4-Iodo-N-(2-nitro­phenyl­sulfanyl)­aniline: [pi]-stacked sheets generated by a combination of N-H...O and C-H...O hydrogen bonds

Molecules of the title compound, C₁₂H₉IN₂O₂S, are linked by one N-H...O hydrogen bond [H...O = 2.16 Å, N...O = 2.935 (4) Å and N-H...O 147°] and two C-H...O hydrogen bonds [H...O both 2.49 Å, C...O = 3.231 (5) and 3.220 (5) Å, and C-H...O = 135 and 134°] into sheets which themselves are weakly linked by an aromatic [pi]-[pi]-stacking interaction between iodinated rings in centrosymmetrically related mole­cules. There are no iodo-nitro interactions.

S1. Comment

As part of a general study of the interplay of hydrogen bonds, iodo–nitro interactions and aromatic π–π-stacking interactions in aromatic systems containing both iodo and nitro substituents, we have recently reported the molecular and supramolecular structures of a range of diaryl species (I) (see Scheme) containing a variety of spacer units X, namely arenesulfonamides (Ia) and (Ib) (Kelly et al., 2002), Schiff base imines (Ic) (Wardell et al., 2002) and (Id) (Glidewell, Howie et al., 2002), and benzylanilines (Ie) (Glidewell, Low et al., 2002). We report here the structure of an analogous compound, 4-iodo-N-(2-nitrophenylsulfanyl)aniline, (II), containing the –NH—S– linker unit.

The conformation of compound (II) (Fig. 1) is dominated by the C1—N1—S1—C11 torsion angle (Table 1), which in turn is determined primarily by the nearly orthogonal lone-pair orbitals on atoms N1 and S1; this conformation minimizes the overlap and resonance integrals between the two occupied orbitals in question. By contrast, the C1–C6 and C11–C16 rings show only small twists away from the S1/N1/C1 and N1/S1/C11 planes, respectively, while the nitro group likewise shows only a small twist away from the C11–C16 plane: the dihedral angle between the C12-nitro and C11–C16 planes is only 5.5 (2)°.

The bond distances N1—C1 and N1—S1 are respectively long and short for their types (Allen et al., 1987), and while C12—N12 is short for its type, the N—O bonds are both long. There is evidence for some quinonoid bond fixation in the nitrated aryl ring C11–C16, and we note that N12—O121 is somewhat longer than N12—O122. Taken together, these observations suggest that forms (IIa)–(IIc) are all significant contributors to the overall molecular–electronic structure.

Consistent with the form (IIc), the internal C—C—C bond angles at atoms C11 and C12 show marked deviations from 120° (Table 1), in a sense indicative of the electron-donor action of the –S—NHAr substituent and the electron-acceptor behaviour of the nitro group (Domenicano & Murray-Rust, 1979); the exocyclic angles at atom C11 are suggestive of a repulsive non-bonded interaction between S1 and O121.

The supramolecular aggregation of (II) is dominated by N—H···O and C—H···O hydrogen bonds, augmented by weak aromatic π–π-stacking interactions. It is perhaps surprising that iodo–nitro interactions are absent; nor are there any C—H···π(arene) interactions. The principal direction-specific intermolecular interaction is the N—H···O hydrogen bond (Table 2). The amino atom N1 in the molecule at (x, y, z) acts as donor to nitro atom O121 in the molecule at (−0.5 + x, y, 0.5 − z), so producing a C(7) chain running parallel to the [100] direction and generated by the a-glide plane at z = 0.25. The action of this hydrogen bond is reinforced by that of a C—H···O hydrogen bond; C6 at (x, y, z) acts as donor to O121 at (0.5 + x, y, 0.5 − z), producing a C(9) chain and generated by the same a-glide plane. The combination of these two chains generates a chain of edge-fused R²₂(16) rings (Fig. 2).

Four of these chain pass through each unit cell and they are linked into a three-dimensional continuum by a combination of a further C—H···O hydrogen bond and a π–π-stacking interaction. Atom C16 in the molecule at (x, y, z) acts as hydrogen-bond donor to O122 in the molecule at (x, 3/2 − y, −0.5 + z), so producing a C(6) chain running parallel to [001] and generated by the c-glide plane at y = 0.75. In this manner, the [100] chains are linked into (010) sheets, and there are two such sheets passing through each unit cell, one in the domain 0.50 < y < 1.00 and the other in the domain 0 < y < 0.50. Finally, the (010) sheets are weakly linked by a centrosymmetric π–π-stacking interaction; the iodinated C1–C6 rings in the molecules at (x, y, z) and (1 − x, 1 − y, −z) are parallel, with an interplanar spacing of 3.341 (2) Å and a centroid separation of 3.800 (2) Å, corresponding to a centroid offset of 1.810 (2) Å (Fig. 3). These two molecules lie in the (010) sheets generated, respectively, by the c-glide planes at y = 0.75 and y = 1/4, and propagation of the interaction by the space group suffices to link together all of the (010) sheets.

S2. Experimental

A sample of compound (II) was prepared by reaction of equimolar quantities of 2-nitrophenylsulfenyl chloride and 4-iodoaniline in dichloromethane solution, in the presence of an excess of triethylamine. Purification was by thin-layer chromatography and crystals of (II) suitable for single-crystal X-ray diffraction were grown by slow evaporation of a solution in ethanol.

S3. Refinement

The space group Pbca was uniquely assigned from the systematic absences. H atoms were treated as riding atoms, with C—H distances of 0.95 Å and N—H distances of 0.88 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 (Sheldrick, 1997) and PRPKAPPA (Ferguson, 1999).

Figures

	Fig. 1. The molecule of (II), showing the atom-labelling scheme and displacement ellipsoids at the 30% probability level.
	Fig. 2. Part of the crystal structure of (II), showing the formation of a chain of edge-fused R^22(16) rings along [100]. For the sake of clarity, H atoms not involved in the hydrogen-bonding motifs shown have been omitted. Atoms marked with an asterisk (*), a hash (#) or an ampersand (&) are at the symmetry positions (−0.5 + x, y, 0.5 − z), (0.5 − x, y, 0.5 + z) and (−1+, y, z), respectively.
	Fig. 3. Part of the crystal structure of (II), showing the π–π-stacking interaction. For the sake of clarity, H atoms bonded to C atoms have been omitted. Atoms marked with an asterisk (*) are at the symmetry position (1 − x, 1 − y, −z).

(I)

Crystal data

C12H9IN2O2S	F(000) = 1440
Mr = 372.18	Dx = 1.919 Mg m^−3
Orthorhombic, Pbca	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ac 2ab	Cell parameters from 2928 reflections
a = 7.4171 (2) Å	θ = 3.6–27.5°
b = 22.1145 (8) Å	µ = 2.64 mm^−1
c = 15.7093 (4) Å	T = 120 K
V = 2576.73 (13) Å^3	Plate, orange
Z = 8	0.35 × 0.20 × 0.08 mm

Data collection

Nonius KappaCCD diffractometer	2928 independent reflections
Radiation source: rotating anode	1867 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.066
ϕ scans, and ω scans with κ offsets	θmax = 27.5°, θmin = 3.6°
Absorption correction: multi-scan (DENZO-SMN; Otwinowski & Minor, 1997)	h = −7→9
Tmin = 0.458, Tmax = 0.817	k = −17→28
10802 measured reflections	l = −16→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)] = 0.040	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.082	H-atom parameters constrained
S = 0.97	w = 1/[σ^2(Fo^2) + (0.0249P)^2] where P = (Fo^2 + 2Fc^2)/3
2928 reflections	(Δ/σ)max = 0.001
163 parameters	Δρmax = 0.76 e Å^−3
0 restraints	Δρmin = −1.02 e Å^−3

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

	x	y	z	Uiso*/Ueq
C1	0.5139 (5)	0.60187 (17)	0.0489 (2)	0.0212 (9)
C2	0.4337 (5)	0.57878 (18)	−0.0242 (2)	0.0256 (10)
C3	0.5363 (6)	0.55240 (18)	−0.0871 (2)	0.0272 (10)
C4	0.7206 (6)	0.54941 (18)	−0.0777 (2)	0.0266 (10)
I4	0.87720 (5)	0.505572 (13)	−0.171435 (16)	0.03766 (13)
C5	0.8042 (6)	0.57209 (18)	−0.0058 (2)	0.0304 (10)
C6	0.6996 (5)	0.59855 (19)	0.0575 (3)	0.0287 (10)
S1	0.46633 (13)	0.64314 (5)	0.21155 (6)	0.0236 (2)
N1	0.4042 (4)	0.62927 (15)	0.11064 (19)	0.0266 (8)
C11	0.5423 (5)	0.71901 (17)	0.2043 (2)	0.0202 (9)
C12	0.5882 (5)	0.75438 (18)	0.2755 (2)	0.0208 (9)
C13	0.6467 (5)	0.81364 (19)	0.2685 (2)	0.0266 (10)
C14	0.6623 (6)	0.84010 (19)	0.1903 (2)	0.0326 (11)
C15	0.6187 (6)	0.8060 (2)	0.1191 (2)	0.0347 (11)
C16	0.5584 (5)	0.74744 (19)	0.1254 (2)	0.0252 (10)
N12	0.5739 (4)	0.72846 (18)	0.3604 (2)	0.0279 (8)
O121	0.5351 (4)	0.67415 (14)	0.36581 (15)	0.0286 (7)
O122	0.6018 (5)	0.76111 (15)	0.42184 (16)	0.0497 (9)
H2	0.3066	0.5812	−0.0309	0.031*
H3	0.4804	0.5364	−0.1365	0.033*
H5	0.9315	0.5696	0.0003	0.036*
H6	0.7558	0.6145	0.1070	0.034*
H1	0.2947	0.6400	0.0953	0.032*
H13	0.6761	0.8360	0.3183	0.032*
H14	0.7020	0.8808	0.1849	0.039*
H15	0.6309	0.8237	0.0643	0.042*
H16	0.5271	0.7259	0.0752	0.030*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
C1	0.025 (2)	0.016 (2)	0.022 (2)	−0.0009 (17)	0.0006 (19)	0.0003 (18)
C2	0.024 (2)	0.025 (2)	0.028 (2)	−0.0011 (18)	−0.0095 (19)	0.0030 (19)
C3	0.037 (3)	0.026 (3)	0.018 (2)	0.002 (2)	−0.003 (2)	−0.0033 (18)
C4	0.035 (3)	0.021 (2)	0.024 (2)	−0.0022 (19)	0.007 (2)	−0.0006 (17)
I4	0.0514 (2)	0.0369 (2)	0.02474 (17)	0.00869 (15)	0.01215 (14)	0.00135 (13)
C5	0.023 (2)	0.031 (3)	0.036 (2)	−0.0057 (19)	0.005 (2)	−0.006 (2)
C6	0.026 (2)	0.033 (3)	0.027 (2)	−0.006 (2)	−0.004 (2)	−0.010 (2)
S1	0.0239 (5)	0.0254 (6)	0.0215 (5)	−0.0023 (5)	0.0015 (5)	0.0012 (5)
N1	0.0196 (18)	0.033 (2)	0.0268 (18)	0.0024 (15)	−0.0075 (15)	−0.0051 (16)
C11	0.016 (2)	0.024 (2)	0.021 (2)	0.0018 (17)	0.0036 (18)	−0.0015 (18)
C12	0.021 (2)	0.027 (2)	0.0145 (19)	0.0025 (17)	0.0028 (17)	0.0003 (18)
C13	0.027 (2)	0.030 (3)	0.023 (2)	0.0005 (19)	0.002 (2)	−0.0097 (19)
C14	0.042 (3)	0.020 (2)	0.035 (3)	−0.003 (2)	0.002 (2)	0.006 (2)
C15	0.044 (3)	0.037 (3)	0.023 (2)	−0.001 (2)	0.006 (2)	0.005 (2)
C16	0.028 (2)	0.030 (3)	0.017 (2)	−0.0004 (18)	0.0003 (18)	0.0001 (18)
N12	0.023 (2)	0.041 (3)	0.0194 (18)	0.0032 (17)	0.0035 (16)	0.0009 (18)
O121	0.0252 (16)	0.038 (2)	0.0228 (15)	0.0003 (14)	0.0022 (13)	0.0101 (14)
O122	0.078 (3)	0.056 (2)	0.0151 (16)	−0.0101 (18)	−0.0001 (16)	−0.0103 (15)

Geometric parameters (Å, º)

C1—C6	1.386 (5)	C12—N12	1.455 (5)
C1—C2	1.390 (5)	N12—O121	1.238 (4)
C2—C3	1.376 (5)	N12—O122	1.224 (4)
C2—H2	0.95	N1—H1	0.88
C3—C4	1.376 (6)	C11—C12	1.407 (5)
C3—H3	0.95	C12—C13	1.385 (6)
C4—C5	1.383 (5)	C13—C14	1.365 (5)
C4—I4	2.111 (4)	C14—C15	1.388 (5)
C5—C6	1.390 (5)	C15—C16	1.374 (6)
C5—H5	0.95	C16—C11	1.394 (5)
C6—H6	0.95	C13—H13	0.95
C1—N1	1.404 (5)	C14—H14	0.95
S1—N1	1.679 (3)	C15—H15	0.95
S1—C11	1.774 (4)	C16—H16	0.95
C6—C1—C2	119.1 (4)	C12—C11—C16	115.8 (4)
C6—C1—N1	122.1 (3)	S1—C11—C12	123.5 (3)
C2—C1—N1	118.8 (3)	S1—C11—C16	120.7 (3)
C3—C2—C1	120.7 (4)	C11—C12—C13	122.6 (3)
C3—C2—H2	119.6	C11—C12—N12	119.5 (4)
C1—C2—H2	119.6	C13—C12—N12	118.0 (3)
C4—C3—C2	119.5 (4)	C14—C13—C12	120.3 (4)
C4—C3—H3	120.2	C14—C13—H13	119.9
C2—C3—H3	120.2	C12—C13—H13	119.9
C3—C4—C5	121.0 (4)	C13—C14—C15	118.2 (4)
C3—C4—I4	119.6 (3)	C13—C14—H14	120.9
C5—C4—I4	119.3 (3)	C15—C14—H14	120.9
C4—C5—C6	119.1 (4)	C16—C15—C14	122.0 (4)
C4—C5—H5	120.5	C16—C15—H15	119.0
C6—C5—H5	120.5	C14—C15—H15	119.0
C1—C6—C5	120.5 (4)	C15—C16—C11	121.2 (4)
C1—C6—H6	119.8	C15—C16—H16	119.4
C5—C6—H6	119.8	C11—C16—H16	119.4
C1—N1—H1	117.5	O122—N12—O121	123.9 (3)
S1—N1—H1	117.5	O122—N12—C12	118.6 (4)
C1—N1—S1	124.9 (3)	O121—N12—C12	117.6 (3)
N1—S1—C11	101.5 (2)
C6—C1—C2—C3	0.6 (6)	C16—C11—C12—C13	−0.3 (6)
N1—C1—C2—C3	179.0 (3)	S1—C11—C12—C13	−179.8 (3)
C1—C2—C3—C4	−0.6 (6)	C16—C11—C12—N12	179.5 (3)
C2—C3—C4—C5	0.5 (6)	S1—C11—C12—N12	0.0 (5)
C2—C3—C4—I4	177.3 (3)	C11—C12—C13—C14	−0.1 (6)
C3—C4—C5—C6	−0.4 (6)	N12—C12—C13—C14	−180.0 (4)
I4—C4—C5—C6	−177.2 (3)	C12—C13—C14—C15	−0.2 (6)
C2—C1—C6—C5	−0.5 (6)	C13—C14—C15—C16	1.0 (7)
N1—C1—C6—C5	−178.8 (4)	C14—C15—C16—C11	−1.5 (7)
C4—C5—C6—C1	0.4 (6)	C12—C11—C16—C15	1.1 (6)
C6—C1—N1—S1	−18.3 (5)	S1—C11—C16—C15	−179.4 (3)
C1—N1—S1—C11	94.7 (3)	C13—C12—N12—O122	5.0 (5)
C2—C1—N1—S1	163.4 (3)	C11—C12—N12—O122	−174.8 (3)
N1—S1—C11—C12	171.7 (3)	C13—C12—N12—O121	−174.5 (3)
N1—S1—C11—C16	−7.7 (3)	C11—C12—N12—O121	5.7 (5)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1···O121^i	0.88	2.16	2.935 (4)	147
C6—H6···O121^ii	0.95	2.49	3.231 (5)	135
C16—H16···O122^iii	0.95	2.49	3.220 (5)	134

Symmetry codes: (i) x−1/2, y, −z+1/2; (ii) x+1/2, y, −z+1/2; (iii) x, −y+3/2, z−1/2.