7-Bromo-1H-indole-2,3-dione

The title compound, C₈H₄BrNO₂, has a single planar mol­ecule in the asymmetric unit with the non-H atoms possessing a mean deviation from planarity of 0.034 Å. The mol­ecules dimerize in the solid state through N—H...O hydrogen bonds. These dimers are further linked by inter­molecular Br...O close contacts of 3.085 (2) Å to yield infinite chains along [20-1]. The nine-membered rings of the isatins stack along the a axis, with parallel slipped π–π inter­actions [inter­centroid distance = 3.8320 (7) Å, inter­planar distance = 3.341 (2) Å and slippage = 1.876 (4) Å].

Key indicators

• Single-crystal X-ray study
• T = 120 K
• Mean [sigma](C-C) = 0.005 Å
• R factor = 0.029
• wR factor = 0.072
• Data-to-parameter ratio = 12.3

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT369_ALERT_2_C Long    C(sp2)-C(sp2) Bond  C1     -   C2     ..       1.56 Ang.
PLAT431_ALERT_2_C Short Inter HL..A  Contact Br1    ..  O2      ..       3.09 Ang.
PLAT911_ALERT_3_C Missing # FCF Refl Between THmin & STh/L=  0.600          2 Report
PLAT975_ALERT_2_C Check Calcd Residual Density  0.88A From      O1       0.44 eA-3

Alert level G
PLAT002_ALERT_2_G Number of Distance or Angle Restraints on AtSite          2 Note
PLAT172_ALERT_4_G The CIF-Embedded .res File Contains DFIX Records          1 Report
PLAT860_ALERT_3_G Number of Least-Squares Restraints .............          1 Note
PLAT909_ALERT_3_G Percentage of Observed Data at Theta(Max) Still          75 %
PLAT910_ALERT_3_G Missing # of FCF Reflection(s) Below Th(Min) ...          2 Report
PLAT978_ALERT_2_G Number C-C Bonds with Positive Residual Density           4 Note

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

   0 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   5 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
   1 ALERT type 4 Improvement, methodology, query or suggestion
   0 ALERT type 5 Informative message, check

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Computing details

Data collection: APEX2 (Bruker, 2014); cell refinement: SAINT (Bruker, 2014); data reduction: SAINT (Bruker, 2014); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL2014 (Sheldrick, 2015); molecular graphics: OLEX2 (Dolomanov et al., 2009); software used to prepare material for publication: OLEX2 (Dolomanov et al., 2009) and publCIF (Westrip, 2010).

7-Bromo-1H-indole-2,3-dione

Crystal data

C8H4BrNO2	F(000) = 440
Mr = 226.03	Dx = 1.999 Mg m^−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 7365 reflections
a = 3.8320 (7) Å	θ = 3.1–25.3°
b = 13.072 (2) Å	µ = 5.42 mm^−1
c = 15.004 (3) Å	T = 120 K
β = 91.917 (7)°	BLOCK, orange
V = 751.1 (2) Å^3	0.18 × 0.14 × 0.08 mm
Z = 4

Data collection

Bruker D8 Venture CMOS diffractometer	1374 independent reflections
Radiation source: Mo	1231 reflections with I > 2σ(I)
TRIUMPH monochromator	Rint = 0.051
φ and ω scans	θmax = 25.3°, θmin = 3.1°
Absorption correction: multi-scan (SADABS; Bruker, 2014)	h = −4→4
Tmin = 0.178, Tmax = 0.259	k = −15→15
17212 measured reflections	l = −18→18

Refinement

Refinement on F^2	1 restraint
Least-squares matrix: full	Hydrogen site location: mixed
R[F^2 > 2σ(F^2)] = 0.029	H atoms treated by a mixture of independent and constrained refinement
wR(F^2) = 0.072	w = 1/[σ^2(Fo^2) + (0.0305P)^2 + 1.3045P] where P = (Fo^2 + 2Fc^2)/3
S = 1.19	(Δ/σ)max = 0.001
1374 reflections	Δρmax = 0.69 e Å^−3
112 parameters	Δρmin = −0.37 e Å^−3

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.

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

	x	y	z	Uiso*/Ueq
Br1	0.78559 (9)	0.81463 (3)	0.42774 (2)	0.02233 (14)
O1	0.2403 (7)	0.47659 (19)	0.59756 (17)	0.0310 (6)
O2	0.0200 (7)	0.6053 (2)	0.74584 (16)	0.0261 (6)
N1	0.4553 (8)	0.6310 (2)	0.54806 (19)	0.0210 (6)
H1	0.553 (9)	0.614 (3)	0.5007 (18)	0.025*
C1	0.2953 (9)	0.5674 (3)	0.6052 (2)	0.0209 (7)
C2	0.1872 (9)	0.6353 (3)	0.6853 (2)	0.0196 (7)
C3	0.3267 (8)	0.7365 (3)	0.6663 (2)	0.0176 (7)
C4	0.3144 (9)	0.8280 (3)	0.7137 (2)	0.0216 (7)
H4	0.2105	0.8314	0.7703	0.026*
C5	0.4604 (9)	0.9145 (3)	0.6752 (2)	0.0241 (8)
H5	0.4629	0.9776	0.7067	0.029*
C6	0.6015 (9)	0.9095 (3)	0.5915 (2)	0.0211 (7)
H6	0.6955	0.9697	0.5661	0.025*
C7	0.6088 (9)	0.8177 (2)	0.5437 (2)	0.0180 (7)
C8	0.4733 (8)	0.7315 (2)	0.5823 (2)	0.0165 (7)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Br1	0.0209 (2)	0.0246 (2)	0.0218 (2)	−0.00089 (15)	0.00512 (13)	0.00333 (14)
O1	0.0463 (17)	0.0174 (13)	0.0300 (14)	−0.0051 (12)	0.0133 (12)	−0.0004 (11)
O2	0.0329 (14)	0.0209 (13)	0.0251 (14)	0.0032 (11)	0.0116 (11)	0.0045 (10)
N1	0.0292 (16)	0.0165 (15)	0.0179 (15)	0.0000 (13)	0.0091 (12)	−0.0006 (12)
C1	0.0243 (18)	0.0176 (18)	0.0211 (17)	0.0046 (15)	0.0039 (14)	0.0002 (14)
C2	0.0164 (16)	0.0201 (18)	0.0224 (18)	0.0047 (14)	0.0023 (14)	0.0015 (14)
C3	0.0132 (16)	0.0196 (18)	0.0200 (17)	0.0035 (13)	−0.0003 (13)	0.0011 (13)
C4	0.0223 (17)	0.0226 (19)	0.0199 (17)	0.0044 (15)	−0.0006 (14)	−0.0022 (14)
C5	0.0233 (18)	0.0193 (17)	0.029 (2)	0.0017 (15)	−0.0053 (15)	−0.0053 (15)
C6	0.0159 (16)	0.0184 (17)	0.0288 (19)	−0.0015 (14)	−0.0023 (14)	0.0024 (14)
C7	0.0169 (15)	0.0209 (18)	0.0162 (16)	0.0014 (14)	−0.0002 (13)	0.0042 (13)
C8	0.0136 (15)	0.0159 (16)	0.0199 (17)	0.0019 (13)	−0.0014 (13)	−0.0011 (13)

Geometric parameters (Å, º)

Br1—C7	1.888 (3)	C3—C8	1.399 (5)
O1—C1	1.210 (4)	C4—H4	0.9500
O2—C2	1.195 (4)	C4—C5	1.396 (5)
N1—H1	0.846 (19)	C5—H5	0.9500
N1—C1	1.356 (4)	C5—C6	1.385 (5)
N1—C8	1.411 (4)	C6—H6	0.9500
C1—C2	1.562 (5)	C6—C7	1.399 (5)
C2—C3	1.458 (5)	C7—C8	1.377 (5)
C3—C4	1.394 (5)
C1—N1—H1	126 (3)	C5—C4—H4	121.2
C1—N1—C8	111.0 (3)	C4—C5—H5	119.6
C8—N1—H1	123 (3)	C6—C5—C4	120.8 (3)
O1—C1—N1	128.6 (3)	C6—C5—H5	119.6
O1—C1—C2	125.5 (3)	C5—C6—H6	119.3
N1—C1—C2	106.0 (3)	C5—C6—C7	121.4 (3)
O2—C2—C1	124.1 (3)	C7—C6—H6	119.3
O2—C2—C3	131.0 (3)	C6—C7—Br1	120.3 (2)
C3—C2—C1	104.9 (3)	C8—C7—Br1	121.5 (3)
C4—C3—C2	131.3 (3)	C8—C7—C6	118.2 (3)
C4—C3—C8	121.4 (3)	C3—C8—N1	110.8 (3)
C8—C3—C2	107.1 (3)	C7—C8—N1	128.6 (3)
C3—C4—H4	121.2	C7—C8—C3	120.6 (3)
C3—C4—C5	117.6 (3)
Br1—C7—C8—N1	3.0 (5)	C2—C3—C8—N1	−3.5 (4)
Br1—C7—C8—C3	−176.6 (2)	C2—C3—C8—C7	176.1 (3)
O1—C1—C2—O2	−4.3 (6)	C3—C4—C5—C6	2.0 (5)
O1—C1—C2—C3	176.9 (4)	C4—C3—C8—N1	180.0 (3)
O2—C2—C3—C4	1.6 (6)	C4—C3—C8—C7	−0.4 (5)
O2—C2—C3—C8	−174.4 (4)	C4—C5—C6—C7	−1.2 (5)
N1—C1—C2—O2	175.1 (3)	C5—C6—C7—Br1	177.4 (3)
N1—C1—C2—C3	−3.7 (4)	C5—C6—C7—C8	−0.5 (5)
C1—N1—C8—C3	1.1 (4)	C6—C7—C8—N1	−179.1 (3)
C1—N1—C8—C7	−178.6 (3)	C6—C7—C8—C3	1.2 (5)
C1—C2—C3—C4	−179.7 (3)	C8—N1—C1—O1	−179.0 (4)
C1—C2—C3—C8	4.3 (3)	C8—N1—C1—C2	1.7 (4)
C2—C3—C4—C5	−176.8 (3)	C8—C3—C4—C5	−1.3 (5)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1···O1^i	0.85 (2)	2.07 (2)	2.878 (4)	161 (4)

Symmetry code: (i) −x+1, −y+1, −z+1.