Piperazine-2,3,5,6-tetra-one.

The mol-ecule of the title compound, C(4)H(2)N(2)O(4), is located around an inversion center and the four O atoms are in the 2,3,5,6-positions of the piperazine ring. In the crystal, bifurcated N-H⋯O hydrogen bonds link the mol-ecules into a corrugated layer parallel to (101).

Related literature

For the synthesis of tetra­one, see: Norcross et al. (2008 ▶). For related structures, see Sletten et al. (1970 ▶, 1980 ▶); Sarangarajan et al. (2005 ▶); Norcross et al. (2008 ▶); Jin et al. (1998 ▶); Sanner et al. (1992 ▶); Ongania et al. (1985 ▶).

Experimental

Crystal data

C4H2N2O4

M = 142.08

Monoclinic,

a = 5.163 (1) Å

b = 8.6220 (17) Å

c = 5.6540 (11) Å

β = 105.25 (3)°

V = 242.83 (8) Å3

Z = 2

Mo Kα radiation

μ = 0.18 mm−1

T = 293 K

0.42 × 0.32 × 0.12 mm

Data collection

Siemens P4 diffractometer

Absorption correction: multi-scan (SADABS; Sheldrick, 1996 ▶) T min = 0.930, T max = 0.978

1357 measured reflections

438 independent reflections

383 reflections with I > 2σ(I)

R int = 0.024

Refinement

R[F 2 > 2σ(F 2)] = 0.048

wR(F 2) = 0.092

S = 1.23

438 reflections

46 parameters

H-atom parameters constrained

Δρmax = 0.20 e Å−3

Δρmin = −0.21 e Å−3

Data collection: XSCANS (Siemens, 1994 ▶); cell refinement: XSCANS; data reduction: XSCANS; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: ORTEPIII (Burnett & Johnson, 1996 ▶), ORTEP-3 for Windows (Farrugia, 1997 ▶) and PLATON (Spek, 2009 ▶); software used to prepare material for publication: SHELXTL (Sheldrick, 2008 ▶).

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536810048075/dn2617sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S1600536810048075/dn2617Isup2.hkl

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

C4H2N2O4	F(000) = 144
Mr = 142.08	Dx = 1.943 Mg m−3
Monoclinic, P21/n	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2yn	Cell parameters from 438 reflections
a = 5.163 (1) Å	θ = 4.4–25.3°
b = 8.6220 (17) Å	µ = 0.18 mm−1
c = 5.6540 (11) Å	T = 293 K
β = 105.25 (3)°	Block, colourless
V = 242.83 (8) Å3	0.42 × 0.32 × 0.12 mm
Z = 2

Siemens P4 diffractometer	438 independent reflections
Radiation source: fine-focus sealed tube	383 reflections with I > 2σ(I)
graphite	Rint = 0.024
ω scans	θmax = 25.3°, θmin = 4.4°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	h = −6→6
Tmin = 0.930, Tmax = 0.978	k = −10→10
1357 measured reflections	l = −6→6

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)] = 0.048	Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.092	H-atom parameters constrained
S = 1.23	w = 1/[σ2(Fo2) + (0.0355P)2 + 0.1147P] where P = (Fo2 + 2Fc2)/3
438 reflections	(Δ/σ)max < 0.001
46 parameters	Δρmax = 0.20 e Å−3
0 restraints	Δρmin = −0.21 e Å−3

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
O1	0.1613 (3)	0.55814 (19)	0.7646 (3)	0.0343 (5)
O2	0.8069 (3)	0.25100 (19)	0.6060 (3)	0.0342 (5)
N1	0.4775 (4)	0.3995 (2)	0.6856 (3)	0.0261 (5)
H1	0.4603	0.3362	0.7981	0.031*
C1	0.6621 (5)	0.3635 (2)	0.5614 (4)	0.0233 (5)
C2	0.3169 (4)	0.5281 (2)	0.6461 (4)	0.0233 (5)

	U11	U22	U33	U12	U13	U23
O1	0.0357 (10)	0.0355 (10)	0.0373 (10)	0.0010 (8)	0.0197 (9)	−0.0034 (8)
O2	0.0348 (10)	0.0268 (9)	0.0402 (10)	0.0099 (8)	0.0086 (8)	0.0048 (7)
N1	0.0330 (11)	0.0229 (10)	0.0248 (11)	0.0004 (9)	0.0120 (9)	0.0053 (8)
C1	0.0221 (12)	0.0205 (11)	0.0256 (12)	−0.0019 (10)	0.0034 (10)	−0.0017 (9)
C2	0.0224 (12)	0.0225 (11)	0.0239 (12)	−0.0027 (10)	0.0042 (10)	−0.0038 (9)

O1—C2	1.202 (3)	N1—C2	1.368 (3)
O2—C1	1.210 (3)	N1—H1	0.8600
N1—C1	1.360 (3)	C1—C2i	1.526 (3)
C1—N1—C2	125.31 (19)	N1—C1—C2i	117.28 (19)
C1—N1—H1	117.3	O1—C2—N1	123.3 (2)
C2—N1—H1	117.3	O1—C2—C1i	119.3 (2)
O2—C1—N1	123.6 (2)	N1—C2—C1i	117.35 (18)
O2—C1—C2i	119.10 (19)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1···O1ii	0.86	2.48	3.060 (2)	125
N1—H1···O2iii	0.86	2.23	3.035 (2)	157

Table 1

Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N1—H1⋯O1i	0.86	2.48	3.060 (2)	125
N1—H1⋯O2ii	0.86	2.23	3.035 (2)	157

Symmetry codes: (i) ; (ii) .