The title compound, C
8H
4N
4O
2, was prepared to explore the synthesis of some 4-substituted imidazoles. The molecule is centrosymmetric and almost planar. In the crystal structure, centrosymmetric dimers are formed
via C—H
N hydrogen bonds. The dimers are linked by further C—H
N hydrogen bonds, forming a three-dimensional network.
Supporting information
CCDC reference: 636657
Key indicators
- Single-crystal X-ray study
- T = 173 K
- Mean (C-C) = 0.004 Å
- R factor = 0.041
- wR factor = 0.104
- Data-to-parameter ratio = 6.5
checkCIF/PLATON results
No syntax errors found
Alert level A
REFLT03_ALERT_3_A Reflection count < 85% complete (theta max?)
From the CIF: _diffrn_reflns_theta_max 25.62
From the CIF: _diffrn_reflns_theta_full 25.00
From the CIF: _reflns_number_total 471
TEST2: Reflns within _diffrn_reflns_theta_max
Count of symmetry unique reflns 691
Completeness (_total/calc) 68.16%
| Author Response: ...see _publ_section_exptl_refinement
|
PLAT022_ALERT_3_A Ratio Unique / Expected Reflections too Low .... 0.68
| Author Response: ...see _publ_section_exptl_refinement
|
PLAT028_ALERT_3_A _diffrn_measured_fraction_theta_max Low ....... 0.68
| Author Response: ...see _publ_section_exptl_refinement
|
Alert level B
PLAT088_ALERT_3_B Poor Data / Parameter Ratio .................... 6.45
3 ALERT level A = In general: serious problem
1 ALERT level B = Potentially serious problem
0 ALERT level C = Check and explain
0 ALERT level G = General alerts; check
0 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
0 ALERT type 2 Indicator that the structure model may be wrong or deficient
4 ALERT type 3 Indicator that the structure quality may be low
0 ALERT type 4 Improvement, methodology, query or suggestion
0 ALERT type 5 Informative message, check
Data collection: X-AREA (Stoe & Cie, 2005); cell refinement: X-AREA; data reduction: X-RED32 (Stoe & Cie, 2005); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: PLATON (Spek, 2003); software used to prepare material for publication: SHELXL97.
Diimidazo[1,5 - a;1',5'-d]pyrazine-5,10-dione
top
Crystal data top
C8H4N4O2 | F(000) = 192 |
Mr = 188.15 | Dx = 1.722 Mg m−3 |
Monoclinic, P21/c | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -P 2ybc | Cell parameters from 2055 reflections |
a = 5.4047 (19) Å | θ = 3.6–26.0° |
b = 6.9777 (18) Å | µ = 0.13 mm−1 |
c = 9.678 (4) Å | T = 173 K |
β = 96.23 (3)° | Rod, pale yellow |
V = 362.8 (2) Å3 | 0.23 × 0.13 × 0.10 mm |
Z = 2 | |
Data collection top
Stoe IPDS-2 diffractometer | 338 reflections with I > 2σ(I) |
Radiation source: fine-focus sealed tube | Rint = 0.051 |
Graphite monochromator | θmax = 25.6°, θmin = 4.8° |
Detector resolution: 6.67 pixels mm-1 | h = −6→6 |
ω and φ scans | k = −8→8 |
1582 measured reflections | l = −11→11 |
471 independent reflections | |
Refinement top
Refinement on F2 | Secondary atom site location: difference Fourier map |
Least-squares matrix: full | Hydrogen site location: difference Fourier map |
R[F2 > 2σ(F2)] = 0.041 | All H-atom parameters refined |
wR(F2) = 0.104 | w = 1/[σ2(Fo2) + (0.0657P)2] where P = (Fo2 + 2Fc2)/3 |
S = 0.97 | (Δ/σ)max < 0.001 |
471 reflections | Δρmax = 0.19 e Å−3 |
73 parameters | Δρmin = −0.16 e Å−3 |
0 restraints | Extinction correction: SHELXL97, Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
Primary atom site location: structure-invariant direct methods | Extinction coefficient: 0.065 (16) |
Special details top
Geometry. Bond distances, angles etc. have been calculated using the rounded
fractional coordinates. All su's are estimated from the variances of the
(full) variance-covariance matrix. The cell e.s.d.'s are taken into account in
the estimation of distances, angles and torsion angles |
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top | x | y | z | Uiso*/Ueq | |
O1 | 0.8612 (4) | −0.2727 (3) | 0.6735 (2) | 0.0399 (7) | |
N1 | 0.8136 (4) | 0.0322 (3) | 0.5832 (2) | 0.0305 (7) | |
N2 | 0.5770 (4) | 0.2850 (3) | 0.6149 (2) | 0.0352 (8) | |
C1 | 0.6301 (5) | 0.1053 (4) | 0.6531 (3) | 0.0311 (8) | |
C2 | 0.7343 (6) | 0.3279 (4) | 0.5177 (3) | 0.0327 (9) | |
C3 | 0.8827 (5) | 0.1761 (4) | 0.4951 (3) | 0.0267 (8) | |
C4 | 0.9248 (5) | −0.1525 (3) | 0.5953 (3) | 0.0296 (8) | |
H1 | 0.545 (6) | 0.027 (4) | 0.716 (3) | 0.041 (8)* | |
H2 | 0.733 (6) | 0.454 (4) | 0.478 (3) | 0.044 (8)* | |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
O1 | 0.0451 (12) | 0.0337 (11) | 0.0420 (12) | −0.0017 (8) | 0.0098 (9) | 0.0112 (9) |
N1 | 0.0344 (14) | 0.0259 (11) | 0.0317 (12) | 0.0024 (9) | 0.0054 (10) | −0.0006 (9) |
N2 | 0.0376 (14) | 0.0306 (13) | 0.0384 (13) | 0.0038 (10) | 0.0090 (11) | 0.0008 (10) |
C1 | 0.0329 (16) | 0.0300 (14) | 0.0313 (14) | 0.0020 (11) | 0.0073 (12) | −0.0027 (11) |
C2 | 0.0371 (17) | 0.0248 (13) | 0.0375 (15) | 0.0032 (12) | 0.0100 (12) | 0.0020 (11) |
C3 | 0.0300 (15) | 0.0202 (11) | 0.0306 (13) | 0.0009 (10) | 0.0067 (11) | 0.0015 (10) |
C4 | 0.0326 (16) | 0.0244 (12) | 0.0312 (14) | 0.0008 (11) | 0.0010 (11) | 0.0016 (11) |
Geometric parameters (Å, º) top
O1—C4 | 1.205 (3) | N2—C2 | 1.368 (4) |
N1—C1 | 1.359 (4) | C2—C3 | 1.361 (4) |
N1—C3 | 1.394 (4) | C3—C4i | 1.440 (4) |
N1—C4 | 1.422 (3) | C1—H1 | 0.97 (3) |
N2—C1 | 1.330 (4) | C2—H2 | 0.96 (3) |
| | | |
O1···C2ii | 3.207 (4) | C1···N1vi | 3.273 (4) |
O1···C1iii | 3.400 (4) | C1···C1vi | 3.466 (4) |
O1···C1iv | 3.178 (4) | C1···C3vi | 3.568 (4) |
O1···N1iv | 3.097 (3) | C1···C2ix | 3.543 (4) |
O1···C3iv | 3.372 (4) | C2···O1x | 3.207 (4) |
O1···H1 | 2.76 (3) | C2···N2viii | 3.362 (4) |
O1···H2ii | 2.72 (3) | C2···C2viii | 3.480 (5) |
O1···H1iii | 2.90 (3) | C2···C1xi | 3.543 (4) |
N1···O1v | 3.097 (3) | C3···C1vi | 3.568 (4) |
N1···N1i | 2.749 (3) | C3···O1v | 3.372 (4) |
N1···C1vi | 3.273 (4) | C4···N2vi | 3.339 (4) |
N2···C1vii | 3.440 (4) | C2···H2viii | 2.95 (3) |
N2···C2viii | 3.362 (4) | H1···O1 | 2.76 (3) |
N2···C4vi | 3.339 (4) | H1···O1vii | 2.90 (3) |
N2···H1vii | 2.49 (3) | H1···N2iii | 2.49 (3) |
N2···H2viii | 2.57 (3) | H2···O1x | 2.72 (3) |
C1···O1vii | 3.400 (4) | H2···N2viii | 2.57 (3) |
C1···O1v | 3.178 (4) | H2···C2viii | 2.95 (3) |
C1···N2iii | 3.440 (4) | | |
| | | |
C1—N1—C3 | 107.0 (2) | C2—C3—C4i | 131.6 (3) |
C1—N1—C4 | 128.6 (2) | O1—C4—N1 | 122.4 (2) |
C3—N1—C4 | 124.4 (2) | O1—C4—C3i | 125.2 (2) |
C1—N2—C2 | 105.4 (2) | N1—C4—C3i | 112.4 (2) |
N1—C1—N2 | 111.3 (2) | N1—C1—H1 | 121.5 (18) |
N2—C2—C3 | 111.2 (2) | N2—C1—H1 | 127.1 (18) |
N1—C3—C2 | 105.1 (2) | N2—C2—H2 | 119.9 (19) |
N1—C3—C4i | 123.3 (2) | C3—C2—H2 | 128.9 (19) |
| | | |
C3—N1—C1—N2 | 0.4 (3) | C3—N1—C4—C3i | −0.5 (4) |
C4—N1—C1—N2 | 179.1 (2) | C2—N2—C1—N1 | −0.4 (3) |
C1—N1—C3—C2 | −0.1 (3) | C1—N2—C2—C3 | 0.4 (3) |
C1—N1—C3—C4i | 179.4 (3) | N2—C2—C3—N1 | −0.1 (3) |
C4—N1—C3—C2 | −179.0 (2) | N2—C2—C3—C4i | −179.6 (3) |
C4—N1—C3—C4i | 0.6 (4) | N1—C3—C4i—O1i | 179.4 (3) |
C1—N1—C4—O1 | 0.9 (4) | N1—C3—C4i—N1i | −0.5 (4) |
C1—N1—C4—C3i | −179.1 (3) | C2—C3—C4i—O1i | −1.2 (5) |
C3—N1—C4—O1 | 179.4 (3) | C2—C3—C4i—N1i | 178.9 (3) |
Symmetry codes: (i) −x+2, −y, −z+1; (ii) x, y−1, z; (iii) −x+1, y−1/2, −z+3/2; (iv) −x+2, y−1/2, −z+3/2; (v) −x+2, y+1/2, −z+3/2; (vi) −x+1, −y, −z+1; (vii) −x+1, y+1/2, −z+3/2; (viii) −x+1, −y+1, −z+1; (ix) x, −y+1/2, z+1/2; (x) x, y+1, z; (xi) x, −y+1/2, z−1/2. |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
C1—H1···N2iii | 0.97 (3) | 2.49 (3) | 3.440 (4) | 166 (3) |
C2—H2···N2viii | 0.96 (3) | 2.57 (3) | 3.362 (4) | 140 (3) |
Symmetry codes: (iii) −x+1, y−1/2, −z+3/2; (viii) −x+1, −y+1, −z+1. |