Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536807044078/im2033sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S1600536807044078/im2033Isup2.hkl |
CCDC reference: 663766
Key indicators
- Single-crystal X-ray study
- T = 120 K
- Mean (C-C) = 0.002 Å
- R factor = 0.033
- wR factor = 0.086
- Data-to-parameter ratio = 21.5
checkCIF/PLATON results
No syntax errors found
Alert level C PLAT062_ALERT_4_C Rescale T(min) & T(max) by ..................... 0.92 PLAT230_ALERT_2_C Hirshfeld Test Diff for C5 - C6 .. 6.15 su PLAT230_ALERT_2_C Hirshfeld Test Diff for C8 - C9 .. 5.63 su
Alert level G ABSTM02_ALERT_3_G When printed, the submitted absorption T values will be replaced by the scaled T values. Since the ratio of scaled T's is identical to the ratio of reported T values, the scaling does not imply a change to the absorption corrections used in the study. Ratio of Tmax expected/reported 0.915 Tmax scaled 0.915 Tmin scaled 0.755
0 ALERT level A = In general: serious problem 0 ALERT level B = Potentially serious problem 3 ALERT level C = Check and explain 1 ALERT level G = General alerts; check 0 ALERT type 1 CIF construction/syntax error, inconsistent or missing data 2 ALERT type 2 Indicator that the structure model may be wrong or deficient 1 ALERT type 3 Indicator that the structure quality may be low 1 ALERT type 4 Improvement, methodology, query or suggestion 0 ALERT type 5 Informative message, check
The title compound has been synthesized by the route shown in the Scheme. 3-Bromo-propionitrile (12.5 ml, 0.15 mmol) was added to a stirred 200 ml acetone solution containing (Bu4N)2[Zn(dmit)2] (28.5 g, 0.030 mmol). After reacting for 12 h at 320 K, the solvent was removed. The residue was dissolved in 250 ml CH2Cl2, and 200 ml water was added. After being stirred overnight and the water layer removed, 100 ml CH3OH was added into the CH2Cl2 solution. Needle-shaped orange crystals of (4,5-bis(2'-cyanoethylsulfanyl)-[1,3]-dithiole-2-thione) (I) formed quickly when most of the CH2Cl2 had evaporated. The solvent remaining in the mother-liquor was removed, the residual mixture which contained both (I) and (II), was separated by column chromatography on silica gel (eluent CH2Cl2). The yields based on (Bu4N)2[Zn(dmit)2] for (I) and (II) were 81% and 9%, respectively. The orange (I) moved faster in the column (Rf = 1/2), followed by 4,5-bis(2'-cyanoethylsulfanyl)-[1,2]-dithiole-3-thion (II) of the same colour (Rf = 0.3), indicating higher polarity of (II). When most of the CH2Cl2 evaporated, platelet crystals of (II) have been obtained with the m.p. of 438–440 K.
All H atoms were located in a difference Fourier map and refined in isotropic approximation without constraints, C—H distances 0.92 (2) to 0.98 (2) Å.
The rapid progress of molecular conductors or superconductors in the past three decades has been triggered by the successful syntheses of novel and useful organic donors. The synthesis of TTF (C6S4H4, tetrathiafulvalene) in 1970 and BEDT-TTF (C10S8H8, bis(ethylenedithio)-tetrathiafulvalene) in the late 1970 s have resulted in more than one hundred TTF-based organic superconductors, such as κ-(BEDT-TTF)2Cu[N(CN)2]Br with Tc = 11.6 K at ambient pressure (Kini et al., 1991). One kind of promising donors for new molecular conductors still seem to be multi-sulfur heterocyclic compounds with more sulfur atoms fused into the TTF skeleton, such as BEDT-TTP (C14S12H8, 2,5-bis(4,5-ethylenedithio-1,3-dithiol-2-ylidene) -1,3,4,6-tetrathiapentalene) and similar donors (Mori et al., 1995). In the course of exploring some derivatives of BEDT-TTP, we obtained their precursor 4,5-bis(2'-cyanoethylsulfanyl)-[1,3]-dithiole-2-thione (I) (Figure 1) and determined its structure (Yu et al., 2003). Here we report the structure and synthesis of its isomer: 4,5-bis(2'-cyanoethylsulfanyl)-[1,2]-dithiole-3-thione (II).
As shown in Figure 2, the five-membered 1,2-dithiole ring is basically planar and the plane (plane 1) can be extended to three peripheral sulfur atoms (S3, S4 and S5) and the C4 atom. Of these nine atoms, S4 shows the biggest deviation from the plane, 0.051 (1) Å. Four atoms (C4, C5, C6 and N1) of one side-chain of the molecule are within the second plane (Plane 2) and the five atoms (S5, C6, C7, C8 and N2) of the other side-chain are arranged in the third plane (Plane 3). The dihedral angels between these planes are 71.6 (1)° (between planes 1 and 2), 84.0 (1)° (1 and 3), and 56.7 (1)° (2 and 3).
The bonding in the C1—C2—C3—S3 fragment of the 1,2-isomer is highly conjugated with the bond lengths being 1.384 (2), 1.430 (2) and 1.661 (1) Å for the C1—C2, C2—C3 and terminal C3—S3 bonds, respectively. The π-conjugation may involve three more atoms (S1, S2 and S4) because of the "conjugated" bond lengths C1—S1 (1.725 (1) Å), C3—S2 (1.733 (1) Å), and C1—S4 (1.737 (1) Å). However, the π-conjugation is not circular because the S1—S2 bond length (2.0702 (5) Å) is indicative for a single bond. By comparison, the conjugation in (I) is not very significant because of the double C═C (1.346 (1) Å) and the terminal double C═S bond (1.644 (1) Å).
As shown in Figure 3, in the crystal of (II) each molecule participates in six strong S···S and S···N intermolecular interactions with its three neighbours. Three of these six contacts are symmetrically independent, viz. S4···S5A (-x, -y, 1 - z) of 3.484 (2) Å, S1···N1B (1 + x, y, z) of 3.112 (2) and S2···N1B (1 + x, y, z) of 3.142 (2) Å. These contacts are significantly shorter than the standard intermolecular (van der Waals) contact distances S···S of 3.60 Å and S···N of 3.45 Å (Rowland & Taylor, 1996). These intermolecular interactions help to form a kind of supramolecular planar moiety involving 20 atoms: nine from the main molecular plane (Plane 1) of the concerned molecule, another nine from the main plane of the adjacent molecule (-x, -y, 1 - z) and two N1 atoms from other two molecules. Furthermore, due to these S···S and S···N interactions, a kind of one-dimensional double chain of molecules can be found along the a-direction. By comparison, there are no short S···S contacts in the crystal of (I), corresponding to the relatively strong intermolecular interactions of (II).
For related literature, see: Mori et al. (1995); Rowland & Taylor (1996); Yu et al. (2003).
For related literature, see: Kini et al. (1990).
Data collection: CrystalClear (Rigaku, 2007); cell refinement: CrystalClear (Rigaku, 2007); data reduction: CrystalClear (Rigaku, 2007); program(s) used to solve structure: SHELXTL (Bruker, 2000); program(s) used to refine structure: SHELXTL (Bruker, 2000); molecular graphics: SHELXTL (Bruker, 2000); software used to prepare material for publication: SHELXTL (Bruker, 2000).
C9H8N2S5 | Z = 2 |
Mr = 304.47 | F(000) = 312 |
Triclinic, P1 | Dx = 1.605 Mg m−3 |
Hall symbol: -P 1 | Melting point: 439(1) K |
a = 8.0216 (4) Å | Mo Kα radiation, λ = 0.71073 Å |
b = 8.9771 (3) Å | Cell parameters from 4653 reflections |
c = 9.4799 (5) Å | θ = 2.3–35.5° |
α = 91.251 (3)° | µ = 0.89 mm−1 |
β = 112.426 (2)° | T = 120 K |
γ = 92.418 (2)° | Platelet, orange |
V = 629.93 (5) Å3 | 0.40 × 0.35 × 0.10 mm |
Rigaku R-AXIS SPIDER IP diffractometer | 3811 independent reflections |
Radiation source: fine-focus sealed tube | 3721 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.040 |
Detector resolution: 10.00 pixels mm-1 | θmax = 30.5°, θmin = 2.3° |
wide ω scans | h = −11→11 |
Absorption correction: multi-scan (CrystalClear; Rigaku, 2007) | k = −12→12 |
Tmin = 0.825, Tmax = 1.000 | l = −13→13 |
12836 measured reflections |
Refinement on F2 | Primary atom site location: structure-invariant direct methods |
Least-squares matrix: full | Secondary atom site location: difference Fourier map |
R[F2 > 2σ(F2)] = 0.033 | Hydrogen site location: difference Fourier map |
wR(F2) = 0.086 | All H-atom parameters refined |
S = 1.10 | w = 1/[σ2(Fo2) + (0.0355P)2 + 0.1882P] where P = (Fo2 + 2Fc2)/3 |
3811 reflections | (Δ/σ)max = 0.001 |
177 parameters | Δρmax = 0.57 e Å−3 |
0 restraints | Δρmin = −0.30 e Å−3 |
C9H8N2S5 | γ = 92.418 (2)° |
Mr = 304.47 | V = 629.93 (5) Å3 |
Triclinic, P1 | Z = 2 |
a = 8.0216 (4) Å | Mo Kα radiation |
b = 8.9771 (3) Å | µ = 0.89 mm−1 |
c = 9.4799 (5) Å | T = 120 K |
α = 91.251 (3)° | 0.40 × 0.35 × 0.10 mm |
β = 112.426 (2)° |
Rigaku R-AXIS SPIDER IP diffractometer | 3811 independent reflections |
Absorption correction: multi-scan (CrystalClear; Rigaku, 2007) | 3721 reflections with I > 2σ(I) |
Tmin = 0.825, Tmax = 1.000 | Rint = 0.040 |
12836 measured reflections |
R[F2 > 2σ(F2)] = 0.033 | 0 restraints |
wR(F2) = 0.086 | All H-atom parameters refined |
S = 1.10 | Δρmax = 0.57 e Å−3 |
3811 reflections | Δρmin = −0.30 e Å−3 |
177 parameters |
Experimental. scan: Number of images: 41 Slice: 51.0000 - 175.0000 Image width: 3.0000 Exp time: 300.0000 Rotation axis: Omega Omega: 0.0000 Chi: 0.0000 Phi: 0.0000 XTD: 127.4000 2theta: -0.0164 scan: Number of images: 40 Slice: 20.0000 - 140.0000 Image width: 3.0000 Exp time: 300.0000 Rotation axis: Omega Omega: 0.0000 Chi: 54.0000 Phi: 0.0000 XTD: 127.4000 2theta: -0.0164 scan: Number of images: 40 Slice: 20.0000 - 140.0000 Image width: 3.0000 Exp time: 300.0000 Rotation axis: Omega Omega: 0.0000 Chi: 54.0000 Phi: 180.0000 XTD: 127.4000 2theta: -0.0164 |
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. |
x | y | z | Uiso*/Ueq | ||
S3 | 0.78564 (4) | 0.08290 (4) | 0.87088 (4) | 0.02157 (9) | |
S1 | 0.46153 (4) | 0.27359 (4) | 0.42090 (4) | 0.01932 (8) | |
S2 | 0.71016 (4) | 0.23908 (4) | 0.59050 (4) | 0.01981 (9) | |
S4 | 0.11016 (4) | 0.14093 (4) | 0.42447 (4) | 0.01854 (8) | |
S5 | 0.32847 (4) | 0.01628 (4) | 0.74868 (4) | 0.01852 (8) | |
C3 | 0.63223 (17) | 0.13923 (14) | 0.70953 (15) | 0.0171 (2) | |
C1 | 0.34299 (16) | 0.17310 (14) | 0.50870 (15) | 0.0169 (2) | |
C2 | 0.43995 (16) | 0.11596 (14) | 0.64918 (14) | 0.0167 (2) | |
C4 | 0.04858 (18) | 0.23962 (16) | 0.24812 (15) | 0.0198 (2) | |
H4' | 0.132 (3) | 0.221 (2) | 0.206 (2) | 0.023 (4)* | |
H4 | −0.060 (3) | 0.193 (2) | 0.187 (3) | 0.031 (5)* | |
C5 | 0.02689 (19) | 0.40643 (16) | 0.26544 (18) | 0.0234 (3) | |
H5' | 0.137 (3) | 0.454 (2) | 0.342 (3) | 0.030 (5)* | |
H5 | 0.002 (3) | 0.452 (2) | 0.170 (3) | 0.029 (5)* | |
C6 | −0.12281 (19) | 0.43476 (16) | 0.31424 (17) | 0.0235 (3) | |
C7 | 0.24831 (17) | 0.17041 (16) | 0.82867 (16) | 0.0205 (2) | |
H7' | 0.189 (3) | 0.240 (2) | 0.749 (2) | 0.029 (5)* | |
H7 | 0.159 (3) | 0.127 (2) | 0.863 (3) | 0.030 (5)* | |
C8 | 0.40294 (19) | 0.25499 (18) | 0.95806 (19) | 0.0251 (3) | |
H8' | 0.488 (3) | 0.300 (2) | 0.924 (3) | 0.032 (5)* | |
H8 | 0.460 (3) | 0.189 (3) | 1.034 (3) | 0.051 (7)* | |
C9 | 0.33548 (19) | 0.37807 (17) | 1.02277 (17) | 0.0244 (3) | |
N1 | −0.23980 (19) | 0.45526 (17) | 0.35162 (18) | 0.0316 (3) | |
N2 | 0.27916 (19) | 0.47209 (17) | 1.07180 (17) | 0.0312 (3) |
U11 | U22 | U33 | U12 | U13 | U23 | |
S3 | 0.01647 (14) | 0.02912 (18) | 0.01666 (17) | 0.00163 (12) | 0.00343 (12) | 0.00306 (13) |
S1 | 0.01699 (14) | 0.02243 (16) | 0.01872 (16) | −0.00061 (11) | 0.00692 (12) | 0.00612 (12) |
S2 | 0.01538 (14) | 0.02338 (17) | 0.02032 (17) | −0.00245 (11) | 0.00665 (12) | 0.00366 (12) |
S4 | 0.01426 (13) | 0.02114 (16) | 0.01837 (16) | −0.00064 (11) | 0.00410 (12) | 0.00548 (12) |
S5 | 0.01756 (14) | 0.01897 (16) | 0.01959 (16) | −0.00034 (11) | 0.00763 (12) | 0.00545 (12) |
C3 | 0.0164 (5) | 0.0181 (5) | 0.0166 (5) | −0.0002 (4) | 0.0062 (4) | 0.0010 (4) |
C1 | 0.0157 (5) | 0.0171 (5) | 0.0176 (6) | −0.0005 (4) | 0.0062 (4) | 0.0025 (4) |
C2 | 0.0149 (5) | 0.0184 (6) | 0.0169 (6) | −0.0004 (4) | 0.0063 (4) | 0.0033 (4) |
C4 | 0.0185 (5) | 0.0234 (6) | 0.0157 (6) | 0.0003 (5) | 0.0045 (5) | 0.0032 (5) |
C5 | 0.0220 (6) | 0.0237 (6) | 0.0278 (7) | 0.0039 (5) | 0.0127 (5) | 0.0091 (5) |
C6 | 0.0241 (6) | 0.0220 (6) | 0.0246 (7) | 0.0036 (5) | 0.0090 (5) | 0.0078 (5) |
C7 | 0.0172 (5) | 0.0247 (6) | 0.0209 (6) | 0.0018 (5) | 0.0085 (5) | 0.0045 (5) |
C8 | 0.0211 (6) | 0.0266 (7) | 0.0260 (7) | 0.0028 (5) | 0.0071 (5) | 0.0006 (5) |
C9 | 0.0241 (6) | 0.0281 (7) | 0.0212 (6) | 0.0015 (5) | 0.0086 (5) | 0.0058 (5) |
N1 | 0.0296 (6) | 0.0359 (7) | 0.0335 (7) | 0.0053 (5) | 0.0161 (6) | 0.0080 (6) |
N2 | 0.0331 (7) | 0.0340 (7) | 0.0291 (7) | 0.0037 (5) | 0.0147 (6) | 0.0017 (6) |
C1—C2 | 1.3837 (19) | C4—H4 | 0.92 (2) |
C2—C3 | 1.4298 (16) | C5—C6 | 1.4715 (19) |
S1—C1 | 1.7248 (12) | C5—H5' | 0.98 (2) |
S1—S2 | 2.0702 (5) | C5—H5 | 0.96 (2) |
S2—C3 | 1.7328 (13) | C6—N1 | 1.143 (2) |
S3—C3 | 1.6613 (14) | C7—C8 | 1.529 (2) |
S4—C1 | 1.7366 (13) | C7—H7' | 0.98 (2) |
S4—C4 | 1.8153 (14) | C7—H7 | 0.96 (2) |
S5—C2 | 1.7616 (12) | C8—C9 | 1.471 (2) |
S5—C7 | 1.8178 (15) | C8—H8' | 0.94 (2) |
C4—C5 | 1.527 (2) | C8—H8 | 0.93 (3) |
C4—H4' | 0.920 (19) | C9—N2 | 1.144 (2) |
C1—S1—S2 | 93.66 (5) | C6—C5—H5' | 107.4 (12) |
C3—S2—S1 | 97.63 (5) | C4—C5—H5' | 110.3 (13) |
C1—S4—C4 | 103.36 (6) | C6—C5—H5 | 107.9 (13) |
C2—S5—C7 | 100.01 (6) | C4—C5—H5 | 109.9 (13) |
C2—C3—S3 | 129.80 (10) | H5'—C5—H5 | 109.5 (17) |
C2—C3—S2 | 112.88 (10) | N1—C6—C5 | 179.28 (17) |
S3—C3—S2 | 117.31 (7) | C8—C7—S5 | 111.61 (9) |
C2—C1—S1 | 117.78 (9) | C8—C7—H7' | 109.0 (12) |
C2—C1—S4 | 120.33 (9) | S5—C7—H7' | 109.6 (12) |
S1—C1—S4 | 121.88 (8) | C8—C7—H7 | 112.2 (13) |
C1—C2—C3 | 117.97 (11) | S5—C7—H7 | 105.9 (13) |
C1—C2—S5 | 120.60 (9) | H7—C7—H7 | 108.5 (17) |
C3—C2—S5 | 121.43 (10) | C9—C8—C7 | 110.91 (12) |
C5—C4—S4 | 114.45 (10) | C9—C8—H8' | 105.7 (13) |
C5—C4—H4' | 112.1 (12) | C7—C8—H8' | 111.8 (14) |
S4—C4—H4' | 108.1 (13) | C9—C8—H8 | 109.7 (16) |
C5—C4—H4 | 109.8 (14) | C7—C8—H8 | 109.0 (16) |
S4—C4—H4 | 103.3 (14) | H8'—C8—H8 | 110 (2) |
H4'—C4—H4 | 108.5 (18) | N2—C9—C8 | 178.41 (15) |
C6—C5—C4 | 111.76 (11) | ||
C1—S1—S2—C3 | −2.15 (6) | S3—C3—C2—C1 | −178.61 (11) |
S1—S2—C3—C2 | 1.46 (10) | S2—C3—C2—C1 | 0.17 (17) |
S1—S2—C3—S3 | −179.59 (7) | S3—C3—C2—S5 | 0.80 (19) |
S2—S1—C1—C2 | 2.73 (11) | S2—C3—C2—S5 | 179.58 (7) |
S2—S1—C1—S4 | −176.32 (8) | C7—S5—C2—C1 | −78.86 (12) |
C4—S4—C1—C2 | 179.01 (11) | C7—S5—C2—C3 | 101.74 (12) |
C4—S4—C1—S1 | −1.97 (10) | C1—S4—C4—C5 | −83.02 (10) |
S1—C1—C2—C3 | −2.27 (18) | S4—C4—C5—C6 | −63.92 (14) |
S4—C1—C2—C3 | 176.80 (10) | C2—S5—C7—C8 | −72.34 (11) |
S1—C1—C2—S5 | 178.32 (7) | S5—C7—C8—C9 | −179.28 (10) |
S4—C1—C2—S5 | −2.62 (17) |
Experimental details
Crystal data | |
Chemical formula | C9H8N2S5 |
Mr | 304.47 |
Crystal system, space group | Triclinic, P1 |
Temperature (K) | 120 |
a, b, c (Å) | 8.0216 (4), 8.9771 (3), 9.4799 (5) |
α, β, γ (°) | 91.251 (3), 112.426 (2), 92.418 (2) |
V (Å3) | 629.93 (5) |
Z | 2 |
Radiation type | Mo Kα |
µ (mm−1) | 0.89 |
Crystal size (mm) | 0.40 × 0.35 × 0.10 |
Data collection | |
Diffractometer | Rigaku R-AXIS SPIDER IP diffractometer |
Absorption correction | Multi-scan (CrystalClear; Rigaku, 2007) |
Tmin, Tmax | 0.825, 1.000 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 12836, 3811, 3721 |
Rint | 0.040 |
(sin θ/λ)max (Å−1) | 0.715 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.033, 0.086, 1.10 |
No. of reflections | 3811 |
No. of parameters | 177 |
H-atom treatment | All H-atom parameters refined |
Δρmax, Δρmin (e Å−3) | 0.57, −0.30 |
Computer programs: CrystalClear (Rigaku, 2007), SHELXTL (Bruker, 2000).
C1—C2 | 1.3837 (19) | S2—C3 | 1.7328 (13) |
C2—C3 | 1.4298 (16) | S3—C3 | 1.6613 (14) |
S1—C1 | 1.7248 (12) | S4—C1 | 1.7366 (13) |
S1—S2 | 2.0702 (5) | S5—C2 | 1.7616 (12) |
The rapid progress of molecular conductors or superconductors in the past three decades has been triggered by the successful syntheses of novel and useful organic donors. The synthesis of TTF (C6S4H4, tetrathiafulvalene) in 1970 and BEDT-TTF (C10S8H8, bis(ethylenedithio)-tetrathiafulvalene) in the late 1970 s have resulted in more than one hundred TTF-based organic superconductors, such as κ-(BEDT-TTF)2Cu[N(CN)2]Br with Tc = 11.6 K at ambient pressure (Kini et al., 1991). One kind of promising donors for new molecular conductors still seem to be multi-sulfur heterocyclic compounds with more sulfur atoms fused into the TTF skeleton, such as BEDT-TTP (C14S12H8, 2,5-bis(4,5-ethylenedithio-1,3-dithiol-2-ylidene) -1,3,4,6-tetrathiapentalene) and similar donors (Mori et al., 1995). In the course of exploring some derivatives of BEDT-TTP, we obtained their precursor 4,5-bis(2'-cyanoethylsulfanyl)-[1,3]-dithiole-2-thione (I) (Figure 1) and determined its structure (Yu et al., 2003). Here we report the structure and synthesis of its isomer: 4,5-bis(2'-cyanoethylsulfanyl)-[1,2]-dithiole-3-thione (II).
As shown in Figure 2, the five-membered 1,2-dithiole ring is basically planar and the plane (plane 1) can be extended to three peripheral sulfur atoms (S3, S4 and S5) and the C4 atom. Of these nine atoms, S4 shows the biggest deviation from the plane, 0.051 (1) Å. Four atoms (C4, C5, C6 and N1) of one side-chain of the molecule are within the second plane (Plane 2) and the five atoms (S5, C6, C7, C8 and N2) of the other side-chain are arranged in the third plane (Plane 3). The dihedral angels between these planes are 71.6 (1)° (between planes 1 and 2), 84.0 (1)° (1 and 3), and 56.7 (1)° (2 and 3).
The bonding in the C1—C2—C3—S3 fragment of the 1,2-isomer is highly conjugated with the bond lengths being 1.384 (2), 1.430 (2) and 1.661 (1) Å for the C1—C2, C2—C3 and terminal C3—S3 bonds, respectively. The π-conjugation may involve three more atoms (S1, S2 and S4) because of the "conjugated" bond lengths C1—S1 (1.725 (1) Å), C3—S2 (1.733 (1) Å), and C1—S4 (1.737 (1) Å). However, the π-conjugation is not circular because the S1—S2 bond length (2.0702 (5) Å) is indicative for a single bond. By comparison, the conjugation in (I) is not very significant because of the double C═C (1.346 (1) Å) and the terminal double C═S bond (1.644 (1) Å).
As shown in Figure 3, in the crystal of (II) each molecule participates in six strong S···S and S···N intermolecular interactions with its three neighbours. Three of these six contacts are symmetrically independent, viz. S4···S5A (-x, -y, 1 - z) of 3.484 (2) Å, S1···N1B (1 + x, y, z) of 3.112 (2) and S2···N1B (1 + x, y, z) of 3.142 (2) Å. These contacts are significantly shorter than the standard intermolecular (van der Waals) contact distances S···S of 3.60 Å and S···N of 3.45 Å (Rowland & Taylor, 1996). These intermolecular interactions help to form a kind of supramolecular planar moiety involving 20 atoms: nine from the main molecular plane (Plane 1) of the concerned molecule, another nine from the main plane of the adjacent molecule (-x, -y, 1 - z) and two N1 atoms from other two molecules. Furthermore, due to these S···S and S···N interactions, a kind of one-dimensional double chain of molecules can be found along the a-direction. By comparison, there are no short S···S contacts in the crystal of (I), corresponding to the relatively strong intermolecular interactions of (II).