(E)-1,1′-(Diazene-1,2-di­yl)bis­(cyclo­hexane-1-carbo­nitrile)

Begum, F.; Twamley, B.; Baker, R.J.

doi:10.1107/S2414314617003698

organic compounds

IUCrDATA

ISSN: 2414-3146

Volume 2| Part 3| March 2017| x170369

https://doi.org/10.1107/S2414314617003698

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(E)-1,1′-(Diazene-1,2-diyl)bis(cyclohexane-1-carbonitrile)

Farzana Begum,^a Brendan Twamley ^a and Robert J. Baker ^a ^*

^aSchool of Chemistry, University of Dublin, Trinity College, Dublin 2, Ireland
^*Correspondence e-mail: bakerrj@tcd.ie

Edited by H. Stoeckli-Evans, University of Neuchâtel, Switzerland (Received 1 March 2017; accepted 7 March 2017; online 10 March 2017)

The whole molecule of the title compound, C₁₄H₂₀N₄, is generated by inversion symmetry. The mid-point of the N=N bond is situated on the inversion centre. The conformation about this central N=N bond is E. The carbonitrile groups occupy axial positions on the cyclohexane rings. In the crystal, there are no significant intermolecular interactions present.

Keywords: crystal structure; VAZO-88; radical initiator; diazene; carbonitrile; cyclohexane.

CCDC reference: 1536557

Structure description

The title compound, known as VAZO-88, is a well known radical initiator that has also been used as a ligand in coordination chemistry (Chainok et al., 2010 ).

The whole molecule of the title compound, illustrated in Fig. 1, is generated by inversion symmetry. The mid-point of the N=N bond is situated on the inversion centre. The conformation about the central N1=N1′ bond, of 1.231 (2) Å, is E. The carbonitrile groups occupy axial positions on the cyclohexane rings and the C2—C3≡N4 bond angle is 176.58 (18) °, with bond length C3≡N4 being 1.147 (2) Å.

Figure 1
The molecular structure of the title compound, with the atom labelling and displacement ellipsoids drawn at the 50% probability level. Unlabelled atoms are related to labelled atoms by the symmetry operation (−x + 1, −y + 1, −z + 1).

In the crystal, molecules stack along the a-axis direction (Fig. 2), but there are no significant intermolecular interactions present.

Figure 2
A view along the a axis of the crystal packing of the title compound.

Synthesis and crystallization

During an attempted radical cyclization reaction, using commercially available VAZO-88, we obtained a few colourless crystals of the title compound, on slow evaporation of a hexane solution.

Refinement

Crystal data, data collection and structure refinement details are summarized in Table 1.

Table 1
Experimental details

Crystal data
Chemical formula	C₁₄H₂₀N₄
M_r	244.34
Crystal system, space group	Monoclinic, P2₁/n
Temperature (K)	100
a, b, c (Å)	5.8740 (19), 21.077 (7), 5.974 (2)
β (°)	110.372 (13)
V (Å³)	693.4 (4)
Z	2
Radiation type	Cu Kα
μ (mm⁻¹)	0.57
Crystal size (mm)	0.16 × 0.13 × 0.12

Data collection
Diffractometer	Bruker APEXII CCD
Absorption correction	Multi-scan (SADABS; Bruker, 2015 )
T_min, T_max	0.666, 0.753
No. of measured, independent and observed [I > 2σ(I)] reflections	7548, 1299, 1213
R_int	0.033
(sin θ/λ)_max (Å⁻¹)	0.608

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.059, 0.160, 1.06
No. of reflections	1299
No. of parameters	82
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.47, −0.16
Computer programs: APEX3 and SAINT (Bruker, 2015), SHELXS2014 (Sheldrick, 2008 ), SHELXL2014 (Sheldrick, 2015 ), Mercury (Macrae et al., 2008 ) and OLEX2 (Dolomanov et al., 2009 ).

Structural data

CCDC reference: 1536557

Crystal structure: contains datablocks Global, I. DOI: https://doi.org/10.1107/S2414314617003698/su4139sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S2414314617003698/su4139Isup2.hkl

Supporting information file. DOI: https://doi.org/10.1107/S2414314617003698/su4139Isup3.mol

Supporting information file. DOI: https://doi.org/10.1107/S2414314617003698/su4139Isup4.cml

checkCIF report

Computing details top

Data collection: APEX3 (Bruker, 2015); cell refinement: SAINT (Bruker, 2015); data reduction: SAINT (Bruker, 2015); program(s) used to solve structure: SHELXS2014 (Sheldrick, 2008); program(s) used to refine structure: SHELXL2014 (Sheldrick, 2015); molecular graphics: Mercury (Macrae et al., 2008); software used to prepare material for publication: OLEX2 (Dolomanov et al., 2009).

(E)-1,1'-(Diazene-1,2-diyl)bis(cyclohexane-1-carbonitrile) top

Crystal data top

C₁₄H₂₀N₄	F(000) = 264
M_r = 244.34	D_x = 1.170 Mg m⁻³
Monoclinic, P2₁/n	Cu Kα radiation, λ = 1.54184 Å
a = 5.8740 (19) Å	Cell parameters from 4485 reflections
b = 21.077 (7) Å	θ = 4.2–69.5°
c = 5.974 (2) Å	µ = 0.57 mm⁻¹
β = 110.372 (13)°	T = 100 K
V = 693.4 (4) Å³	Block, colourless
Z = 2	0.16 × 0.13 × 0.12 mm

Data collection top

Bruker APEXII CCD diffractometer	1299 independent reflections
Radiation source: microfocus sealed X-ray tube, Incoatec Iµs	1213 reflections with I > 2σ(I)
Mirror optics monochromator	R_int = 0.033
Detector resolution: 7.9 pixels mm^-1	θ_max = 69.7°, θ_min = 8.2°
ω and φ scans	h = −7→7
Absorption correction: multi-scan (SADABS; Bruker, 2015)	k = −25→25
T_min = 0.666, T_max = 0.753	l = −7→7
7548 measured reflections

Refinement top

Refinement on F²	Primary atom site location: dual
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F² > 2σ(F²)] = 0.059	H-atom parameters constrained
wR(F²) = 0.160	w = 1/[σ²(F_o²) + (0.0875P)² + 0.4078P] where P = (F_o² + 2F_c²)/3
S = 1.06	(Δ/σ)_max < 0.001
1299 reflections	Δρ_max = 0.47 e Å⁻³
82 parameters	Δρ_min = −0.16 e Å⁻³
0 restraints

Special details top

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq
C2	0.5458 (3)	0.42030 (8)	0.4069 (3)	0.0259 (4)
C3	0.7721 (3)	0.40938 (8)	0.6143 (3)	0.0286 (4)
C5	0.3418 (3)	0.37594 (8)	0.4188 (3)	0.0295 (4)
H5A	0.3201	0.3814	0.5748	0.035*
H5B	0.1876	0.3878	0.2920	0.035*
C6	0.3981 (3)	0.30654 (8)	0.3880 (3)	0.0309 (5)
H6A	0.5404	0.2930	0.5261	0.037*
H6B	0.2580	0.2800	0.3846	0.037*
C7	0.4513 (3)	0.29635 (8)	0.1585 (3)	0.0320 (5)
H7A	0.3027	0.3049	0.0194	0.038*
H7B	0.4982	0.2516	0.1493	0.038*
C8	0.6554 (3)	0.33973 (8)	0.1480 (3)	0.0306 (5)
H8A	0.8083	0.3281	0.2772	0.037*
H8B	0.6797	0.3337	−0.0065	0.037*
C9	0.5977 (3)	0.40919 (8)	0.1749 (3)	0.0280 (4)
H9A	0.4544	0.4221	0.0368	0.034*
H9B	0.7368	0.4358	0.1757	0.034*
N1	0.4544 (3)	0.48574 (7)	0.4049 (3)	0.0285 (4)
N4	0.9502 (3)	0.39882 (8)	0.7674 (3)	0.0382 (5)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
C2	0.0226 (8)	0.0294 (9)	0.0254 (8)	0.0012 (6)	0.0079 (7)	−0.0005 (6)
C3	0.0255 (9)	0.0331 (9)	0.0291 (9)	0.0010 (7)	0.0118 (8)	−0.0008 (7)
C5	0.0215 (8)	0.0357 (10)	0.0333 (9)	−0.0010 (7)	0.0120 (7)	−0.0009 (7)
C6	0.0252 (9)	0.0316 (10)	0.0364 (10)	−0.0015 (7)	0.0114 (7)	0.0020 (7)
C7	0.0306 (9)	0.0295 (9)	0.0341 (9)	−0.0002 (7)	0.0089 (7)	−0.0023 (7)
C8	0.0307 (9)	0.0336 (10)	0.0298 (9)	0.0015 (7)	0.0133 (7)	−0.0010 (7)
C9	0.0247 (9)	0.0347 (10)	0.0255 (9)	−0.0012 (6)	0.0099 (7)	−0.0005 (7)
N1	0.0247 (8)	0.0320 (8)	0.0301 (7)	−0.0008 (5)	0.0111 (6)	−0.0023 (5)
N4	0.0284 (9)	0.0505 (10)	0.0323 (8)	0.0056 (7)	0.0063 (7)	0.0012 (7)

Geometric parameters (Å, º) top

C2—C3	1.486 (2)	C6—C7	1.524 (3)
C2—C5	1.541 (2)	C7—H7A	0.9900
C2—C9	1.537 (2)	C7—H7B	0.9900
C2—N1	1.479 (2)	C7—C8	1.526 (2)
C3—N4	1.147 (2)	C8—H8A	0.9900
C5—H5A	0.9900	C8—H8B	0.9900
C5—H5B	0.9900	C8—C9	1.524 (2)
C5—C6	1.525 (2)	C9—H9A	0.9900
C6—H6A	0.9900	C9—H9B	0.9900
C6—H6B	0.9900	N1—N1ⁱ	1.231 (3)

C3—C2—C5	110.60 (14)	C6—C7—H7A	109.4
C3—C2—C9	109.11 (14)	C6—C7—H7B	109.4
C9—C2—C5	110.54 (14)	C6—C7—C8	111.24 (14)
N1—C2—C3	111.60 (13)	H7A—C7—H7B	108.0
N1—C2—C5	106.26 (13)	C8—C7—H7A	109.4
N1—C2—C9	108.69 (13)	C8—C7—H7B	109.4
N4—C3—C2	176.58 (18)	C7—C8—H8A	109.3
C2—C5—H5A	109.3	C7—C8—H8B	109.3
C2—C5—H5B	109.3	H8A—C8—H8B	108.0
H5A—C5—H5B	107.9	C9—C8—C7	111.40 (14)
C6—C5—C2	111.80 (14)	C9—C8—H8A	109.3
C6—C5—H5A	109.3	C9—C8—H8B	109.3
C6—C5—H5B	109.3	C2—C9—H9A	109.4
C5—C6—H6A	109.3	C2—C9—H9B	109.4
C5—C6—H6B	109.3	C8—C9—C2	111.26 (14)
H6A—C6—H6B	108.0	C8—C9—H9A	109.4
C7—C6—C5	111.41 (14)	C8—C9—H9B	109.4
C7—C6—H6A	109.3	H9A—C9—H9B	108.0
C7—C6—H6B	109.3	N1ⁱ—N1—C2	114.07 (18)

C2—C5—C6—C7	−54.82 (19)	C6—C7—C8—C9	−56.00 (19)
C3—C2—C5—C6	−66.44 (18)	C7—C8—C9—C2	56.17 (19)
C3—C2—C9—C8	66.81 (18)	C9—C2—C5—C6	54.51 (19)
C3—C2—N1—N1ⁱ	−15.1 (2)	C9—C2—N1—N1ⁱ	−135.45 (18)
C5—C2—C9—C8	−55.02 (19)	N1—C2—C5—C6	172.27 (13)
C5—C2—N1—N1ⁱ	105.57 (19)	N1—C2—C9—C8	−171.28 (13)
C5—C6—C7—C8	55.17 (19)

Symmetry code: (i) −x+1, −y+1, −z+1.

Funding information

Funding for this research was provided by: Higher Education Commission, Pakistan.

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