5,5′-Dinitro-2,2′-dithio­dipyridine

In the title disulfide, (5-O₂NC₅H₃N)₂S₂ or C₁₀H₆N₄O₄S₂, the mol­ecule has a center of inversion. All bond lengths and angles are within normal ranges, and the mol­ecules are linked into centrosymmetric R₂²(22) dimers by a simple C—H...O inter­action. In the crystal structure, there are no aromatic π–π stacking and no C—H...π(arene) inter­actions.

Key indicators

• Single-crystal X-ray study
• T = 293 K
• Mean [sigma](C-C) = 0.004 Å
• R factor = 0.059
• wR factor = 0.139
• Data-to-parameter ratio = 13.9

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT029_ALERT_3_C _diffrn_measured_fraction_theta_full Low .......       0.96
PLAT180_ALERT_3_C Check Cell Rounding: # of Values Ending with 0 =          3

Alert level G
PLAT199_ALERT_1_G Check the Reported _cell_measurement_temperature        293 K
PLAT200_ALERT_1_G Check the Reported _diffrn_ambient_temperature .        293 K

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

   2 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   0 ALERT type 2 Indicator that the structure model may be wrong or deficient
   2 ALERT type 3 Indicator that the structure quality may be low
   0 ALERT type 4 Improvement, methodology, query or suggestion
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S1. Comment

This paper forms part of our continuing study of the synthesis and structural characterization of divalent sulfur compounds (Brito et al., 2006 and references therein). We are particularly interested in the utility of the title compound, (Fig. 1 and Table 1), as a flexible ligand, and its binding modes, for the fabrication of different coordination polymer topologies. A database survey of C—S—S—C fragments (Allen et al., 1987) found that S—S bond distances are bimodally distributed; for torsion angles in the ranges 75–105° and 0–20°, S—S bond-distance means were found to be 2.031 (15) and 2.070 (22) Å respectively. The corresponding value in the title compound is 2.0719 (11) Å, placing it in the upper quartile for Allen's first set. Further more, the torsion angles X—C—S—S, (where X=N or C), N2—C1—S1—S1ⁱ = 5.2 (3)° (symmetry code (i): -x + 1, -y + 1, -z) are close to 0 or 180° and within the range found in other substituted aromatic disulfides with an equatorial conformation according to the Shefter classification (Shefter, 1970). A search in the Cambridge Structural Database (version 5.28; Allen 2002) for the pyridyl disulfide fragment yielded fifteen structures of those which only two have an equatorial conformation, namely S,S'-bis(3-(Ethoxycarbonyl)pyridin-2-yl)disulfide (refcode TATPUA; Toma et al., 2004), and S,S'-bis(3-(n-Butoxycarbonyl)pyridin-2-yl)disulfide (refcode OCOYIO; Cindric et al., 2001). The C—S bond length of 1.761 (3) Å is between the value for a C—S single-bond distance of about 1.81 (2) Å and that for a double-bond distance of about 1.56 (4) Å (Etter et al., 1992) and is shorter than to those observed in organic disulfides with an equatorial conformation. Also noteworthy are the C—C—C, C—C—S and C—C—N angles at the ipso positions (Table 1), where the C—C—C angles, in particular, are consistent with the electron-donating and electron-withdrawing properties of thiolate and nitro substituents, respectively (Domenicano & Murray-Rust, 1979). The nitro group is nearly coplanar with the adjacent aryl ring (Fig. 1). The C4—N1 bond distance is 1.459 (4) Å; this value is typical of C(aryl)-NO₂ distances, where the mean value is 1.468 Å (Allen et al., 1987) with upper and lower quartile values of 1.476 and 1.460 Å respectively.

Molecules of the title compound are linked into centrosymmetric R₂²(22) dimers by a simple C—H···O interaction,. [H···O = 2.58 Å, O···O = 3.389 (4) Å and C—H···O = 146°]. Nitro atom O₂ in the molecule at (x + 1, y + 1, -z) acts as hydrogen-bond acceptor to a C₂ atom H₂ in the molecule at (x, y, z), so generating a centro-symmetric dimer characterized by R₂²(22) motif and centred at (1/2, 1/2, 0), Fig. 2, (Bernstein et al., 1995). 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). The title compound retains equatorial conformation in its complex formed with AgNO₃ (to within 22°) (López-Rodríguez et al., 2006). The coordination of silver(I) ion to either sulfur or nitrogen atoms of the title compound has not required an unusual X—C—S—S angle (X=C or N) angle, therefore the S—S bond is unaffected by complexation (2.031 (2) for the complex and 2.0719 (15) Å for the title compound). The larger observed deviation due to complexation is in the phenyl ring orientation (C—S—S—C = 70.8 (2)° for the complex and 180° for the title compound).

Related literature

For related literature, see: Allen (2002); Allen et al. (1987); Aupers et al. (1999); Bernstein et al. (1995); Boese et al. (1992); Boonstra (1963); Brito et al. (2006); Choi & Abel (1972); Cindric et al. (2001); Domenicano & Murray-Rust (1979); Etter et al. (1992); Glidewell et al. (2000); Herbstein & Kapon (1990); Kucsman et al. (1984); López-Rodríguez et al. (2006); Low et al. (2000); Sekine et al. (1994); Shefter (1970); Toma et al. (2004); Trotter & Williston (1966).

S2. Experimental

A sample of 2,2'-dithio-bis(5-nitropyridine) was purchased from Aldrich. Crystals suitable for single-crystal x-ray diffraction analysis were grown by slow evaporation of a solution in ethyl acetate. FT—IR (KBr pellet, cm^-1): ν (w, C– H) 3087, ν (s, N ═ O of NO₂ asymmetric) 1563, ν (v.s. N ═ O of NO₂ symmetric) 1343, ν (w, C - H disubstitution 1,4) 1958, ν (s, C - H disubstitution 1,4) 856, ν (w, C - N) 1101, ν (s, C ═ C) 1590, ν (w, C - H) 1006, (s, C ═ N) 1519, ν (w, C - S) 735, ν (w, S—S) 540.

S3. Refinement

In the final cycles of the refinement, all H atoms were constrained to ride on their parent atoms, with aryl C - H distances of 0.93 Å, and with U_iso(H) = 1.2U_eq(C). 112 unique reflections were not included in the data set as they were either partially obscured by the beam stop or were eliminated during data reduction.

Computing details

Data collection: COLLECT (Nonius, 1998); cell refinement: DENZO–SMN (Otwinowski & Minor, 1997); data reduction: DENZO–SMN; program(s) used to solve structure: SIR97 (Altomare et al., 1999); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997) and PLATON (Spek, 2003); software used to prepare material for publication: WinGX (Farrugia, 1999).

Figures

	Fig. 1. A view of the molecular structure, with the atom-numbering scheme. Displacement ellipsoids are drawn at the 50% probability level and H atoms are shown as small spheres of arbitrary radii. Unlabeled atoms are related to labeled atoms by the symmetry code (-x + 1, -y + 2, -z).
	Fig. 2. The molecular packing. Dashed lines indicate hydrogen bond [Symmetry code: (i) x + 1, y + 1, z]. H atoms not involved in hydrogen bonds have been omitted for clarity.

5,5'-Dinitro-2,2'-dithiodipyridine

Crystal data

C10H6N4O4S2	F(000) = 316
Mr = 310.31	Dx = 1.725 Mg m^−3
Monoclinic, P21/n	Melting point = 428–430 K
Hall symbol: -P 2yn	Mo Kα radiation, λ = 0.71073 Å
a = 5.2610 (15) Å	Cell parameters from 2999 reflections
b = 6.0440 (13) Å	θ = 3.5–27.5°
c = 18.8070 (19) Å	µ = 0.47 mm^−1
β = 92.839 (12)°	T = 293 K
V = 597.3 (2) Å^3	Prism, colourless
Z = 2	0.43 × 0.30 × 0.22 mm

Data collection

Nonius KappaCCD area-detector diffractometer	1267 independent reflections
Radiation source: fine-focus sealed tube	1122 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.067
φ scans, and ω scans with κ offsets	θmax = 27.5°, θmin = 3.5°
Absorption correction: multi-scan (SORTAV; Blessing, 1995)	h = −6→6
Tmin = 0.842, Tmax = 0.901	k = −6→7
3529 measured reflections	l = −19→24

Refinement

Refinement on F^2	0 restraints
Least-squares matrix: full	H-atom parameters constrained
R[F^2 > 2σ(F^2)] = 0.059	w = 1/[σ^2(Fo^2) + 1.3711P] where P = (Fo^2 + 2Fc^2)/3
wR(F^2) = 0.139	(Δ/σ)max = 0.014
S = 1.08	Δρmax = 0.48 e Å^−3
1267 reflections	Δρmin = −0.31 e Å^−3
91 parameters

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
S1	0.64977 (15)	0.47850 (13)	0.03722 (4)	0.0348 (3)
O1	0.4118 (5)	−0.4104 (4)	0.22547 (13)	0.0486 (7)
O2	0.0696 (5)	−0.3958 (5)	0.15797 (16)	0.0615 (9)
N1	0.2791 (5)	−0.3234 (5)	0.17826 (13)	0.0345 (6)
N2	0.3161 (5)	0.1460 (4)	0.05263 (13)	0.0314 (6)
C1	0.5303 (6)	0.2418 (5)	0.07878 (15)	0.0285 (6)
C2	0.6740 (6)	0.1634 (5)	0.13849 (16)	0.0328 (7)
H2	0.8211	0.2363	0.155	0.039*
C3	0.5917 (6)	−0.0239 (5)	0.17193 (16)	0.0322 (7)
H3	0.6816	−0.0821	0.2114	0.039*
C4	0.3700 (6)	−0.1227 (5)	0.14469 (15)	0.0281 (6)
C5	0.2369 (6)	−0.0362 (5)	0.08584 (16)	0.0309 (6)
H5	0.0886	−0.1061	0.0688	0.037*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
S1	0.0363 (5)	0.0301 (4)	0.0372 (4)	−0.0081 (3)	−0.0048 (3)	0.0063 (3)
O1	0.0510 (15)	0.0434 (15)	0.0504 (14)	−0.0051 (12)	−0.0078 (11)	0.0192 (11)
O2	0.0546 (17)	0.0570 (18)	0.0706 (18)	−0.0317 (15)	−0.0185 (13)	0.0224 (15)
N1	0.0384 (15)	0.0303 (14)	0.0346 (13)	−0.0055 (11)	0.0002 (11)	0.0023 (11)
N2	0.0293 (13)	0.0298 (14)	0.0347 (13)	−0.0020 (11)	−0.0022 (10)	0.0018 (10)
C1	0.0319 (15)	0.0249 (14)	0.0289 (14)	−0.0001 (12)	0.0037 (11)	−0.0011 (11)
C2	0.0306 (15)	0.0326 (17)	0.0347 (15)	−0.0058 (13)	−0.0029 (12)	−0.0004 (12)
C3	0.0338 (16)	0.0321 (16)	0.0300 (14)	0.0016 (13)	−0.0042 (11)	0.0025 (12)
C4	0.0298 (15)	0.0236 (14)	0.0311 (14)	0.0000 (12)	0.0026 (11)	−0.0002 (11)
C5	0.0299 (15)	0.0299 (16)	0.0327 (15)	−0.0043 (12)	−0.0006 (11)	−0.0007 (12)

Geometric parameters (Å, º)

S1—C1	1.761 (3)	C1—C2	1.405 (4)
S1—S1^i	2.0719 (15)	C2—C3	1.375 (4)
O1—N1	1.221 (3)	C2—H2	0.93
O2—N1	1.229 (4)	C3—C4	1.386 (4)
N1—C4	1.459 (4)	C3—H3	0.93
N2—C1	1.339 (4)	C4—C5	1.383 (4)
N2—C5	1.343 (4)	C5—H5	0.93
C1—S1—S1^i	97.22 (11)	C1—C2—H2	120.9
O1—N1—O2	123.0 (3)	C2—C3—C4	117.7 (3)
O1—N1—C4	119.0 (3)	C2—C3—H3	121.2
O2—N1—C4	118.0 (3)	C4—C3—H3	121.2
C1—N2—C5	117.3 (3)	C5—C4—C3	121.1 (3)
N2—C1—C2	123.9 (3)	C5—C4—N1	119.8 (3)
N2—C1—S1	120.0 (2)	C3—C4—N1	119.1 (3)
C2—C1—S1	116.0 (2)	N2—C5—C4	121.7 (3)
C3—C2—C1	118.3 (3)	N2—C5—H5	119.1
C3—C2—H2	120.9	C4—C5—H5	119.1
C5—N2—C1—C2	−0.3 (5)	C2—C3—C4—N1	179.1 (3)
C5—N2—C1—S1	178.9 (2)	O1—N1—C4—C5	172.6 (3)
S1^i—S1—C1—N2	5.2 (3)	O2—N1—C4—C5	−8.2 (4)
S1^i—S1—C1—C2	−175.5 (2)	O1—N1—C4—C3	−6.4 (4)
N2—C1—C2—C3	0.6 (5)	O2—N1—C4—C3	172.8 (3)
S1—C1—C2—C3	−178.6 (2)	C1—N2—C5—C4	0.0 (4)
C1—C2—C3—C4	−0.5 (5)	C3—C4—C5—N2	0.1 (5)
C2—C3—C4—C5	0.2 (5)	N1—C4—C5—N2	−178.9 (3)

Symmetry code: (i) −x+1, −y+1, −z.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
C2—H2···O2^ii	0.93	2.58	3.389 (4)	146

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