2,9-Di­chloro-5,12-di­hydro­quino­[2,3-b]­acridine-7,14-dione

The title compound, C₂₀H₁₀Cl₂N₂O₂, is an industrially important red pigment. The mol­ecule has inversion symmetry. The mol­ecule is not entirely planar, as shown by the dihedral angle of 176.7 (3)° between the planes of the benzene ring at the center and that at the extremity. The mol­ecules are stacked in a `hunter's fence' fashion (i.e. when viewed from the side, the mol­ecules cross one another with an angle of about 50° in a grid-like structure) along the a axis.

Key indicators

• Single-crystal X-ray study
• T = 93 K
• Mean [sigma](C-C) = 0.012 Å
• R factor = 0.100
• wR factor = 0.350
• Data-to-parameter ratio = 10.3

checkCIF/PLATON results

No syntax errors found



Alert level A
PLAT029_ALERT_3_A _diffrn_measured_fraction_theta_full Low .......       0.91

Author Response: A two-dimensional detector (IP) was used in combination with a Cu target as radiation.

Alert level B
PLAT340_ALERT_3_B Low Bond Precision on C-C bonds (x 1000) Ang ...         12
PLAT415_ALERT_2_B Short Inter D-H..H-X       H1     ..  H1N     ..       1.99 Ang.

Alert level C
REFLT03_ALERT_3_C  Reflection count < 95% complete
           From the CIF: _diffrn_reflns_theta_max           68.23
           From the CIF: _diffrn_reflns_theta_full           0.00
           From the CIF: _reflns_number_total               1222
           TEST2: Reflns within _diffrn_reflns_theta_max
           Count of symmetry unique reflns         1334
           Completeness (_total/calc)             91.60%
RFACR01_ALERT_3_C  The value of the weighted R factor is > 0.25
            Weighted R factor given   0.350
PLAT022_ALERT_3_C Ratio Unique / Expected Reflections too Low ....       0.92
PLAT084_ALERT_2_C High R2 Value ..................................       0.35
PLAT250_ALERT_2_C Large U3/U1 Ratio for Average U(i,j) Tensor ....       2.03
PLAT420_ALERT_2_C D-H Without Acceptor       N1     -   H1N    ...          ?
PLAT431_ALERT_2_C Short Inter HL..A Contact  Cl1    ..  O1      ..       3.08 Ang.

   1 ALERT level A = In general: serious problem
   2 ALERT level B = Potentially serious problem
   7 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
   5 ALERT type 2 Indicator that the structure model may be wrong or deficient
   5 ALERT type 3 Indicator that the structure quality may be low
   0 ALERT type 4 Improvement, methodology, query or suggestion

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Computing details

Data collection: PROCESS-AUTO (Rigaku Corporation, 1998); cell refinement: PROCESS-AUTO; data reduction: CrystalStructure (Rigaku/MSC & Rigaku Corporation, 2004); program(s) used to solve structure: SIR2002 (Burla et al., 2003); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEPIII (Burnett & Johnson, 1996); software used to prepare material for publication: CrystalStructure.

2,9-Dichloro-5,12-dihydroquino[2,3-b]acridine-7,14-dione

Crystal data

C20H10Cl2N2O2	F(000) = 388.00
Mr = 381.20	Dx = 1.744 Mg m^−3
Monoclinic, P21/c	Cu Kα radiation, λ = 1.5418 Å
Hall symbol: -P 2ybc	Cell parameters from 4881 reflections
a = 3.782 (1) Å	θ = 3.0–68.1°
b = 14.840 (4) Å	µ = 4.20 mm^−1
c = 12.942 (3) Å	T = 93 K
β = 91.93 (2)°	Needle, black
V = 726.0 (3) Å^3	0.40 × 0.05 × 0.02 mm
Z = 2

Data collection

Rigaku R-AXIS RAPID imaging plate diffractometer	745 reflections with F^2 > 2σ(F^2)
Detector resolution: 10.00 pixels mm^-1	Rint = 0.078
ω scans	θmax = 68.2°
Absorption correction: multi-scan (ABSCOR; Higashi, 1995)	h = −3→3
Tmin = 0.677, Tmax = 0.919	k = −17→17
6026 measured reflections	l = −15→15
1222 independent reflections

Refinement

Refinement on F^2	H-atom parameters constrained
R[F^2 > 2σ(F^2)] = 0.100	w = 1/[σ^2(Fo^2) + (0.1985P)^2 + 2.3331P] where P = (Fo^2 + 2Fc^2)/3
wR(F^2) = 0.350	(Δ/σ)max < 0.001
S = 1.14	Δρmax = 0.56 e Å^−3
1222 reflections	Δρmin = −0.93 e Å^−3
119 parameters

Special details

Geometry. ENTER SPECIAL DETAILS OF THE MOLECULAR GEOMETRY

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.

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

	x	y	z	Uiso*/Ueq
Cl1	0.2925 (8)	0.4666 (2)	0.6599 (2)	0.045 (1)
O1	0.908 (2)	0.1444 (4)	0.7335 (4)	0.018 (2)
N1	0.638 (2)	0.1441 (5)	0.4199 (5)	0.020 (2)
C1	0.573 (2)	0.3006 (6)	0.6447 (6)	0.018 (2)
C2	0.401 (2)	0.3720 (6)	0.5953 (7)	0.018 (2)
C3	0.308 (2)	0.3678 (6)	0.4899 (7)	0.021 (2)
C4	0.382 (2)	0.2901 (6)	0.4343 (6)	0.017 (2)
C5	0.559 (2)	0.2181 (6)	0.4814 (6)	0.016 (2)
C6	0.653 (2)	0.2233 (6)	0.5898 (6)	0.016 (2)
C7	0.833 (2)	0.1454 (6)	0.6395 (6)	0.018 (2)
C8	0.927 (2)	0.0718 (6)	0.5700 (6)	0.017 (2)
C9	0.805 (2)	0.0760 (6)	0.4608 (6)	0.016 (2)
C10	1.108 (2)	−0.0018 (6)	0.6047 (6)	0.017 (2)
H1	0.6344	0.3046	0.7148	0.022*
H1N	0.5755	0.1437	0.3553	0.024*
H3	0.1963	0.4164	0.4572	0.026*
H4	0.3131	0.2864	0.3648	0.020*
H10	1.1793	−0.0043	0.6742	0.020*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Cl1	0.049 (2)	0.045 (2)	0.039 (2)	0.002 (1)	−0.002 (1)	−0.001 (1)
O1	0.017 (4)	0.029 (3)	0.008 (3)	−0.002 (3)	−0.005 (2)	−0.001 (2)
N1	0.020 (5)	0.030 (4)	0.010 (3)	−0.002 (3)	−0.001 (3)	0.001 (3)
C1	0.007 (6)	0.032 (5)	0.016 (4)	−0.004 (4)	0.005 (3)	−0.000 (3)
C2	0.011 (5)	0.022 (4)	0.022 (4)	−0.001 (4)	0.005 (3)	−0.001 (4)
C3	0.009 (6)	0.025 (5)	0.030 (5)	0.002 (4)	0.004 (4)	0.005 (4)
C4	0.009 (5)	0.027 (5)	0.015 (4)	0.002 (4)	0.004 (3)	0.003 (3)
C5	0.008 (6)	0.023 (4)	0.017 (4)	−0.004 (4)	0.004 (3)	0.004 (3)
C6	0.005 (5)	0.028 (5)	0.014 (4)	−0.002 (4)	0.001 (3)	0.005 (3)
C7	0.009 (6)	0.023 (5)	0.022 (4)	−0.004 (4)	0.005 (3)	0.001 (4)
C8	0.018 (6)	0.020 (4)	0.013 (4)	−0.006 (4)	−0.002 (4)	−0.002 (3)
C9	0.010 (6)	0.026 (5)	0.011 (4)	−0.001 (4)	0.001 (3)	0.004 (3)
C10	0.013 (5)	0.028 (5)	0.010 (3)	−0.003 (4)	−0.003 (3)	0.001 (3)

Geometric parameters (Å, º)

Cl1—C2	1.691 (9)	C4—C5	1.39 (1)
O1—C7	1.24 (1)	C4—H4	0.9300
N1—C5	1.39 (1)	C5—C6	1.44 (1)
N1—C9	1.30 (1)	C6—C7	1.48 (1)
N1—H1N	0.8601	C7—C8	1.47 (1)
C1—C2	1.39 (1)	C8—C9	1.47 (1)
C1—C6	1.39 (1)	C8—C10	1.36 (1)
C1—H1	0.9300	C9—C10^i	1.43 (1)
C2—C3	1.40 (1)	C10—C9^i	1.43 (1)
C3—C4	1.39 (1)	C10—H10	0.9300
C3—H3	0.9300
Cl1···O1^ii	3.084 (6)	H1···H1N^iii	1.994
Cl1—C2—C1	121.5 (7)	H3—C3—C4	120.2440
Cl1—C2—C3	117.6 (7)	C3—C4—C5	120.8 (8)
O1—C7—C6	121.5 (8)	C3—C4—H4	119.5789
O1—C7—C8	122.8 (8)	C4—C5—C6	119.0 (8)
N1—C5—C6	123.4 (7)	H4—C4—C5	119.5922
N1—C5—C4	117.6 (7)	C5—C6—C7	118.5 (7)
C9—N1—C5	119.4 (7)	C6—C7—C8	115.7 (7)
H1N—N1—C5	120.2990	C7—C8—C10	121.7 (7)
N1—C9—C8	123.9 (7)	C7—C8—C9	118.9 (7)
N1—C9—C10^i	118.3 (7)	C10—C8—C9	119.3 (7)
H1N—N1—C9	120.3002	C8—C9—C10^i	117.7 (7)
C1—C2—C3	120.9 (8)	C8—C10—H10	118.5189
H1—C1—C2	119.9576	C8—C10—C9^i	123.0 (7)
C6—C1—C2	120.1 (8)	C9—C10^i—H10^i	118.5083
H1—C1—C6	119.9639	C9—C10^i—C8^i	123.0 (7)
C1—C6—C7	121.9 (7)	H10—C10—C9^i	118.5083
C1—C6—C5	119.6 (8)	C10—C9^i—C8^i	117.7 (7)
C2—C3—H3	120.2419	C10—C9^i—N1^i	118.3 (7)
C2—C3—C4	119.5 (8)

Symmetry codes: (i) −x+2, −y, −z+1; (ii) −x+1, y+1/2, −z+3/2; (iii) x, −y+1/2, z+1/2.