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Acta Crystallogr Sect E Struct Rep Online. 2010 December 1; 66(Pt 12): o3177.
Published online 2010 November 13. doi:  10.1107/S1600536810045447
PMCID: PMC3011790

Low-temperature redetermination of 1,3-bis­(penta­fluoro­phen­yl)triazene

Abstract

The crystal structure of the title compound, (C6F5)2N3H, is stabilized by N—H(...)N hydrogen bonding, forming centrosymmetric dimers organized in a herringbone motif. Important geometrical parameters are N—N = 1.272 (2) and 1.330 (2) Å and N—N—N = 112.56 (15)°. The dihedral angle between C6F5 groups is 21.22 (9)°. The room temperature structure was reported by Leman et al. (1993). Inorg. Chem. 32, 4324–4336]. In the current determination, the data were collected to a higher θ angle, resulting in higher precision for the C—C bond lengths(0.001–0.005 versus 0.003 Å).

Related literature

Average bond lengths were obtained from the Cambridge Structural Database (Allen, 2000 [triangle]); For the synthesis of nitro­formazans, see: Pelkis et al. (1957 [triangle]); and for the synthesis of triazenes, see: Brooke et al. (1965 [triangle]). For use of triazenes in both synthesis and as metal coordinating ligands, see: Leman et al. (1993 [triangle]).

An external file that holds a picture, illustration, etc.
Object name is e-66-o3177-scheme1.jpg

Experimental

Crystal data

  • C12HF10N3
  • M r = 377.16
  • Monoclinic, An external file that holds a picture, illustration, etc.
Object name is e-66-o3177-efi1.jpg
  • a = 9.9930 (8) Å
  • b = 9.4850 (8) Å
  • c = 12.9200 (11) Å
  • β = 95.585 (2)°
  • V = 1218.79 (18) Å3
  • Z = 4
  • Mo Kα radiation
  • μ = 0.23 mm−1
  • T = 100 K
  • 0.3 × 0.19 × 0.15 mm

Data collection

  • Bruker X8 APEXII 4K Kappa CCD diffractometer
  • Absorption correction: multi-scan (SADABS; Bruker; 2004 [triangle]) T min = 0.933, T max = 0.966
  • 12525 measured reflections
  • 3013 independent reflections
  • 2177 reflections with I > 2σ(I)
  • R int = 0.039

Refinement

  • R[F 2 > 2σ(F 2)] = 0.039
  • wR(F 2) = 0.107
  • S = 1.07
  • 3013 reflections
  • 226 parameters
  • H-atom parameters constrained
  • Δρmax = 0.36 e Å−3
  • Δρmin = −0.31 e Å−3

Data collection: APEX2 (Bruker, 2005 [triangle]); cell refinement: SAINT-Plus (Bruker, 2004 [triangle]); data reduction: SAINT-Plus and XPREP (Bruker, 2004 [triangle]); program(s) used to solve structure: SIR97 (Altomare et al., 1999 [triangle]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 [triangle]); molecular graphics: DIAMOND (Brandenburg & Putz, 2005 [triangle]); software used to prepare material for publication: WinGX (Farrugia, 1999 [triangle]).

Table 1
Hydrogen-bond geometry (Å, °)

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536810045447/kp2288sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S1600536810045447/kp2288Isup2.hkl

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Acknowledgments

Financial assistance from the National Research Foundation of South Africa is gratefully acknowledged.

supplementary crystallographic information

Comment

A series of dithizones with varying number of fluorines on the phenyl rings were synthesised. During this process the nitroformazan precursor is initially prepared from the substituted aniline, as described by Pelkis et al., 1957. In the final step the nitro group is substituted by sulfur, to form dithizone. However, during the first step to prepare pentafluorophenyldithizone it was found that, contrary to expectation, a triazene formed instead of the usual nitroformazan. Previous studies show the extensive use of triazenes in both synthesis and as metal coordinating ligand, as illustrated by Leman et al., 1993. Triazenes, in general, are traditionally synthesised slightly different, according to a method by Brooke et al., 1965.

The title compound (Fig.1) and geometrical data are within expected values (average values obtained from the Cambridge Structural Database; Allen, 200). The C6F5 groups are twisted out of the plane formed by the N—N═N fragment 30.91 (16)° for ring C1—C6 and 38.49 (13)° for ring C7—C12. Hydrogen bonding (Fig. 2, Table 1) creates a centrosymmetric dimers that organise in a herring-bone motif along the c axis (Fig. 3).

Experimental

Reagent chemicals and solvents were purchased from Sigma-Aldrich and used without further purification. For the synthesis 2,3,4,5,6 pentafluoroaniline (5 g, 27.3 mmol) was added to a mixture of concentrated hydrochloric acid (20 mL) and water (35 mL) at 273 K, and diazotized by the slow addition of sodium nitrite (3 g, 43 mmol), stirring for 30 min. The resulting solution was added, with stirring, to a cold mixture of sodium acetate (80 g), glacial acetic acid (45 mL) and water (25 mL). Nitromethane (5.0 g, 82 mmol) was added after 10 min. While heating at 343 K and stirring for 20 h the colour changed to dark-red. Filtering the precipitated 1,3 bis-pentafluorophenyltriazene off, gave the product in 52% yield. Crystals suitable for X-ray crystallography were grown from a mixture of dichloromethane and methanol. Although this method is typically used for the preparation of nitroformazan as precursor for the synthesis of dithizone, nitromethane did not serve here as coupling reagent in the synthesis of this highly fluorinated compound. The unexpected outcome is ascribed to the large electron-withdrawing capacity of the five fluorines on each phenyl ring.

Refinement

The imine H atom was placed in a geometrically idealized position (C—H = 0.88) and constrained to ride on the parent atom with Uiso(H) = 1.2Ueq(C). The highest residual electron density peak of 0.36 e.Å is 0.70 Å from C9 and the deepest hole of -0.31 e.Å is 0.37 Å from H3 representing no physical meaning.

Figures

Fig. 1.
A view of (I). Displacement ellipsoids are drawn at the 30% probability level.
Fig. 2.
Hydrogen bonding of (I) showing the dimeric units formed.
Fig. 3.
Packing diagram of (I) showing the herring-bone motif.

Crystal data

C12HF10N3F(000) = 736
Mr = 377.16Dx = 2.055 Mg m3
Monoclinic, P21/cMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybcCell parameters from 2521 reflections
a = 9.9930 (8) Åθ = 3.5–28.1°
b = 9.4850 (8) ŵ = 0.23 mm1
c = 12.9200 (11) ÅT = 100 K
β = 95.585 (2)°Cuboid, red
V = 1218.79 (18) Å30.3 × 0.19 × 0.15 mm
Z = 4

Data collection

Bruker X8 APEXII 4K Kappa CCD diffractometer3013 independent reflections
graphite2177 reflections with I > 2σ(I)
Detector resolution: 8.4 pixels mm-1Rint = 0.039
[var phi] scansθmax = 28.3°, θmin = 2.7°
Absorption correction: multi-scan (SADABS; Bruker; 2004)h = −12→13
Tmin = 0.933, Tmax = 0.966k = −12→12
12525 measured reflectionsl = −17→17

Refinement

Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.039Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.107H-atom parameters constrained
S = 1.07w = 1/[σ2(Fo2) + (0.0438P)2 + 0.6444P] where P = (Fo2 + 2Fc2)/3
3013 reflections(Δ/σ)max < 0.001
226 parametersΔρmax = 0.36 e Å3
0 restraintsΔρmin = −0.31 e Å3

Special details

Experimental. The intensity data was collected on a Bruker X8 Apex II 4 K Kappa CCD diffractometer using an exposure time of 10 s/frame. A total of 1126 frames were collected with a frame width of 0.5° covering up to θ = 28.33° with 98.8% completeness accomplished.
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)

xyzUiso*/Ueq
N10.32054 (15)−0.00606 (18)0.51342 (13)0.0176 (4)
N20.29181 (15)0.01759 (18)0.41693 (13)0.0170 (4)
N30.39984 (15)0.04639 (18)0.36826 (13)0.0187 (4)
H30.47930.05540.40340.022*
C10.38491 (18)0.0620 (2)0.26046 (15)0.0161 (4)
C20.28659 (18)−0.0055 (2)0.19428 (16)0.0170 (4)
C30.27844 (18)0.0129 (2)0.08793 (16)0.0183 (4)
C40.37001 (19)0.0977 (2)0.04420 (16)0.0198 (4)
C50.46978 (19)0.1626 (2)0.10765 (16)0.0199 (4)
C60.47531 (18)0.1467 (2)0.21357 (16)0.0184 (4)
C70.20622 (17)−0.0486 (2)0.56306 (15)0.0156 (4)
C80.20040 (18)−0.0106 (2)0.66629 (16)0.0178 (4)
C90.09951 (19)−0.0571 (2)0.72416 (15)0.0190 (4)
C100.00216 (18)−0.1471 (2)0.67859 (16)0.0187 (4)
C110.00446 (18)−0.1863 (2)0.57591 (16)0.0174 (4)
C120.10529 (18)−0.1381 (2)0.51888 (15)0.0165 (4)
F20.19834 (11)−0.09374 (13)0.23200 (9)0.0218 (3)
F30.18284 (12)−0.05460 (13)0.02754 (9)0.0254 (3)
F40.36352 (12)0.11346 (14)−0.05941 (9)0.0272 (3)
F50.56138 (12)0.24230 (14)0.06517 (10)0.0283 (3)
F60.57237 (11)0.21376 (13)0.27471 (9)0.0246 (3)
F80.29674 (11)0.07433 (13)0.71246 (9)0.0241 (3)
F90.09641 (12)−0.01701 (14)0.82274 (9)0.0269 (3)
F10−0.09396 (11)−0.19674 (13)0.73422 (10)0.0243 (3)
F11−0.09111 (11)−0.27180 (13)0.53101 (10)0.0245 (3)
F120.10472 (11)−0.18344 (13)0.42082 (9)0.0218 (3)

Atomic displacement parameters (Å2)

U11U22U33U12U13U23
N10.0153 (7)0.0214 (9)0.0163 (9)0.0000 (6)0.0024 (6)−0.0012 (7)
N20.0160 (7)0.0181 (9)0.0172 (9)0.0000 (6)0.0031 (6)−0.0005 (7)
N30.0142 (7)0.0247 (10)0.0172 (9)−0.0037 (7)0.0009 (6)0.0012 (7)
C10.0152 (8)0.0164 (10)0.0167 (10)0.0014 (7)0.0017 (7)0.0008 (8)
C20.0158 (8)0.0147 (10)0.0209 (11)0.0001 (7)0.0035 (7)0.0003 (8)
C30.0173 (9)0.0182 (10)0.0190 (11)0.0016 (8)−0.0006 (8)−0.0006 (8)
C40.0244 (10)0.0200 (11)0.0155 (10)0.0055 (8)0.0040 (8)0.0026 (8)
C50.0193 (9)0.0177 (11)0.0236 (11)0.0004 (8)0.0070 (8)0.0035 (9)
C60.0150 (8)0.0167 (10)0.0230 (11)−0.0002 (7)−0.0003 (8)−0.0013 (8)
C70.0138 (8)0.0171 (10)0.0159 (10)0.0027 (7)0.0014 (7)0.0014 (8)
C80.0144 (8)0.0186 (11)0.0199 (11)0.0000 (7)−0.0003 (7)−0.0018 (8)
C90.0210 (9)0.0226 (11)0.0134 (10)0.0053 (8)0.0023 (8)0.0014 (8)
C100.0163 (9)0.0192 (11)0.0215 (11)0.0035 (8)0.0060 (8)0.0069 (8)
C110.0155 (8)0.0152 (10)0.0211 (11)−0.0005 (7)−0.0009 (7)0.0004 (8)
C120.0176 (9)0.0187 (10)0.0130 (10)0.0025 (7)0.0004 (7)−0.0002 (8)
F20.0208 (5)0.0244 (7)0.0203 (6)−0.0077 (5)0.0023 (5)0.0023 (5)
F30.0293 (6)0.0275 (7)0.0183 (7)−0.0069 (5)−0.0036 (5)−0.0011 (5)
F40.0334 (7)0.0318 (8)0.0171 (7)0.0016 (6)0.0055 (5)0.0032 (5)
F50.0265 (6)0.0308 (7)0.0292 (7)−0.0082 (5)0.0106 (5)0.0064 (6)
F60.0197 (5)0.0285 (7)0.0252 (7)−0.0087 (5)−0.0005 (5)−0.0005 (5)
F80.0226 (6)0.0298 (7)0.0195 (7)−0.0071 (5)0.0004 (5)−0.0053 (5)
F90.0304 (6)0.0342 (8)0.0168 (6)−0.0011 (5)0.0060 (5)−0.0033 (5)
F100.0212 (6)0.0270 (7)0.0260 (7)−0.0008 (5)0.0098 (5)0.0048 (5)
F110.0198 (5)0.0260 (7)0.0274 (7)−0.0088 (5)−0.0002 (5)−0.0008 (5)
F120.0241 (6)0.0249 (7)0.0162 (6)−0.0046 (5)0.0018 (5)−0.0029 (5)

Geometric parameters (Å, °)

N1—N21.272 (2)C5—C61.373 (3)
N1—C71.422 (2)C6—F61.349 (2)
N2—N31.330 (2)C7—C81.388 (3)
N3—C11.394 (2)C7—C121.397 (3)
N3—H30.88C8—F81.349 (2)
C1—C61.391 (3)C8—C91.385 (3)
C1—C21.394 (3)C9—F91.332 (2)
C2—F21.341 (2)C9—C101.382 (3)
C2—C31.380 (3)C10—F101.340 (2)
C3—F31.336 (2)C10—C111.380 (3)
C3—C41.380 (3)C11—F111.341 (2)
C4—F41.342 (2)C11—C121.383 (3)
C4—C51.373 (3)C12—F121.337 (2)
C5—F51.345 (2)
N2—N1—C7112.19 (15)F6—C6—C1118.53 (18)
N1—N2—N3112.56 (15)C5—C6—C1122.21 (18)
N2—N3—C1118.78 (15)C8—C7—C12117.02 (17)
N2—N3—H3120.6C8—C7—N1118.04 (17)
C1—N3—H3120.6C12—C7—N1124.61 (18)
C6—C1—C2116.55 (18)F8—C8—C9118.51 (18)
C6—C1—N3119.05 (17)F8—C8—C7119.02 (17)
C2—C1—N3124.38 (17)C9—C8—C7122.46 (18)
F2—C2—C3117.62 (17)F9—C9—C10120.19 (17)
F2—C2—C1120.85 (18)F9—C9—C8120.73 (18)
C3—C2—C1121.51 (18)C10—C9—C8119.08 (18)
F3—C3—C2119.36 (17)F10—C10—C11120.04 (18)
F3—C3—C4120.34 (18)F10—C10—C9120.00 (18)
C2—C3—C4120.28 (18)C11—C10—C9119.95 (17)
F4—C4—C5120.47 (18)F11—C11—C10120.08 (17)
F4—C4—C3120.24 (18)F11—C11—C12119.65 (18)
C5—C4—C3119.27 (19)C10—C11—C12120.28 (18)
F5—C5—C6120.39 (18)F12—C12—C11117.55 (17)
F5—C5—C4119.46 (19)F12—C12—C7121.24 (17)
C6—C5—C4120.14 (18)C11—C12—C7121.18 (18)
F6—C6—C5119.25 (17)
C7—N1—N2—N3−174.92 (16)N3—C1—C6—C5177.51 (18)
N1—N2—N3—C1174.28 (17)N2—N1—C7—C8−147.83 (18)
N2—N3—C1—C6152.97 (18)N2—N1—C7—C1238.9 (3)
N2—N3—C1—C2−29.0 (3)C12—C7—C8—F8179.22 (17)
C6—C1—C2—F2177.31 (17)N1—C7—C8—F85.4 (3)
N3—C1—C2—F2−0.7 (3)C12—C7—C8—C9−0.5 (3)
C6—C1—C2—C3−1.0 (3)N1—C7—C8—C9−174.24 (18)
N3—C1—C2—C3−179.05 (18)F8—C8—C9—F91.1 (3)
F2—C2—C3—F31.3 (3)C7—C8—C9—F9−179.21 (18)
C1—C2—C3—F3179.65 (17)F8—C8—C9—C10−178.35 (17)
F2—C2—C3—C4−177.26 (17)C7—C8—C9—C101.3 (3)
C1—C2—C3—C41.1 (3)F9—C9—C10—F10−1.5 (3)
F3—C3—C4—F40.2 (3)C8—C9—C10—F10177.96 (17)
C2—C3—C4—F4178.76 (17)F9—C9—C10—C11178.85 (17)
F3—C3—C4—C5−178.06 (18)C8—C9—C10—C11−1.7 (3)
C2—C3—C4—C50.5 (3)F10—C10—C11—F111.4 (3)
F4—C4—C5—F5−0.1 (3)C9—C10—C11—F11−178.93 (17)
C3—C4—C5—F5178.22 (18)F10—C10—C11—C12−178.43 (17)
F4—C4—C5—C6179.63 (18)C9—C10—C11—C121.2 (3)
C3—C4—C5—C6−2.1 (3)F11—C11—C12—F12−2.0 (3)
F5—C5—C6—F61.1 (3)C10—C11—C12—F12177.86 (17)
C4—C5—C6—F6−178.58 (18)F11—C11—C12—C7179.80 (17)
F5—C5—C6—C1−178.10 (18)C10—C11—C12—C7−0.3 (3)
C4—C5—C6—C12.2 (3)C8—C7—C12—F12−178.17 (17)
C2—C1—C6—F6−179.85 (17)N1—C7—C12—F12−4.9 (3)
N3—C1—C6—F6−1.7 (3)C8—C7—C12—C110.0 (3)
C2—C1—C6—C5−0.6 (3)N1—C7—C12—C11173.28 (18)

Hydrogen-bond geometry (Å, °)

D—H···AD—HH···AD···AD—H···A
N3—H3···N1i0.882.233.076 (2)162

Symmetry codes: (i) −x+1, −y, −z+1.

Footnotes

Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: KP2288).

References

  • Allen, F. H. (2002). Acta Cryst. B58, 380–388. [PubMed]
  • Altomare, A., Burla, M. C., Camalli, M., Cascarano, G. L., Giacovazzo, C., Guagliardi, A., Moliterni, A. G. G., Polidori, G. & Spagna, R. (1999). J. Appl. Cryst.32, 115–119.
  • Brandenburg, K. & Putz, M. (2005). DIAMOND Crystal Impact GbR, Bonn, Germany.
  • Brooke, G. M., Forbes, E. J., Richardson, R. D., Stacey, M. & Tatlow, J. C. (1965). J. Chem. Soc. pp. 2088–2094.
  • Bruker (2004). SADABS, SAINT-Plus and XPREP Bruker AXS Inc., Madison, Wisconsin, USA.
  • Bruker (2005). APEX2 Bruker AXS Inc., Madison, Wisconsin, USA.
  • Farrugia, L. J. (1999). J. Appl. Cryst.32, 837–838.
  • Leman, J. T., Braddock-Wilking, J., Coolong, A. J. & Barron, A. R. (1993). Inorg. Chem.32, 4324–4336.
  • Pelkis, P. S., Dubenko, R. G. & Pupko, L. S. (1957). J. Org. Chem. USSR, 27, 2190–2194.
  • Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. [PubMed]

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