Hexane-1,6-diammonium dinitrate

Blerk, C. van; Kruger, G.J.

doi:10.1107/S1600536809012963

organic compounds

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ISSN: 2056-9890

Volume 65| Part 5| May 2009| Page o1008

doi:10.1107/S1600536809012963

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Hexane-1,6-diammonium dinitrate

Charmaine van Blerk ^a ^* and Gert J. Kruger ^a

^aUniversity of Johannesburg, Department of Chemistry, P O Box 524, Auckland Park, Johannesburg 2006, South Africa
^*Correspondence e-mail: cvanblerk@uj.ac.za

(Received 2 April 2009; accepted 6 April 2009; online 8 April 2009)

The hexane-1,6-diammonium cation of the title compound, C₆H₁₈N₂²⁺·2NO₃⁻, lies across a crystallographic inversion centre and shows significant deviation from planarity in the hydrocarbon chain. This is evident from the torsion angle of −64.0°(2) along the N—C—C—C bond and thse torsion angle of −67.1°(2) along the C—C—C—C bonds. An intricate three-dimensional hydrogen-bonding network exists in the crystal structure, with each H atom on the ammonium group exhibiting bifurcated interactions to the nitrate anion. Complex hydrogen-bonded ring and chain motifs are also evident, in particular a 26-membered ring with graph-set notation R₄⁴(26) is observed.

Related literature

For related structural studies of hexane-1,6-diammonium salts, see: van Blerk & Kruger (2008 ). For hydrogen-bond motifs, see: Bernstein et al. (1995 ). For a description of the Cambridge Structural Database, see: Allen (2002 ).

Experimental

Crystal data

C₆H₁₈N₂²⁺·2NO₃⁻
M_r = 242.24
Monoclinic, P 2₁ /n
a = 6.2947 (1) Å
b = 11.6783 (3) Å
c = 8.1211 (2) Å
β = 92.840 (1)°
V = 596.26 (2) Å³
Z = 2
Mo Kα radiation
μ = 0.12 mm⁻¹
T = 295 K
0.46 × 0.20 × 0.16 mm

Data collection

Bruker SMART CCD diffractometer
Absorption correction: multi-scan (AX-Scale; Bruker, 2008 ) T_min = 0.948, T_max = 0.981
14665 measured reflections
1718 independent reflections
1107 reflections with I > 2σ(I)
R_int = 0.026

Refinement

R[F² > 2σ(F²)] = 0.045
wR(F²) = 0.147
S = 1.02
1718 reflections
74 parameters
H-atom parameters constrained
Δρ_max = 0.37 e Å⁻³
Δρ_min = −0.19 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N1—H1C⋯O2	0.89	2.53	3.1760 (19)	130
N1—H1C⋯O3	0.89	2.04	2.9184 (19)	171
N1—H1D⋯O1ⁱⁱ	0.89	2.13	2.9692 (18)	158
N1—H1D⋯O2ⁱⁱ	0.89	2.36	3.1374 (19)	146
N1—H1E⋯O1ⁱⁱⁱ	0.89	2.26	3.0561 (18)	149
N1—H1E⋯O3ⁱⁱⁱ	0.89	2.23	3.0110 (18)	146
Symmetry codes: (ii) x+1, y, z; (iii) $[x+{\script{1\over 2}}, -y+{\script{1\over 2}}, z+{\script{1\over 2}}]$ .

Data collection: SMART-NT (Bruker, 1998 ); cell refinement: SAINT (Bruker, 2008); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: X-SEED (Barbour, 2001 ) and Mercury (Macrae et al., 2006 ); software used to prepare material for publication: publCIF (Westrip, 2009 ).

Supporting information

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536809012963/fj2206sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536809012963/fj2206Isup2.hkl

checkCIF report

Comment top

The crystal structure of the title compound (I) adds to our current ongoing studies of long-chained diammonium salts. Colourless needle-like rectangular crystals of hexane-1,6-diammonium dinitrate were synthesized and formed as part of our structural chemistry study of the inorganic mineral acid salts of hexane-1,6-diamine. A search of the Cambridge Structural Database (Version 5.30, February 2009 release; Allen, 2002) revealed that this compound had not previously been determined.

The diammonium hexane chain lies across a crystallographic inversion centre and hence the asymmetric unit contains one nitrate anion and one-half of the hexane diammonium cation. The hydrocarbon chain is also not extended as is common in long chained hydrocarbons but shows significant folding and deviation from planarity. This is clearly evident from the torsion angle along the N1—C1—C2—C3 bond (–64.0°(2)) and along the C1—C2—C3—C3ⁱ bond (–67.1°(2)). Selected torsion angles can be found in Table 1. The molecular structure of (I) is shown in Figure 1.

Figure 2 illustrates the layered packing arrangement of the title compound (I). Single stacked layers of folded cations pack in between layers of nitrate anions showing a distinct inorganic - organic layering effect that is a common feature of these long-chained diammonium salts. The diammonium cations form bridges between the nitrate anion layers and an extensive three-dimensional hydrogen-bonding network is formed.

A close-up view of the hydrogen bonding interactions can be viewed in Figure 3 where very clear evidence of bifurcated interactions can be seen on each hydrogen atom of both ammonium groups. The hydrogen bond distances and angles for (I) can be found in Table 2. Since the hydrogen bonding network is complex, we focus on one particularly interesting hydrogen-bonding ring motif in the structure. Figure 4 shows a view of two diammonium cations and two nitrate anions (viewed down the c axis) that are hydrogen bonded together to form a large, 26-membered ring motif with graph set notation R₄⁴(26). Another smaller ring motif is evident as a result of the bifurcated hydrogen-bond interaction with the nitrate anion and this ring has the graph-set notation R²₁(4) but is not depicted graphically. Chain motifs also exist and were identified with Mercury (Macrae et al.), but again, these are not shown graphically.

Related literature top

For related structural studies of hexane-1,6-diammonium salts, see: van Blerk & Kruger (2008). For hydrogen-bond motifs, see: Bernstein et al. (1995). For a description of the Cambridge Structural Database, see: Allen (2002).

Experimental top

Compound (I) was prepared by adding 1,6-diamino-hexane (0.50 g, 4.30 mmol) to 55% nitric acid (2 ml, 42.5 mmol) in a sample vial. The mixture was then refluxed at 363 K for 2 h. The solution was cooled at 2 K h^-1 to room temperature. Colourless rectangular needles of hexane-1,6-diammonium dinitrate were collected and a suitable single-crystal was selected for the X-ray diffraction study.

Computing details top

Data collection: SMART-NT (Bruker, 1998); cell refinement: SAINT (Bruker, 2008); data reduction: SAINT (Bruker, 2008); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: X-SEED (Barbour, 2001) and Mercury (Macrae et al., 2006); software used to prepare material for publication: publCIF (Westrip, 2009).

Figures top

	Fig. 1. : Molecular structure of (I), with atomic numbering scheme and displacement ellipsoids drawn at the 50% probability level. Atoms labelled with (i) are at the symmetry position (1 - x, - y, - z)
	Fig. 2. : Packing arrangement if (I) viewed down the a axis. Hydrogen bonds are indicated by dashed lines.
	Fig. 3. : Close-up view of (I) viewed down the a axis clearly showing the bifurcated hydrogen-bonding interactions. Hydrogen bonds are indicated by dashed lines.
	Fig. 4. : Close up view of (I) viewed down the c axis showing the ring motif involving two diammonium cations and two nitrate anions. Hydrogen atoms on the hydrocarbon chain are omitted for clarity.

Hexane-1,6-diammonium dinitrate top

Crystal data top

C₆H₁₈N₂²⁺·2NO₃⁻	F(000) = 260
M_r = 242.24	D_x = 1.349 Mg m⁻³
Monoclinic, P2₁/n	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2yn	Cell parameters from 5933 reflections
a = 6.2947 (1) Å	θ = 2.5–25.2°
b = 11.6783 (3) Å	µ = 0.12 mm⁻¹
c = 8.1211 (2) Å	T = 295 K
β = 92.840 (1)°	Rectangular, colourless
V = 596.26 (2) Å³	0.46 × 0.20 × 0.16 mm
Z = 2

Data collection top

Bruker SMART CCD diffractometer	1718 independent reflections
Radiation source: fine-focus sealed tube	1107 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.026
ϕ and ω scans	θ_max = 30.0°, θ_min = 3.1°
Absorption correction: multi-scan (AX-Scale; Bruker, 2008)	h = −8→8
T_min = 0.948, T_max = 0.981	k = −16→16
14665 measured reflections	l = −11→11

Refinement top

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)] = 0.045	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.147	H-atom parameters constrained
S = 1.02	w = 1/[σ²(F_o²) + (0.0674P)² + 0.1254P] where P = (F_o² + 2F_c²)/3
1718 reflections	(Δ/σ)_max < 0.001
74 parameters	Δρ_max = 0.37 e Å⁻³
0 restraints	Δρ_min = −0.19 e Å⁻³

Crystal data top

C₆H₁₈N₂²⁺·2NO₃⁻	V = 596.26 (2) Å³
M_r = 242.24	Z = 2
Monoclinic, P2₁/n	Mo Kα radiation
a = 6.2947 (1) Å	µ = 0.12 mm⁻¹
b = 11.6783 (3) Å	T = 295 K
c = 8.1211 (2) Å	0.46 × 0.20 × 0.16 mm
β = 92.840 (1)°

Data collection top

Bruker SMART CCD diffractometer	1718 independent reflections
Absorption correction: multi-scan (AX-Scale; Bruker, 2008)	1107 reflections with I > 2σ(I)
T_min = 0.948, T_max = 0.981	R_int = 0.026
14665 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.045	0 restraints
wR(F²) = 0.147	H-atom parameters constrained
S = 1.02	Δρ_max = 0.37 e Å⁻³
1718 reflections	Δρ_min = −0.19 e Å⁻³
74 parameters

Special details top

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

	x	y	z	U_iso*/U_eq
C1	0.7036 (3)	0.01369 (13)	0.31554 (19)	0.0599 (4)
H1A	0.5614	−0.0134	0.3351	0.072*
H1B	0.8020	−0.0243	0.3934	0.072*
C2	0.7584 (3)	−0.01708 (14)	0.1427 (2)	0.0593 (4)
H2A	0.7644	−0.0999	0.1351	0.071*
H2B	0.9000	0.0117	0.1251	0.071*
C3	0.6095 (2)	0.02648 (14)	0.00229 (18)	0.0540 (4)
H3A	0.5955	0.1088	0.0126	0.065*
H3B	0.6737	0.0110	−0.1016	0.065*
N1	0.7138 (2)	0.13945 (11)	0.34353 (15)	0.0544 (4)
H1C	0.6044	0.1730	0.2893	0.082*
H1D	0.8350	0.1667	0.3072	0.082*
H1E	0.7082	0.1539	0.4508	0.082*
N2	0.2075 (2)	0.23209 (11)	0.22415 (16)	0.0510 (3)
O1	0.03639 (19)	0.26482 (12)	0.15889 (16)	0.0710 (4)
O2	0.2102 (2)	0.15918 (11)	0.33405 (15)	0.0732 (4)
O3	0.3767 (2)	0.27276 (12)	0.17480 (16)	0.0714 (4)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
C1	0.0791 (11)	0.0552 (9)	0.0448 (8)	0.0006 (8)	−0.0042 (7)	0.0031 (6)
C2	0.0622 (9)	0.0591 (9)	0.0559 (9)	0.0067 (7)	−0.0052 (7)	−0.0109 (7)
C3	0.0632 (9)	0.0583 (9)	0.0407 (7)	−0.0024 (7)	0.0046 (6)	−0.0062 (6)
N1	0.0544 (8)	0.0610 (8)	0.0479 (7)	−0.0035 (6)	0.0033 (6)	−0.0087 (5)
N2	0.0584 (8)	0.0501 (7)	0.0451 (7)	0.0059 (6)	0.0070 (6)	−0.0002 (5)
O1	0.0567 (7)	0.0808 (9)	0.0755 (9)	0.0130 (6)	0.0018 (6)	0.0188 (6)
O2	0.0782 (9)	0.0798 (8)	0.0615 (7)	0.0012 (7)	0.0045 (6)	0.0279 (6)
O3	0.0576 (8)	0.0846 (9)	0.0731 (8)	−0.0041 (6)	0.0131 (6)	0.0188 (6)

Geometric parameters (Å, º) top

C1—N1	1.487 (2)	C3—H3A	0.9700
C1—C2	1.505 (2)	C3—H3B	0.9700
C1—H1A	0.9700	N1—H1C	0.8900
C1—H1B	0.9700	N1—H1D	0.8900
C2—C3	1.527 (2)	N1—H1E	0.8900
C2—H2A	0.9700	N2—O2	1.2330 (16)
C2—H2B	0.9700	N2—O1	1.2369 (17)
C3—C3ⁱ	1.510 (3)	N2—O3	1.2504 (17)

N1—C1—C2	111.60 (13)	C2—C3—H3A	108.7
N1—C1—H1A	109.3	C3ⁱ—C3—H3B	108.7
C2—C1—H1A	109.3	C2—C3—H3B	108.7
N1—C1—H1B	109.3	H3A—C3—H3B	107.6
C2—C1—H1B	109.3	C1—N1—H1C	109.5
H1A—C1—H1B	108.0	C1—N1—H1D	109.5
C1—C2—C3	117.17 (14)	H1C—N1—H1D	109.5
C1—C2—H2A	108.0	C1—N1—H1E	109.5
C3—C2—H2A	108.0	H1C—N1—H1E	109.5
C1—C2—H2B	108.0	H1D—N1—H1E	109.5
C3—C2—H2B	108.0	O2—N2—O1	120.27 (14)
H2A—C2—H2B	107.2	O2—N2—O3	120.85 (14)
C3ⁱ—C3—C2	114.07 (17)	O1—N2—O3	118.86 (13)
C3ⁱ—C3—H3A	108.7

N1—C1—C2—C3	−64.0 (2)	C1—C2—C3—C3ⁱ	−67.1 (2)

Symmetry code: (i) −x+1, −y, −z.

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1C···O2	0.89	2.53	3.1760 (19)	130
N1—H1C···O3	0.89	2.04	2.9184 (19)	171
N1—H1D···O1ⁱⁱ	0.89	2.13	2.9692 (18)	158
N1—H1D···O2ⁱⁱ	0.89	2.36	3.1374 (19)	146
N1—H1E···O1ⁱⁱⁱ	0.89	2.26	3.0561 (18)	149
N1—H1E···O3ⁱⁱⁱ	0.89	2.23	3.0110 (18)	146

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

Experimental details

Crystal data
Chemical formula	C₆H₁₈N₂²⁺·2NO₃⁻
M_r	242.24
Crystal system, space group	Monoclinic, P2₁/n
Temperature (K)	295
a, b, c (Å)	6.2947 (1), 11.6783 (3), 8.1211 (2)
β (°)	92.840 (1)
V (Å³)	596.26 (2)
Z	2
Radiation type	Mo Kα
µ (mm⁻¹)	0.12
Crystal size (mm)	0.46 × 0.20 × 0.16

Data collection
Diffractometer	Bruker SMART CCD diffractometer
Absorption correction	Multi-scan (AX-Scale; Bruker, 2008)
T_min, T_max	0.948, 0.981
No. of measured, independent and observed [I > 2σ(I)] reflections	14665, 1718, 1107
R_int	0.026
(sin θ/λ)_max (Å⁻¹)	0.703

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.045, 0.147, 1.02
No. of reflections	1718
No. of parameters	74
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.37, −0.19

Computer programs: SMART-NT (Bruker, 1998), SAINT (Bruker, 2008), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), X-SEED (Barbour, 2001) and Mercury (Macrae et al., 2006), publCIF (Westrip, 2009).

Selected torsion angles (º) top

N1—C1—C2—C3

−64.0 (2)

C1—C2—C3—C3ⁱ

−67.1 (2)

Symmetry code: (i) −x+1, −y, −z.

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1C···O2	0.89	2.53	3.1760 (19)	130
N1—H1C···O3	0.89	2.04	2.9184 (19)	171
N1—H1D···O1ⁱⁱ	0.89	2.13	2.9692 (18)	158
N1—H1D···O2ⁱⁱ	0.89	2.36	3.1374 (19)	146
N1—H1E···O1ⁱⁱⁱ	0.89	2.26	3.0561 (18)	149
N1—H1E···O3ⁱⁱⁱ	0.89	2.23	3.0110 (18)	146

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

Acknowledgements

The authors acknowledge the National Research Foundation Thuthuka programme (GUN 66314) and the University of Johannesburg for funding for this study. The University of the Witwatersrand is thanked for the use of their facilities and the use of the diffractometer in the Jan Boeyens Structural Chemistry Laboratory.

References

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