2,3-Diphenyl­quinoxaline

In the title compound, C₂₀H₁₄N₂, the presence of adjacent phenyl rings causes an out-of-plane twist in the quinoxaline system of approximately 12°.

Key indicators

• Single-crystal X-ray study
• T = 100 K
• Mean [sigma](C-C) = 0.002 Å
• R factor = 0.044
• wR factor = 0.112
• Data-to-parameter ratio = 17.1

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT432_ALERT_2_C Short Inter X...Y Contact  C6     ..  C12     ..       3.19 Ang.

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

---

Computing details

Data collection: CrysAlis CCD (Oxford Diffraction, 2003); cell refinement: CrysAlis RED (Oxford Diffraction, 2003); data reduction: CrysAlis RED; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997); software used to prepare material for publication: PARST95 (Nardelli, 1995) and PLATON (Spek, 2003).

2,3-diphenylquinoxaline

Crystal data

C20H14N2	F(000) = 592
Mr = 282.33	Dx = 1.268 Mg m^−3
Monoclinic, P21/n	Melting point: 398 K
Hall symbol: -P 2yn	Mo Kα radiation, λ = 0.71073 Å
a = 6.0306 (2) Å	Cell parameters from 25 reflections
b = 10.9269 (5) Å	θ = 6.5–13.8°
c = 22.5309 (8) Å	µ = 0.08 mm^−1
β = 95.005 (3)°	T = 100 K
V = 1479.03 (10) Å^3	Prism, light yellow
Z = 4	0.5 × 0.45 × 0.3 mm

Data collection

Oxford Diffraction CrysAlisCCD diffractometer	3413 independent reflections
Radiation source: fine-focus sealed tube	2773 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.027
ω/2θ scans	θmax = 27.6°, θmin = 2.6°
Absorption correction: multi-scan (SADABS; Sheldrick, 2003)	h = −7→7
Tmin = 0.93, Tmax = 0.98	k = −14→14
16180 measured reflections	l = −29→29

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F^2 > 2σ(F^2)] = 0.044	H-atom parameters constrained
wR(F^2) = 0.112	w = 1/[σ^2(Fo^2) + (0.0404P)^2 + 0.715P] where P = (Fo^2 + 2Fc^2)/3
S = 1.13	(Δ/σ)max < 0.001
3413 reflections	Δρmax = 0.30 e Å^−3
200 parameters	Δρmin = −0.17 e Å^−3
0 restraints	Extinction correction: SHELXL97, Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.0092 (16)

Special details

Experimental. To a glass vial, Benzil (0.50 mg, 2,38 mmol), 1,2-diamino benzene (0.26 mg, 2.40 mmol), molecular sieves (1 g) and manganese oxide (0.10 mg) as a catalyst was heated under microwave irradiation using domestic microwave M197DL. After one min the vial was cooled to room temperature. The solution was filtered and solid obtained was recrystallized from ethanol to give 2,3-diphenyl quinoxaline (0.570 mg, 76.49%).

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
N1	0.7349 (2)	0.79330 (11)	0.18973 (5)	0.0191 (3)
C2	0.5488 (2)	0.83953 (13)	0.16342 (6)	0.0180 (3)
C3	0.4405 (2)	0.94333 (13)	0.18815 (6)	0.0175 (3)
N4	0.5096 (2)	0.98709 (11)	0.24124 (5)	0.0184 (3)
C5	0.6961 (2)	0.93603 (13)	0.27012 (6)	0.0185 (3)
C6	0.8142 (2)	0.84227 (13)	0.24330 (6)	0.0184 (3)
C7	1.0153 (2)	0.79688 (14)	0.27257 (7)	0.0206 (3)
H7	1.0957	0.7340	0.2547	0.025*
C8	1.0928 (3)	0.84432 (14)	0.32675 (7)	0.0225 (3)
H8	1.2279	0.8144	0.3463	0.027*
C9	0.9731 (3)	0.93757 (14)	0.35382 (7)	0.0229 (3)
H9	1.0287	0.9692	0.3915	0.028*
C10	0.7784 (3)	0.98275 (14)	0.32639 (7)	0.0217 (3)
H10	0.6992	1.0450	0.3450	0.026*
C11	0.2511 (2)	1.00973 (13)	0.15553 (6)	0.0180 (3)
C12	0.0850 (2)	1.05899 (13)	0.18797 (7)	0.0195 (3)
H12	0.0942	1.0493	0.2300	0.023*
C13	−0.0932 (3)	1.12187 (14)	0.15923 (7)	0.0235 (3)
H13	−0.2073	1.1531	0.1815	0.028*
C14	−0.1052 (3)	1.13922 (14)	0.09807 (8)	0.0269 (4)
H14	−0.2285	1.1812	0.0784	0.032*
C15	0.0633 (3)	1.09510 (15)	0.06561 (7)	0.0266 (4)
H15	0.0576	1.1094	0.0239	0.032*
C16	0.2404 (3)	1.03005 (14)	0.09405 (7)	0.0230 (3)
H16	0.3545	0.9993	0.0716	0.028*
C17	0.4574 (2)	0.77395 (13)	0.10864 (6)	0.0191 (3)
C18	0.2414 (3)	0.72696 (14)	0.10354 (7)	0.0223 (3)
H18	0.1451	0.7421	0.1339	0.027*
C19	0.1673 (3)	0.65773 (14)	0.05379 (7)	0.0245 (3)
H19	0.0211	0.6245	0.0507	0.029*
C20	0.3059 (3)	0.63694 (14)	0.00873 (7)	0.0257 (4)
H20	0.2546	0.5898	−0.0251	0.031*
C21	0.5196 (3)	0.68520 (15)	0.01330 (7)	0.0259 (4)
H21	0.6138	0.6720	−0.0177	0.031*
C22	0.5958 (3)	0.75273 (14)	0.06318 (7)	0.0229 (3)
H22	0.7428	0.7847	0.0664	0.027*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
N1	0.0192 (6)	0.0170 (6)	0.0211 (6)	−0.0017 (5)	0.0013 (5)	0.0008 (5)
C2	0.0181 (7)	0.0175 (7)	0.0187 (7)	−0.0014 (6)	0.0031 (6)	0.0007 (5)
C3	0.0186 (7)	0.0166 (7)	0.0177 (7)	−0.0011 (6)	0.0033 (6)	0.0012 (5)
N4	0.0194 (6)	0.0167 (6)	0.0192 (6)	−0.0005 (5)	0.0023 (5)	0.0011 (5)
C5	0.0209 (7)	0.0158 (7)	0.0189 (7)	−0.0021 (6)	0.0018 (6)	0.0023 (5)
C6	0.0205 (7)	0.0153 (7)	0.0195 (7)	−0.0028 (6)	0.0025 (6)	0.0016 (5)
C7	0.0210 (7)	0.0171 (7)	0.0236 (8)	0.0002 (6)	0.0018 (6)	0.0018 (6)
C8	0.0221 (8)	0.0206 (7)	0.0238 (8)	−0.0014 (6)	−0.0033 (6)	0.0064 (6)
C9	0.0279 (8)	0.0210 (7)	0.0191 (7)	−0.0046 (6)	−0.0025 (6)	0.0006 (6)
C10	0.0263 (8)	0.0189 (7)	0.0200 (7)	−0.0012 (6)	0.0024 (6)	−0.0003 (6)
C11	0.0178 (7)	0.0144 (7)	0.0215 (7)	−0.0016 (5)	0.0004 (6)	−0.0004 (5)
C12	0.0207 (7)	0.0161 (7)	0.0219 (7)	−0.0030 (6)	0.0022 (6)	0.0000 (6)
C13	0.0191 (7)	0.0191 (7)	0.0328 (9)	0.0004 (6)	0.0042 (6)	−0.0012 (6)
C14	0.0240 (8)	0.0210 (8)	0.0344 (9)	0.0034 (6)	−0.0051 (7)	0.0031 (7)
C15	0.0339 (9)	0.0239 (8)	0.0210 (8)	0.0026 (7)	−0.0026 (7)	0.0023 (6)
C16	0.0257 (8)	0.0209 (7)	0.0226 (8)	0.0026 (6)	0.0028 (6)	−0.0014 (6)
C17	0.0219 (7)	0.0162 (7)	0.0186 (7)	0.0036 (6)	−0.0014 (6)	−0.0002 (6)
C18	0.0217 (8)	0.0218 (8)	0.0233 (8)	0.0027 (6)	0.0011 (6)	−0.0017 (6)
C19	0.0219 (8)	0.0212 (7)	0.0293 (8)	0.0017 (6)	−0.0039 (6)	−0.0026 (6)
C20	0.0318 (9)	0.0217 (8)	0.0222 (8)	0.0045 (7)	−0.0058 (6)	−0.0043 (6)
C21	0.0301 (8)	0.0274 (8)	0.0202 (8)	0.0056 (7)	0.0025 (6)	−0.0031 (6)
C22	0.0221 (8)	0.0228 (8)	0.0236 (8)	0.0024 (6)	0.0013 (6)	−0.0008 (6)

Geometric parameters (Å, º)

N1—C2	1.3228 (18)	C12—H12	0.9500
N1—C6	1.3678 (19)	C13—C14	1.386 (2)
C2—C3	1.445 (2)	C13—H13	0.9500
C2—C17	1.491 (2)	C14—C15	1.389 (2)
C3—N4	1.3213 (19)	C14—H14	0.9500
C3—C11	1.492 (2)	C15—C16	1.392 (2)
N4—C5	1.3683 (19)	C15—H15	0.9500
C5—C6	1.413 (2)	C16—H16	0.9500
C5—C10	1.416 (2)	C17—C18	1.396 (2)
C6—C7	1.419 (2)	C17—C22	1.396 (2)
C7—C8	1.370 (2)	C18—C19	1.393 (2)
C7—H7	0.9500	C18—H18	0.9500
C8—C9	1.417 (2)	C19—C20	1.389 (2)
C8—H8	0.9500	C19—H19	0.9500
C9—C10	1.370 (2)	C20—C21	1.388 (2)
C9—H9	0.9500	C20—H20	0.9500
C10—H10	0.9500	C21—C22	1.389 (2)
C11—C12	1.399 (2)	C21—H21	0.9500
C11—C16	1.399 (2)	C22—H22	0.9500
C12—C13	1.387 (2)
C2—N1—C6	117.61 (13)	C11—C12—H12	119.7
N1—C2—C3	121.43 (13)	C14—C13—C12	120.19 (15)
N1—C2—C17	115.18 (13)	C14—C13—H13	119.9
C3—C2—C17	123.34 (13)	C12—C13—H13	119.9
N4—C3—C2	121.04 (13)	C13—C14—C15	119.91 (15)
N4—C3—C11	115.94 (13)	C13—C14—H14	120.0
C2—C3—C11	122.99 (12)	C15—C14—H14	120.0
C3—N4—C5	117.65 (13)	C14—C15—C16	120.15 (15)
N4—C5—C6	121.09 (13)	C14—C15—H15	119.9
N4—C5—C10	119.22 (13)	C16—C15—H15	119.9
C6—C5—C10	119.60 (13)	C15—C16—C11	120.26 (15)
N1—C6—C5	120.71 (13)	C15—C16—H16	119.9
N1—C6—C7	119.49 (13)	C11—C16—H16	119.9
C5—C6—C7	119.80 (13)	C18—C17—C22	119.46 (14)
C8—C7—C6	119.55 (14)	C18—C17—C2	121.35 (13)
C8—C7—H7	120.2	C22—C17—C2	119.07 (13)
C6—C7—H7	120.2	C19—C18—C17	119.85 (14)
C7—C8—C9	120.58 (14)	C19—C18—H18	120.1
C7—C8—H8	119.7	C17—C18—H18	120.1
C9—C8—H8	119.7	C20—C19—C18	120.37 (15)
C10—C9—C8	120.89 (14)	C20—C19—H19	119.8
C10—C9—H9	119.6	C18—C19—H19	119.8
C8—C9—H9	119.6	C21—C20—C19	119.86 (14)
C9—C10—C5	119.58 (14)	C21—C20—H20	120.1
C9—C10—H10	120.2	C19—C20—H20	120.1
C5—C10—H10	120.2	C20—C21—C22	120.09 (15)
C12—C11—C16	118.90 (13)	C20—C21—H21	120.0
C12—C11—C3	118.84 (13)	C22—C21—H21	120.0
C16—C11—C3	122.16 (13)	C21—C22—C17	120.36 (15)
C13—C12—C11	120.51 (14)	C21—C22—H22	119.8
C13—C12—H12	119.7	C17—C22—H22	119.8
C6—N1—C2—C3	4.1 (2)	C2—C3—C11—C12	146.09 (14)
C6—N1—C2—C17	−173.67 (12)	N4—C3—C11—C16	140.78 (14)
N1—C2—C3—N4	−7.6 (2)	C2—C3—C11—C16	−37.4 (2)
C17—C2—C3—N4	169.90 (13)	C16—C11—C12—C13	3.1 (2)
N1—C2—C3—C11	170.49 (13)	C3—C11—C12—C13	179.68 (13)
C17—C2—C3—C11	−12.0 (2)	C11—C12—C13—C14	−1.7 (2)
C2—C3—N4—C5	4.3 (2)	C12—C13—C14—C15	−1.0 (2)
C11—C3—N4—C5	−173.93 (12)	C13—C14—C15—C16	2.1 (2)
C3—N4—C5—C6	1.8 (2)	C14—C15—C16—C11	−0.6 (2)
C3—N4—C5—C10	178.34 (13)	C12—C11—C16—C15	−2.0 (2)
C2—N1—C6—C5	2.1 (2)	C3—C11—C16—C15	−178.41 (14)
C2—N1—C6—C7	−178.91 (13)	N1—C2—C17—C18	123.30 (15)
N4—C5—C6—N1	−5.3 (2)	C3—C2—C17—C18	−54.4 (2)
C10—C5—C6—N1	178.20 (13)	N1—C2—C17—C22	−52.69 (19)
N4—C5—C6—C7	175.72 (13)	C3—C2—C17—C22	129.63 (15)
C10—C5—C6—C7	−0.8 (2)	C22—C17—C18—C19	1.1 (2)
N1—C6—C7—C8	−178.82 (13)	C2—C17—C18—C19	−174.86 (13)
C5—C6—C7—C8	0.2 (2)	C17—C18—C19—C20	−1.1 (2)
C6—C7—C8—C9	0.4 (2)	C18—C19—C20—C21	0.1 (2)
C7—C8—C9—C10	−0.3 (2)	C19—C20—C21—C22	0.9 (2)
C8—C9—C10—C5	−0.3 (2)	C20—C21—C22—C17	−0.9 (2)
N4—C5—C10—C9	−175.75 (14)	C18—C17—C22—C21	−0.1 (2)
C6—C5—C10—C9	0.8 (2)	C2—C17—C22—C21	175.93 (14)
N4—C3—C11—C12	−35.69 (19)