Adipo­nitrile at 100 K

Adipo­nitrile, C₆H₈N₂, is a key inter­mediate in the synthesis of the polyamide Nylon 66 and is produced industrially on a large scale. We have determined the crystal and mol­ecular structure of adipo­nitrile by single-crystal X-ray analysis at 100 K, a suitable crystal (m.p. 275 K) having been grown from the melt at low temperature. The compound crystallizes in the monoclinic space group P2₁/c with Z = 2. In the crystal structure, the mol­ecule adopts an exact C_i-symmetric gauche–anti–gauche conformation of the C—C—C—C skeleton about an inversion centre. The mol­ecules are densely packed, with short intermolecular contacts between the α-H and nitrile N atoms.

Computing details

Data collection: APEX2 (Bruker, 2013); cell refinement: SAINT (Bruker, 2013); data reduction: SAINT (Bruker, 2013); program(s) used to solve structure: SHELXT (Sheldrick, 2015a); program(s) used to refine structure: SHELXL2017 (Sheldrick, 2015b); molecular graphics: DIAMOND (Brandenburg, 2014); software used to prepare material for publication: enCIFer (Allen et al., 2004).

Hexane-1,6-dinitrile

Crystal data

C6H8N2	Dx = 1.153 Mg m^−3
Mr = 108.14	Melting point: 275 K
Monoclinic, P21/c	Cu Kα radiation, λ = 1.54178 Å
a = 4.5031 (11) Å	Cell parameters from 2360 reflections
b = 6.5860 (16) Å	θ = 4.2–71.6°
c = 10.572 (3) Å	µ = 0.57 mm^−1
β = 96.540 (6)°	T = 100 K
V = 311.51 (13) Å^3	Cylinder, colourless
Z = 2	1.60 × 0.50 × 0.50 mm
F(000) = 116

Data collection

Bruker X8 Proteum diffractometer	604 independent reflections
Radiation source: rotating-anode X-ray tube	593 reflections with I > 2σ(I)
Montel graded multilayer optics monochromator	Rint = 0.042
Detector resolution: 66.67 pixels mm^-1	θmax = 72.0°, θmin = 7.9°
φ and ω scans	h = −5→5
Absorption correction: gaussian (SADABS; Bruker, 2012)	k = −7→8
Tmin = 0.597, Tmax = 0.783	l = −12→12
4525 measured reflections

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F^2 > 2σ(F^2)] = 0.045	H-atom parameters constrained
wR(F^2) = 0.131	w = 1/[σ^2(Fo^2) + (0.0706P)^2 + 0.0851P] where P = (Fo^2 + 2Fc^2)/3
S = 1.14	(Δ/σ)max < 0.001
604 reflections	Δρmax = 0.19 e Å^−3
38 parameters	Δρmin = −0.18 e Å^−3
0 restraints	Extinction correction: SHELXL2017 (Sheldrick, 2015b), Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
Primary atom site location: dual	Extinction coefficient: 0.20 (3)

Special details

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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
N1	0.1132 (3)	0.62026 (19)	0.19625 (11)	0.0365 (5)
C1	0.2346 (3)	0.6812 (2)	0.28969 (12)	0.0299 (5)
C2	0.3942 (3)	0.7541 (2)	0.40971 (12)	0.0315 (5)
H2A	0.247075	0.802155	0.465812	0.038*
H2B	0.521409	0.870968	0.391941	0.038*
C3	0.5900 (3)	0.5893 (2)	0.47906 (11)	0.0292 (5)
H3A	0.733603	0.539156	0.422013	0.035*
H3B	0.706337	0.649791	0.554887	0.035*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
N1	0.0440 (8)	0.0359 (8)	0.0285 (7)	0.0028 (5)	−0.0002 (5)	0.0020 (4)
C1	0.0328 (7)	0.0290 (8)	0.0280 (7)	0.0017 (5)	0.0043 (5)	0.0044 (5)
C2	0.0373 (8)	0.0297 (8)	0.0270 (7)	−0.0027 (5)	0.0014 (5)	0.0002 (5)
C3	0.0282 (7)	0.0336 (8)	0.0253 (7)	−0.0041 (5)	0.0004 (5)	0.0010 (5)

Geometric parameters (Å, º)

N1—C1	1.1458 (17)	C2—H2B	0.9900
C1—C2	1.4662 (18)	C3—C3^i	1.523 (2)
C2—C3	1.5316 (18)	C3—H3A	0.9900
C2—H2A	0.9900	C3—H3B	0.9900
N1—C1—C2	178.49 (14)	C3^i—C3—C2	112.98 (13)
C1—C2—C3	112.39 (11)	C3^i—C3—H3A	109.0
C1—C2—H2A	109.1	C2—C3—H3A	109.0
C3—C2—H2A	109.1	C3^i—C3—H3B	109.0
C1—C2—H2B	109.1	C2—C3—H3B	109.0
C3—C2—H2B	109.1	H3A—C3—H3B	107.8
H2A—C2—H2B	107.9
C1—C2—C3—C3^i	−63.88 (17)

Symmetry code: (i) −x+1, −y+1, −z+1.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
C2—H2A···N1^ii	0.99	2.63	3.5123 (18)	149
C2—H2B···N1^iii	0.99	2.57	3.5436 (19)	167

Symmetry codes: (ii) x, −y+3/2, z+1/2; (iii) −x+1, y+1/2, −z+1/2.