Bis(3-nitro­phenyl) di­sulfide forms no C-H...O hydrogen bonds

In the title compound, C₁₂H₈N₂O₄S₂, the mol­ecules lie across twofold rotation axes in the space group C2/c. There are no intermolecular C-H...O hydrogen bonds, but the mol­ecules are linked into chains along [001] by aromatic [pi]...[pi] stacking interactions.

S1. Comment

Although the structures of bis(2-nitrophenyl) disulfide and bis(4-nitrophenyl) disulfide were determined many years ago from photographic data (Ricci & Bernal, 1969, 1970), we have recently used low-temperature CCD data to redetermine these structures and to analyse the extensive intermolecular aggregation (Glidewell et al., 2000; Wardell et al., 2000). In the 2,2'-isomer, the molecules act as single donors of C—H···O hydrogen bonds and as single acceptors, so that chain formation results; the chains are further linked into sheets by aromatic π···π stacking interactions. Molecules of the 4,4'-isomer lie across twofold rotation axes and act as twofold donors and twofold acceptors of hydrogen bonds; the resulting sheets are linked into a three-dimensional framework by aromatic π···π stacking interactions. It is noteworthy that for both compounds, the original structure reports indicated that there were no intermolecular interactions.

As a continuation of this study, we have now determined the structure of the 3,3'-isomer, i.e. bis-(3-nitrophenyl) disulfide, (I), whose structure turns out to contain no C—H.·O hydrogen bonds, in contrast to the 2,2'- and 4,4'-isomers. The molecules in (I) lie across twofold rotation axes in space group C2/c (Fig. 1), just as in the 4,4'-isomer, but there are only two intermolecular C···O contacts of less than 3.50 Å and these are associated with H···O distances greater than 2.75 Å and C—H···O angles well below 120°. All other intermolecular C···O distances are greater than 3.50 Å with H···O distances greater than 2.85 Å.

The absence of any C—H···O hydrogen bonds in (I) is highly unusual, as such interactions are generally the dominant feature of the crystal structures of compounds containing nitroarenethiolate (O₂NC₆H₄SX) fragments (Kucsman et al., 1984; Aupers et al., 1999; Low et al., 2000; Glidewell et al., 2000), as well as those of simple nitrobenzenes (Boonstra, 1963; Trotter & Williston, 1966; Choi & Abel, 1972; Herbstein & Kapon, 1990; Boese et al., 1992; Sekine et al., 1994).

Despite the absence of hydrogen bonds, the molecules of (I) are nonetheless linked into chains by means of aromatic π···π stacking interactions. The aryl ring at (x, y, z) is part of a molecule lying across the rotation axis along (0, y, 1/4): this ring forms a π···π stacking interaction across the inversion centre at the origin with the ring at (-x, −y, −z), which is part of a molecule lying across the rotation axis along (0, y, −0.25). The separation of the ring planes is 3.587 (3) Å and the centroid offset is 1.429 (3) Å. The symmetry-related ring in the reference molecule lying across the axis along (0, y, 1/4) is at (-x, y, 0.5 − z) and this in turn forms a stacking interaction across the inversion centre at (0, 0, 1/2) with the ring at (x, −y, 0.5 + z); this ring is itself part of a molecule lying across the twofold axis along (0, y, 3/4). Propagation of this π···π stacking interaction by the inversion centres at (0, 0, n/2) (n = zero or integer) and the twofold rotation axes along (0, y, 0.25+n/2) (n = zero or integer) produces a chain parallel to the [001] direction (Fig. 2). A second such chain related to the first by the action of the C-centring operation is generated by the glide plane at y = 1/2, and these two chains accommodate all the unit-cell contents and thus are sufficient to define the entire crystal structure.

Molecules of the 2,2'-, 3,3'- and 4,4'-isomers of dinitrophenyl disulfide are thus hydrogen bonded to two, zero and four other molecules, respectively, and they are linked via π···π stacking interactions to one, two and two other molecules, respectively. Very modest changes to the molecular constitutions lead to significant changes in the supramolecular aggregation.

The bond lengths and angles which show significant differences between the three isomers are listed in Table 1. Particularly noteworthy are the C—C—C and S—C—C angles at the ipso position, the C—S—S—C torsion angles and the torsion angles defining the twist of the nitro groups from the plane of the adjacent aryl ring.

S2. Experimental

A sample of compound (I) was obtained from Aldrich. Crystals suitable for single-crystal X-ray diffraction were grown from a solution in ethanol.

S3. Refinement

Compound (I) crystallized in the monoclinic system; space group C2/c was assumed from the systematic absences and confirmed by the analysis. The H atoms were treated as riding with C—H = 0.93 Å. Examination of the structure with PLATON (Spek, 2000) showed that there were no solvent-accessible voids in the crystal lattice.

Computing details

Data collection: SMART (Bruker, 1997); cell refinement: SAINT (Bruker, 1997); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: PLATON (Spek, 2000); software used to prepare material for publication: SHELXL97 and WORDPERFECT macro PRPKAPPA (Ferguson, 1999).

Figures

	Fig. 1. The molecule of (I) showing the atom-labelling scheme. Displacement ellipsoids are drawn at the 30% probability level [symmetry code: (i) −x, y, 0.5 − z].
	Fig. 2. Part of the crystal structure of (I) showing one of the [001] chains formed by the aromatic π···π stacking interactions. H atoms have been omitted for the sake of clarity.

Bis-(3-nitrophenyl) disulfide

Crystal data

C12H8N2O4S2	F(000) = 632
Mr = 308.32	Dx = 1.560 Mg m^−3
Monoclinic, C2/c	Mo Kα radiation, λ = 0.71073 Å
a = 13.6731 (9) Å	Cell parameters from 2212 reflections
b = 8.9078 (6) Å	θ = 2.9–24.9°
c = 12.4539 (8) Å	µ = 0.42 mm^−1
β = 120.070 (1)°	T = 306 K
V = 1312.70 (15) Å^3	Block, yellow
Z = 4	0.47 × 0.26 × 0.16 mm

Data collection

Bruker 1000 CCD diffractometer	1156 independent reflections
Radiation source: fine-focus sealed X-ray tube	983 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.018
ϕ–ω scans	θmax = 25.0°, θmin = 2.9°
Absorption correction: multi-scan (SADABS; Bruker, 1997)	h = −10→16
Tmin = 0.831, Tmax = 0.940	k = −10→9
4030 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)] = 0.030	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.089	H-atom parameters constrained
S = 1.05	w = 1/[σ^2(Fo^2) + (0.0576P)^2 + 0.2399P] where P = (Fo^2 + 2Fc^2)/3
1156 reflections	(Δ/σ)max = 0.005
91 parameters	Δρmax = 0.18 e Å^−3
0 restraints	Δρmin = −0.15 e Å^−3

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

	x	y	z	Uiso*/Ueq
S1	0.02628 (4)	0.33466 (6)	0.18704 (4)	0.0621 (2)
C1	−0.06472 (13)	0.2079 (2)	0.06750 (14)	0.0473 (4)
C2	−0.14224 (13)	0.11524 (19)	0.07274 (14)	0.0460 (4)
C3	−0.20767 (13)	0.02443 (19)	−0.02873 (14)	0.0452 (4)
N3	−0.29339 (12)	−0.07141 (17)	−0.02498 (14)	0.0535 (4)
O31	−0.34811 (13)	−0.15644 (17)	−0.11204 (14)	0.0717 (4)
O32	−0.30734 (12)	−0.06137 (18)	0.06422 (12)	0.0711 (4)
C4	−0.19806 (14)	0.0228 (2)	−0.13356 (15)	0.0542 (4)
C5	−0.12072 (17)	0.1180 (2)	−0.13717 (16)	0.0618 (5)
C6	−0.05410 (15)	0.2104 (2)	−0.03857 (16)	0.0577 (5)
H2	−0.1507	0.1134	0.1423	0.055*
H4	−0.2424	−0.0406	−0.1997	0.065*
H5	−0.1133	0.1201	−0.2074	0.074*
H6	−0.0022	0.2743	−0.0424	0.069*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
S1	0.0642 (3)	0.0642 (4)	0.0471 (3)	−0.0130 (2)	0.0198 (2)	0.0018 (2)
C1	0.0438 (8)	0.0521 (9)	0.0409 (8)	0.0051 (7)	0.0175 (7)	0.0065 (7)
C2	0.0490 (9)	0.0513 (9)	0.0373 (8)	0.0065 (7)	0.0213 (7)	0.0055 (7)
C3	0.0430 (8)	0.0481 (9)	0.0429 (8)	0.0063 (7)	0.0203 (7)	0.0059 (7)
N3	0.0528 (8)	0.0539 (9)	0.0503 (8)	0.0000 (7)	0.0233 (7)	0.0026 (7)
O31	0.0736 (9)	0.0718 (9)	0.0653 (8)	−0.0192 (7)	0.0314 (7)	−0.0144 (7)
O32	0.0765 (9)	0.0895 (11)	0.0596 (8)	−0.0177 (8)	0.0433 (7)	−0.0015 (7)
C4	0.0558 (10)	0.0637 (11)	0.0414 (9)	0.0015 (8)	0.0230 (8)	−0.0023 (8)
C5	0.0666 (11)	0.0816 (13)	0.0469 (10)	0.0006 (10)	0.0357 (9)	0.0015 (9)
C6	0.0533 (10)	0.0698 (12)	0.0531 (10)	−0.0028 (9)	0.0290 (8)	0.0076 (9)

Geometric parameters (Å, º)

S1—C1	1.7840 (17)	N3—O32	1.221 (2)
S1—S1^i	2.0260 (10)	N3—O31	1.223 (2)
C1—C2	1.371 (2)	C4—C5	1.374 (3)
C1—C6	1.400 (2)	C4—H4	0.9300
C2—C3	1.385 (2)	C5—C6	1.376 (3)
C2—H2	0.9300	C5—H5	0.9300
C3—C4	1.376 (2)	C6—H6	0.9300
C3—N3	1.470 (2)
C1—S1—S1^i	106.05 (6)	O32—N3—C3	118.49 (14)
C2—C1—C6	120.18 (16)	O31—N3—C3	118.35 (15)
C2—C1—S1	125.03 (13)	C5—C4—C3	117.75 (16)
C6—C1—S1	114.77 (14)	C5—C4—H4	121.1
C1—C2—C3	118.02 (15)	C3—C4—H4	121.1
C1—C2—H2	121.0	C6—C5—C4	121.07 (16)
C3—C2—H2	121.0	C6—C5—H5	119.5
C4—C3—C2	123.13 (16)	C4—C5—H5	119.5
C4—C3—N3	118.74 (15)	C5—C6—C1	119.84 (17)
C2—C3—N3	118.10 (14)	C5—C6—H6	120.1
O32—N3—O31	123.15 (16)	C1—C6—H6	120.1
C1^i—S1^i—S1—C1	97.63 (9)	C4—C3—N3—O31	4.7 (2)
S1^i—S1—C1—C2	−8.56 (16)	C2—C3—N3—O31	−176.97 (15)
S1^i—S1—C1—C6	170.06 (12)	C2—C3—C4—C5	−1.0 (3)
C6—C1—C2—C3	0.7 (2)	N3—C3—C4—C5	177.27 (16)
S1—C1—C2—C3	179.24 (12)	C3—C4—C5—C6	0.8 (3)
C1—C2—C3—C4	0.2 (2)	C4—C5—C6—C1	0.1 (3)
C1—C2—C3—N3	−178.04 (14)	C2—C1—C6—C5	−0.8 (3)
C4—C3—N3—O32	−174.62 (16)	S1—C1—C6—C5	−179.53 (15)
C2—C3—N3—O32	3.7 (2)

Symmetry code: (i) −x, y, −z+1/2.