meso-3,6-Dioxopiperazine-2,5-diacet-amide.

The title compound, C(8)H(12)N(4)O(4), was obtained by cyclization of the two l-asparagine mol-ecules and reveals a crystallographic inversion symmetry, and accordingly the two stereogenic centres are of opposite chirality. Thus, an asymmetric unit comprises a half of a mol-ecule. The mol-ecules are assembled into a three-dimensional hydrogen-bonding network by N-H⋯O hydrogen bonds.

Related literature

For general background to coordination polymers, see: Anitha et al. (2005 ▶); Aarthy et al. (2005 ▶); Guenifa et al. (2009 ▶); Moussa Slimane et al. (2009 ▶). For related structures, see: Howes et al. (1983 ▶).

Experimental

Crystal data

C8H12N4O4

M = 228.22

Monoclinic,

a = 5.0409 (10) Å

b = 8.3178 (17) Å

c = 12.900 (3) Å

β = 109.76 (3)°

V = 509.0 (2) Å3

Z = 2

Mo Kα radiation

μ = 0.12 mm−1

T = 293 K

0.10 × 0.10 × 0.10 mm

Data collection

Rigaku R-AXIS RAPID diffractometer

Absorption correction: multi-scan (ABSCOR; Higashi, 1995 ▶) T min = 0.988, T max = 0.988

4836 measured reflections

1166 independent reflections

889 reflections with I > 2σ(I)

R int = 0.028

Refinement

R[F 2 > 2σ(F 2)] = 0.037

wR(F 2) = 0.098

S = 1.07

1166 reflections

73 parameters

H-atom parameters constrained

Δρmax = 0.24 e Å−3

Δρmin = −0.16 e Å−3

Data collection: RAPID-AUTO (Rigaku, 1998 ▶); cell refinement: RAPID-AUTO; data reduction: CrystalStructure (Rigaku/MSC, 2004 ▶); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: SHELXTL (Sheldrick, 2008 ▶); software used to prepare material for publication: SHELXL97.

Crystal structure: contains datablock(s) global, I. DOI: 10.1107/S1600536811043376/kp2350sup1.cif

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536811043376/kp2350Isup2.hkl

Supplementary material file. DOI: 10.1107/S1600536811043376/kp2350Isup3.cml

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

C8H12N4O4	F(000) = 240
Mr = 228.22	Dx = 1.489 Mg m−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 3368 reflections
a = 5.0409 (10) Å	θ = 3.4–27.4°
b = 8.3178 (17) Å	µ = 0.12 mm−1
c = 12.900 (3) Å	T = 293 K
β = 109.76 (3)°	Needle, colourless
V = 509.0 (2) Å3	0.10 × 0.10 × 0.10 mm
Z = 2

Rigaku R-AXIS RAPID diffractometer	1166 independent reflections
Radiation source: fine-focus sealed tube	889 reflections with I > 2σ(I)
graphite	Rint = 0.028
Detector resolution: 0 pixels mm-1	θmax = 27.5°, θmin = 3.4°
ω scans	h = −6→5
Absorption correction: multi-scan (ABSCOR; Higashi, 1995)	k = −10→10
Tmin = 0.988, Tmax = 0.988	l = −16→16
4836 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)] = 0.037	Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.098	H-atom parameters constrained
S = 1.07	w = 1/[σ2(Fo2) + (0.0415P)2 + 0.146P] where P = (Fo2 + 2Fc2)/3
1166 reflections	(Δ/σ)max < 0.001
73 parameters	Δρmax = 0.24 e Å−3
0 restraints	Δρmin = −0.16 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
O1	0.0282 (2)	−0.01262 (16)	0.31172 (9)	0.0483 (4)
O2	0.2805 (3)	0.29340 (13)	0.49666 (9)	0.0482 (3)
N1	0.0676 (4)	0.0393 (2)	0.14760 (11)	0.0580 (5)
H1A	−0.0736	−0.0213	0.1141	0.070*
H1B	0.1561	0.0889	0.1107	0.070*
N2	0.6588 (2)	−0.04206 (14)	0.43619 (9)	0.0316 (3)
H2C	0.7546	−0.0678	0.3948	0.038*
C1	0.1482 (3)	0.05588 (18)	0.25545 (11)	0.0320 (3)
C2	0.3991 (3)	0.16430 (17)	0.30689 (11)	0.0300 (3)
H2A	0.3353	0.2749	0.3022	0.036*
H2B	0.5274	0.1554	0.2656	0.036*
C3	0.5568 (3)	0.12212 (17)	0.42763 (11)	0.0289 (3)
H3A	0.7224	0.1923	0.4531	0.035*
C4	0.3792 (3)	0.15646 (18)	0.49910 (11)	0.0307 (3)

	U11	U22	U33	U12	U13	U23
O1	0.0425 (6)	0.0752 (9)	0.0326 (6)	−0.0194 (6)	0.0199 (5)	−0.0009 (5)
O2	0.0730 (8)	0.0412 (6)	0.0366 (6)	0.0250 (6)	0.0267 (6)	0.0066 (5)
N1	0.0743 (11)	0.0739 (11)	0.0270 (7)	−0.0402 (9)	0.0185 (7)	−0.0063 (7)
N2	0.0336 (6)	0.0399 (7)	0.0266 (6)	0.0094 (5)	0.0172 (5)	0.0028 (5)
C1	0.0331 (7)	0.0392 (8)	0.0267 (7)	0.0000 (6)	0.0140 (6)	0.0016 (6)
C2	0.0347 (7)	0.0327 (7)	0.0261 (7)	−0.0005 (6)	0.0150 (6)	0.0024 (6)
C3	0.0292 (7)	0.0322 (7)	0.0268 (7)	−0.0005 (6)	0.0116 (6)	−0.0003 (6)
C4	0.0329 (7)	0.0364 (7)	0.0227 (7)	0.0067 (6)	0.0093 (6)	0.0003 (6)

O1—C1	1.2304 (17)	C1—C2	1.512 (2)
O2—C4	1.2392 (17)	C2—C3	1.5309 (19)
N1—C1	1.3182 (19)	C2—H2A	0.9700
N1—H1A	0.8599	C2—H2B	0.9700
N1—H1B	0.8599	C3—C4	1.5135 (19)
N2—C4i	1.3219 (18)	C3—H3A	0.9800
N2—C3	1.4502 (18)	C4—N2i	1.3219 (18)
N2—H2C	0.8599
C1—N1—H1A	119.9	C1—C2—H2B	109.1
C1—N1—H1B	120.1	C3—C2—H2B	109.1
H1A—N1—H1B	120.0	H2A—C2—H2B	107.9
C4i—N2—C3	127.05 (12)	N2—C3—C4	113.51 (11)
C4i—N2—H2C	116.4	N2—C3—C2	110.01 (11)
C3—N2—H2C	116.5	C4—C3—C2	111.46 (11)
O1—C1—N1	122.47 (14)	N2—C3—H3A	107.2
O1—C1—C2	121.49 (13)	C4—C3—H3A	107.2
N1—C1—C2	116.05 (13)	C2—C3—H3A	107.2
C1—C2—C3	112.30 (12)	O2—C4—N2i	122.34 (13)
C1—C2—H2A	109.1	O2—C4—C3	118.24 (13)
C3—C2—H2A	109.1	N2i—C4—C3	119.39 (12)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1A···O2ii	0.86	2.12	2.9185 (19)	154.
N1—H1B···O2iii	0.86	2.03	2.8795 (18)	167.
N2—H2C···O1iv	0.86	2.06	2.8509 (17)	152.

Table 1

Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N1—H1A⋯O2i	0.86	2.12	2.9185 (19)	154
N1—H1B⋯O2ii	0.86	2.03	2.8795 (18)	167
N2—H2C⋯O1iii	0.86	2.06	2.8509 (17)	152

Symmetry codes: (i) ; (ii) ; (iii) .