(E)-1-(3,3′-Dimeth­oxy-4′-{[(E)-4-nitro­benzyl­idene]amino}-[1,1′-biphen­yl]-4-yl)-N-(4-nitro­phen­yl)methanimine

Boukhemis, O.; Boulkedid, A.L.; Boutebdja, M.; Marir, A.; Benlatreche, M.S.; Jeanneau, E.

doi:10.1107/S2414314626002208

organic compounds

IUCrDATA

ISSN: 2414-3146

Volume 11| Part 3| March 2026| x260220

https://doi.org/10.1107/S2414314626002208

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(E)-1-(3,3′-Dimethoxy-4′-{[(E)-4-nitrobenzylidene]amino}-[1,1′-biphenyl]-4-yl)-N-(4-nitrophenyl)methanimine

Ouafa Boukhemis,^a Ahlem Linda Boulkedid,^b Mehdi Boutebdja,^c ^* Amel Marir,^d Mohamed Salah Benlatreche ^e and Erwann Jeanneau ^f

^aNational Biotechnology Research Center (CRBT), Industrial Biotechnology Division, Ali Mendjli New City, UV 03 BP E73, Constantine 25000, Algeria, ^bUnité de Recherche de Chimie de l'Environnement et Moléculaire Structurale, Université de Constantine-1 25000, Constantine, Algeria, ^cLaboratoire de Technologie des Matériaux Avancés, École Nationale Polytechnique de Constantine, Algeria, ^dUniversité Constantine 1, Algeria, ^eThe Environmental Engineering and Technologies Laboratory, Abdelhafid Boussouf Mila University, Algeria, and ^fCentre de Diffractométrie Henri Longchambon, Université Claude Bernard Lyon1, 5 rue de la Doua, 69100 Villeurbanne, France
^*Correspondence e-mail: [email protected]

Edited by M. Zeller, Purdue University, USA (Received 19 January 2026; accepted 27 February 2026; online 5 March 2026)

The title compound, C₂₈H₂₂N₄O₆, crystallizes with one half-molecule in the asymmetric unit centered on a twofold rotation axis located at the midpoint of the central C—C bond. The structure is non-planar overall, with nearly planar anisole-imine and nitrophenyl-methanimine fragments. In the crystal, a cooperative network of intermolecular C—H⋯O hydrogen bonds organizes the molecules into layers parallel to the (101) plane, which are further consolidated by offset π–π stacking between centrosymmetrically related phenyl rings and C—H⋯π interactions. Collectively, these non-covalent interactions contribute to the cohesion of the three-dimensional supramolecular framework.

Keywords: crystal structure; Schiff base.

CCDC reference: 2487703

Structure description

The title Schiff base was synthesized as part of a broader search for multifunctional imine-based molecules, whose tunable π-conjugation underpins applications in catalysis, sensing, materials science and medicinal chemistry. The title compound crystallizes in the monoclinic space group I2/a, with one half-molecule in the asymmetric unit. The molecule is centered on a crystallographic twofold rotation axis located at the midpoint of the C11—C11ⁱ bond of the amine molecule [symmetry code: (i) $[{3\over 2}]$ − x, 1 − y, 1 − z] (Fig. 1). The molecule is not planar. Within the asymmetric unit, the two Schiff base moieties are also non-planar, whereas the anisole-imine and nitrophenyl-methanimine are each individually nearly planar (C1—C6 and N, O1, O2, C7 are planar with a maximum deviation of 0.045 (2) Å for the azomethine carbon atom C7; and C8–C13, N2, O3 and C14 are planar with a maximum deviation of 0.148 (1) Å for the azomethine nitrogen atom N2). In the two six-membered rings, the largest distance between atom and the mean plane is 0.005 (2) Å, and 0.018 (2) Å in the nearly planar parts, respectively. Bond length analysis indicates an extended network of π bonds across the molecule, consistent with pronounced electronic delocalization. The N2—C7 bond length of 1.266 (2) Å is characteristic of a C=N double bond, confirming significant π character within the imine fragment. The C7—N2—C8 bond angle of 122.82 (14)° shows that atom N2 adopts an essentially trigonal–planar geometry, in agreement with sp² hybridization and conjugation with the adjacent aromatic ring system. The imine unit adopts an almost perfectly trans arrangement, with the atoms around the C=N bond being essentially coplanar as indicated by the C8—N2—C7—C4 torsion angle of −179.82(14°). The bond distances and angles are normal and are in good agreement with those in analogous structures (Hernández Téllez et al., 2025 ; Adam et al., 2015 ; Madhuprasad et al., 2014 ). The dihedral angle between the aromatic rings in the asymmetric unit is 35.68 (7)° and is largely controlled by the cooperative effect of the intramolecular C7—H7⋯O3 and the intermolecular C2—H2⋯O3 hydrogen bonds (Table 1). The latter interaction links neighboring molecules, forming layers parallel to the (101) plane (Fig. 2). In the crystal, slightly offset π–π stacking interactions are present between centrosymmetrically related phenyl rings with a Cg1⋯Cg1( $[{1\over 2}]$ − x, $[{3\over 2}]$ − y, $[{3\over 2}]$ − z) separation of 3.5385 (10) Å, slippage = 1.235 Å, where Cg1 is the centroid of the C1–C6 ring. The overall crystal cohesion is reinforced by C—H⋯π interactions involving C5—H5⋯Cg2(− $[{1\over 2}]$ + x, 1 − y, z) and C14—H14A⋯Cg2(1 − x, 1 − y, 1 − z) interactions, with H⋯Cg separations of 3.4898 (18) and 3.6757 (17) Å, respectively, and C—H⋯Cg angles of 140 and 129°, respectively, where Cg2 is the centroid of the C8–C13 ring (Fig. 3). Collectively, these non-covalent interactions contribute to the cohesion of the three-dimensional supramolecular framework.

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C2—H2⋯O3ⁱ	0.95	2.59	3.3833 (19)	141
C7—H7⋯O3	0.95	2.25	2.7783 (19)	114
Symmetry code: (i) $[-x+1, y+{\script{1\over 2}}, -z+{\script{3\over 2}}]$ .

Figure 1
View of the title compound with the atom-numbering scheme. Displacement ellipsoids for non-H atoms are drawn at the 50% probability level. Symmetry code (i): $[{3\over 2}]$ − x, 1 − y, 1 − z.

Figure 2
Extended packing arrangement viewed in the [010] direction of the unit cell showing C—H⋯O intermolecular interactions (red line).

Figure 3
Graphical view of C—H⋯π and π-π stacking interactions.

Synthesis and crystallization

An ethanolic solution of 4-nitrosalicylaldehyde (0.02 mmol, 3.34 mg) was added dropwise to a methanolic solution of O-dianisidine (0.01 mmol, 2.44 mg) under constant magnetic stirring at room temperature. The reaction mixture was stirred for 1 h, during which the solution gradually turned orange. The product was obtained as brown crystals suitable for X-ray diffraction analysis after slow evaporation of the solvent, washed with cold ethanol, and dried in a desiccator. Yield: 76.24%. m.p 529.15 K.

FTIR (ATR, cm⁻¹): 3100–3000 (w) (aromatic/sp² C—H stretching), 2924 (w) (asymmetric aliphatic C—H stretching), 2857 (w) (symmetric aliphatic C—H stretching), 1687 (w)–1630 (vs) (azomethine stretching vibration C=N), 1599 (s) (N—O asymmetric stretching), 1371 (w) (N—O symmetric stretching).

Refinement

Crystal data, data collection and structure refinement details are summarized in Table 2.

Table 2
Experimental details

Crystal data
Chemical formula	C₂₈H₂₂N₄O₆
M_r	510.49
Crystal system, space group	Monoclinic, I2/a
Temperature (K)	150
a, b, c (Å)	14.2099 (14), 8.0341 (8), 20.899 (2)
β (°)	92.171 (9)
V (Å³)	2384.2 (4)
Z	4
Radiation type	Cu Kα
μ (mm⁻¹)	0.85
Crystal size (mm)	0.28 × 0.15 × 0.07

Data collection
Diffractometer	Xcalibur, Atlas, Gemini ultra
Absorption correction	Multi-scan (CrysAlis PRO; Rigaku OD, 2022 )
T_min, T_max	0.729, 1.000
No. of measured, independent and observed [I > 2σ(I)] reflections	9789, 2120, 1821
R_int	0.038
(sin θ/λ)_max (Å⁻¹)	0.597

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.042, 0.121, 1.06
No. of reflections	2120
No. of parameters	173
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.19, −0.23
Computer programs: CrysAlis PRO (Rigaku OD, 2022), OLEX2.solve (Dolomanov et al., 2009 ), SHELXL2019/3 (Sheldrick, 2015 ) and OLEX2 (Dolomanov et al., 2009).

Structural data

CCDC reference: 2487703

Crystal structure: contains datablocks global, I. DOI: https://doi.org/10.1107/S2414314626002208/zl4090sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S2414314626002208/zl4090Isup3.hkl

The ATRFTIR spectrum. DOI: https://doi.org/10.1107/S2414314626002208/zl4090sup4.docx

Supporting information file. DOI: https://doi.org/10.1107/S2414314626002208/zl4090Isup4.cml

checkCIF report

Computing details top

(E)-1-(3,3'-Dimethoxy-4'-{[(E)-4-nitrobenzylidene]amino}-[1,1'-biphenyl]-4-yl)-N-(4-nitrophenyl)methanimine top

Crystal data top

C₂₈H₂₂N₄O₆	F(000) = 1064
M_r = 510.49	D_x = 1.422 Mg m⁻³
Monoclinic, I2/a	Cu Kα radiation, λ = 1.54184 Å
Hall symbol: -I 2ya	Cell parameters from 5072 reflections
a = 14.2099 (14) Å	θ = 4.1–66.9°
b = 8.0341 (8) Å	µ = 0.85 mm⁻¹
c = 20.899 (2) Å	T = 150 K
β = 92.171 (9)°	Plate, brown
V = 2384.2 (4) Å³	0.28 × 0.15 × 0.07 mm
Z = 4

Data collection top

Xcalibur, Atlas, Gemini ultra diffractometer	2120 independent reflections
Mirror monochromator	1821 reflections with I > 2σ(I)
Detector resolution: 10.4685 pixels mm^-1	R_int = 0.038
ω scans	θ_max = 67.0°, θ_min = 4.2°
Absorption correction: multi-scan (CrysAlisPro; Rigaku OD, 2022)	h = −16→16
T_min = 0.729, T_max = 1.000	k = −9→9
9789 measured reflections	l = −24→20

Refinement top

Refinement on F²	Primary atom site location: dual
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F² > 2σ(F²)] = 0.042	H-atom parameters constrained
wR(F²) = 0.121	W = 1/[Σ²(FO²) + (0.068P)² + 1.2673P] WHERE P = (FO² + 2FC²)/3
S = 1.06	(Δ/σ)_max = 0.001
2120 reflections	Δρ_max = 0.19 e Å⁻³
173 parameters	Δρ_min = −0.23 e Å⁻³
0 restraints	Absolute structure: All H atoms were placed in geometrically idealized positions and constrained to ride on their parent atoms, with C—H distances of 0.95–0.98 Å with U_iso(H) values of 1.2 or 1.5 U_eq of the parent atoms.

Special details top

Geometry. Bond distances, angles etc. have been calculated using the rounded fractional coordinates. All su's are estimated from the variances of the (full) variance-covariance matrix. The cell esds are taken into account in the estimation of distances, angles and torsion angles

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq
O1	0.08857 (11)	0.4892 (2)	0.84954 (7)	0.0664 (6)
O2	0.18453 (10)	0.64173 (19)	0.90565 (6)	0.0538 (5)
O3	0.53245 (7)	0.32934 (13)	0.58125 (5)	0.0311 (3)
N1	0.16324 (11)	0.56187 (19)	0.85733 (7)	0.0409 (5)
N2	0.50068 (9)	0.61140 (16)	0.66003 (6)	0.0305 (4)
C1	0.23150 (11)	0.55294 (19)	0.80633 (7)	0.0313 (5)
C2	0.31525 (12)	0.6393 (2)	0.81402 (7)	0.0330 (5)
C3	0.37976 (11)	0.6307 (2)	0.76630 (7)	0.0318 (5)
C4	0.35916 (11)	0.53793 (19)	0.71097 (7)	0.0297 (5)
C5	0.27422 (11)	0.4534 (2)	0.70499 (8)	0.0339 (5)
C6	0.20921 (11)	0.4594 (2)	0.75260 (8)	0.0345 (5)
C7	0.42422 (11)	0.5304 (2)	0.65778 (8)	0.0327 (5)
C8	0.56487 (10)	0.60829 (19)	0.61024 (7)	0.0280 (4)
C9	0.61697 (11)	0.75257 (19)	0.60148 (7)	0.0298 (5)
C10	0.68751 (11)	0.76153 (19)	0.55758 (7)	0.0298 (5)
C11	0.71028 (10)	0.62133 (19)	0.52197 (7)	0.0271 (4)
C12	0.65722 (11)	0.47610 (18)	0.52939 (7)	0.0272 (4)
C13	0.58502 (10)	0.46875 (18)	0.57190 (7)	0.0261 (4)
C14	0.54558 (11)	0.19137 (19)	0.53924 (7)	0.0331 (5)
H2	0.32825	0.70356	0.85148	0.0400*
H3	0.43814	0.68782	0.77112	0.0380*
H5	0.26035	0.39003	0.66742	0.0410*
H6	0.15118	0.40094	0.74839	0.0410*
H7	0.40857	0.46390	0.62132	0.0390*
H9	0.60377	0.84807	0.62640	0.0360*
H10	0.72033	0.86310	0.55175	0.0360*
H12	0.67113	0.38055	0.50469	0.0330*
H14A	0.53360	0.22693	0.49482	0.0500*
H14B	0.50174	0.10202	0.54958	0.0500*
H14C	0.61042	0.15064	0.54454	0.0500*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
O1	0.0501 (9)	0.0891 (12)	0.0617 (9)	−0.0142 (8)	0.0233 (7)	−0.0021 (8)
O2	0.0611 (9)	0.0675 (9)	0.0334 (7)	0.0152 (7)	0.0106 (6)	−0.0032 (6)
O3	0.0330 (6)	0.0246 (5)	0.0364 (6)	−0.0020 (4)	0.0089 (4)	−0.0027 (4)
N1	0.0429 (9)	0.0456 (8)	0.0348 (8)	0.0107 (7)	0.0093 (6)	0.0070 (7)
N2	0.0283 (7)	0.0316 (7)	0.0317 (7)	0.0034 (5)	0.0039 (5)	0.0007 (5)
C1	0.0335 (8)	0.0320 (8)	0.0287 (8)	0.0090 (6)	0.0054 (6)	0.0059 (6)
C2	0.0383 (9)	0.0329 (8)	0.0274 (7)	0.0048 (6)	−0.0034 (6)	−0.0012 (6)
C3	0.0297 (8)	0.0330 (8)	0.0323 (8)	0.0014 (6)	−0.0024 (6)	0.0011 (6)
C4	0.0286 (8)	0.0294 (8)	0.0312 (8)	0.0041 (6)	0.0012 (6)	−0.0006 (6)
C5	0.0317 (8)	0.0341 (9)	0.0360 (8)	0.0011 (6)	0.0022 (6)	−0.0083 (7)
C6	0.0301 (8)	0.0320 (8)	0.0414 (9)	0.0006 (6)	0.0020 (7)	0.0003 (7)
C7	0.0305 (8)	0.0359 (8)	0.0315 (8)	0.0043 (7)	−0.0004 (6)	−0.0052 (7)
C8	0.0261 (7)	0.0313 (8)	0.0265 (7)	0.0047 (6)	0.0001 (6)	−0.0004 (6)
C9	0.0311 (8)	0.0263 (8)	0.0319 (8)	0.0025 (6)	0.0004 (6)	−0.0039 (6)
C10	0.0300 (8)	0.0252 (8)	0.0342 (8)	−0.0006 (6)	−0.0005 (6)	−0.0012 (6)
C11	0.0267 (7)	0.0284 (8)	0.0261 (7)	0.0011 (6)	−0.0012 (6)	0.0012 (6)
C12	0.0292 (7)	0.0254 (7)	0.0271 (7)	0.0022 (6)	0.0008 (6)	−0.0010 (6)
C13	0.0248 (7)	0.0254 (7)	0.0278 (7)	0.0011 (6)	−0.0009 (6)	0.0021 (6)
C14	0.0383 (9)	0.0282 (8)	0.0330 (8)	−0.0032 (6)	0.0037 (6)	−0.0025 (6)

Geometric parameters (Å, º) top

O1—N1	1.217 (2)	C9—C10	1.386 (2)
O2—N1	1.225 (2)	C10—C11	1.395 (2)
O3—C13	1.3645 (18)	C11—C12	1.401 (2)
O3—C14	1.4306 (18)	C11—C11ⁱ	1.482 (2)
N1—C1	1.470 (2)	C12—C13	1.384 (2)
N2—C7	1.266 (2)	C2—H2	0.9500
N2—C8	1.4097 (19)	C3—H3	0.9500
C1—C2	1.382 (2)	C5—H5	0.9500
C1—C6	1.378 (2)	C6—H6	0.9500
C2—C3	1.382 (2)	C7—H7	0.9500
C3—C4	1.397 (2)	C9—H9	0.9500
C4—C5	1.386 (2)	C10—H10	0.9500
C4—C7	1.474 (2)	C12—H12	0.9500
C5—C6	1.384 (2)	C14—H14A	0.9800
C8—C9	1.391 (2)	C14—H14B	0.9800
C8—C13	1.414 (2)	C14—H14C	0.9800

C13—O3—C14	117.60 (11)	O3—C13—C8	116.49 (13)
O1—N1—O2	123.28 (16)	O3—C13—C12	123.39 (13)
O1—N1—C1	118.41 (14)	C8—C13—C12	120.08 (13)
O2—N1—C1	118.32 (15)	C1—C2—H2	121.00
C7—N2—C8	122.82 (14)	C3—C2—H2	121.00
N1—C1—C2	118.71 (13)	C2—C3—H3	120.00
N1—C1—C6	118.68 (14)	C4—C3—H3	120.00
C2—C1—C6	122.62 (14)	C4—C5—H5	119.00
C1—C2—C3	118.88 (14)	C6—C5—H5	119.00
C2—C3—C4	120.01 (15)	C1—C6—H6	121.00
C3—C4—C5	119.36 (14)	C5—C6—H6	121.00
C3—C4—C7	121.89 (14)	N2—C7—H7	120.00
C5—C4—C7	118.73 (14)	C4—C7—H7	120.00
C4—C5—C6	121.38 (15)	C8—C9—H9	119.00
C1—C6—C5	117.76 (15)	C10—C9—H9	119.00
N2—C7—C4	120.86 (15)	C9—C10—H10	120.00
N2—C8—C9	116.41 (13)	C11—C10—H10	120.00
N2—C8—C13	125.67 (13)	C11—C12—H12	119.00
C9—C8—C13	117.77 (13)	C13—C12—H12	119.00
C8—C9—C10	122.15 (14)	O3—C14—H14A	109.00
C9—C10—C11	119.96 (14)	O3—C14—H14B	109.00
C10—C11—C12	118.48 (13)	O3—C14—H14C	109.00
C10—C11—C11ⁱ	121.88 (14)	H14A—C14—H14B	109.00
C11ⁱ—C11—C12	119.63 (13)	H14A—C14—H14C	109.00
C11—C12—C13	121.46 (13)	H14B—C14—H14C	109.00

C14—O3—C13—C8	174.58 (12)	C5—C4—C7—N2	176.96 (15)
C14—O3—C13—C12	−7.9 (2)	C4—C5—C6—C1	0.2 (2)
O1—N1—C1—C2	178.07 (16)	N2—C8—C9—C10	174.91 (14)
O1—N1—C1—C6	−1.6 (2)	C13—C8—C9—C10	−0.9 (2)
O2—N1—C1—C2	−2.2 (2)	N2—C8—C13—O3	5.0 (2)
O2—N1—C1—C6	178.16 (15)	N2—C8—C13—C12	−172.64 (14)
C8—N2—C7—C4	−179.82 (14)	C9—C8—C13—O3	−179.61 (13)
C7—N2—C8—C9	148.63 (15)	C9—C8—C13—C12	2.7 (2)
C7—N2—C8—C13	−36.0 (2)	C8—C9—C10—C11	−2.1 (2)
N1—C1—C2—C3	179.75 (14)	C9—C10—C11—C12	3.2 (2)
C6—C1—C2—C3	−0.6 (2)	C9—C10—C11—C11ⁱ	−175.41 (14)
N1—C1—C6—C5	179.64 (14)	C10—C11—C12—C13	−1.4 (2)
C2—C1—C6—C5	0.0 (2)	C11ⁱ—C11—C12—C13	177.27 (14)
C1—C2—C3—C4	1.0 (2)	C10—C11—C11ⁱ—C10ⁱ	−36.0 (2)
C2—C3—C4—C5	−0.8 (2)	C10—C11—C11ⁱ—C12ⁱ	145.35 (15)
C2—C3—C4—C7	177.62 (15)	C12—C11—C11ⁱ—C10ⁱ	145.35 (15)
C3—C4—C5—C6	0.2 (2)	C12—C11—C11ⁱ—C12ⁱ	−33.3 (2)
C7—C4—C5—C6	−178.29 (15)	C11—C12—C13—O3	−179.10 (13)
C3—C4—C7—N2	−1.5 (2)	C11—C12—C13—C8	−1.6 (2)

Symmetry code: (i) −x+3/2, y, −z+1.

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C2—H2···O3ⁱⁱ	0.95	2.59	3.3833 (19)	141
C7—H7···O3	0.95	2.25	2.7783 (19)	114

Symmetry code: (ii) −x+1, y+1/2, −z+3/2.

Acknowledgements

The authors thank the Cambridge Crystallographic Data Center (CCDC) for access to the Cambridge Structural Database (CSD) through the FAIRE program.

References

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