2,3-Bis(4-ethoxy-phen-yl)quinoxaline.

The title compound, C(24)H(22)N(2)O(2), was prepared by condensation of 1,2-bis-(4-ethoxy-phen-yl)ethane-1,2-dione and 1,2-diamino-benzene. The asymmetric unit contains one half-mol-ecule, close to a twofold axis. The plane of the quinoxaline ring is twisted with respect to the planes of the two ethoxy-phenyl ring systems, exhibiting dihedral angles of 39.95 (9)°. The crystal packing is dominated by weak C-H⋯π inter-actions. No classical hydrogen bonds or stacking inter-actions are observed.

Related literature

For applications of quinoxaline derivatives, see: Seitz et al. (2002 ▶); He et al. (2003 ▶); Dailey et al. (2001 ▶). For the syntheses of quinoxaline derivatives, see: Bhosale et al. (2005 ▶); More et al. (2006 ▶); Raw et al. (2003 ▶). For the synthesis of the title compound, see: Heravi et al. (2006 ▶).

Experimental

Crystal data

C24H22N2O2

M = 370.44

Monoclinic,

a = 19.4837 (18) Å

b = 11.2682 (11) Å

c = 9.2629 (9) Å

β = 100.196 (1)°

V = 2001.5 (3) Å3

Z = 4

Mo Kα radiation

μ = 0.08 mm−1

T = 293 K

0.37 × 0.27 × 0.24 mm

Data collection

Bruker SMART CCD area-detector diffractometer

Absorption correction: multi-scan (SADABS; Sheldrick, 1996 ▶) T min = 0.972, T max = 0.981

6487 measured reflections

1743 independent reflections

1560 reflections with I > 2σ(I)

R int = 0.028

Refinement

R[F 2 > 2σ(F 2)] = 0.035

wR(F 2) = 0.092

S = 1.03

1743 reflections

128 parameters

H-atom parameters constrained

Δρmax = 0.17 e Å−3

Δρmin = −0.12 e Å−3

Data collection: SMART (Bruker, 2004 ▶); cell refinement: SAINT (Bruker, 2004 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXL97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: ORTEP-3 (Farrugia, 1997 ▶); software used to prepare material for publication: WinGX (Farrugia, 1999 ▶).

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536809052295/bh2259sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S1600536809052295/bh2259Isup2.hkl

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

C24H22N2O2	F(000) = 784
Mr = 370.44	Dx = 1.229 Mg m−3
Monoclinic, C2/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -C 2yc	Cell parameters from 3608 reflections
a = 19.4837 (18) Å	θ = 5.6–52.7°
b = 11.2682 (11) Å	µ = 0.08 mm−1
c = 9.2629 (9) Å	T = 293 K
β = 100.196 (1)°	Prism, yellow
V = 2001.5 (3) Å3	0.37 × 0.27 × 0.24 mm
Z = 4

Bruker SMART CCD area-detector diffractometer	1743 independent reflections
Radiation source: fine-focus sealed tube	1560 reflections with I > 2σ(I)
graphite	Rint = 0.028
φ and ω scans	θmax = 25.0°, θmin = 2.1°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	h = −23→22
Tmin = 0.972, Tmax = 0.981	k = −12→13
6487 measured reflections	l = −10→10

Refinement on F2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.035	H-atom parameters constrained
wR(F2) = 0.092	w = 1/[σ2(Fo2) + (0.0422P)2 + 0.9006P] where P = (Fo2 + 2Fc2)/3
S = 1.03	(Δ/σ)max < 0.001
1743 reflections	Δρmax = 0.17 e Å−3
128 parameters	Δρmin = −0.12 e Å−3
0 restraints	Extinction correction: SHELXL97 (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.0289 (19)

	x	y	z	Uiso*/Ueq
C1	0.46773 (6)	−0.00154 (10)	0.19704 (12)	0.0281 (3)
N1	0.43983 (5)	−0.10164 (8)	0.14060 (11)	0.0321 (3)
C2	0.47078 (6)	−0.20565 (10)	0.19257 (13)	0.0333 (3)
C3	0.44262 (8)	−0.31482 (11)	0.13548 (16)	0.0459 (4)
H3	0.4044	−0.3157	0.0594	0.055*
C4	0.47143 (9)	−0.41910 (12)	0.19182 (17)	0.0580 (4)
H4	0.4531	−0.4908	0.1529	0.070*
O1	0.31520 (5)	0.41927 (8)	0.03771 (11)	0.0503 (3)
C8	0.35080 (6)	0.31489 (10)	0.06662 (14)	0.0369 (3)
C6	0.41928 (6)	0.19601 (11)	0.25439 (13)	0.0365 (3)
H6	0.4395	0.1856	0.3523	0.044*
C10	0.39626 (6)	0.12701 (10)	0.00690 (13)	0.0334 (3)
H10	0.4003	0.0690	−0.0625	0.040*
C5	0.42812 (6)	0.10907 (10)	0.15155 (12)	0.0294 (3)
C7	0.38108 (7)	0.29661 (11)	0.21256 (14)	0.0402 (3)
H7	0.3754	0.3532	0.2826	0.048*
C9	0.35851 (6)	0.22927 (11)	−0.03675 (14)	0.0368 (3)
H9	0.3385	0.2403	−0.1347	0.044*
C11	0.28097 (7)	0.44243 (12)	−0.10928 (17)	0.0514 (4)
H11A	0.2476	0.3801	−0.1428	0.062*
H11B	0.3148	0.4455	−0.1745	0.062*
C12	0.24435 (8)	0.55950 (14)	−0.1089 (2)	0.0689 (5)
H12A	0.2209	0.5777	−0.2065	0.103*
H12B	0.2778	0.6204	−0.0755	0.103*
H12C	0.2109	0.5552	−0.0445	0.103*

	U11	U22	U33	U12	U13	U23
C1	0.0309 (6)	0.0289 (6)	0.0251 (6)	−0.0019 (5)	0.0067 (5)	0.0001 (4)
N1	0.0342 (5)	0.0298 (6)	0.0320 (6)	−0.0025 (4)	0.0051 (4)	−0.0004 (4)
C2	0.0394 (6)	0.0289 (6)	0.0328 (7)	−0.0020 (5)	0.0096 (5)	−0.0004 (5)
C3	0.0582 (8)	0.0346 (7)	0.0437 (8)	−0.0107 (6)	0.0053 (6)	−0.0041 (6)
C4	0.0851 (12)	0.0279 (7)	0.0607 (10)	−0.0092 (7)	0.0119 (8)	−0.0052 (6)
O1	0.0515 (6)	0.0377 (5)	0.0575 (6)	0.0140 (4)	−0.0017 (5)	0.0093 (4)
C8	0.0338 (6)	0.0303 (7)	0.0451 (8)	0.0029 (5)	0.0032 (5)	0.0078 (5)
C6	0.0426 (7)	0.0371 (7)	0.0286 (6)	0.0073 (5)	0.0030 (5)	0.0014 (5)
C10	0.0343 (6)	0.0331 (7)	0.0320 (7)	−0.0020 (5)	0.0037 (5)	−0.0010 (5)
C5	0.0285 (5)	0.0290 (6)	0.0307 (6)	−0.0010 (5)	0.0048 (4)	0.0015 (5)
C7	0.0472 (7)	0.0345 (7)	0.0383 (7)	0.0093 (6)	0.0061 (6)	−0.0027 (5)
C9	0.0365 (6)	0.0385 (7)	0.0327 (7)	−0.0014 (5)	−0.0015 (5)	0.0065 (5)
C11	0.0398 (7)	0.0482 (8)	0.0622 (10)	0.0006 (6)	−0.0024 (6)	0.0242 (7)
C12	0.0434 (8)	0.0553 (10)	0.1049 (14)	0.0103 (7)	0.0049 (8)	0.0361 (9)

C1—N1	1.3193 (14)	C6—C7	1.3737 (17)
C1—C1i	1.452 (2)	C6—C5	1.3981 (16)
C1—C5	1.4871 (15)	C6—H6	0.9300
N1—C2	1.3660 (15)	C10—C9	1.3881 (17)
C2—C3	1.4111 (17)	C10—C5	1.3882 (16)
C2—C2i	1.414 (2)	C10—H10	0.9300
C3—C4	1.3655 (19)	C7—H7	0.9300
C3—H3	0.9300	C9—H9	0.9300
C4—C4i	1.406 (3)	C11—C12	1.500 (2)
C4—H4	0.9300	C11—H11A	0.9700
O1—C8	1.3676 (14)	C11—H11B	0.9700
O1—C11	1.4301 (17)	C12—H12A	0.9600
C8—C9	1.3860 (18)	C12—H12B	0.9600
C8—C7	1.3912 (18)	C12—H12C	0.9600
N1—C1—C1i	120.98 (6)	C5—C10—H10	119.2
N1—C1—C5	116.59 (10)	C10—C5—C6	117.88 (11)
C1i—C1—C5	122.38 (6)	C10—C5—C1	121.10 (10)
C1—N1—C2	117.95 (10)	C6—C5—C1	120.97 (10)
N1—C2—C3	119.85 (11)	C6—C7—C8	120.77 (11)
N1—C2—C2i	120.77 (6)	C6—C7—H7	119.6
C3—C2—C2i	119.33 (8)	C8—C7—H7	119.6
C4—C3—C2	120.05 (13)	C8—C9—C10	119.56 (11)
C4—C3—H3	120.0	C8—C9—H9	120.2
C2—C3—H3	120.0	C10—C9—H9	120.2
C3—C4—C4i	120.61 (8)	O1—C11—C12	107.47 (14)
C3—C4—H4	119.7	O1—C11—H11A	110.2
C4i—C4—H4	119.7	C12—C11—H11A	110.2
C8—O1—C11	118.57 (11)	O1—C11—H11B	110.2
O1—C8—C9	125.21 (11)	C12—C11—H11B	110.2
O1—C8—C7	115.51 (11)	H11A—C11—H11B	108.5
C9—C8—C7	119.28 (11)	C11—C12—H12A	109.5
C7—C6—C5	120.80 (11)	C11—C12—H12B	109.5
C7—C6—H6	119.6	H12A—C12—H12B	109.5
C5—C6—H6	119.6	C11—C12—H12C	109.5
C9—C10—C5	121.69 (11)	H12A—C12—H12C	109.5
C9—C10—H10	119.2	H12B—C12—H12C	109.5

Cg1 is the centroid of the N1,C1,C1',N1',C2 ring and Cg2 is the centroid of the C5–C10 ring.

D—H···A	D—H	H···A	D···A	D—H···A
C10—H10···Cg1ii	0.93	2.85	3.3936 (17)	119
C11—H11A···Cg2iii	0.96	2.93	3.743 (2)	143

Table 1

Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C10—H10⋯Cg1i	0.93	2.85	3.3936 (17)	119
C11—H11A⋯Cg2ii	0.96	2.93	3.743 (2)	143

Symmetry codes: (i) ; (ii) . Cg1 is the centroid of the N1,C1,C1′,N1′,C2 ring and Cg2 is the centroid of the C5–C10 ring.