—C3—H3A	120.0
C2—N2—H2A	118.3	C2—C3—H3A	120.0
N1—C1—N2	125.13 (19)	C3—C4—C4i	120.25 (14)
N1—C1—C1i	117.89 (12)	C3—C4—H4A	119.9
N2—C1—C1i	116.98 (12)	C4i—C4—H4A	119.9
C3—C2—C2i	119.62 (13)
C1—N2—C2—C3	−177.8 (2)	C2—N2—C1—C1i	−11.4 (4)
C1—N2—C2—C2i	2.2 (4)	C2i—C2—C3—C4	−2.1 (4)
O1—N1—C1—N2	0.8 (3)	N2—C2—C3—C4	177.9 (2)
O1—N1—C1—C1i	−178.7 (2)	C2—C3—C4—C4i	0.4 (5)
C2—N2—C1—N1	169.1 (2)

D—H···A	D—H	H···A	D···A	D—H···A
O1—H1···N1ii	0.852 (13)	1.971 (10)	2.763 (2)	154
N2—H2A···O1	0.86	2.25	2.566 (3)	102

Table 1

Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O1—H1⋯N1i	0.852 (13)	1.971 (10)	2.763 (2)	154
N2—H2A⋯O1	0.86	2.25	2.566 (3)	102

Symmetry code: (i) .