(E)-N′-(3-Nitro­benzyl­idene)-4-(8-quinol­yloxy)butano­hydrazide

In the title Schiff base compound, C₂₀H₁₈N₄O₄, the conformation along the bond sequence linking the benzene and quinoline rings is trans–(+)gauche–trans–trans–(+)gauche–trans–trans. The dihedral angle between the aromatic ring systems is 80.3 (6)°. In the crystal, a pair of inter­molecular N—H...N hydrogen bonds link the mol­ecules into centrosymmetric R₂²(20) dimers, which are aggregated via π–π inter­actions into sheets [quinoline–benzene ring centroid–centroid separation = 3.572 (2)–3.773 (3) Å].

Key indicators

• Single-crystal X-ray study
• T = 296 K
• Mean [sigma](C-C) = 0.006 Å
• R factor = 0.065
• wR factor = 0.268
• Data-to-parameter ratio = 13.5

checkCIF/PLATON results

No syntax errors found



Alert level C
RFACR01_ALERT_3_C  The value of the weighted R factor is > 0.25
            Weighted R factor given   0.268
PLAT084_ALERT_2_C High wR2 Value .................................       0.27
PLAT241_ALERT_2_C Check High      Ueq as Compared to Neighbors for         C2
PLAT242_ALERT_2_C Check Low       Ueq as Compared to Neighbors for         N4
PLAT340_ALERT_3_C Low Bond Precision on  C-C Bonds (x 1000) Ang ..          6
PLAT601_ALERT_2_C Structure Contains Solvent Accessible VOIDS of .      81.00 A   3 
PLAT911_ALERT_3_C Missing # FCF Refl Between THmin & STh/L=  0.596         39

Alert level G
PLAT072_ALERT_2_G SHELXL First Parameter in WGHT Unusually Large.       0.14

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

   0 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   5 ALERT type 2 Indicator that the structure model may be wrong or deficient
   3 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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S1. Comment

In this article, we present the synthesis and crystal structure of a new Schiff base, (I), which contains oxygen and nitrogen donors and flexible aliphatic spacers. A closely related structure with the nitro group at the 4-position was reported recently (XiaHou et al., 2010). X-ray diffraction analysis reveals that (I) contains a trans-(+)gauche-trans-trans-(+)gauche-trans-trans conformation along the quinoline ring–benzene ring bond sequence [torsion angles (°): C8–O1–C10–C11, 178.5 (3); O1–C10–C11–C12, 70.1 (4); C10–C11–C12–C13, -173.2 (3); C11–C12–C13–N2, -174.8 (3); C12–C13–N2–N3, 0.8 (5); C13–N2–N3–C14, -176.8 (3); N2–N3–C14–C15, -180.0 (3)] (Fig.1). The bond lengths and angles in (I) are in good agreement with the expected values (Allen et al., 1987). The C14—N3 and C13—O2 bond length of 1.276 (5) and 1.214 (4) Å, respectively, indicate the presence of a typical C═N and C═O. The C═N–N angle of 116.6 (3) ° is significantly smaller than the ideal value of 120 ° expected for sp²-hybridized N atoms. This is probably a consequence of repulsion between the nitrogen lone pairs and the adjacent N atom (Zheng et al., 2006). In the crystal structure, a pair of intermolecular N—H···N hydrogen bonds link the molecules into centrosymmetric cyclic R²₂(20) (Bernstein et al., 1995) dimers(Fig.2) which are aggregated via π–π interactions into parallel sheets [quinoline–benzene ring centroid separation = 3.572 (2)–3.773 (3) Å], giving a supramolecular two dimensional network(Fig. 3).

Related literature

For a closely related isomeric structure and background references, see: XiaHou et al. (2010). For further synthetic details, see: Zheng et al. (2006). For reference bond lengths, see: Allen et al. (1987). For hydrogen-bond motifs, see: Bernstein et al. (1995).

S2. Experimental

The title compound was synthesized according to the method of Zheng et al. (2006): 4-(quinolin-8-yloxy)butanehydrazide (0.01 mol), 3-nitrobenzaldehyde (0.01 mol), ethanol (40 ml) and some drops of acetic acid were added to a 100 ml flask and refluxed for 6 h. After cooling to room temperature, the solid product was separated by filtration. Yellow blocks of (I) were obtained by slow evaporation of a tetrahydrofuran solution of the title compound over a period of six days.

S3. Refinement

All H atoms were placed in idealized positions (C—H = 0.93–0.97 Å, N—H = 0.86 Å and refined as riding atoms with U_iso(H) = 1.2U_eq(C or N).

Computing details

Data collection: SMART (Bruker, 2007); cell refinement: SAINT (Bruker, 2007); data reduction: SAINT (Bruker, 2007); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

Figures

	Fig. 1. The molecular structure of (I), with displacement ellipsoids at the 30% probability level.
	Fig. 2. The cyclic hydrogen-bonded dimer in (I) with hydrogen bonds shown as dashed lines. H atoms, except for those involved in hydrogen bonds, are not included.
	Fig. 3. Part of the crystal structure of (I) showing hydrogen bonds as dashed lines. H atoms, except for those involved in hydrogen bonds, are not included.

(E)-N'-(3-Nitrobenzylidene)-4-(8-quinolyloxy)butanohydrazide

Crystal data

C20H18N4O4	Z = 2
Mr = 378.38	F(000) = 396
Triclinic, P1	Dx = 1.289 Mg m^−3
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 8.3664 (12) Å	Cell parameters from 1258 reflections
b = 10.4882 (15) Å	θ = 2.4–24.1°
c = 11.5855 (16) Å	µ = 0.09 mm^−1
α = 100.595 (3)°	T = 296 K
β = 91.968 (3)°	Block, yellow
γ = 101.898 (4)°	0.19 × 0.17 × 0.15 mm
V = 975.0 (2) Å^3

Data collection

Bruker SMART CCD diffractometer	3409 independent reflections
Radiation source: fine-focus sealed tube	1926 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.023
ϕ and ω scans	θmax = 25.1°, θmin = 1.8°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	h = −9→9
Tmin = 0.983, Tmax = 0.986	k = −12→11
5434 measured reflections	l = −13→12

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)] = 0.065	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.268	H-atom parameters constrained
S = 1.08	w = 1/[σ^2(Fo^2) + (0.1425P)^2 + 0.1889P] where P = (Fo^2 + 2Fc^2)/3
3409 reflections	(Δ/σ)max < 0.001
253 parameters	Δρmax = 0.45 e Å^−3
0 restraints	Δρmin = −0.26 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
O1	0.2886 (3)	−0.1013 (3)	0.68540 (19)	0.0613 (8)
O2	0.2305 (4)	−0.0360 (3)	1.0959 (2)	0.0740 (9)
O3	0.8883 (6)	0.6809 (5)	0.8111 (4)	0.1341 (17)
O4	0.6888 (6)	0.5092 (4)	0.7739 (3)	0.1053 (12)
N1	0.5334 (4)	−0.2125 (3)	0.6100 (2)	0.0625 (9)
N2	0.4230 (4)	0.1503 (3)	1.1241 (3)	0.0642 (9)
H2A	0.4367	0.1491	1.1978	0.077*
N3	0.5149 (4)	0.2515 (3)	1.0792 (3)	0.0566 (8)
C1	0.6550 (6)	−0.2666 (5)	0.5723 (4)	0.0872 (15)
H1	0.7215	−0.2894	0.6277	0.105*
C2	0.6912 (7)	−0.2923 (6)	0.4538 (4)	0.0991 (17)
H2	0.7791	−0.3306	0.4316	0.119*
C3	0.5935 (6)	−0.2595 (5)	0.3724 (4)	0.0786 (13)
H3	0.6141	−0.2765	0.2933	0.094*
C4	0.4625 (5)	−0.2005 (4)	0.4064 (3)	0.0592 (10)
C5	0.3618 (6)	−0.1590 (4)	0.3276 (3)	0.0685 (12)
H5	0.3790	−0.1723	0.2478	0.082*
C6	0.2416 (6)	−0.1004 (4)	0.3671 (3)	0.0711 (12)
H6	0.1778	−0.0709	0.3147	0.085*
C7	0.2099 (5)	−0.0826 (4)	0.4869 (3)	0.0670 (11)
H7	0.1221	−0.0456	0.5119	0.080*
C8	0.3055 (5)	−0.1187 (4)	0.5660 (3)	0.0558 (10)
C9	0.4356 (5)	−0.1781 (4)	0.5281 (3)	0.0524 (9)
C10	0.1507 (5)	−0.0514 (5)	0.7282 (3)	0.0621 (10)
H10A	0.0496	−0.1098	0.6910	0.074*
H10B	0.1552	0.0363	0.7112	0.074*
C11	0.1582 (5)	−0.0454 (4)	0.8588 (3)	0.0617 (11)
H11A	0.0553	−0.0295	0.8878	0.074*
H11B	0.1703	−0.1309	0.8740	0.074*
C12	0.2951 (5)	0.0599 (4)	0.9259 (3)	0.0560 (10)
H12A	0.2762	0.1465	0.9191	0.067*
H12B	0.3971	0.0506	0.8913	0.067*
C13	0.3110 (5)	0.0523 (4)	1.0542 (3)	0.0507 (9)
C14	0.6227 (5)	0.3359 (4)	1.1503 (3)	0.0624 (10)
H14	0.6351	0.3263	1.2282	0.075*
C15	0.7263 (5)	0.4469 (4)	1.1114 (3)	0.0629 (11)
C16	0.7079 (5)	0.4681 (4)	0.9964 (3)	0.0597 (10)
H16	0.6269	0.4117	0.9428	0.072*
C17	0.8108 (5)	0.5730 (4)	0.9636 (4)	0.0637 (11)
C18	0.9289 (6)	0.6604 (4)	1.0400 (5)	0.0755 (13)
H18	0.9950	0.7321	1.0160	0.091*
C19	0.9478 (6)	0.6398 (5)	1.1533 (5)	0.0840 (14)
H19	1.0292	0.6964	1.2064	0.101*
C20	0.8451 (6)	0.5343 (5)	1.1875 (4)	0.0761 (13)
H20	0.8571	0.5224	1.2646	0.091*
N4	0.7921 (6)	0.5887 (4)	0.8403 (4)	0.0813 (11)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O1	0.0655 (17)	0.0903 (19)	0.0358 (12)	0.0323 (15)	0.0088 (11)	0.0135 (12)
O2	0.077 (2)	0.095 (2)	0.0570 (16)	0.0159 (17)	0.0094 (14)	0.0357 (16)
O3	0.118 (3)	0.132 (3)	0.157 (4)	−0.016 (3)	−0.020 (3)	0.094 (3)
O4	0.135 (3)	0.091 (2)	0.082 (2)	−0.001 (2)	−0.010 (2)	0.030 (2)
N1	0.069 (2)	0.087 (2)	0.0414 (16)	0.0367 (19)	0.0070 (15)	0.0150 (16)
N2	0.076 (2)	0.081 (2)	0.0409 (16)	0.020 (2)	0.0077 (16)	0.0199 (16)
N3	0.062 (2)	0.068 (2)	0.0473 (17)	0.0246 (17)	0.0096 (15)	0.0160 (16)
C1	0.105 (4)	0.119 (4)	0.056 (2)	0.064 (3)	0.011 (2)	0.020 (2)
C2	0.114 (4)	0.135 (5)	0.065 (3)	0.070 (4)	0.018 (3)	0.010 (3)
C3	0.082 (3)	0.106 (3)	0.047 (2)	0.031 (3)	0.011 (2)	0.001 (2)
C4	0.064 (3)	0.071 (3)	0.0405 (19)	0.011 (2)	0.0023 (17)	0.0085 (17)
C5	0.087 (3)	0.078 (3)	0.0318 (18)	0.002 (2)	−0.0028 (19)	0.0081 (18)
C6	0.081 (3)	0.086 (3)	0.044 (2)	0.013 (3)	−0.013 (2)	0.013 (2)
C7	0.065 (3)	0.092 (3)	0.047 (2)	0.029 (2)	−0.0074 (18)	0.009 (2)
C8	0.067 (3)	0.067 (2)	0.0328 (17)	0.017 (2)	−0.0001 (16)	0.0066 (16)
C9	0.057 (2)	0.065 (2)	0.0346 (17)	0.0117 (19)	0.0013 (15)	0.0093 (16)
C10	0.046 (2)	0.085 (3)	0.055 (2)	0.013 (2)	0.0090 (17)	0.013 (2)
C11	0.049 (2)	0.090 (3)	0.050 (2)	0.020 (2)	0.0113 (17)	0.014 (2)
C12	0.067 (3)	0.072 (2)	0.0379 (18)	0.032 (2)	0.0137 (17)	0.0140 (17)
C13	0.046 (2)	0.067 (2)	0.047 (2)	0.0224 (19)	0.0096 (17)	0.0211 (19)
C14	0.064 (3)	0.079 (3)	0.049 (2)	0.024 (2)	0.0043 (19)	0.012 (2)
C15	0.060 (3)	0.073 (3)	0.059 (2)	0.030 (2)	0.0037 (19)	0.002 (2)
C16	0.064 (3)	0.056 (2)	0.061 (2)	0.024 (2)	0.0003 (19)	0.0053 (18)
C17	0.064 (3)	0.057 (2)	0.078 (3)	0.030 (2)	0.006 (2)	0.014 (2)
C18	0.066 (3)	0.054 (3)	0.104 (4)	0.018 (2)	0.011 (3)	0.000 (2)
C19	0.066 (3)	0.082 (3)	0.088 (4)	0.016 (3)	−0.005 (2)	−0.021 (3)
C20	0.072 (3)	0.083 (3)	0.065 (3)	0.019 (3)	0.005 (2)	−0.007 (2)
N4	0.087 (3)	0.070 (3)	0.097 (3)	0.022 (2)	0.005 (2)	0.035 (2)

Geometric parameters (Å, º)

O1—C8	1.378 (4)	C7—H7	0.9300
O1—C10	1.429 (4)	C8—C9	1.406 (5)
O2—C13	1.214 (4)	C10—C11	1.501 (5)
O3—N4	1.231 (5)	C10—H10A	0.9700
O4—N4	1.207 (5)	C10—H10B	0.9700
N1—C1	1.313 (5)	C11—C12	1.495 (5)
N1—C9	1.377 (4)	C11—H11A	0.9700
N2—C13	1.355 (5)	C11—H11B	0.9700
N2—N3	1.372 (4)	C12—C13	1.505 (5)
N2—H2A	0.8600	C12—H12A	0.9700
N3—C14	1.276 (5)	C12—H12B	0.9700
C1—C2	1.406 (6)	C14—C15	1.454 (6)
C1—H1	0.9300	C14—H14	0.9300
C2—C3	1.363 (6)	C15—C20	1.368 (6)
C2—H2	0.9300	C15—C16	1.399 (5)
C3—C4	1.399 (6)	C16—C17	1.372 (5)
C3—H3	0.9300	C16—H16	0.9300
C4—C5	1.407 (5)	C17—C18	1.367 (6)
C4—C9	1.419 (5)	C17—N4	1.474 (6)
C5—C6	1.334 (6)	C18—C19	1.379 (7)
C5—H5	0.9300	C18—H18	0.9300
C6—C7	1.408 (5)	C19—C20	1.382 (6)
C6—H6	0.9300	C19—H19	0.9300
C7—C8	1.350 (5)	C20—H20	0.9300
C8—O1—C10	117.5 (3)	C12—C11—C10	114.0 (3)
C1—N1—C9	117.9 (3)	C12—C11—H11A	108.8
C13—N2—N3	120.9 (3)	C10—C11—H11A	108.8
C13—N2—H2A	119.5	C12—C11—H11B	108.8
N3—N2—H2A	119.5	C10—C11—H11B	108.8
C14—N3—N2	116.6 (3)	H11A—C11—H11B	107.7
N1—C1—C2	124.3 (4)	C11—C12—C13	112.4 (3)
N1—C1—H1	117.9	C11—C12—H12A	109.1
C2—C1—H1	117.9	C13—C12—H12A	109.1
C3—C2—C1	118.0 (4)	C11—C12—H12B	109.1
C3—C2—H2	121.0	C13—C12—H12B	109.1
C1—C2—H2	121.0	H12A—C12—H12B	107.9
C2—C3—C4	120.8 (4)	O2—C13—N2	119.8 (3)
C2—C3—H3	119.6	O2—C13—C12	123.5 (4)
C4—C3—H3	119.6	N2—C13—C12	116.6 (3)
C3—C4—C5	123.5 (3)	N3—C14—C15	120.9 (4)
C3—C4—C9	117.2 (3)	N3—C14—H14	119.6
C5—C4—C9	119.2 (4)	C15—C14—H14	119.6
C6—C5—C4	120.1 (3)	C20—C15—C16	118.1 (4)
C6—C5—H5	119.9	C20—C15—C14	120.4 (4)
C4—C5—H5	119.9	C16—C15—C14	121.5 (4)
C5—C6—C7	121.0 (4)	C17—C16—C15	119.2 (4)
C5—C6—H6	119.5	C17—C16—H16	120.4
C7—C6—H6	119.5	C15—C16—H16	120.4
C8—C7—C6	120.8 (4)	C18—C17—C16	122.5 (4)
C8—C7—H7	119.6	C18—C17—N4	119.9 (4)
C6—C7—H7	119.6	C16—C17—N4	117.6 (4)
C7—C8—O1	125.3 (3)	C17—C18—C19	118.5 (5)
C7—C8—C9	119.8 (3)	C17—C18—H18	120.7
O1—C8—C9	114.9 (3)	C19—C18—H18	120.7
N1—C9—C8	119.1 (3)	C18—C19—C20	119.6 (4)
N1—C9—C4	121.9 (3)	C18—C19—H19	120.2
C8—C9—C4	119.0 (3)	C20—C19—H19	120.2
O1—C10—C11	107.0 (3)	C15—C20—C19	122.1 (4)
O1—C10—H10A	110.3	C15—C20—H20	118.9
C11—C10—H10A	110.3	C19—C20—H20	118.9
O1—C10—H10B	110.3	O4—N4—O3	124.2 (4)
C11—C10—H10B	110.3	O4—N4—C17	118.8 (4)
H10A—C10—H10B	108.6	O3—N4—C17	116.9 (5)
C13—N2—N3—C14	−176.8 (3)	C8—O1—C10—C11	178.5 (3)
C9—N1—C1—C2	−0.4 (8)	O1—C10—C11—C12	70.1 (4)
N1—C1—C2—C3	−0.3 (9)	C10—C11—C12—C13	−173.2 (3)
C1—C2—C3—C4	0.8 (8)	N3—N2—C13—O2	−179.7 (3)
C2—C3—C4—C5	177.1 (5)	N3—N2—C13—C12	0.8 (5)
C2—C3—C4—C9	−0.7 (7)	C11—C12—C13—O2	5.7 (5)
C3—C4—C5—C6	−178.3 (4)	C11—C12—C13—N2	−174.8 (3)
C9—C4—C5—C6	−0.7 (6)	N2—N3—C14—C15	−180.0 (3)
C4—C5—C6—C7	−1.9 (7)	N3—C14—C15—C20	−177.9 (3)
C5—C6—C7—C8	3.2 (7)	N3—C14—C15—C16	2.4 (5)
C6—C7—C8—O1	177.6 (4)	C20—C15—C16—C17	1.4 (5)
C6—C7—C8—C9	−1.8 (6)	C14—C15—C16—C17	−178.9 (3)
C10—O1—C8—C7	5.6 (6)	C15—C16—C17—C18	−1.7 (5)
C10—O1—C8—C9	−175.0 (3)	C15—C16—C17—N4	177.5 (3)
C1—N1—C9—C8	−179.3 (4)	C16—C17—C18—C19	1.8 (6)
C1—N1—C9—C4	0.5 (6)	N4—C17—C18—C19	−177.3 (4)
C7—C8—C9—N1	179.0 (4)	C17—C18—C19—C20	−1.7 (6)
O1—C8—C9—N1	−0.3 (5)	C16—C15—C20—C19	−1.3 (6)
C7—C8—C9—C4	−0.8 (6)	C14—C15—C20—C19	178.9 (4)
O1—C8—C9—C4	179.8 (3)	C18—C19—C20—C15	1.5 (6)
C3—C4—C9—N1	0.0 (6)	C18—C17—N4—O4	178.7 (4)
C5—C4—C9—N1	−177.8 (4)	C16—C17—N4—O4	−0.4 (6)
C3—C4—C9—C8	179.8 (4)	C18—C17—N4—O3	1.3 (6)
C5—C4—C9—C8	2.0 (6)	C16—C17—N4—O3	−177.9 (4)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N2—H2A···N1^i	0.86	2.19	3.022 (4)	162

Symmetry code: (i) −x+1, −y, −z+2.