A triclinic modification of 5,5′-dinitro-2,2′-dithio­dipyridine

Brito, I.; Mundaca, A.; Cárdenas, A.; López-Rodríguez, M.

doi:10.1107/S1600536807062630

A triclinic modification of 5,5′-dinitro-2,2′-dithiodipyridine

I. Brito, A. Mundaca, A. Cárdenas and M. López-Rodríguez

The asymmetric unit of the title compound, C₁₀H₆N₄O₄S₂, contains two independent but similar molecules. The structure is a triclinic polymorph of the monoclinic structure reported previously [Brito, Mundaca, Cárdenas, López-Rodríguez & Vargas (2007). Acta Cryst. E63, o3351–o3352]. The most obvious difference between the two polymorphs is the C—S—S—C torsion angle [−80.13 (16), −79.8 (2) and 0° for the two molecules of the triclinic polymorph and the monoclinic polymorph, respectively]. The crystal structure of the title compound has two intramolecular C—H

S interactions with average H

S distances of 2.69 Å, whereas this kind of interaction is not evident in the monoclinic polymorph.

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Supporting information

	Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536807062630/bt2643sup1.cif Contains datablocks global, I
	Structure factor file (CIF format) https://doi.org/10.1107/S1600536807062630/bt2643Isup2.hkl Contains datablock I

CCDC reference: 674441

checkCIF report

Key indicators

Single-crystal X-ray study
T = 298 K
Mean (C-C) = 0.006 Å
R factor = 0.087
wR factor = 0.209
Data-to-parameter ratio = 13.6

checkCIF/PLATON results

No syntax errors found



Alert level B
PLAT029_ALERT_3_B _diffrn_measured_fraction_theta_full Low .......       0.95

Alert level C
REFLT03_ALERT_3_C  Reflection count < 95% complete
           From the CIF: _diffrn_reflns_theta_max           26.50
           From the CIF: _diffrn_reflns_theta_full          26.50
           From the CIF: _reflns_number_total               4931
           TEST2: Reflns within _diffrn_reflns_theta_max
           Count of symmetry unique reflns         5207
           Completeness (_total/calc)             94.70%
PLAT022_ALERT_3_C Ratio Unique / Expected Reflections too Low ....       0.95
PLAT241_ALERT_2_C Check High      Ueq as Compared to Neighbors for         S3
PLAT242_ALERT_2_C Check Low       Ueq as Compared to Neighbors for         N1
PLAT242_ALERT_2_C Check Low       Ueq as Compared to Neighbors for         N4
PLAT242_ALERT_2_C Check Low       Ueq as Compared to Neighbors for         N5
PLAT242_ALERT_2_C Check Low       Ueq as Compared to Neighbors for         N8
PLAT242_ALERT_2_C Check Low       Ueq as Compared to Neighbors for        C11
PLAT340_ALERT_3_C Low Bond Precision on C-C Bonds (x 1000) Ang ...          6

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

   0 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   6 ALERT type 2 Indicator that the structure model may be wrong or deficient
   4 ALERT type 3 Indicator that the structure quality may be low
   0 ALERT type 4 Improvement, methodology, query or suggestion
   0 ALERT type 5 Informative message, check

Comment top

This paper forms part of our continuing study of the synthesis and structural characterization of divalent sulfur compounds (Brito et al., 2007 and references therein). We are particularly interested in the utility of the title compound of as flexible ligand, and its binding modes, for the fabrication of different coordination polymers topologies. We report here the structure of a new polymorph of 5,5'-Dinitro-2,2'-dithiodipyridine isolated during attempts to synthetize coordination polymers with silver trifluoromethanesulfonate of the ligand (Fig. 1, Table 1). The bond lenghts and the conformation are significantly different from those found in the monoclinic modification (Brito et al., 2007). The observed difference between (I) and the previously reported polymorph is in the torsion angle C—S—S—C [80.0 (2) and 0°, respectively]. 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°, the mean S—S bond distances are 2.031 (15) and 2.070 (22) Å, respectively. The corresponding value in the title compound is 2.025 (2) Å and 2.0719 (11) Å for the previously polymorph placing it in the lower quartile for Allen's first set. In both polymorphs the torsion angles X—C—S—S (where X=N or C) 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).

The molecular conformations are dominated by near orthogonality of the lone pairs on the two adjacent S atoms (Glidewell et al., 2000). The molecular packing in the title compound is completely different from that of the monoclinic polymorph. Only in the triclinic form the phenyl rings participant in significant intramolecular C—H···S interactions with average H···S distances of 2.69 Å. These interactions may stabilize the conformation adopted by the molecules in the solid state (Fig. 1). The molecules are linked into chains by two intermolecular C—H···O hydrogen bond. Atoms C8 and C18 in the molecules at (x,y,z) acts as hydrogen bonds donor vía atom H8 and H18 to atoms O1 and O5 in the molecule at (x,-1 + y,z) respectively, so generating by translation two C(12) chains running parallel to [010] direction (Bernstein et al., 1995), (Fig. 2, Table 2). The triclinic modification is much less compact, as noted from the lower density (1.638 Mg m^-3compared with 1.725 Mg m^-3 for the monoclinic form).

Related literature top

For related literature, see: Allen et al. (1987); Bernstein et al. (1995); Brito et al. (2007); Glidewell et al. (2000); Shefter (1970).

Experimental top

All reactions were carried out under an atmosphere of purified nitrogen. Solvents were dried and distilled prior to use. 5,5'-dinitro-2,2'-dithiodipyridine and silver trifluoromethanesulfonate were purchased from Aldrich. The title compound was obtained as light yellow prismatic crystals, in an attempts to prepare coordination polymers with silver trifluoromethanesulfonate of the ligand. A mixture of 5,5'-dinitro-2,2'-dithiodipyridine (1 mmol, 310 mg) and silver trifluoromethanesulfonate (1 mmol, 256.9 mg) in methanol (20 ml) was refluxed for 8 h. After slow cooling of the reaction system to room temperature, light yellow prismatic crystals of (I) were formed that were filtered off and washed with cold diethyl ether. FT–IR (KBr pellet, cm^-1): ν (w, C—H) 3082, ν(s, N=O of NO₂ asymmetric) 1578, ν (v.s. of NO₂ symmetric) 1356, ν(w, C—H disubstitution 1,4) 1964, ν(s, C—H disubstitution 1,4) 856, ν (w, C—N) 1101, ν(s, C=C) 1600, ν (w, C—H) 1014, (s, C=N) 1512, ν (w, C—S) 743, ν(w S—S) 555.

Structure description top

For related literature, see: Allen et al. (1987); Bernstein et al. (1995); Brito et al. (2007); Glidewell et al. (2000); Shefter (1970).

Computing details top

Data collection: COLLECT (Nonius, 1998); cell refinement: DENZO-SMN (Otwinowski & Minor, 1997); data reduction: DENZO-SMN (Otwinowski & Minor, 1997); 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 top

	Fig. 1. A view of the molecular structure of (I), showing both molecules in the asymmetric unit with displacement ellipsoids draw at the 30% probability level. Dashed lines indicate the intramolecular C–H···S hydrogen bonds. H atoms are shown as small spheres of arbitrary radii.
	Fig. 2. Part of the crystal structure of (I) showing the formation of two C(12) chains. For the sake of clarity, H atoms not involved in hydrogen bonding have been omitted. [Symmetry codes: (i) 1 - x, -y, 1 - z; (ii) -x, -y, 1 - z].

5,5'-dinitro-2,2'-dithiodipyridine top

Crystal data top

C₁₀H₆N₄O₄S₂	Z = 4
M_r = 310.31	F(000) = 632
Triclinic, P1	D_x = 1.638 Mg m⁻³
Hall symbol: -P 1	Melting point: 420 K
a = 7.7832 (12) Å	Mo Kα radiation, λ = 0.71073 Å
b = 11.8515 (11) Å	Cell parameters from 11236 reflections
c = 14.513 (2) Å	θ = 1.4–26.5°
α = 82.353 (4)°	µ = 0.44 mm⁻¹
β = 82.095 (5)°	T = 298 K
γ = 72.460 (9)°	Prismatic, light yellow
V = 1258.4 (3) Å³	0.20 × 0.10 × 0.10 mm

Data collection top

Nonius KappaCCD area-detector diffractometer	4931 independent reflections
Radiation source: fine-focus sealed tube	4101 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.062
φ scans, and ω scans with κ offsets	θ_max = 26.5°, θ_min = 1.4°
Absorption correction: multi-scan (SORTAV; Blessing, 1995)	h = −9→9
T_min = 0.937, T_max = 0.948	k = −12→14
11205 measured reflections	l = −18→18

Refinement top

Refinement on F²	0 restraints
Least-squares matrix: full	H-atom parameters constrained
R[F² > 2σ(F²)] = 0.088	w = 1/[σ²(F_o²) + (0.0368P)² + 1.5007P] where P = (F_o² + 2F_c²)/3
wR(F²) = 0.209	(Δ/σ)_max = 0.007
S = 1.16	Δρ_max = 0.33 e Å⁻³
4931 reflections	Δρ_min = −0.28 e Å⁻³
362 parameters

Crystal data top

C₁₀H₆N₄O₄S₂	γ = 72.460 (9)°
M_r = 310.31	V = 1258.4 (3) Å³
Triclinic, P1	Z = 4
a = 7.7832 (12) Å	Mo Kα radiation
b = 11.8515 (11) Å	µ = 0.44 mm⁻¹
c = 14.513 (2) Å	T = 298 K
α = 82.353 (4)°	0.20 × 0.10 × 0.10 mm
β = 82.095 (5)°

Data collection top

Nonius KappaCCD area-detector diffractometer	4931 independent reflections
Absorption correction: multi-scan (SORTAV; Blessing, 1995)	4101 reflections with I > 2σ(I)
T_min = 0.937, T_max = 0.948	R_int = 0.062
11205 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.088	0 restraints
wR(F²) = 0.209	H-atom parameters constrained
S = 1.16	Δρ_max = 0.33 e Å⁻³
4931 reflections	Δρ_min = −0.28 e Å⁻³
362 parameters

Special details top

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 (Å²) top

	x	y	z	U_iso*/U_eq
S1	−0.28532 (14)	0.36598 (9)	0.47963 (7)	0.0648 (3)
S2	−0.33244 (12)	0.21846 (9)	0.55311 (8)	0.0597 (3)
S3	0.2159 (2)	0.37139 (15)	0.72593 (9)	0.1008 (5)
S4	0.17109 (18)	0.22078 (14)	0.79400 (11)	0.0932 (5)
O1	−0.1425 (5)	0.7608 (3)	0.7099 (3)	0.0932 (11)
O2	−0.2430 (7)	0.6621 (3)	0.8270 (3)	0.1114 (15)
O3	0.5190 (4)	−0.0383 (3)	0.6160 (3)	0.1013 (14)
O4	0.4123 (4)	−0.1761 (3)	0.6849 (3)	0.0830 (10)
O5	0.3423 (6)	0.7628 (3)	0.9636 (3)	0.1124 (14)
O6	0.2541 (7)	0.6562 (3)	1.0807 (3)	0.1078 (13)
O7	1.0125 (5)	−0.0429 (5)	0.8735 (4)	0.143 (2)
O8	0.8920 (5)	−0.1686 (3)	0.9535 (3)	0.0985 (12)
N1	−0.2025 (5)	0.6797 (3)	0.7443 (3)	0.0695 (10)
N2	−0.2166 (5)	0.5481 (3)	0.5290 (3)	0.0675 (9)
N3	0.0258 (4)	0.1755 (2)	0.5594 (2)	0.0485 (7)
N4	0.3948 (4)	−0.0788 (3)	0.6427 (2)	0.0562 (8)
N5	0.2906 (5)	0.6772 (3)	0.9981 (3)	0.0765 (11)
N6	0.2519 (6)	0.5608 (4)	0.7817 (3)	0.0945 (15)
N7	0.5273 (5)	0.1785 (3)	0.8105 (3)	0.0725 (10)
N8	0.8822 (6)	−0.0777 (4)	0.9035 (3)	0.0798 (11)
C1	−0.2263 (5)	0.5991 (3)	0.6821 (3)	0.0536 (9)
C2	−0.2820 (6)	0.5018 (3)	0.7196 (3)	0.0607 (10)
H2	−0.3062	0.4877	0.784	0.073*
C3	−0.3013 (5)	0.4261 (3)	0.6612 (3)	0.0570 (9)
H3	−0.3366	0.3586	0.6846	0.078 (6)*
C4	−0.2670 (4)	0.4527 (3)	0.5671 (3)	0.0521 (9)
C5	−0.1959 (5)	0.6208 (3)	0.5874 (3)	0.0632 (11)
H5	−0.1598	0.6876	0.5627	0.078 (6)*
C6	−0.1129 (4)	0.1300 (3)	0.5804 (2)	0.0448 (7)
C7	−0.0971 (5)	0.0159 (3)	0.6229 (3)	0.0503 (8)
H7	−0.1982	−0.0121	0.6366	0.078 (6)*
C8	0.0692 (5)	−0.0546 (3)	0.6443 (3)	0.0483 (8)
H8	0.0851	−0.1316	0.6728	0.058*
C9	0.2126 (4)	−0.0072 (3)	0.6222 (2)	0.0425 (7)
C10	0.1881 (5)	0.1059 (3)	0.5803 (3)	0.0505 (8)
H10	0.2877	0.1353	0.5658	0.061*
C11	0.2288 (6)	0.4547 (4)	0.8158 (3)	0.0728 (13)
C12	0.2218 (6)	0.4174 (4)	0.9095 (3)	0.0706 (12)
H12	0.2054	0.3436	0.9313	0.078 (6)*
C13	0.2395 (6)	0.4909 (4)	0.9697 (3)	0.0691 (11)
H13	0.2342	0.4685	1.0337	0.083*
C14	0.2653 (6)	0.5984 (4)	0.9348 (3)	0.0680 (11)
C15	0.2697 (7)	0.6302 (5)	0.8413 (4)	0.0888 (16)
H15	0.286	0.7038	0.8184	0.107*
C16	0.3897 (6)	0.1317 (4)	0.8230 (3)	0.0690 (11)
C17	0.4031 (6)	0.0156 (4)	0.8614 (4)	0.0771 (13)
H17	0.3032	−0.0136	0.8688	0.078 (6)*
C18	0.5647 (6)	−0.0536 (4)	0.8877 (3)	0.0708 (11)
H18	0.5788	−0.1315	0.9137	0.085*
C19	0.7070 (5)	−0.0059 (3)	0.8749 (3)	0.0586 (9)
C20	0.6845 (6)	0.1087 (4)	0.8371 (3)	0.0686 (11)
H20	0.7831	0.1392	0.8298	0.082*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
S1	0.0590 (6)	0.0586 (6)	0.0625 (6)	0.0052 (5)	−0.0153 (5)	0.0013 (5)
S2	0.0394 (5)	0.0547 (6)	0.0817 (7)	−0.0040 (4)	−0.0121 (4)	−0.0117 (5)
S3	0.0942 (10)	0.1143 (11)	0.0657 (8)	0.0208 (8)	−0.0239 (7)	−0.0129 (7)
S4	0.0649 (8)	0.1047 (10)	0.1078 (11)	−0.0014 (7)	−0.0275 (7)	−0.0382 (8)
O1	0.090 (2)	0.0562 (18)	0.140 (3)	−0.0325 (17)	−0.023 (2)	0.0072 (19)
O2	0.192 (5)	0.070 (2)	0.087 (3)	−0.056 (3)	−0.024 (3)	−0.0074 (19)
O3	0.0428 (16)	0.090 (2)	0.167 (4)	−0.0267 (16)	−0.0314 (19)	0.040 (2)
O4	0.0621 (18)	0.0593 (18)	0.115 (3)	−0.0056 (14)	−0.0246 (17)	0.0246 (18)
O5	0.114 (3)	0.083 (2)	0.153 (4)	−0.057 (2)	−0.017 (3)	0.014 (2)
O6	0.157 (4)	0.080 (2)	0.092 (3)	−0.044 (3)	−0.017 (3)	−0.001 (2)
O7	0.064 (2)	0.148 (4)	0.205 (5)	−0.039 (3)	−0.031 (3)	0.056 (4)
O8	0.097 (3)	0.074 (2)	0.113 (3)	−0.0104 (19)	−0.024 (2)	0.013 (2)
N1	0.069 (2)	0.0378 (17)	0.103 (3)	−0.0172 (15)	−0.021 (2)	0.0058 (18)
N2	0.060 (2)	0.057 (2)	0.071 (2)	−0.0063 (16)	−0.0025 (17)	0.0161 (17)
N3	0.0421 (15)	0.0390 (14)	0.0646 (18)	−0.0129 (12)	−0.0090 (13)	0.0010 (13)
N4	0.0443 (17)	0.0510 (18)	0.072 (2)	−0.0121 (14)	−0.0162 (14)	0.0044 (15)
N5	0.071 (2)	0.057 (2)	0.097 (3)	−0.0150 (18)	−0.014 (2)	0.005 (2)
N6	0.095 (3)	0.092 (3)	0.064 (2)	0.003 (2)	−0.002 (2)	0.027 (2)
N7	0.072 (2)	0.065 (2)	0.076 (2)	−0.0121 (18)	−0.0121 (19)	−0.0057 (18)
N8	0.073 (3)	0.070 (2)	0.091 (3)	−0.016 (2)	−0.009 (2)	0.003 (2)
C1	0.0452 (19)	0.0357 (17)	0.075 (3)	−0.0060 (14)	−0.0102 (17)	0.0040 (16)
C2	0.074 (3)	0.0427 (19)	0.063 (2)	−0.0202 (18)	0.0015 (19)	0.0056 (17)
C3	0.067 (2)	0.0396 (18)	0.063 (2)	−0.0177 (17)	−0.0033 (18)	0.0037 (16)
C4	0.0350 (17)	0.0418 (18)	0.068 (2)	0.0017 (14)	−0.0067 (15)	0.0060 (16)
C5	0.054 (2)	0.045 (2)	0.084 (3)	−0.0157 (17)	−0.007 (2)	0.019 (2)
C6	0.0363 (16)	0.0450 (18)	0.0523 (19)	−0.0070 (13)	−0.0070 (14)	−0.0104 (14)
C7	0.0410 (18)	0.0476 (19)	0.065 (2)	−0.0199 (15)	−0.0026 (15)	−0.0033 (16)
C8	0.0481 (19)	0.0377 (17)	0.059 (2)	−0.0153 (14)	−0.0053 (15)	0.0011 (15)
C9	0.0374 (16)	0.0399 (16)	0.0516 (18)	−0.0112 (13)	−0.0096 (14)	−0.0039 (14)
C10	0.0406 (18)	0.0445 (18)	0.070 (2)	−0.0198 (15)	−0.0090 (16)	0.0027 (16)
C11	0.057 (2)	0.077 (3)	0.061 (2)	0.011 (2)	−0.0061 (19)	0.003 (2)
C12	0.082 (3)	0.061 (3)	0.060 (3)	−0.015 (2)	−0.001 (2)	0.005 (2)
C13	0.073 (3)	0.061 (2)	0.063 (3)	−0.013 (2)	−0.003 (2)	0.009 (2)
C14	0.055 (2)	0.061 (2)	0.075 (3)	−0.0069 (19)	−0.003 (2)	0.011 (2)
C15	0.091 (4)	0.072 (3)	0.081 (3)	−0.005 (3)	0.001 (3)	0.021 (3)
C16	0.063 (3)	0.075 (3)	0.068 (3)	−0.009 (2)	−0.006 (2)	−0.029 (2)
C17	0.061 (3)	0.083 (3)	0.096 (3)	−0.030 (2)	−0.001 (2)	−0.029 (3)
C18	0.072 (3)	0.059 (2)	0.084 (3)	−0.023 (2)	−0.002 (2)	−0.014 (2)
C19	0.057 (2)	0.059 (2)	0.059 (2)	−0.0137 (18)	−0.0014 (18)	−0.0117 (18)
C20	0.062 (3)	0.061 (2)	0.082 (3)	−0.018 (2)	−0.004 (2)	−0.005 (2)

Geometric parameters (Å, º) top

S1—C4	1.781 (4)	C1—C2	1.372 (5)
S1—S2	2.0275 (15)	C2—C3	1.367 (6)
S2—C6	1.781 (3)	C2—H2	0.93
S3—C11	1.768 (5)	C3—C4	1.368 (5)
S3—S4	2.023 (2)	C3—H3	0.93
S4—C16	1.784 (5)	C5—H5	0.93
O1—N1	1.213 (4)	C6—C7	1.387 (5)
O2—N1	1.205 (5)	C7—C8	1.363 (5)
O3—N4	1.200 (4)	C7—H7	0.93
O4—N4	1.211 (4)	C8—C9	1.376 (4)
O5—N5	1.223 (5)	C8—H8	0.93
O6—N5	1.204 (5)	C9—C10	1.366 (4)
O7—N8	1.213 (5)	C10—H10	0.93
O8—N8	1.204 (5)	C11—C12	1.371 (6)
N1—C1	1.464 (6)	C12—C13	1.360 (6)
N2—C4	1.334 (5)	C12—H12	0.93
N2—C5	1.342 (6)	C13—C14	1.369 (6)
N3—C6	1.329 (4)	C13—H13	0.93
N3—C10	1.333 (4)	C14—C15	1.358 (7)
N4—C9	1.464 (4)	C15—H15	0.93
N5—C14	1.463 (6)	C16—C17	1.393 (6)
N6—C15	1.317 (8)	C17—C18	1.351 (6)
N6—C11	1.343 (6)	C17—H17	0.93
N7—C20	1.329 (6)	C18—C19	1.369 (6)
N7—C16	1.329 (6)	C18—H18	0.93
N8—C19	1.455 (6)	C19—C20	1.365 (5)
C1—C5	1.365 (6)	C20—H20	0.93

C4—S1—S2	104.06 (13)	C6—C7—H7	120.6
C6—S2—S1	103.36 (12)	C7—C8—C9	117.4 (3)
C11—S3—S4	104.51 (17)	C7—C8—H8	121.3
C16—S4—S3	104.02 (18)	C9—C8—H8	121.3
O2—N1—O1	123.3 (4)	C10—C9—C8	120.9 (3)
O2—N1—C1	118.6 (3)	C10—C9—N4	119.0 (3)
O1—N1—C1	118.2 (4)	C8—C9—N4	120.0 (3)
C4—N2—C5	117.4 (3)	N3—C10—C9	122.0 (3)
C6—N3—C10	117.2 (3)	N3—C10—H10	119
O3—N4—O4	123.5 (3)	C9—C10—H10	119
O3—N4—C9	118.3 (3)	N6—C11—C12	122.5 (5)
O4—N4—C9	118.1 (3)	N6—C11—S3	111.9 (4)
O6—N5—O5	123.8 (5)	C12—C11—S3	125.6 (4)
O6—N5—C14	118.2 (4)	C13—C12—C11	118.5 (4)
O5—N5—C14	117.9 (4)	C13—C12—H12	120.8
C15—N6—C11	118.0 (4)	C11—C12—H12	120.8
C20—N7—C16	116.7 (4)	C12—C13—C14	119.0 (4)
O8—N8—O7	123.4 (5)	C12—C13—H13	120.5
O8—N8—C19	119.3 (4)	C14—C13—H13	120.5
O7—N8—C19	117.3 (4)	C15—C14—C13	119.5 (5)
C5—C1—C2	119.9 (4)	C15—C14—N5	120.6 (5)
C5—C1—N1	120.7 (3)	C13—C14—N5	119.9 (4)
C2—C1—N1	119.4 (4)	N6—C15—C14	122.5 (5)
C3—C2—C1	119.1 (4)	N6—C15—H15	118.7
C3—C2—H2	120.5	C14—C15—H15	118.7
C1—C2—H2	120.5	N7—C16—C17	123.7 (4)
C2—C3—C4	117.8 (3)	N7—C16—S4	119.9 (4)
C2—C3—H3	121.1	C17—C16—S4	116.5 (4)
C4—C3—H3	121.1	C18—C17—C16	118.5 (4)
N2—C4—C3	124.1 (4)	C18—C17—H17	120.8
N2—C4—S1	111.2 (3)	C16—C17—H17	120.8
C3—C4—S1	124.7 (3)	C17—C18—C19	118.2 (4)
N2—C5—C1	121.7 (3)	C17—C18—H18	120.9
N2—C5—H5	119.2	C19—C18—H18	120.9
C1—C5—H5	119.2	C20—C19—C18	120.4 (4)
N3—C6—C7	123.6 (3)	C20—C19—N8	120.0 (4)
N3—C6—S2	119.2 (3)	C18—C19—N8	119.5 (4)
C7—C6—S2	117.3 (2)	N7—C20—C19	122.6 (4)
C8—C7—C6	118.8 (3)	N7—C20—H20	118.7
C8—C7—H7	120.6	C19—C20—H20	118.7

C4—S1—S2—C6	−80.13 (16)	N4—C9—C10—N3	179.7 (3)
C11—S3—S4—C16	−79.8 (2)	C15—N6—C11—C12	0.5 (7)
O2—N1—C1—C5	174.8 (4)	C15—N6—C11—S3	−177.8 (4)
O1—N1—C1—C5	−5.3 (5)	S4—S3—C11—N6	−177.7 (3)
O2—N1—C1—C2	−4.4 (6)	S4—S3—C11—C12	4.1 (4)
O1—N1—C1—C2	175.5 (4)	N6—C11—C12—C13	−0.2 (7)
C5—C1—C2—C3	1.8 (6)	S3—C11—C12—C13	177.9 (4)
N1—C1—C2—C3	−179.0 (4)	C11—C12—C13—C14	−0.6 (7)
C1—C2—C3—C4	−1.2 (6)	C12—C13—C14—C15	1.1 (7)
C5—N2—C4—C3	1.1 (5)	C12—C13—C14—N5	−178.0 (4)
C5—N2—C4—S1	−179.4 (3)	O6—N5—C14—C15	167.0 (5)
C2—C3—C4—N2	−0.2 (6)	O5—N5—C14—C15	−10.7 (7)
C2—C3—C4—S1	−179.7 (3)	O6—N5—C14—C13	−13.9 (6)
S2—S1—C4—N2	173.4 (2)	O5—N5—C14—C13	168.3 (4)
S2—S1—C4—C3	−7.1 (3)	C11—N6—C15—C14	−0.1 (8)
C4—N2—C5—C1	−0.5 (6)	C13—C14—C15—N6	−0.7 (8)
C2—C1—C5—N2	−0.9 (6)	N5—C14—C15—N6	178.4 (5)
N1—C1—C5—N2	179.9 (3)	C20—N7—C16—C17	−0.3 (7)
C10—N3—C6—C7	0.6 (5)	C20—N7—C16—S4	177.3 (3)
C10—N3—C6—S2	−179.4 (3)	S3—S4—C16—N7	9.5 (4)
S1—S2—C6—N3	6.6 (3)	S3—S4—C16—C17	−172.8 (3)
S1—S2—C6—C7	−173.5 (3)	N7—C16—C17—C18	0.1 (7)
N3—C6—C7—C8	−0.4 (6)	S4—C16—C17—C18	−177.6 (4)
S2—C6—C7—C8	179.6 (3)	C16—C17—C18—C19	−0.1 (7)
C6—C7—C8—C9	0.1 (5)	C17—C18—C19—C20	0.4 (7)
C7—C8—C9—C10	−0.1 (5)	C17—C18—C19—N8	179.2 (4)
C7—C8—C9—N4	−179.5 (3)	O8—N8—C19—C20	164.9 (4)
O3—N4—C9—C10	−5.0 (6)	O7—N8—C19—C20	−16.6 (7)
O4—N4—C9—C10	175.6 (4)	O8—N8—C19—C18	−14.0 (7)
O3—N4—C9—C8	174.3 (4)	O7—N8—C19—C18	164.5 (5)
O4—N4—C9—C8	−5.0 (5)	C16—N7—C20—C19	0.5 (7)
C6—N3—C10—C9	−0.6 (5)	C18—C19—C20—N7	−0.6 (7)
C8—C9—C10—N3	0.4 (6)	N8—C19—C20—N7	−179.5 (4)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C3—H3···S2	0.93	2.68	3.173 (4)	114
C8—H8···O1ⁱ	0.93	2.44	3.098 (5)	127
C12—H12···S4	0.93	2.70	3.189 (5)	113
C18—H18···O5ⁱ	0.93	2.50	3.171 (6)	129

Symmetry code: (i) x, y−1, z.

Experimental details

Crystal data
Chemical formula	C₁₀H₆N₄O₄S₂
M_r	310.31
Crystal system, space group	Triclinic, P1
Temperature (K)	298
a, b, c (Å)	7.7832 (12), 11.8515 (11), 14.513 (2)
α, β, γ (°)	82.353 (4), 82.095 (5), 72.460 (9)
V (Å³)	1258.4 (3)
Z	4
Radiation type	Mo Kα
µ (mm⁻¹)	0.44
Crystal size (mm)	0.20 × 0.10 × 0.10

Data collection
Diffractometer	Nonius KappaCCD area-detector
Absorption correction	Multi-scan (SORTAV; Blessing, 1995)
T_min, T_max	0.937, 0.948
No. of measured, independent and observed [I > 2σ(I)] reflections	11205, 4931, 4101
R_int	0.062
(sin θ/λ)_max (Å⁻¹)	0.628

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.088, 0.209, 1.16
No. of reflections	4931
No. of parameters	362
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.33, −0.28

Computer programs: COLLECT (Nonius, 1998), DENZO-SMN (Otwinowski & Minor, 1997), SIR97 (Altomare et al., 1999), SHELXL97 (Sheldrick, 1997), ORTEP-3 for Windows (Farrugia, 1997) and PLATON (Spek, 2003), WinGX (Farrugia, 1999).

Selected torsion angles (º) top

C4—S1—S2—C6	−80.13 (16)	S1—S2—C6—C7	−173.5 (3)
C11—S3—S4—C16	−79.8 (2)	S4—S3—C11—N6	−177.7 (3)
S2—S1—C4—N2	173.4 (2)	S4—S3—C11—C12	4.1 (4)
S2—S1—C4—C3	−7.1 (3)	S3—S4—C16—N7	9.5 (4)
S1—S2—C6—N3	6.6 (3)	S3—S4—C16—C17	−172.8 (3)