2,3-Bis(5-bromo­thien-2-yl)­quinoxaline

2,3-Bis(5-bromo­thien-2-yl)­quinoxaline, C₁₆H₈Br₂N₂S₂, is a bromo-substituted 2,3-di­(thien-2-yl)­quinoxaline which can be easily synthesized by the Schiff base reaction between 1,2-phenyl­enedi­amine and 1,2-bis(5-bromo­thien-2-yl)-1,2-ethanedione. The molecule has twofold non-crystallographic symmetry.

Key indicators

• Single-crystal X-ray study
• T = 100 K
• Mean [sigma](C-C) = 0.005 Å
• R factor = 0.044
• wR factor = 0.119
• Data-to-parameter ratio = 19.2

checkCIF/PLATON results

No syntax errors found



Alert level B
PLAT063_ALERT_3_B Crystal Probably too Large for Beam Size .......       0.88 mm

Alert level C
PLAT029_ALERT_3_C _diffrn_measured_fraction_theta_full Low .......       0.97
PLAT431_ALERT_2_C Short Inter HL..A Contact  Br1    ..  Br2     ..       3.58 Ang.

   0 ALERT level A = In general: serious problem
   1 ALERT level B = Potentially serious problem
   2 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
   1 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
   0 ALERT type 4 Improvement, methodology, query or suggestion

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Computing details

Data collection: SMART (Bruker, 1999); cell refinement: SMART; data reduction: SAINT (Bruker, 1999); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 (Farrugia, 1997); software used to prepare material for publication: SHELXL97.

2,3-bis(5-bromothien-2-yl)quinoxaline

Crystal data

C16H8Br2N2S2	Z = 2
Mr = 452.18	F(000) = 440
Triclinic, P1	Dx = 1.922 Mg m^−3
Hall symbol: -P 1	Melting point: 368 K
a = 8.8701 (9) Å	Mo Kα radiation, λ = 0.71073 Å
b = 9.0664 (9) Å	Cell parameters from 7531 reflections
c = 11.1751 (11) Å	θ = 1.9–28.4°
α = 86.380 (2)°	µ = 5.45 mm^−1
β = 79.998 (2)°	T = 100 K
γ = 62.033 (2)°	Needle, yellow
V = 781.51 (13) Å^3	0.88 × 0.35 × 0.14 mm

Data collection

Bruker SMART APEX diffractometer	3818 independent reflections
Radiation source: sealed tube	3126 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.044
ω scans	θmax = 28.4°, θmin = 1.9°
Absorption correction: multi-scan (Sheldrick, 2003)	h = −11→11
Tmin = 0.018, Tmax = 0.466	k = −12→12
7531 measured reflections	l = −14→14

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)] = 0.044	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.119	H-atom parameters constrained
S = 0.85	w = 1/[σ^2(Fo^2) + (0.0927P)^2] where P = (Fo^2 + 2Fc^2)/3
3818 reflections	(Δ/σ)max = 0.001
199 parameters	Δρmax = 1.39 e Å^−3
0 restraints	Δρmin = −1.08 e Å^−3

Special details

Experimental. All hydrogen atoms were included in calculated positions with a C—H distance of 0.95 Å and were included in the refinement in riding motion approximation with U_iso = 1.2U_eq of the carrier atom.

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
Br1	0.74798 (4)	0.02160 (4)	1.07397 (3)	0.02684 (12)
S2	0.52759 (10)	0.79864 (10)	0.52100 (7)	0.02219 (18)
C1	0.3562 (4)	0.5443 (4)	0.7784 (3)	0.0179 (6)
N1	0.2053 (3)	0.5538 (3)	0.8266 (2)	0.0195 (5)
Br2	0.84862 (4)	0.77765 (5)	0.34107 (3)	0.02922 (13)
S1	0.47675 (10)	0.26675 (10)	0.91902 (7)	0.01947 (18)
N2	0.2293 (3)	0.7769 (3)	0.6481 (2)	0.0197 (5)
C2	0.3705 (4)	0.6505 (4)	0.6791 (3)	0.0174 (6)
C3	0.0719 (4)	0.7940 (4)	0.7025 (3)	0.0199 (6)
C4	−0.0799 (4)	0.9231 (4)	0.6666 (3)	0.0233 (7)
H4A	−0.0735	1.0061	0.6127	0.028*
C5	−0.2371 (4)	0.9280 (5)	0.7101 (3)	0.0258 (7)
H5A	−0.3393	1.0136	0.6851	0.031*
C6	−0.2475 (4)	0.8065 (5)	0.7919 (3)	0.0259 (7)
H6A	−0.3568	0.8105	0.8201	0.031*
C7	−0.1033 (4)	0.6832 (5)	0.8312 (3)	0.0235 (7)
H7A	−0.1129	0.6039	0.8877	0.028*
C8	0.0612 (4)	0.6745 (4)	0.7869 (3)	0.0199 (6)
C9	0.5031 (4)	0.4231 (4)	0.8361 (3)	0.0181 (6)
C10	0.6556 (4)	0.4208 (4)	0.8476 (3)	0.0202 (6)
H10A	0.6919	0.4978	0.8089	0.024*
C11	0.7536 (4)	0.2921 (4)	0.9229 (3)	0.0220 (7)
H11A	0.8617	0.2735	0.9413	0.026*
C12	0.6735 (4)	0.1985 (4)	0.9656 (3)	0.0205 (6)
C13	0.5322 (4)	0.6279 (4)	0.6031 (3)	0.0177 (6)
C14	0.6882 (4)	0.4883 (4)	0.5724 (3)	0.0189 (6)
H14A	0.7141	0.3818	0.6061	0.023*
C15	0.8075 (4)	0.5187 (4)	0.4850 (3)	0.0193 (6)
H15A	0.9215	0.4361	0.4543	0.023*
C16	0.7377 (4)	0.6801 (4)	0.4512 (3)	0.0221 (6)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Br1	0.02553 (19)	0.0204 (2)	0.0273 (2)	−0.00466 (15)	−0.00685 (14)	0.00685 (14)
S2	0.0184 (4)	0.0171 (4)	0.0251 (4)	−0.0048 (3)	−0.0013 (3)	0.0066 (3)
C1	0.0180 (14)	0.0176 (15)	0.0135 (13)	−0.0053 (12)	−0.0001 (11)	−0.0006 (11)
N1	0.0182 (12)	0.0196 (14)	0.0175 (12)	−0.0067 (11)	−0.0017 (10)	0.0007 (10)
Br2	0.0259 (2)	0.0297 (2)	0.0280 (2)	−0.01253 (16)	0.00043 (14)	0.01158 (15)
S1	0.0176 (4)	0.0169 (4)	0.0202 (4)	−0.0059 (3)	−0.0014 (3)	0.0025 (3)
N2	0.0193 (12)	0.0173 (14)	0.0187 (13)	−0.0061 (11)	−0.0010 (10)	0.0006 (10)
C2	0.0167 (14)	0.0172 (15)	0.0155 (14)	−0.0062 (12)	0.0003 (11)	−0.0019 (11)
C3	0.0185 (14)	0.0196 (16)	0.0162 (14)	−0.0051 (13)	0.0008 (11)	−0.0035 (12)
C4	0.0220 (16)	0.0185 (17)	0.0219 (15)	−0.0045 (13)	0.0000 (12)	−0.0009 (13)
C5	0.0205 (15)	0.0252 (18)	0.0214 (16)	−0.0022 (13)	−0.0033 (12)	−0.0001 (13)
C6	0.0159 (14)	0.033 (2)	0.0230 (16)	−0.0074 (14)	−0.0002 (12)	−0.0018 (14)
C7	0.0176 (14)	0.0294 (19)	0.0197 (15)	−0.0091 (14)	0.0006 (12)	0.0011 (13)
C8	0.0163 (14)	0.0222 (17)	0.0158 (14)	−0.0050 (13)	0.0002 (11)	−0.0027 (12)
C9	0.0182 (14)	0.0157 (15)	0.0159 (14)	−0.0052 (12)	0.0002 (11)	0.0007 (11)
C10	0.0193 (14)	0.0211 (17)	0.0175 (14)	−0.0077 (13)	−0.0017 (11)	0.0014 (12)
C11	0.0165 (14)	0.0221 (17)	0.0209 (15)	−0.0041 (13)	−0.0003 (12)	−0.0027 (13)
C12	0.0182 (14)	0.0151 (15)	0.0192 (15)	−0.0007 (12)	−0.0022 (11)	0.0006 (12)
C13	0.0186 (14)	0.0140 (15)	0.0173 (14)	−0.0059 (12)	−0.0008 (11)	0.0025 (11)
C14	0.0194 (14)	0.0167 (15)	0.0169 (14)	−0.0062 (12)	−0.0005 (11)	0.0019 (12)
C15	0.0186 (14)	0.0198 (16)	0.0165 (14)	−0.0076 (13)	0.0013 (11)	−0.0011 (12)
C16	0.0217 (15)	0.0232 (17)	0.0192 (15)	−0.0103 (14)	0.0002 (12)	0.0052 (13)

Geometric parameters (Å, º)

Br1—C12	1.875 (3)	C5—C6	1.413 (5)
S2—C16	1.720 (3)	C5—H5A	0.9500
S2—C13	1.736 (3)	C6—C7	1.367 (5)
C1—N1	1.318 (4)	C6—H6A	0.9500
C1—C2	1.451 (4)	C7—C8	1.424 (4)
C1—C9	1.477 (4)	C7—H7A	0.9500
N1—C8	1.361 (4)	C9—C10	1.371 (4)
Br2—C16	1.877 (3)	C10—C11	1.415 (5)
S1—C12	1.721 (3)	C10—H10A	0.9500
S1—C9	1.730 (3)	C11—C12	1.359 (5)
N2—C2	1.325 (4)	C11—H11A	0.9500
N2—C3	1.362 (4)	C13—C14	1.372 (4)
C2—C13	1.464 (4)	C14—C15	1.425 (4)
C3—C4	1.413 (5)	C14—H14A	0.9500
C3—C8	1.417 (5)	C15—C16	1.352 (5)
C4—C5	1.376 (4)	C15—H15A	0.9500
C4—H4A	0.9500
C16—S2—C13	90.85 (15)	N1—C8—C7	120.0 (3)
N1—C1—C2	121.1 (3)	C3—C8—C7	119.1 (3)
N1—C1—C9	114.6 (3)	C10—C9—C1	131.1 (3)
C2—C1—C9	124.2 (3)	C10—C9—S1	111.4 (2)
C1—N1—C8	118.1 (3)	C1—C9—S1	117.1 (2)
C12—S1—C9	90.67 (15)	C9—C10—C11	113.2 (3)
C2—N2—C3	118.7 (3)	C9—C10—H10A	123.4
N2—C2—C1	120.1 (3)	C11—C10—H10A	123.4
N2—C2—C13	114.5 (3)	C12—C11—C10	111.5 (3)
C1—C2—C13	125.4 (3)	C12—C11—H11A	124.2
N2—C3—C4	119.5 (3)	C10—C11—H11A	124.2
N2—C3—C8	120.2 (3)	C11—C12—S1	113.2 (2)
C4—C3—C8	120.1 (3)	C11—C12—Br1	127.0 (2)
C5—C4—C3	119.6 (3)	S1—C12—Br1	119.67 (18)
C5—C4—H4A	120.2	C14—C13—C2	131.6 (3)
C3—C4—H4A	120.2	C14—C13—S2	110.9 (2)
C4—C5—C6	120.4 (3)	C2—C13—S2	117.0 (2)
C4—C5—H5A	119.8	C13—C14—C15	113.4 (3)
C6—C5—H5A	119.8	C13—C14—H14A	123.3
C7—C6—C5	121.3 (3)	C15—C14—H14A	123.3
C7—C6—H6A	119.3	C16—C15—C14	111.3 (3)
C5—C6—H6A	119.3	C16—C15—H15A	124.3
C6—C7—C8	119.5 (3)	C14—C15—H15A	124.3
C6—C7—H7A	120.3	C15—C16—S2	113.5 (2)
C8—C7—H7A	120.3	C15—C16—Br2	126.3 (2)
N1—C8—C3	120.8 (3)	S2—C16—Br2	120.28 (19)