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One of the possible strategies for the synthesis of electrically conductive mol­ecular materials based on unsymmetrically substituted tetra­thia­fulvalenes implies the use of a precursor bearing cyano­ethyl­sulfanyl groups attached to the tetra­thia­fulvalene (TTF) core. The title compound, C16H16N2S6, is such a precursor. The two cyano­ethyl­sulfanyl groups are attached to the two adjacent C atoms of one of the two C3S2 rings of the TTF core and protrude on both sides of the mol­ecule. In the crystal structure, the TTF core is not planar and adopts a boat conformation; the two C3S2 rings are folded around the S...S hinges, the dihedral angles being 12.19 (6) and 22.70 (4)°. There are no unusual inter­molecular contacts in the solid state. The crystal studied was a partial inversion twin, with contributions of 0.72 (4) and 0.28 (4) for the two twin domains.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536807034873/cf2117sup1.cif
Contains datablocks I, global

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S1600536807034873/cf2117Isup2.hkl
Contains datablock I

CCDC reference: 657816

Key indicators

  • Single-crystal X-ray study
  • T = 180 K
  • Mean [sigma](C-C) = 0.002 Å
  • R factor = 0.026
  • wR factor = 0.051
  • Data-to-parameter ratio = 28.0

checkCIF/PLATON results

No syntax errors found



Alert level B PLAT029_ALERT_3_B _diffrn_measured_fraction_theta_full Low ....... 0.96
Alert level C PLAT230_ALERT_2_C Hirshfeld Test Diff for C12 - C13 .. 5.43 su PLAT230_ALERT_2_C Hirshfeld Test Diff for C15 - C16 .. 5.98 su
Alert level G REFLT03_ALERT_4_G Please check that the estimate of the number of Friedel pairs is correct. If it is not, please give the correct count in the _publ_section_exptl_refinement section of the submitted CIF. From the CIF: _diffrn_reflns_theta_max 32.10 From the CIF: _reflns_number_total 6122 Count of symmetry unique reflns 3530 Completeness (_total/calc) 173.43% TEST3: Check Friedels for noncentro structure Estimate of Friedel pairs measured 2592 Fraction of Friedel pairs measured 0.734 Are heavy atom types Z>Si present yes PLAT033_ALERT_2_G Flack Parameter Value Deviates 2 * su from zero. 0.28 PLAT860_ALERT_3_G Note: Number of Least-Squares Restraints ....... 1
0 ALERT level A = In general: serious problem 1 ALERT level B = Potentially serious problem 2 ALERT level C = Check and explain 3 ALERT level G = General alerts; check 0 ALERT type 1 CIF construction/syntax error, inconsistent or missing data 3 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 1 ALERT type 4 Improvement, methodology, query or suggestion 0 ALERT type 5 Informative message, check

Comment top

The search for molecular systems liable to afford interesting electrical properties – such as metallic or even superconducting behaviour – follows several strategies. One of them is to use unsymmetrically substituted tetrathiafulvalenes as building blocks (Fabre, 2000; Yamada & Sugimoto, 2004; Batail, 2004). When these target molecules are to be functionalized with hydroxyl or amine groups (e.g. in order to obtain H-bond networks) one of the possible synthesis strategies implies the use of a precursor bearing cyanoethylthio groups attached to the tetrathiafulvalene (TTF) core (Binet et al., 1996). The title compound was synthesized in this context and its crystal structure was determined to ascertain that the expected precursor was really obtained. The molecular structure is shown in Fig. 1. The main features of the structure are as follows. The two cyanoethylthio groups protrude on both sides of the TTF core, almost perpendicular to the external S3/S4/C5/C6/S7/S8 plane (Fig. 2). The TTF core is not planar and shows a boat conformation: the two C3S2 rings are folded around the S···S hinges. The central C1/C2/S1/S2/S3/S4 group is planar; the external S1/S2/C3/C4 and S3/S4/C5/C6 planes make dihedral angles of 12.19 (6)° and 22.70 (4)° respectively with the central plane (Fig. 2). The crystal investigated was an inversion twin, with contributions of 0.72:0.28 (4) for the twin domains. In this crystal structure there are no unusual intermolecular interactions, and no packing effect can be invoked to explain the folding of the TTF core (Fig. 3).

Related literature top

For general background on molecular metals based on tetrathiafulvalene (TTF) derivatives, see: Fabre (2000); Yamada & Sugimoto (2004); Batail (2004). For the synthesis of the title compound, see: Binet et al. (1996). Analogous precursors are used to obtain functionalized TTF derivatives (Legros et al., 2000; Benbellat et al., 2006) and oligo-TTF (Carcel et al., 2006).

Experimental top

The title compound was synthesized as described in the literature for the analogous compound 2,3-bis(2-cyanoethylthio)-6,7-dimethyltetrathiafulvalene (Binet et al., 1996). The red crystals (mp. 424 K) of the studied compound were isolated by slow evaporation of a solution in acetonitrile.

Refinement top

H atoms were located in a difference map then positioned geometrically and refined using a riding model with C—H distances set to 0.97 Å. A common Uiso(H) was refined and converged to a value of 0.037 (2) Å2.

Structure description top

The search for molecular systems liable to afford interesting electrical properties – such as metallic or even superconducting behaviour – follows several strategies. One of them is to use unsymmetrically substituted tetrathiafulvalenes as building blocks (Fabre, 2000; Yamada & Sugimoto, 2004; Batail, 2004). When these target molecules are to be functionalized with hydroxyl or amine groups (e.g. in order to obtain H-bond networks) one of the possible synthesis strategies implies the use of a precursor bearing cyanoethylthio groups attached to the tetrathiafulvalene (TTF) core (Binet et al., 1996). The title compound was synthesized in this context and its crystal structure was determined to ascertain that the expected precursor was really obtained. The molecular structure is shown in Fig. 1. The main features of the structure are as follows. The two cyanoethylthio groups protrude on both sides of the TTF core, almost perpendicular to the external S3/S4/C5/C6/S7/S8 plane (Fig. 2). The TTF core is not planar and shows a boat conformation: the two C3S2 rings are folded around the S···S hinges. The central C1/C2/S1/S2/S3/S4 group is planar; the external S1/S2/C3/C4 and S3/S4/C5/C6 planes make dihedral angles of 12.19 (6)° and 22.70 (4)° respectively with the central plane (Fig. 2). The crystal investigated was an inversion twin, with contributions of 0.72:0.28 (4) for the twin domains. In this crystal structure there are no unusual intermolecular interactions, and no packing effect can be invoked to explain the folding of the TTF core (Fig. 3).

For general background on molecular metals based on tetrathiafulvalene (TTF) derivatives, see: Fabre (2000); Yamada & Sugimoto (2004); Batail (2004). For the synthesis of the title compound, see: Binet et al. (1996). Analogous precursors are used to obtain functionalized TTF derivatives (Legros et al., 2000; Benbellat et al., 2006) and oligo-TTF (Carcel et al., 2006).

Computing details top

Data collection: CrysAlis CCD (Oxford Diffraction, 2006); cell refinement: CrysAlis RED (Oxford Diffraction, 2006); data reduction: CrysAlis RED; program(s) used to solve structure: SIR92 (Altomare et al., 1993); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEPIII (Burnett & Johnson, 1996), CAMERON (Watkin et al., 1993) and ORTEP-3 (Farrugia, 1997); software used to prepare material for publication: WinGX (Farrugia, 1999).

Figures top
[Figure 1] Fig. 1. The molecular structure of the title compound, with atom labels and 50% probability displacement ellipsoids for non-H atoms.
[Figure 2] Fig. 2. Side view of the molecule (hydrogen atoms omitted). For overlapping atoms the upper labels refer to the hidden atoms.
[Figure 3] Fig. 3. Unit-cell content (hydrogen atoms omitted).
2,3-Bis(2-cyanoethylsulfanyl)-6,7-tetramethylenetetrathiafulvalene top
Crystal data top
C16H16N2S6Dx = 1.519 Mg m3
Mr = 428.67Melting point: 424 K
Orthorhombic, Pca21Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 2c -2acCell parameters from 6238 reflections
a = 30.4738 (14) Åθ = 3.0–32.1°
b = 8.8963 (4) ŵ = 0.73 mm1
c = 6.9150 (3) ÅT = 180 K
V = 1874.68 (15) Å3Block, orange
Z = 40.40 × 0.25 × 0.15 mm
F(000) = 888
Data collection top
Oxford Diffraction Xcalibur
diffractometer with CCD detector
6122 independent reflections
Radiation source: fine-focus sealed tube5344 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.026
φω scansθmax = 32.1°, θmin = 3.0°
Absorption correction: numerical
[using a multifaceted crystal model based on expressions derived by Clark & Reid (1995)]
h = 3745
Tmin = 0.83, Tmax = 0.90k = 1312
19080 measured reflectionsl = 910
Refinement top
Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.026H-atom parameters constrained
wR(F2) = 0.051 w = 1/[σ2(Fo2) + (0.0248P)2]
where P = (Fo2 + 2Fc2)/3
S = 0.96(Δ/σ)max = 0.003
6122 reflectionsΔρmax = 0.34 e Å3
219 parametersΔρmin = 0.25 e Å3
1 restraintAbsolute structure: Flack (1983), with 2592 Friedel pairs
Primary atom site location: structure-invariant direct methodsAbsolute structure parameter: 0.28 (4)
Crystal data top
C16H16N2S6V = 1874.68 (15) Å3
Mr = 428.67Z = 4
Orthorhombic, Pca21Mo Kα radiation
a = 30.4738 (14) ŵ = 0.73 mm1
b = 8.8963 (4) ÅT = 180 K
c = 6.9150 (3) Å0.40 × 0.25 × 0.15 mm
Data collection top
Oxford Diffraction Xcalibur
diffractometer with CCD detector
6122 independent reflections
Absorption correction: numerical
[using a multifaceted crystal model based on expressions derived by Clark & Reid (1995)]
5344 reflections with I > 2σ(I)
Tmin = 0.83, Tmax = 0.90Rint = 0.026
19080 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.026H-atom parameters constrained
wR(F2) = 0.051Δρmax = 0.34 e Å3
S = 0.96Δρmin = 0.25 e Å3
6122 reflectionsAbsolute structure: Flack (1983), with 2592 Friedel pairs
219 parametersAbsolute structure parameter: 0.28 (4)
1 restraint
Special details top

Experimental. Cooling Device: Oxford Instruments Cryojet. Excalibur (Oxford Diffraction) four-circle Kappa geometry diffractometer equipped with an area CCD detector. Crystal-detector distance (mm): 70.0

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
xyzUiso*/Ueq
S10.480152 (12)0.18707 (4)0.71619 (6)0.02209 (8)
S20.504941 (12)0.20238 (5)1.12758 (6)0.02285 (9)
S30.392867 (12)0.00712 (4)0.83085 (6)0.02141 (8)
S40.416522 (12)0.01365 (4)1.24278 (6)0.02122 (8)
S70.296701 (12)0.05864 (4)0.90997 (6)0.02033 (8)
S80.325115 (12)0.04576 (4)1.38378 (6)0.01986 (8)
C10.46686 (5)0.13945 (17)0.9560 (2)0.0192 (3)
C20.43072 (5)0.06014 (17)1.0032 (2)0.0187 (3)
C30.52257 (4)0.31129 (16)0.7803 (2)0.0199 (3)
C40.53333 (5)0.31976 (17)0.9663 (2)0.0202 (3)
C50.35007 (4)0.02832 (16)0.9997 (2)0.0166 (3)
C60.36087 (4)0.01888 (16)1.1878 (2)0.0169 (3)
C70.54676 (5)0.38981 (19)0.6199 (3)0.0270 (3)
H710.52850.46900.56700.0369 (14)*
H720.55300.31870.51720.0369 (14)*
C80.58959 (6)0.4571 (2)0.6940 (3)0.0354 (4)
H810.61150.37850.70370.0369 (14)*
H820.60010.53130.60230.0369 (14)*
C90.58370 (6)0.53047 (19)0.8900 (3)0.0345 (4)
H910.56160.60860.88050.0369 (14)*
H920.61110.57720.92880.0369 (14)*
C100.56982 (5)0.41627 (19)1.0434 (3)0.0289 (4)
H1010.59470.35371.07800.0369 (14)*
H1020.56000.46851.15870.0369 (14)*
C110.29071 (5)0.25865 (18)0.9490 (2)0.0237 (3)
H1110.29620.28131.08410.0369 (14)*
H1120.26080.28820.91960.0369 (14)*
C120.32253 (5)0.34943 (19)0.8223 (3)0.0280 (4)
H1210.31740.32490.68750.0369 (14)*
H1220.35240.32090.85360.0369 (14)*
C130.31747 (5)0.5116 (2)0.8493 (2)0.0278 (4)
C140.31976 (5)0.14875 (18)1.4600 (2)0.0235 (3)
H1410.30460.15271.58330.0369 (14)*
H1420.34870.19201.47740.0369 (14)*
C150.29443 (5)0.24071 (19)1.3115 (3)0.0292 (4)
H1510.30640.22121.18390.0369 (14)*
H1520.26400.20871.31160.0369 (14)*
C160.29636 (5)0.40254 (19)1.3501 (2)0.0258 (3)
N10.31410 (5)0.63897 (17)0.8655 (2)0.0380 (4)
N20.29893 (5)0.52864 (16)1.3764 (2)0.0336 (3)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
S10.02102 (17)0.02499 (19)0.02027 (18)0.00603 (15)0.00037 (16)0.00098 (16)
S20.02127 (18)0.0250 (2)0.02230 (18)0.00701 (15)0.00391 (16)0.00209 (16)
S30.01632 (16)0.0290 (2)0.01892 (16)0.00528 (15)0.00099 (14)0.00146 (16)
S40.01668 (16)0.0275 (2)0.01951 (17)0.00304 (14)0.00214 (15)0.00305 (17)
S70.01445 (16)0.02107 (18)0.02546 (18)0.00232 (14)0.00238 (15)0.00118 (16)
S80.02178 (17)0.01618 (16)0.02161 (18)0.00153 (13)0.00558 (15)0.00128 (15)
C10.0177 (7)0.0195 (7)0.0205 (7)0.0006 (6)0.0012 (6)0.0006 (6)
C20.0149 (7)0.0214 (7)0.0196 (7)0.0001 (6)0.0011 (6)0.0002 (6)
C30.0159 (7)0.0173 (7)0.0264 (8)0.0001 (5)0.0023 (6)0.0004 (6)
C40.0145 (7)0.0177 (7)0.0285 (8)0.0012 (5)0.0003 (6)0.0003 (6)
C50.0126 (7)0.0164 (7)0.0209 (7)0.0015 (5)0.0017 (6)0.0003 (6)
C60.0150 (6)0.0157 (7)0.0200 (7)0.0003 (5)0.0028 (5)0.0001 (6)
C70.0267 (8)0.0246 (9)0.0298 (8)0.0023 (6)0.0070 (7)0.0045 (7)
C80.0269 (9)0.0337 (10)0.0455 (12)0.0107 (7)0.0107 (8)0.0008 (8)
C90.0285 (9)0.0288 (9)0.0460 (11)0.0112 (7)0.0063 (9)0.0028 (8)
C100.0228 (8)0.0262 (9)0.0378 (10)0.0061 (7)0.0060 (7)0.0009 (8)
C110.0218 (8)0.0209 (8)0.0283 (9)0.0052 (6)0.0017 (6)0.0011 (6)
C120.0336 (9)0.0242 (9)0.0262 (8)0.0020 (7)0.0038 (7)0.0020 (7)
C130.0315 (9)0.0299 (9)0.0221 (9)0.0002 (7)0.0011 (7)0.0039 (7)
C140.0308 (8)0.0188 (8)0.0209 (7)0.0022 (6)0.0035 (7)0.0003 (6)
C150.0348 (9)0.0202 (8)0.0326 (9)0.0032 (7)0.0057 (8)0.0008 (7)
C160.0262 (8)0.0271 (9)0.0242 (8)0.0071 (6)0.0007 (7)0.0004 (7)
N10.0528 (10)0.0283 (8)0.0329 (9)0.0008 (7)0.0007 (8)0.0026 (7)
N20.0392 (8)0.0253 (8)0.0364 (9)0.0075 (6)0.0032 (7)0.0001 (7)
Geometric parameters (Å, º) top
S1—C31.7573 (15)C8—H810.970
S1—C11.7590 (15)C8—H820.970
S2—C11.7514 (15)C9—C101.529 (3)
S2—C41.7558 (16)C9—H910.970
S3—C51.7605 (14)C9—H920.970
S3—C21.7631 (15)C10—H1010.970
S4—C21.7617 (16)C10—H1020.970
S4—C61.7620 (14)C11—C121.536 (2)
S7—C51.7616 (15)C11—H1110.970
S7—C111.8089 (16)C11—H1120.970
S8—C61.7552 (15)C12—C131.463 (2)
S8—C141.8162 (16)C12—H1210.970
C1—C21.3479 (19)C12—H1220.970
C3—C41.330 (2)C13—N11.143 (2)
C3—C71.504 (2)C14—C151.523 (2)
C4—C101.503 (2)C14—H1410.970
C5—C61.344 (2)C14—H1420.970
C7—C81.524 (2)C15—C161.465 (2)
C7—H710.970C15—H1510.970
C7—H720.970C15—H1520.970
C8—C91.515 (3)C16—N21.139 (2)
C3—S1—C194.77 (7)C8—C9—H91109.3
C1—S2—C494.95 (7)C10—C9—H91109.3
C5—S3—C294.18 (7)C8—C9—H92109.3
C2—S4—C694.13 (7)C10—C9—H92109.3
C5—S7—C11101.03 (7)H91—C9—H92108.0
C6—S8—C1498.62 (7)C4—C10—C9109.78 (15)
C2—C1—S2123.02 (12)C4—C10—H101109.7
C2—C1—S1122.83 (11)C9—C10—H101109.7
S2—C1—S1114.15 (8)C4—C10—H102109.7
C1—C2—S4123.44 (11)C9—C10—H102109.7
C1—C2—S3123.28 (12)H101—C10—H102108.2
S4—C2—S3113.28 (8)C12—C11—S7111.60 (11)
C4—C3—C7124.49 (14)C12—C11—H111109.3
C4—C3—S1117.44 (11)S7—C11—H111109.3
C7—C3—S1117.83 (11)C12—C11—H112109.3
C3—C4—C10123.92 (15)S7—C11—H112109.3
C3—C4—S2117.35 (11)H111—C11—H112108.0
C10—C4—S2118.63 (12)C13—C12—C11112.28 (14)
C6—C5—S3116.98 (11)C13—C12—H121109.1
C6—C5—S7125.19 (11)C11—C12—H121109.1
S3—C5—S7117.83 (9)C13—C12—H122109.1
C5—C6—S8125.92 (11)C11—C12—H122109.1
C5—C6—S4117.04 (10)H121—C12—H122107.9
S8—C6—S4116.95 (9)N1—C13—C12178.0 (2)
C3—C7—C8110.74 (14)C15—C14—S8111.22 (11)
C3—C7—H71109.5C15—C14—H141109.4
C8—C7—H71109.5S8—C14—H141109.4
C3—C7—H72109.5C15—C14—H142109.4
C8—C7—H72109.5S8—C14—H142109.4
H71—C7—H72108.1H141—C14—H142108.0
C9—C8—C7111.63 (14)C16—C15—C14112.62 (14)
C9—C8—H81109.3C16—C15—H151109.1
C7—C8—H81109.3C14—C15—H151109.1
C9—C8—H82109.3C16—C15—H152109.1
C7—C8—H82109.3C14—C15—H152109.1
H81—C8—H82108.0H151—C15—H152107.8
C8—C9—C10111.53 (15)N2—C16—C15177.89 (18)

Experimental details

Crystal data
Chemical formulaC16H16N2S6
Mr428.67
Crystal system, space groupOrthorhombic, Pca21
Temperature (K)180
a, b, c (Å)30.4738 (14), 8.8963 (4), 6.9150 (3)
V3)1874.68 (15)
Z4
Radiation typeMo Kα
µ (mm1)0.73
Crystal size (mm)0.40 × 0.25 × 0.15
Data collection
DiffractometerOxford Diffraction Xcalibur
diffractometer with CCD detector
Absorption correctionNumerical
[using a multifaceted crystal model based on expressions derived by Clark & Reid (1995)]
Tmin, Tmax0.83, 0.90
No. of measured, independent and
observed [I > 2σ(I)] reflections
19080, 6122, 5344
Rint0.026
(sin θ/λ)max1)0.748
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.026, 0.051, 0.96
No. of reflections6122
No. of parameters219
No. of restraints1
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.34, 0.25
Absolute structureFlack (1983), with 2592 Friedel pairs
Absolute structure parameter0.28 (4)

Computer programs: CrysAlis CCD (Oxford Diffraction, 2006), CrysAlis RED (Oxford Diffraction, 2006), CrysAlis RED, SIR92 (Altomare et al., 1993), SHELXL97 (Sheldrick, 1997), ORTEPIII (Burnett & Johnson, 1996), CAMERON (Watkin et al., 1993) and ORTEP-3 (Farrugia, 1997), WinGX (Farrugia, 1999).

 

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