N-(2-Iodobenzylidene)-3-nitroaniline: sheets formed by a combination of C—H...O hydrogen bonds and two aromatic π–π-stacking interactions

Molecules of the title compound, C₁₃H₉IN₂O₂, are linked into [010] chains by a single C—H...O hydrogen bond and these chains are linked into (100) sheets by two independent aromatic π–π-stacking interactions, each involving one of the two substituted arene rings.

S1. Comment

We recently reported (Kelly et al., 2002) the molecular and supramolecular structures of a range of iodo-nitroarenesulfonamides, in which widely differing patterns of supramolecular aggregation reflect the subtle interplay of hard and soft (Braga et al., 1995) hydrogen bonds, iodo···nitro interactions and aromatic π···π stacking interactions. Here, we report the molecular and supramolecular structure of an analogous compound, (I), N-(2-iodobenzylidene)-3-nitroaniline, which has been specifically designed to preclude the formation of hard hydrogen bonds. In the event, there are, in fact, no I···O₂N interactions in (I) and the supramolecular aggregation depends solely on a single, rather weak, C—H···O hydrogen bond and on π···π stacking interactions in which both arene rings participate. \sch

Within the molecule of (I) (Fig. 1), the central C1—N1—C17—C11 unit is effectively planar, as expected, and the overall molecular conformation can readily be defined in terms of the torsion angles involving this fragment (Table 1). The nitro group is almost coplanar with the adjacent arene ring. Although there is a short intramolecular contact between atoms H17 and I2 (Table 2), the exocyclic bond angles at atoms C11 and C12 (Table 1) suggest that this contact may be repulsive. Otherwise, the bond distances and angles show no unusual features; in particular, there is no evidence for any bond fixation within the rings.

The molecules of (I) are linked by the C—H···O hydrogen bond into a C(7) chain running parallel to the [010] direction. Atom C6 in the molecule at (x, y, z) acts as a hydrogen-bond donor to atom O31 in the molecule at (x, 1 + y, z) (Fig. 2), but the nitro atom O32 plays no role in the supramolecular aggregation. Two chains of this type, related to one another by inversion, pass through each unit cell.

The nitrated rings in the molecules at (x, y, z) and (1 - x, -y, 1 - z) form a π···π stacking interaction across the inversion centre at (1/2, 0, 1/2) (Fig. 3); the interplanar spacing and centroid separation are 3.449 (2) and 3.724 (2) Å, respectively, corresponding to a centroid offset of 1.404 (2) Å. Similarly, the iodinated rings in the molecules at (x, y, z) and (1 - x, 1 - y, -z) form a second π···π stacking interaction across the inversion centre at (1/2, 1/2, 0), where the interplanar spacing and centroid separation are 3.420 (2) and 3.594 (2) Å, respectively, corresponding to a centroid offset of 1.105 (2) Å. Propagation of these interactions by inversion thus generates a chain running parallel to the [011] direction (Fig. 3), and the combination of the hydrogen-bonded [010] chains and the π-stacked [011] chains generates sheets parallel to (100).

Table 2. Hydrogen-bond parameters and short intramolecular contacts (Å, °).

S2. Experimental

A sample of (I) (m.p. 364–365 K) was prepared by condensation of 2-iodobenzaldehyde with 3-nitroaniline. Crystals suitable for single-crystal X-ray diffraction were grown by slow evaporation of a solution in ethanol.

S3. Refinement

Compound (I) crystallized in the triclinic system; space group P1 was assumed and confirmed by the analysis. H atoms were treated as riding atoms, with C—H = 0.95 Å.

Computing details

Data collection: KappaCCD Server Software (Nonius, 1997); cell refinement: DENZO-SMN (Otwinowski & Minor, 1997); data reduction: DENZO-SMN; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: PLATON (Spek, 2002); software used to prepare material for publication: SHELXL97 and PRPKAPPA (Ferguson, 1999).

Figures

	Fig. 1. The molecule of (I) showing the atom-labelling scheme. Displacement ellipsoids are drawn at the 30% probability level and H atoms are shown as small spheres of arbitrary radii.
	Fig. 2. Part of the crystal structure of (I) showing formation of a hydrogen-bonded C(7) chain along [010]. The atoms marked with an asterisk (*) or hash sign (#) are at the symmetry positions (x, 1 + y, z) and (x, y - 1, z), respectively.
	Fig. 3. Part of the crystal structure of (I) showing formation of a π-stacked chain along [011]. The atoms marked with an asterisk (*) or hash sign (#) are at the symmetry positions (1 - x, -y, 1 - z) and (1 - x, 1 - y, -z), respectively.

N-(2-Iodobenzylidene)-3-nitroaniline

Crystal data

C13H9IN2O2	Z = 2
Mr = 352.12	F(000) = 340
Triclinic, P1	Dx = 1.898 Mg m^−3
Hall symbol: -P 1	Melting point: 346 K
a = 7.7405 (2) Å	Mo Kα radiation, λ = 0.71073 Å
b = 8.3297 (2) Å	Cell parameters from 2720 reflections
c = 11.3317 (3) Å	θ = 3.1–27.5°
α = 82.2570 (9)°	µ = 2.59 mm^−1
β = 71.5605 (8)°	T = 120 K
γ = 62.7543 (10)°	Plate, pale yellow
V = 616.17 (3) Å^3	0.35 × 0.15 × 0.03 mm

Data collection

Nonius KappaCCD diffractometer	2720 independent reflections
Radiation source: fine-focus sealed X-ray tube	2596 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.064
ϕ scans, and ω scans with κ offsets	θmax = 27.5°, θmin = 3.1°
Absorption correction: multi-scan (DENZO-SMN; Otwinowski & Minor, 1997)	h = −10→10
Tmin = 0.464, Tmax = 0.926	k = −10→10
8201 measured reflections	l = −14→14

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)] = 0.028	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.068	H-atom parameters constrained
S = 1.07	w = 1/[σ^2(Fo^2) + (0.0278P)^2 + 0.361P] where P = (Fo^2 + 2Fc^2)/3
2720 reflections	(Δ/σ)max < 0.001
163 parameters	Δρmax = 0.80 e Å^−3
0 restraints	Δρmin = −1.60 e Å^−3

Special details

Experimental. The program DENZO-SMN (Otwinowski & Minor, 1997) uses a scaling algorithm [Fox, G. C. & Holmes, K. C. (1966). Acta Cryst. 20, 886–891] which effectively corrects for absorption effects. High-redundancy data were used in the scaling program, hence the `multi-scan' code word was used.

Geometry. Mean-plane data from the final SHELXL97 refinement run:-

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
C1	0.7422 (3)	0.0695 (3)	0.3077 (2)	0.0164 (5)
N1	0.7310 (3)	0.1564 (3)	0.1922 (2)	0.0183 (4)
C2	0.7499 (4)	−0.1018 (3)	0.3290 (2)	0.0165 (5)
C3	0.7636 (4)	−0.1796 (3)	0.4437 (2)	0.0172 (5)
N3	0.7716 (3)	−0.3600 (3)	0.4652 (2)	0.0225 (5)
O31	0.7780 (4)	−0.4380 (3)	0.3785 (2)	0.0371 (5)
O32	0.7710 (3)	−0.4248 (3)	0.5691 (2)	0.0322 (5)
C4	0.7705 (4)	−0.0952 (4)	0.5378 (2)	0.0214 (5)
C5	0.7635 (4)	0.0749 (4)	0.5149 (3)	0.0235 (6)
C6	0.7519 (4)	0.1560 (4)	0.4008 (3)	0.0201 (5)
C11	0.5803 (4)	0.2370 (3)	0.0246 (2)	0.0163 (5)
C12	0.4086 (4)	0.2768 (3)	−0.0131 (2)	0.0153 (5)
I12	0.15723 (2)	0.23901 (2)	0.102073 (14)	0.02085 (8)
C13	0.3940 (4)	0.3507 (3)	−0.1292 (2)	0.0185 (5)
C14	0.5492 (4)	0.3842 (4)	−0.2092 (3)	0.0201 (5)
C15	0.7211 (4)	0.3454 (3)	−0.1738 (3)	0.0205 (5)
C16	0.7343 (4)	0.2734 (3)	−0.0579 (3)	0.0196 (5)
C17	0.6006 (4)	0.1579 (3)	0.1460 (2)	0.0168 (5)
H2	0.7458	−0.1640	0.2662	0.020*
H4	0.7798	−0.1519	0.6156	0.026*
H5	0.7666	0.1367	0.5782	0.028*
H6	0.7505	0.2715	0.3860	0.024*
H13	0.2767	0.3780	−0.1534	0.022*
H14	0.5393	0.4339	−0.2887	0.024*
H15	0.8285	0.3684	−0.2289	0.025*
H16	0.8513	0.2482	−0.0341	0.023*
H17	0.5131	0.1058	0.1918	0.020*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
C1	0.0097 (10)	0.0194 (12)	0.0192 (12)	−0.0061 (9)	−0.0044 (9)	0.0025 (9)
N1	0.0185 (10)	0.0161 (11)	0.0204 (11)	−0.0074 (8)	−0.0073 (9)	0.0038 (8)
C2	0.0144 (11)	0.0187 (12)	0.0176 (12)	−0.0071 (9)	−0.0068 (9)	0.0007 (10)
C3	0.0117 (11)	0.0199 (12)	0.0205 (13)	−0.0080 (9)	−0.0045 (9)	0.0022 (10)
N3	0.0178 (10)	0.0233 (12)	0.0257 (12)	−0.0092 (9)	−0.0090 (9)	0.0093 (10)
O31	0.0610 (15)	0.0246 (11)	0.0399 (13)	−0.0245 (10)	−0.0278 (12)	0.0093 (10)
O32	0.0323 (11)	0.0358 (12)	0.0282 (11)	−0.0182 (9)	−0.0104 (9)	0.0176 (9)
C4	0.0148 (11)	0.0306 (14)	0.0165 (12)	−0.0081 (10)	−0.0059 (10)	0.0031 (10)
C5	0.0180 (12)	0.0295 (15)	0.0226 (14)	−0.0077 (11)	−0.0071 (11)	−0.0058 (11)
C6	0.0153 (12)	0.0203 (13)	0.0268 (14)	−0.0076 (10)	−0.0079 (11)	−0.0031 (11)
C11	0.0151 (11)	0.0127 (12)	0.0196 (13)	−0.0046 (9)	−0.0056 (10)	−0.0007 (9)
C12	0.0138 (11)	0.0138 (12)	0.0174 (12)	−0.0053 (9)	−0.0041 (9)	−0.0003 (9)
I12	0.01522 (11)	0.02461 (13)	0.02394 (13)	−0.01003 (8)	−0.00601 (8)	0.00203 (8)
C13	0.0193 (12)	0.0161 (12)	0.0208 (13)	−0.0052 (10)	−0.0098 (10)	−0.0015 (10)
C14	0.0233 (13)	0.0183 (13)	0.0158 (12)	−0.0067 (10)	−0.0060 (10)	0.0007 (10)
C15	0.0187 (12)	0.0202 (13)	0.0200 (13)	−0.0083 (10)	−0.0028 (10)	0.0004 (10)
C16	0.0159 (11)	0.0201 (13)	0.0227 (13)	−0.0079 (10)	−0.0065 (10)	0.0025 (10)
C17	0.0153 (11)	0.0142 (12)	0.0193 (12)	−0.0056 (9)	−0.0049 (9)	0.0014 (9)

Geometric parameters (Å, º)

C1—C2	1.392 (4)	C6—H6	0.9500
C1—C6	1.394 (4)	C11—C16	1.392 (4)
C1—N1	1.415 (3)	C11—C12	1.406 (3)
N1—C17	1.270 (3)	C11—C17	1.467 (4)
C2—C3	1.385 (4)	C12—C13	1.391 (4)
C2—H2	0.9500	C12—I12	2.105 (2)
C3—C4	1.381 (4)	C13—C14	1.376 (4)
C3—N3	1.466 (3)	C13—H13	0.9500
N3—O31	1.224 (3)	C14—C15	1.394 (4)
N3—O32	1.227 (3)	C14—H14	0.9500
C4—C5	1.384 (4)	C15—C16	1.382 (4)
C4—H4	0.9500	C15—H15	0.9500
C5—C6	1.385 (4)	C16—H16	0.9500
C5—H5	0.9500	C17—H17	0.9500
C2—C1—C6	119.4 (2)	C16—C11—C12	117.9 (2)
C2—C1—N1	121.6 (2)	C12—C11—C17	122.0 (2)
C6—C1—N1	119.0 (2)	C16—C11—C17	120.2 (2)
C17—N1—C1	117.4 (2)	C11—C12—I12	122.97 (18)
C3—C2—C1	118.4 (2)	C13—C12—I12	116.26 (17)
C3—C2—H2	120.8	C13—C12—C11	120.7 (2)
C1—C2—H2	120.8	C14—C13—C12	120.1 (2)
C4—C3—C2	123.0 (2)	C14—C13—H13	120.0
C4—C3—N3	118.9 (2)	C12—C13—H13	120.0
C2—C3—N3	118.0 (2)	C13—C14—C15	120.1 (2)
O31—N3—O32	123.5 (2)	C13—C14—H14	119.9
O31—N3—C3	118.3 (2)	C15—C14—H14	119.9
O32—N3—C3	118.2 (2)	C16—C15—C14	119.6 (2)
C3—C4—C5	117.8 (2)	C16—C15—H15	120.2
C3—C4—H4	121.1	C14—C15—H15	120.2
C5—C4—H4	121.1	C15—C16—C11	121.6 (2)
C4—C5—C6	120.8 (2)	C15—C16—H16	119.2
C4—C5—H5	119.6	C11—C16—H16	119.2
C6—C5—H5	119.6	N1—C17—C11	122.4 (2)
C5—C6—C1	120.6 (3)	N1—C17—H17	118.8
C5—C6—H6	119.7	C11—C17—H17	118.8
C1—C6—H6	119.7
C1—N1—C17—C11	−177.4 (2)	C17—N1—C1—C2	47.9 (4)
N1—C17—C11—C12	−164.7 (2)	C2—C3—N3—O31	4.3 (4)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
C6—H6···O31^i	0.95	2.51	3.450 (4)	169
C17—H17···I12	0.95	2.92	3.369 (2)	110

Symmetry code: (i) x, y+1, z.