5-Bromo-2-iodo­pyrimidine

The title compound, C₄H₂BrIN₂, is a useful inter­mediate for various sytheses. The complete mol­ecule is located on a crystallographic mirror plane.

Key indicators

• Single-crystal X-ray study
• T = 293 K
• Mean [sigma](C-C) = 0.015 Å
• R factor = 0.048
• wR factor = 0.091
• Data-to-parameter ratio = 14.6

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT030_ALERT_1_C _diffrn_reflns_number .LE.  _reflns_number_total          ?
PLAT066_ALERT_1_C Predicted and Reported Transmissions Identical .          ?
PLAT342_ALERT_3_C Low Bond Precision on C-C bonds (x 1000) Ang ...         16

Alert level G
PLAT199_ALERT_1_G Check the Reported _cell_measurement_temperature        293 K
PLAT200_ALERT_1_G Check the Reported _diffrn_ambient_temperature .        293 K

   0 ALERT level A = In general: serious problem
   0 ALERT level B = Potentially serious problem
   3 ALERT level C = Check and explain
   2 ALERT level G = General alerts; check

   4 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
   1 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

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Computing details

Data collection: CAD-4 Software (Enraf–Nonius, 1989); cell refinement: CAD-4 Software; data reduction: XCAD4 (Harms & Wocadlo, 1995); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SHELXTL (Siemens, 1996); software used to prepare material for publication: SHELXL97.

5-Bromo-2-iodopyrimidine

Crystal data

C4H2BrIN2	F(000) = 512
Mr = 284.88	Dx = 2.824 Mg m^−3
Orthorhombic, Pnma	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ac 2n	Cell parameters from 25 reflections
a = 6.1410 (12) Å	θ = 9–12°
b = 6.7890 (14) Å	µ = 10.64 mm^−1
c = 16.071 (3) Å	T = 293 K
V = 670.0 (2) Å^3	Block, colourless
Z = 4	0.20 × 0.10 × 0.10 mm

Data collection

Enraf–Nonius CAD-4 diffractometer	392 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.000
Graphite monochromator	θmax = 25.9°, θmin = 2.5°
ω/2θ scans	h = 0→7
Absorption correction: ψ scan (North et al., 1968)	k = 0→8
Tmin = 0.290, Tmax = 0.345	l = 0→19
716 measured reflections	3 standard reflections every 200 reflections
716 independent reflections	intensity decay: none

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.048	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.091	H-atom parameters constrained
S = 1.00	w = 1/[σ^2(Fo^2) + (0.0301P)^2] where P = (Fo^2 + 2Fc^2)/3
716 reflections	(Δ/σ)max < 0.001
49 parameters	Δρmax = 0.52 e Å^−3
0 restraints	Δρmin = −0.51 e Å^−3

Special details

Experimental. ¹H NMR (CDCl₃): δ 8.46 (m, 2H),

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
I	−0.03162 (15)	0.7500	0.67389 (5)	0.0669 (4)
Br	0.5534 (2)	0.7500	0.33008 (8)	0.0756 (5)
N1	0.0463 (14)	0.7500	0.4944 (5)	0.049 (2)
C2	0.483 (2)	0.7500	0.5054 (7)	0.051 (3)
H1	0.6342	0.7500	0.5090	0.061*
C1	0.1563 (18)	0.7500	0.5649 (6)	0.045 (3)
C4	0.1601 (19)	0.7500	0.4255 (7)	0.048 (3)
H2	0.0882	0.7500	0.3746	0.058*
C3	0.3825 (18)	0.7500	0.4269 (6)	0.043 (3)
N2	0.3665 (15)	0.7500	0.5733 (5)	0.051 (3)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
I	0.0597 (6)	0.0921 (7)	0.0488 (5)	0.000	0.0070 (6)	0.000
Br	0.0717 (11)	0.1026 (11)	0.0525 (7)	0.000	0.0165 (8)	0.000
N1	0.040 (5)	0.063 (6)	0.044 (4)	0.000	−0.003 (4)	0.000
C2	0.037 (5)	0.058 (6)	0.056 (5)	0.000	−0.001 (4)	0.000
C1	0.042 (5)	0.052 (7)	0.042 (5)	0.000	0.003 (5)	0.000
C4	0.048 (5)	0.054 (7)	0.043 (5)	0.000	−0.007 (4)	0.000
C3	0.047 (5)	0.040 (6)	0.041 (5)	0.000	0.008 (4)	0.000
N2	0.045 (5)	0.056 (6)	0.051 (5)	0.000	−0.001 (4)	0.000

Geometric parameters (Å, º)

I—C1	2.097 (11)	C2—C3	1.404 (14)
Br—C3	1.877 (10)	C2—H1	0.9300
N1—C4	1.309 (12)	C1—N2	1.298 (13)
N1—C1	1.320 (12)	C4—C3	1.366 (14)
C2—N2	1.305 (13)	C4—H2	0.9300
C4—N1—C1	116.9 (9)	N1—C4—C3	121.3 (10)
N2—C2—C3	120.7 (11)	N1—C4—H2	119.3
N2—C2—H1	119.7	C3—C4—H2	119.3
C3—C2—H1	119.7	C4—C3—C2	117.0 (10)
N2—C1—N1	126.7 (10)	C4—C3—Br	123.0 (8)
N2—C1—I	117.4 (8)	C2—C3—Br	119.9 (9)
N1—C1—I	115.8 (8)	C1—N2—C2	117.3 (10)
C4—N1—C1—N2	0.000 (4)	N2—C2—C3—C4	0.000 (4)
C4—N1—C1—I	180.000 (2)	N2—C2—C3—Br	180.000 (4)
C1—N1—C4—C3	0.000 (4)	N1—C1—N2—C2	0.000 (6)
N1—C4—C3—C2	0.000 (4)	I—C1—N2—C2	180.000 (4)
N1—C4—C3—Br	180.000 (3)	C3—C2—N2—C1	0.000 (4)