3-[(2,3-Diphenyl­quinoxalin-5-ylamino)methyl­ene]pentane-2,4-dione

In the title compound, C₂₆H₂₁N₃O₂, the enaminone portion of the mol­ecule is almost exactly planar owing to strong conjugation across the ethyl­ene double bond and is inclined at an angle of 20.8 (1)° to the mean plane of the quinoxaline heterocycle. The mol­ecule has an intra­molecular hydrogen bond between the NH and CO groups in the Z configuration, adopting the chelated form. The phenyl rings are twisted by ca 46° from the heterocyclic plane.

Key indicators

• Single-crystal X-ray study
• T = 296 K
• Mean [sigma](C-C) = 0.003 Å
• R factor = 0.054
• wR factor = 0.181
• Data-to-parameter ratio = 16.8

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT026_ALERT_3_C Ratio Observed / Unique Reflections too Low ....         47 Perc.
PLAT230_ALERT_2_C Hirshfeld Test Diff for    C4     -   C5      ..       6.71 su
PLAT230_ALERT_2_C Hirshfeld Test Diff for    C10    -   C11     ..       5.25 su
PLAT230_ALERT_2_C Hirshfeld Test Diff for    C25    -   C26     ..       6.58 su
PLAT242_ALERT_2_C Check Low       Ueq as Compared to Neighbors for        C25

   0 ALERT level A = In general: serious problem
   0 ALERT level B = Potentially serious problem
   5 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
   4 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: CrysAlis CCD (Oxford Diffraction, 2001); 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: PLATON (Spek, 2003); software used to prepare material for publication: SHELXL97.

3-[(2,3-Diphenylquinoxalin-5-ylamino)methylene]pentane-2,4-dione

Crystal data

C26H21N3O2	F(000) = 856
Mr = 407.46	Dx = 1.293 Mg m^−3
Monoclinic, P21/n	Melting point: 475 K
Hall symbol: -P 2yn	Mo Kα radiation, λ = 0.71073 Å
a = 12.326 (3) Å	Cell parameters from 20 reflections
b = 10.726 (2) Å	θ = 7–19°
c = 15.999 (3) Å	µ = 0.08 mm^−1
β = 98.43 (3)°	T = 296 K
V = 2092.4 (8) Å^3	Prism, yellow
Z = 4	0.30 × 0.20 × 0.15 mm

Data collection

Oxford Diffraction Gemini R CCD diffractometer	2246 reflections with I > 2σ(I)
Radiation source: fine-focus sealed X-ray tube	Rint = 0.040
Graphite monochromator	θmax = 27.5°, θmin = 3.2°
ω and φ scans	h = −15→15
25458 measured reflections	k = 0→13
4748 independent reflections	l = 0→20

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)] = 0.054	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.181	H-atom parameters constrained
S = 0.94	w = 1/[σ^2(Fo^2) + (0.1045P)^2] where P = (Fo^2 + 2Fc^2)/3
4748 reflections	(Δ/σ)max = 0.001
282 parameters	Δρmax = 0.27 e Å^−3
0 restraints	Δρmin = −0.17 e Å^−3

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
C1	0.76904 (13)	0.50668 (16)	0.10874 (12)	0.0523 (4)
C2	0.70195 (13)	0.48812 (16)	0.17440 (11)	0.0525 (4)
C3	0.57207 (13)	0.39370 (16)	0.07810 (11)	0.0530 (5)
C4	0.46487 (14)	0.34159 (16)	0.05642 (12)	0.0540 (5)
C5	0.43650 (15)	0.29116 (17)	−0.02195 (13)	0.0631 (5)
H5	0.3677	0.2549	−0.0360	0.076*
C6	0.50906 (16)	0.29300 (17)	−0.08176 (13)	0.0641 (5)
H6	0.4876	0.2573	−0.1346	0.077*
C7	0.61008 (15)	0.34585 (17)	−0.06429 (12)	0.0608 (5)
H7	0.6568	0.3478	−0.1049	0.073*
C8	0.64296 (14)	0.39771 (15)	0.01666 (11)	0.0530 (5)
C9	0.87002 (13)	0.58473 (17)	0.12126 (11)	0.0557 (5)
C10	0.96316 (14)	0.5427 (2)	0.09333 (12)	0.0657 (5)
H10	0.9640	0.4638	0.0693	0.079*
C11	1.05623 (16)	0.6167 (2)	0.10054 (14)	0.0791 (6)
H11	1.1195	0.5868	0.0822	0.095*
C12	1.05518 (17)	0.7332 (2)	0.13451 (14)	0.0788 (6)
H12	1.1174	0.7831	0.1384	0.095*
C13	0.96264 (18)	0.7770 (2)	0.16304 (14)	0.0761 (6)
H13	0.9621	0.8565	0.1862	0.091*
C14	0.87049 (16)	0.70274 (19)	0.15721 (13)	0.0689 (6)
H14	0.8082	0.7318	0.1775	0.083*
C15	0.74192 (14)	0.52106 (17)	0.26374 (11)	0.0551 (5)
C16	0.84613 (15)	0.48440 (17)	0.30097 (12)	0.0631 (5)
H16	0.8911	0.4402	0.2697	0.076*
C17	0.88271 (17)	0.5136 (2)	0.38426 (14)	0.0720 (6)
H17	0.9523	0.4884	0.4090	0.086*
C18	0.81833 (19)	0.5785 (2)	0.43042 (14)	0.0806 (6)
H18	0.8439	0.5978	0.4865	0.097*
C19	0.7151 (2)	0.6161 (2)	0.39458 (15)	0.0855 (7)
H19	0.6716	0.6618	0.4263	0.103*
C20	0.67594 (16)	0.58603 (19)	0.31115 (14)	0.0702 (6)
H20	0.6055	0.6096	0.2874	0.084*
C21	0.29583 (15)	0.30206 (18)	0.11336 (13)	0.0664 (5)
H21	0.2745	0.2464	0.0694	0.080*
C22	0.22077 (15)	0.3248 (2)	0.16813 (14)	0.0694 (6)
C23	0.24582 (17)	0.4184 (2)	0.23467 (14)	0.0734 (6)
C24	0.16573 (19)	0.4527 (3)	0.29325 (17)	0.1022 (8)
H24A	0.1985	0.5131	0.3335	0.153*
H24B	0.1467	0.3796	0.3225	0.153*
H24C	0.1009	0.4875	0.2611	0.153*
C25	0.11727 (17)	0.2549 (2)	0.15632 (17)	0.0827 (7)
C26	0.0941 (2)	0.1653 (3)	0.08330 (18)	0.1091 (9)
H26A	0.0226	0.1294	0.0827	0.164*
H26B	0.1483	0.1004	0.0894	0.164*
H26C	0.0965	0.2091	0.0313	0.164*
N1	0.74097 (11)	0.45906 (13)	0.03286 (9)	0.0547 (4)
N2	0.60379 (11)	0.43696 (13)	0.15743 (9)	0.0537 (4)
N3	0.39484 (11)	0.35158 (14)	0.11729 (10)	0.0621 (4)
H3	0.4184	0.3942	0.1618	0.075*
O1	0.33428 (12)	0.47245 (15)	0.24391 (10)	0.0839 (5)
O2	0.04798 (14)	0.26864 (18)	0.20244 (15)	0.1201 (7)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
C1	0.0413 (9)	0.0592 (10)	0.0570 (11)	0.0012 (8)	0.0090 (8)	−0.0038 (9)
C2	0.0426 (9)	0.0602 (11)	0.0556 (11)	0.0015 (8)	0.0103 (8)	0.0016 (8)
C3	0.0457 (10)	0.0543 (10)	0.0589 (12)	0.0009 (8)	0.0075 (8)	0.0052 (8)
C4	0.0425 (9)	0.0585 (10)	0.0611 (12)	−0.0038 (7)	0.0078 (8)	0.0027 (8)
C5	0.0472 (10)	0.0607 (11)	0.0797 (15)	−0.0051 (9)	0.0038 (10)	−0.0022 (10)
C6	0.0630 (12)	0.0620 (11)	0.0658 (13)	−0.0005 (9)	0.0044 (10)	−0.0084 (9)
C7	0.0583 (11)	0.0637 (12)	0.0610 (12)	0.0008 (9)	0.0106 (9)	−0.0021 (9)
C8	0.0476 (10)	0.0546 (10)	0.0575 (11)	−0.0017 (8)	0.0101 (8)	0.0017 (8)
C9	0.0428 (9)	0.0719 (12)	0.0543 (11)	−0.0060 (8)	0.0131 (8)	−0.0017 (9)
C10	0.0483 (11)	0.0783 (13)	0.0725 (14)	−0.0031 (9)	0.0151 (9)	−0.0148 (10)
C11	0.0493 (11)	0.1078 (18)	0.0829 (15)	−0.0033 (11)	0.0186 (10)	−0.0153 (13)
C12	0.0568 (13)	0.1017 (17)	0.0785 (15)	−0.0255 (11)	0.0119 (11)	−0.0115 (13)
C13	0.0724 (14)	0.0775 (14)	0.0792 (15)	−0.0177 (11)	0.0131 (11)	−0.0136 (11)
C14	0.0587 (12)	0.0745 (14)	0.0756 (14)	−0.0039 (10)	0.0168 (10)	−0.0087 (10)
C15	0.0442 (10)	0.0642 (11)	0.0583 (12)	−0.0015 (8)	0.0124 (8)	−0.0005 (9)
C16	0.0558 (11)	0.0710 (12)	0.0625 (12)	0.0065 (9)	0.0089 (9)	−0.0009 (9)
C17	0.0640 (13)	0.0811 (14)	0.0679 (14)	0.0016 (10)	−0.0007 (10)	0.0002 (11)
C18	0.0863 (16)	0.0916 (16)	0.0611 (14)	−0.0057 (13)	0.0018 (12)	−0.0110 (11)
C19	0.0763 (15)	0.1034 (17)	0.0796 (16)	0.0046 (13)	0.0203 (12)	−0.0259 (13)
C20	0.0529 (11)	0.0855 (14)	0.0729 (14)	0.0039 (10)	0.0118 (10)	−0.0133 (11)
C21	0.0473 (10)	0.0695 (12)	0.0818 (15)	−0.0090 (9)	0.0074 (10)	0.0130 (10)
C22	0.0433 (10)	0.0838 (14)	0.0817 (15)	−0.0028 (9)	0.0110 (10)	0.0194 (11)
C23	0.0538 (12)	0.0914 (15)	0.0756 (15)	−0.0019 (11)	0.0115 (10)	0.0202 (12)
C24	0.0697 (15)	0.143 (2)	0.1006 (19)	−0.0014 (15)	0.0345 (13)	−0.0036 (16)
C25	0.0531 (13)	0.0950 (16)	0.1008 (19)	−0.0128 (11)	0.0144 (12)	0.0199 (13)
C26	0.0691 (15)	0.150 (3)	0.105 (2)	−0.0393 (15)	0.0023 (14)	0.0167 (18)
N1	0.0461 (8)	0.0599 (9)	0.0596 (10)	0.0000 (7)	0.0132 (7)	−0.0012 (7)
N2	0.0437 (8)	0.0607 (9)	0.0574 (10)	−0.0001 (6)	0.0100 (7)	0.0015 (7)
N3	0.0437 (8)	0.0723 (10)	0.0706 (11)	−0.0062 (7)	0.0094 (7)	0.0035 (8)
O1	0.0637 (9)	0.1013 (11)	0.0897 (11)	−0.0113 (8)	0.0221 (8)	−0.0055 (8)
O2	0.0711 (11)	0.1279 (15)	0.174 (2)	−0.0286 (10)	0.0593 (12)	−0.0030 (13)

Geometric parameters (Å, º)

C1—N1	1.316 (2)	C15—C20	1.380 (3)
C1—C2	1.443 (2)	C15—C16	1.391 (2)
C1—C9	1.489 (2)	C16—C17	1.379 (3)
C2—N2	1.320 (2)	C16—H16	0.9300
C2—C15	1.485 (2)	C17—C18	1.353 (3)
C3—N2	1.354 (2)	C17—H17	0.9300
C3—C8	1.408 (2)	C18—C19	1.377 (3)
C3—C4	1.430 (2)	C18—H18	0.9300
C4—C5	1.363 (3)	C19—C20	1.389 (3)
C4—N3	1.397 (2)	C19—H19	0.9300
C5—C6	1.402 (3)	C20—H20	0.9300
C5—H5	0.9300	C21—N3	1.324 (2)
C6—C7	1.359 (3)	C21—C22	1.386 (3)
C6—H6	0.9300	C21—H21	0.9300
C7—C8	1.413 (3)	C22—C23	1.463 (3)
C7—H7	0.9300	C22—C25	1.468 (3)
C8—N1	1.367 (2)	C23—O1	1.225 (2)
C9—C10	1.368 (2)	C23—C24	1.503 (3)
C9—C14	1.390 (3)	C24—H24A	0.9600
C10—C11	1.386 (3)	C24—H24B	0.9600
C10—H10	0.9300	C24—H24C	0.9600
C11—C12	1.363 (3)	C25—O2	1.217 (3)
C11—H11	0.9300	C25—C26	1.507 (4)
C12—C13	1.372 (3)	C26—H26A	0.9600
C12—H12	0.9300	C26—H26B	0.9600
C13—C14	1.379 (3)	C26—H26C	0.9600
C13—H13	0.9300	N3—H3	0.8600
C14—H14	0.9300
N1—C1—C2	121.13 (15)	C17—C16—C15	120.03 (18)
N1—C1—C9	116.35 (15)	C17—C16—H16	120.0
C2—C1—C9	122.46 (16)	C15—C16—H16	120.0
N2—C2—C1	120.90 (16)	C18—C17—C16	120.6 (2)
N2—C2—C15	117.50 (15)	C18—C17—H17	119.7
C1—C2—C15	121.56 (15)	C16—C17—H17	119.7
N2—C3—C8	121.35 (15)	C17—C18—C19	120.2 (2)
N2—C3—C4	119.40 (16)	C17—C18—H18	119.9
C8—C3—C4	119.24 (16)	C19—C18—H18	119.9
C5—C4—N3	124.77 (16)	C18—C19—C20	120.1 (2)
C5—C4—C3	118.79 (17)	C18—C19—H19	119.9
N3—C4—C3	116.38 (16)	C20—C19—H19	119.9
C4—C5—C6	121.25 (17)	C15—C20—C19	119.72 (19)
C4—C5—H5	119.4	C15—C20—H20	120.1
C6—C5—H5	119.4	C19—C20—H20	120.1
C7—C6—C5	121.48 (18)	N3—C21—C22	126.5 (2)
C7—C6—H6	119.3	N3—C21—H21	116.7
C5—C6—H6	119.3	C22—C21—H21	116.7
C6—C7—C8	118.91 (18)	C21—C22—C23	119.43 (18)
C6—C7—H7	120.5	C21—C22—C25	118.5 (2)
C8—C7—H7	120.5	C23—C22—C25	122.1 (2)
N1—C8—C3	120.27 (16)	O1—C23—C22	120.13 (19)
N1—C8—C7	119.34 (16)	O1—C23—C24	117.6 (2)
C3—C8—C7	120.25 (16)	C22—C23—C24	122.3 (2)
C10—C9—C14	118.84 (17)	C23—C24—H24A	109.5
C10—C9—C1	119.72 (16)	C23—C24—H24B	109.5
C14—C9—C1	121.36 (16)	H24A—C24—H24B	109.5
C9—C10—C11	120.55 (19)	C23—C24—H24C	109.5
C9—C10—H10	119.7	H24A—C24—H24C	109.5
C11—C10—H10	119.7	H24B—C24—H24C	109.5
C12—C11—C10	120.13 (19)	O2—C25—C22	122.3 (2)
C12—C11—H11	119.9	O2—C25—C26	118.5 (2)
C10—C11—H11	119.9	C22—C25—C26	119.2 (2)
C11—C12—C13	120.22 (19)	C25—C26—H26A	109.5
C11—C12—H12	119.9	C25—C26—H26B	109.5
C13—C12—H12	119.9	H26A—C26—H26B	109.5
C12—C13—C14	119.8 (2)	C25—C26—H26C	109.5
C12—C13—H13	120.1	H26A—C26—H26C	109.5
C14—C13—H13	120.1	H26B—C26—H26C	109.5
C13—C14—C9	120.49 (18)	C1—N1—C8	117.86 (15)
C13—C14—H14	119.8	C2—N2—C3	117.72 (15)
C9—C14—H14	119.8	C21—N3—C4	126.55 (17)
C20—C15—C16	119.28 (18)	C21—N3—H3	116.7
C20—C15—C2	120.69 (16)	C4—N3—H3	116.7
C16—C15—C2	120.02 (16)
N1—C1—C2—N2	−8.9 (3)	N2—C2—C15—C16	130.68 (18)
C9—C1—C2—N2	168.19 (15)	C1—C2—C15—C16	−47.0 (2)
N1—C1—C2—C15	168.75 (16)	C20—C15—C16—C17	−0.3 (3)
C9—C1—C2—C15	−14.2 (3)	C2—C15—C16—C17	−179.14 (18)
N2—C3—C4—C5	−175.86 (16)	C15—C16—C17—C18	−0.4 (3)
C8—C3—C4—C5	3.5 (2)	C16—C17—C18—C19	0.1 (3)
N2—C3—C4—N3	6.8 (2)	C17—C18—C19—C20	0.9 (4)
C8—C3—C4—N3	−173.84 (15)	C16—C15—C20—C19	1.3 (3)
N3—C4—C5—C6	175.18 (17)	C2—C15—C20—C19	−179.85 (19)
C3—C4—C5—C6	−1.9 (3)	C18—C19—C20—C15	−1.6 (3)
C4—C5—C6—C7	−0.5 (3)	N3—C21—C22—C23	4.7 (3)
C5—C6—C7—C8	1.3 (3)	N3—C21—C22—C25	−176.36 (18)
N2—C3—C8—N1	−7.8 (2)	C21—C22—C23—O1	−3.0 (3)
C4—C3—C8—N1	172.86 (15)	C25—C22—C23—O1	178.10 (19)
N2—C3—C8—C7	176.57 (16)	C21—C22—C23—C24	176.6 (2)
C4—C3—C8—C7	−2.7 (2)	C25—C22—C23—C24	−2.3 (3)
C6—C7—C8—N1	−175.26 (16)	C21—C22—C25—O2	179.1 (2)
C6—C7—C8—C3	0.4 (3)	C23—C22—C25—O2	−1.9 (3)
N1—C1—C9—C10	−47.1 (2)	C21—C22—C25—C26	−2.6 (3)
C2—C1—C9—C10	135.69 (19)	C23—C22—C25—C26	176.4 (2)
N1—C1—C9—C14	129.71 (19)	C2—C1—N1—C8	3.8 (2)
C2—C1—C9—C14	−47.5 (3)	C9—C1—N1—C8	−173.43 (14)
C14—C9—C10—C11	−0.2 (3)	C3—C8—N1—C1	4.1 (2)
C1—C9—C10—C11	176.71 (17)	C7—C8—N1—C1	179.76 (16)
C9—C10—C11—C12	−1.0 (3)	C1—C2—N2—C3	5.1 (2)
C10—C11—C12—C13	1.1 (4)	C15—C2—N2—C3	−172.59 (15)
C11—C12—C13—C14	0.0 (3)	C8—C3—N2—C2	2.9 (2)
C12—C13—C14—C9	−1.2 (3)	C4—C3—N2—C2	−177.84 (15)
C10—C9—C14—C13	1.3 (3)	C22—C21—N3—C4	−171.10 (18)
C1—C9—C14—C13	−175.58 (18)	C5—C4—N3—C21	8.4 (3)
N2—C2—C15—C20	−48.1 (2)	C3—C4—N3—C21	−174.50 (16)
C1—C2—C15—C20	134.16 (19)