2,5-Di­bromo-6-iso­propyl-3-methyl-p-benzo­quinone

The title compound, C₁₀H₁₀Br₂O₂, is a well known inhibitor of respiratory and photosynthetic processes. The methyl groups of the iso­propyl group assume approximately equal distances from the ring plane and maximum distances from the neighboring Br atom, possibly to avoid unfavourable steric interactions.

Key indicators

• Single-crystal X-ray study
• T = 295 K
• Mean [sigma](C-C) = 0.006 Å
• R factor = 0.024
• wR factor = 0.064
• Data-to-parameter ratio = 16.4

checkCIF results

No syntax errors found

ADDSYM reports no extra symmetry

General Notes



REFLT_03
         From the CIF: _diffrn_reflns_theta_max           26.36
         From the CIF: _reflns_number_total               2145
         Count of symmetry unique reflns         1169
         Completeness (_total/calc)            183.49%
         TEST3: Check Friedels for noncentro structure
         Estimate of Friedel pairs measured       976
         Fraction of Friedel pairs measured     0.835
         Are heavy atom types Z>Si present          yes
          Please check that the estimate of the number of Friedel pairs is
          correct. If it is not, please give the correct count in the
          _publ_section_exptl_refinement section of the submitted CIF.

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Computing details

Data collection: COLLECT (Nonius, 1999); cell refinement: DENZO (Otwinowski & Minor, 1997); data reduction: DENZO and SCALEPACK (Otwinowski & Minor, 1997); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: PLATON (Spek, 2001) and ORTEP-32 (Farrugia, 1997).

2,5-Dibromo-3-methyl-6-isopropyl-1,4-benzoquinone

Crystal data

C10H10Br2O2	F(000) = 624
Mr = 322.00	Dx = 1.881 Mg m^−3
Monoclinic, Cc	Melting point: 343(2) K
Hall symbol: C -2yc	Mo Kα radiation, λ = 0.71073 Å
a = 5.4507 (2) Å	Cell parameters from 15747 reflections
b = 18.5945 (9) Å	θ = 0.9–27.1°
c = 11.4256 (6) Å	µ = 7.10 mm^−1
β = 100.941 (3)°	T = 295 K
V = 1136.97 (9) Å^3	Rod, yellow
Z = 4	0.54 × 0.21 × 0.12 mm

Data collection

Nonius KappaCCD diffractometer	2145 independent reflections
Radiation source: fine-focus sealed tube	2042 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.000
φ scans	θmax = 26.4°, θmin = 3.6°
Absorption correction: empirical (using intensity measurements) (SCALEPACK; Otwinowski & Minor, 1997)	h = −5→5
Tmin = 0.180, Tmax = 0.426	k = −22→22
2145 measured reflections	l = −14→14

Refinement

Refinement on F^2	Hydrogen site location: inferred from neighbouring sites
Least-squares matrix: full	H-atom parameters constrained
R[F^2 > 2σ(F^2)] = 0.024	w = 1/[σ^2(Fo^2) + (0.0396P)^2 + 1.0226P] where P = (Fo^2 + 2Fc^2)/3
wR(F^2) = 0.064	(Δ/σ)max = 0.004
S = 1.04	Δρmax = 0.53 e Å^−3
2145 reflections	Δρmin = −0.34 e Å^−3
131 parameters	Extinction correction: SHELXL97, Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
2 restraints	Extinction coefficient: 0.0105 (8)
Primary atom site location: structure-invariant direct methods	Absolute structure: (Flack, 1983), 976 Friedel pairs
Secondary atom site location: difference Fourier map	Absolute structure parameter: 0.026 (12)

Special details

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.

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

	x	y	z	Uiso*/Ueq
O1	0.6118 (7)	0.12918 (18)	0.6483 (3)	0.0683 (9)
C1	0.5103 (7)	0.09766 (19)	0.7196 (3)	0.0482 (7)
C2	0.5612 (7)	0.0203 (2)	0.7464 (3)	0.0488 (8)
Br1	0.78142 (7)	−0.02215 (2)	0.65665 (4)	0.06701 (16)
C3	0.4630 (8)	−0.01686 (19)	0.8259 (4)	0.0489 (9)
C7	0.5110 (13)	−0.0950 (2)	0.8549 (5)	0.0802 (14)
H7A	0.4641	−0.1232	0.7838	0.120*
H7B	0.4143	−0.1098	0.9127	0.120*
H7C	0.6854	−0.1020	0.8869	0.120*
C4	0.2946 (7)	0.0223 (2)	0.8934 (3)	0.0488 (8)
O2	0.1980 (7)	−0.0095 (2)	0.9650 (3)	0.0719 (9)
C5	0.2491 (7)	0.09999 (19)	0.8687 (3)	0.0459 (7)
Br2	0.04670 (6)	0.14325 (2)	0.96623 (3)	0.06778 (17)
C6	0.3369 (8)	0.1366 (2)	0.7847 (3)	0.0480 (8)
C8	0.2736 (9)	0.2142 (2)	0.7493 (4)	0.0606 (10)
H8	0.1531	0.2307	0.7970	0.073*
C9	0.5040 (11)	0.2635 (2)	0.7795 (5)	0.0750 (13)
H9A	0.6276	0.2485	0.7348	0.113*
H9B	0.5723	0.2604	0.8632	0.113*
H9C	0.4556	0.3122	0.7592	0.113*
C10	0.1496 (11)	0.2216 (3)	0.6200 (5)	0.0843 (15)
H10A	0.1052	0.2710	0.6032	0.126*
H10B	0.0017	0.1925	0.6045	0.126*
H10C	0.2629	0.2062	0.5702	0.126*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O1	0.088 (2)	0.0629 (17)	0.0675 (19)	−0.0089 (16)	0.0494 (17)	−0.0030 (14)
C1	0.049 (2)	0.0536 (18)	0.0456 (18)	−0.0051 (15)	0.0187 (14)	−0.0018 (15)
C2	0.049 (2)	0.057 (2)	0.0417 (16)	0.0015 (15)	0.0110 (14)	−0.0078 (13)
Br1	0.0641 (3)	0.0808 (3)	0.0603 (2)	0.0180 (2)	0.02230 (16)	−0.0113 (2)
C3	0.056 (3)	0.0431 (19)	0.049 (2)	0.0021 (14)	0.0119 (16)	−0.0012 (14)
C7	0.116 (4)	0.048 (2)	0.081 (3)	0.010 (2)	0.031 (3)	0.003 (2)
C4	0.048 (2)	0.056 (2)	0.0438 (17)	−0.0028 (15)	0.0138 (14)	0.0003 (15)
O2	0.076 (2)	0.0716 (19)	0.077 (2)	0.0032 (16)	0.0386 (18)	0.0242 (16)
C5	0.046 (2)	0.0515 (19)	0.0420 (16)	−0.0006 (14)	0.0140 (13)	0.0011 (14)
Br2	0.0760 (3)	0.0755 (3)	0.0633 (2)	0.0104 (2)	0.04223 (19)	0.0018 (2)
C6	0.050 (2)	0.055 (2)	0.0427 (18)	0.0050 (14)	0.0169 (14)	0.0052 (14)
C8	0.066 (3)	0.064 (2)	0.060 (2)	0.0155 (18)	0.0317 (18)	0.0169 (18)
C9	0.090 (3)	0.051 (2)	0.081 (3)	0.008 (2)	0.008 (2)	−0.004 (2)
C10	0.068 (3)	0.097 (4)	0.084 (3)	0.002 (3)	0.005 (2)	0.035 (3)

Geometric parameters (Å, º)

O1—C1	1.218 (5)	C5—C6	1.338 (5)
C1—C2	1.485 (5)	C5—Br2	1.890 (4)
C1—C6	1.496 (6)	C6—C8	1.519 (6)
C2—C3	1.332 (6)	C8—C10	1.510 (6)
C2—Br1	1.893 (4)	C8—C9	1.540 (7)
C3—C4	1.494 (6)	C8—H8	0.9800
C3—C7	1.502 (6)	C9—H9A	0.9600
C7—H7A	0.9600	C9—H9B	0.9600
C7—H7B	0.9600	C9—H9C	0.9600
C7—H7C	0.9600	C10—H10A	0.9600
C4—O2	1.208 (5)	C10—H10B	0.9600
C4—C5	1.485 (5)	C10—H10C	0.9600
O1—C1—C2	120.9 (4)	C5—C6—C1	117.1 (3)
O1—C1—C6	120.6 (3)	C5—C6—C8	125.5 (4)
C2—C1—C6	118.5 (3)	C1—C6—C8	117.4 (3)
C3—C2—C1	124.0 (3)	C10—C8—C6	112.6 (4)
C3—C2—Br1	122.1 (3)	C10—C8—C9	111.0 (4)
C1—C2—Br1	113.9 (3)	C6—C8—C9	111.8 (4)
C2—C3—C4	117.7 (3)	C10—C8—H8	107.0
C2—C3—C7	125.2 (4)	C6—C8—H8	107.0
C4—C3—C7	117.1 (4)	C9—C8—H8	107.0
C3—C7—H7A	109.5	C8—C9—H9A	109.5
C3—C7—H7B	109.5	C8—C9—H9B	109.5
H7A—C7—H7B	109.5	H9A—C9—H9B	109.5
C3—C7—H7C	109.5	C8—C9—H9C	109.5
H7A—C7—H7C	109.5	H9A—C9—H9C	109.5
H7B—C7—H7C	109.5	H9B—C9—H9C	109.5
O2—C4—C5	121.7 (4)	C8—C10—H10A	109.5
O2—C4—C3	120.1 (4)	C8—C10—H10B	109.5
C5—C4—C3	118.2 (3)	H10A—C10—H10B	109.5
C6—C5—C4	124.2 (3)	C8—C10—H10C	109.5
C6—C5—Br2	122.3 (3)	H10A—C10—H10C	109.5
C4—C5—Br2	113.4 (2)	H10B—C10—H10C	109.5
O1—C1—C2—C3	177.8 (4)	O2—C4—C5—Br2	3.6 (5)
C6—C1—C2—C3	−0.5 (5)	C3—C4—C5—Br2	−176.9 (3)
O1—C1—C2—Br1	−2.1 (5)	C4—C5—C6—C1	−5.7 (6)
C6—C1—C2—Br1	179.5 (3)	Br2—C5—C6—C1	175.6 (3)
C1—C2—C3—C4	−1.0 (6)	C4—C5—C6—C8	173.8 (4)
Br1—C2—C3—C4	179.0 (3)	Br2—C5—C6—C8	−4.9 (6)
C1—C2—C3—C7	−180.0 (5)	O1—C1—C6—C5	−174.6 (4)
Br1—C2—C3—C7	0.0 (6)	C2—C1—C6—C5	3.8 (5)
C2—C3—C4—O2	178.8 (4)	O1—C1—C6—C8	5.9 (6)
C7—C3—C4—O2	−2.1 (6)	C2—C1—C6—C8	−175.7 (4)
C2—C3—C4—C5	−0.6 (5)	C5—C6—C8—C10	−119.6 (5)
C7—C3—C4—C5	178.5 (4)	C1—C6—C8—C10	59.9 (5)
O2—C4—C5—C6	−175.2 (4)	C5—C6—C8—C9	114.6 (5)
C3—C4—C5—C6	4.2 (6)	C1—C6—C8—C9	−65.9 (5)