6-Chloro-1,4-di­ethyl­quinoxaline-2,3(1H,4H)-dione

In the title compound, C₁₂H₁₃ClN₂O₂, the terminal C atoms of the ethyl groups deviate from the mean plane of the quinoxaline-2,3(1H,4H)-dione ring (r.m.s. deviation = 0.016 Å) in opposite directions by −1.451 (2) and 1.472 (2) Å. In the crystal, weak C—H...O inter­actions link the mol­ecules into [100] chains and aromatic π–π stacking inter­actions [shortest centroid–centroid separation = 3.6631 (9) Å] are also observed.

Key indicators

• Single-crystal X-ray study
• T = 293 K
• Mean [sigma](C-C) = 0.003 Å
• R factor = 0.045
• wR factor = 0.128
• Data-to-parameter ratio = 14.7

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT911_ALERT_3_C Missing # FCF Refl Between THmin & STh/L=  0.600          3 Report
PLAT918_ALERT_3_C Reflection(s) with I(obs) much Smaller I(calc) .          1 Check
PLAT978_ALERT_2_C Number C-C Bonds with Positive Residual Density.          0 Note

Alert level G
PLAT199_ALERT_1_G Reported _cell_measurement_temperature ..... (K)        293 Check
PLAT200_ALERT_1_G Reported   _diffrn_ambient_temperature ..... (K)        293 Check
PLAT912_ALERT_4_G Missing # of FCF Reflections Above STh/L=  0.600         41 Note
PLAT933_ALERT_2_G Number of OMIT Records in Embedded .res File ...          1 Note

   0 ALERT level A = Most likely a serious problem - resolve or explain
   0 ALERT level B = A potentially serious problem, consider carefully
   3 ALERT level C = Check. Ensure it is not caused by an omission or oversight
   4 ALERT level G = General information/check it is not something unexpected

   2 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   2 ALERT type 2 Indicator that the structure model may be wrong or deficient
   2 ALERT type 3 Indicator that the structure quality may be low
   1 ALERT type 4 Improvement, methodology, query or suggestion
   0 ALERT type 5 Informative message, check


checkCIF publication errors

Alert level A
PUBL024_ALERT_1_A The number of authors is greater than 5.
              Please specify the role of each of the co-authors
              for your paper.

   1 ALERT level A = Data missing that is essential or data in wrong format
   0 ALERT level G = General alerts. Data that may be required is missing

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Computing details

Data collection: CrysAlis PRO (Rigaku Oxford Diffraction, 2015); cell refinement: CrysAlis PRO (Rigaku Oxford Diffraction, 2015); data reduction: CrysAlis PRO (Rigaku Oxford Diffraction, 2015); program(s) used to solve structure: SHELXT2014 (Sheldrick, 2015b); program(s) used to refine structure: SHELXL (Sheldrick, 2015a); molecular graphics: OLEX2 (Dolomanov et al., 2009); software used to prepare material for publication: OLEX2 (Dolomanov et al., 2009).

6-Chloro-1,4-diethylquinoxaline-2,3(1H,4H)-dione

Crystal data

C12H13ClN2O2	F(000) = 1056
Mr = 252.69	Dx = 1.397 Mg m^−3
Monoclinic, I2/a	Cu Kα radiation, λ = 1.54184 Å
a = 14.6454 (8) Å	Cell parameters from 1748 reflections
b = 12.0415 (5) Å	θ = 3.5–71.4°
c = 15.1149 (9) Å	µ = 2.76 mm^−1
β = 115.621 (7)°	T = 293 K
V = 2403.5 (3) Å^3	Irregular, orange
Z = 8	0.22 × 0.18 × 0.12 mm

Data collection

Rigaku, Oxford diffraction diffractometer	2291 independent reflections
Radiation source: fine-focus sealed X-ray tube, Enhance (Cu) X-ray Source	1944 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.015
Detector resolution: 16.0416 pixels mm^-1	θmax = 71.3°, θmin = 4.9°
ω scans	h = −15→17
Absorption correction: multi-scan (CrysAlis PRO; Rigaku Oxford Diffraction, 2015)	k = −14→14
Tmin = 0.749, Tmax = 1.000	l = −16→18
4349 measured reflections

Refinement

Refinement on F^2	Primary atom site location: dual
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F^2 > 2σ(F^2)] = 0.045	H-atom parameters constrained
wR(F^2) = 0.128	w = 1/[σ^2(Fo^2) + (0.0765P)^2 + 0.5895P] where P = (Fo^2 + 2Fc^2)/3
S = 1.03	(Δ/σ)max < 0.001
2291 reflections	Δρmax = 0.23 e Å^−3
156 parameters	Δρmin = −0.31 e Å^−3
0 restraints

Special details

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. All the H atoms were placed in calculated positions and refined using the riding model with C—H bond lengths of 0.93 Å (CH) or 0.97 Å (CH₂) or 0.96 Å (CH₃). Isotropic displacement parameters for these atoms were set to 1.2 (CH) or 1.5 (CH₃) times U_eq of the parent atom. Idealized Me groups were refined as rotating groups.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
Cl1	0.13648 (4)	0.04185 (5)	0.36551 (4)	0.0703 (2)
O1	0.45160 (11)	0.58336 (12)	0.38236 (13)	0.0645 (4)
O2	0.56068 (10)	0.39761 (13)	0.40065 (12)	0.0646 (4)
N1	0.31793 (10)	0.48193 (12)	0.37493 (10)	0.0429 (3)
N2	0.42883 (10)	0.28937 (12)	0.38566 (10)	0.0429 (3)
C1	0.41348 (13)	0.49391 (16)	0.38203 (13)	0.0464 (4)
C2	0.47412 (13)	0.38917 (16)	0.39038 (13)	0.0465 (4)
C3	0.33032 (12)	0.28080 (14)	0.37896 (10)	0.0392 (4)
C4	0.28666 (13)	0.17761 (15)	0.37675 (11)	0.0446 (4)
H4	0.3225	0.1128	0.3799	0.054*
C5	0.18971 (14)	0.17216 (16)	0.36987 (12)	0.0484 (4)
C6	0.13456 (13)	0.26574 (18)	0.36620 (12)	0.0496 (4)
H6	0.0696	0.2601	0.3623	0.059*
C7	0.17739 (13)	0.36817 (16)	0.36843 (12)	0.0454 (4)
H7	0.1408	0.4321	0.3661	0.054*
C8	0.27497 (12)	0.37745 (15)	0.37412 (10)	0.0392 (4)
C9	0.25998 (14)	0.58452 (16)	0.36690 (15)	0.0525 (4)
H9A	0.3067	0.6458	0.3947	0.063*
H9B	0.2212	0.5762	0.4047	0.063*
C10	0.18908 (18)	0.6114 (2)	0.26220 (18)	0.0694 (6)
H10A	0.2268	0.6166	0.2239	0.104*
H10B	0.1561	0.6810	0.2599	0.104*
H10C	0.1392	0.5538	0.2361	0.104*
C11	0.49092 (14)	0.18977 (17)	0.39550 (14)	0.0514 (4)
H11A	0.5418	0.2065	0.3725	0.062*
H11B	0.4482	0.1309	0.3547	0.062*
C12	0.54246 (17)	0.15049 (17)	0.50063 (16)	0.0628 (5)
H12A	0.5870	0.0899	0.5055	0.094*
H12B	0.4923	0.1262	0.5213	0.094*
H12C	0.5809	0.2104	0.5418	0.094*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Cl1	0.0777 (4)	0.0587 (3)	0.0866 (4)	−0.0233 (2)	0.0469 (3)	−0.0045 (2)
O1	0.0571 (8)	0.0507 (8)	0.0965 (11)	−0.0130 (6)	0.0433 (8)	−0.0084 (7)
O2	0.0429 (7)	0.0682 (9)	0.0922 (11)	−0.0037 (6)	0.0380 (7)	0.0008 (8)
N1	0.0392 (7)	0.0452 (8)	0.0479 (7)	−0.0025 (6)	0.0221 (6)	−0.0040 (6)
N2	0.0403 (7)	0.0482 (8)	0.0447 (7)	−0.0005 (6)	0.0225 (6)	−0.0036 (6)
C1	0.0422 (8)	0.0493 (10)	0.0517 (9)	−0.0068 (7)	0.0242 (7)	−0.0054 (7)
C2	0.0402 (8)	0.0550 (10)	0.0494 (9)	−0.0019 (7)	0.0241 (7)	−0.0016 (7)
C3	0.0392 (7)	0.0481 (9)	0.0334 (7)	−0.0039 (7)	0.0186 (6)	−0.0033 (6)
C4	0.0506 (9)	0.0462 (9)	0.0419 (8)	−0.0024 (7)	0.0245 (7)	−0.0019 (7)
C5	0.0524 (9)	0.0551 (10)	0.0430 (8)	−0.0154 (8)	0.0256 (7)	−0.0030 (7)
C6	0.0434 (8)	0.0630 (11)	0.0488 (9)	−0.0078 (8)	0.0261 (7)	0.0008 (8)
C7	0.0405 (8)	0.0559 (10)	0.0447 (8)	0.0003 (7)	0.0231 (7)	0.0011 (7)
C8	0.0392 (8)	0.0485 (9)	0.0327 (7)	−0.0043 (7)	0.0182 (6)	−0.0026 (6)
C9	0.0465 (9)	0.0466 (9)	0.0669 (11)	−0.0023 (8)	0.0269 (8)	−0.0100 (8)
C10	0.0692 (13)	0.0590 (12)	0.0808 (14)	0.0115 (10)	0.0331 (11)	0.0122 (11)
C11	0.0481 (9)	0.0526 (10)	0.0605 (10)	0.0039 (8)	0.0302 (8)	−0.0069 (8)
C12	0.0639 (12)	0.0498 (10)	0.0673 (12)	0.0076 (9)	0.0214 (10)	−0.0022 (9)

Geometric parameters (Å, º)

Cl1—C5	1.7407 (19)	C6—C7	1.378 (3)
O1—C1	1.212 (2)	C7—H7	0.9300
O2—C2	1.213 (2)	C7—C8	1.399 (2)
N1—C1	1.364 (2)	C9—H9A	0.9700
N1—C8	1.404 (2)	C9—H9B	0.9700
N1—C9	1.474 (2)	C9—C10	1.505 (3)
N2—C2	1.359 (2)	C10—H10A	0.9600
N2—C3	1.406 (2)	C10—H10B	0.9600
N2—C11	1.473 (2)	C10—H10C	0.9600
C1—C2	1.516 (3)	C11—H11A	0.9700
C3—C4	1.391 (2)	C11—H11B	0.9700
C3—C8	1.402 (2)	C11—C12	1.510 (3)
C4—H4	0.9300	C12—H12A	0.9600
C4—C5	1.380 (2)	C12—H12B	0.9600
C5—C6	1.373 (3)	C12—H12C	0.9600
C6—H6	0.9300
C1—N1—C8	122.40 (15)	C3—C8—N1	119.77 (14)
C1—N1—C9	116.90 (15)	C7—C8—N1	120.93 (16)
C8—N1—C9	120.69 (14)	C7—C8—C3	119.30 (16)
C2—N2—C3	122.07 (15)	N1—C9—H9A	109.2
C2—N2—C11	116.65 (14)	N1—C9—H9B	109.2
C3—N2—C11	121.12 (14)	N1—C9—C10	112.20 (16)
O1—C1—N1	123.32 (18)	H9A—C9—H9B	107.9
O1—C1—C2	119.13 (16)	C10—C9—H9A	109.2
N1—C1—C2	117.55 (16)	C10—C9—H9B	109.2
O2—C2—N2	122.68 (18)	C9—C10—H10A	109.5
O2—C2—C1	118.88 (17)	C9—C10—H10B	109.5
N2—C2—C1	118.43 (15)	C9—C10—H10C	109.5
C4—C3—N2	120.94 (15)	H10A—C10—H10B	109.5
C4—C3—C8	119.39 (15)	H10A—C10—H10C	109.5
C8—C3—N2	119.67 (15)	H10B—C10—H10C	109.5
C3—C4—H4	120.3	N2—C11—H11A	109.3
C5—C4—C3	119.45 (17)	N2—C11—H11B	109.3
C5—C4—H4	120.3	N2—C11—C12	111.54 (15)
C4—C5—Cl1	118.37 (15)	H11A—C11—H11B	108.0
C6—C5—Cl1	119.48 (14)	C12—C11—H11A	109.3
C6—C5—C4	122.15 (17)	C12—C11—H11B	109.3
C5—C6—H6	120.7	C11—C12—H12A	109.5
C5—C6—C7	118.69 (16)	C11—C12—H12B	109.5
C7—C6—H6	120.7	C11—C12—H12C	109.5
C6—C7—H7	119.5	H12A—C12—H12B	109.5
C6—C7—C8	121.02 (17)	H12A—C12—H12C	109.5
C8—C7—H7	119.5	H12B—C12—H12C	109.5
Cl1—C5—C6—C7	−179.16 (13)	C4—C3—C8—N1	−179.12 (14)
O1—C1—C2—O2	2.5 (3)	C4—C3—C8—C7	0.8 (2)
O1—C1—C2—N2	−177.21 (17)	C4—C5—C6—C7	0.7 (3)
N1—C1—C2—O2	−177.15 (16)	C5—C6—C7—C8	0.1 (2)
N1—C1—C2—N2	3.1 (2)	C6—C7—C8—N1	179.05 (15)
N2—C3—C4—C5	−179.83 (13)	C6—C7—C8—C3	−0.9 (2)
N2—C3—C8—N1	0.7 (2)	C8—N1—C1—O1	179.63 (17)
N2—C3—C8—C7	−179.38 (13)	C8—N1—C1—C2	−0.7 (2)
C1—N1—C8—C3	−1.2 (2)	C8—N1—C9—C10	−81.9 (2)
C1—N1—C8—C7	178.90 (14)	C8—C3—C4—C5	0.0 (2)
C1—N1—C9—C10	97.43 (19)	C9—N1—C1—O1	0.3 (3)
C2—N2—C3—C4	−178.34 (15)	C9—N1—C1—C2	179.98 (15)
C2—N2—C3—C8	1.8 (2)	C9—N1—C8—C3	178.14 (14)
C2—N2—C11—C12	93.20 (19)	C9—N1—C8—C7	−1.8 (2)
C3—N2—C2—O2	176.57 (16)	C11—N2—C2—O2	1.1 (3)
C3—N2—C2—C1	−3.7 (2)	C11—N2—C2—C1	−179.15 (15)
C3—N2—C11—C12	−82.3 (2)	C11—N2—C3—C4	−3.1 (2)
C3—C4—C5—Cl1	179.10 (12)	C11—N2—C3—C8	177.12 (14)
C3—C4—C5—C6	−0.8 (3)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
C7—H7···O2^i	0.93	2.53	3.440 (2)	167
C9—H9B···O2^i	0.97	2.35	3.180 (2)	144

Symmetry code: (i) x−1/2, −y+1, z.