(S)-1-(2-Ammonio-3-methyl­butyl)-1,2-dihydro­pyridin-2-iminium dibromide

Wang, Y.; Zhang, J.; Chen, H.; Luo, S.

doi:10.1107/S1600536808012154

organic compounds

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ISSN: 2056-9890

Volume 64| Part 6| June 2008| Page o1025

doi:10.1107/S1600536808012154

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(S)-1-(2-Ammonio-3-methylbutyl)-1,2-dihydropyridin-2-iminium dibromide

Yifeng Wang,^a Jixv Zhang,^a Hui Chen ^a and Shuping Luo ^a ^*

^aState Key Laboratory Breeding Base of Green Chemistry–Synthesis Technology, Zhejiang University of Technology, Hangzhou 310014, People's Republic of China
^*Correspondence e-mail: yifengwang108@gmail.com

(Received 4 March 2008; accepted 27 April 2008; online 10 May 2008)

In the title compound, C₁₀H₁₉N₃²⁺·2Br⁻, the plane of the three butyl C atoms nearest to the pyridine ring is almost perpendicular to the ring [dihedral angle = 84.80 (2)°]. The N atom of the ammonium group is displaced by 1.150 (8) Å from the plane of these three C atoms. The iminium N atom lies on the opposite side of this plane. The crystal structure is stabilized by hydrogen bonds between the N and Br atoms, as well as by intermolecular C—H⋯Br interactions.

Related literature

For the synthesis of (S)-1-bromo-3-methylbutan-2-amine hydrobromide, see: Xu et al. (2006 ). For related literature, see: Luo et al. (2006 ).

Experimental

Crystal data

C₁₀H₁₉N₃²⁺·2Br⁻
M_r = 341.10
Monoclinic, P 2₁
a = 5.9311 (11) Å
b = 12.456 (2) Å
c = 9.6807 (18) Å
β = 99.733 (3)°
V = 704.9 (2) Å³
Z = 2
Mo Kα radiation
μ = 5.73 mm⁻¹
T = 293 (2) K
0.45 × 0.34 × 0.20 mm

Data collection

Bruker SMART APEX CCD diffractometer
Absorption correction: multi-scan (SADABS; Sheldrick, 1996 ) T_min = 0.381, T_max = 1.000 (expected range = 0.119–0.313)
4117 measured reflections
2307 independent reflections
2054 reflections with I > 2σ(I)
R_int = 0.038

Refinement

R[F² > 2σ(F²)] = 0.041
wR(F²) = 0.092
S = 0.99
2307 reflections
147 parameters
3 restraints
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.91 e Å⁻³
Δρ_min = −0.71 e Å⁻³
Absolute structure: Flack (1983 ), 696 Friedel pairs
Flack parameter: 0.06 (2)

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N2—H2B⋯Br2	0.84 (7)	2.55 (7)	3.368 (7)	167 (8)
N2—H2A⋯Br1ⁱ	0.84 (8)	2.53 (8)	3.357 (6)	168 (10)
N3—H3C⋯Br2ⁱⁱ	0.89	2.50	3.369 (5)	166
N3—H3B⋯Br1	0.89	2.46	3.238 (5)	147
N3—H3A⋯Br2ⁱⁱⁱ	0.89	2.43	3.281 (5)	160
C3—H3⋯Br1^iv	0.93	3.02	3.892 (8)	157
C4—H4⋯Br1^v	0.93	2.91	3.748 (8)	150
C6—H6A⋯Br1^vi	0.97	2.96	3.528 (7)	119
C5—H5⋯Br2ⁱⁱ	0.93	2.83	3.721 (7)	162
C8—H8⋯Br2	0.98	2.93	3.793 (7)	147
Symmetry codes: (i) $[-x+1, y+{\script{1\over 2}}, -z+1]$ ; (ii) $[-x+2, y-{\script{1\over 2}}, -z+1]$ ; (iii) $[-x+1, y-{\script{1\over 2}}, -z+1]$ ; (iv) x-1, y, z-1; (v) x, y, z-1; (vi) $[-x+2, y+{\script{1\over 2}}, -z+1]$ .

Data collection: SMART (Bruker, 2001 ); cell refinement: SAINT-Plus (Bruker, 2000 ); data reduction: SAINT-Plus; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL.

Supporting information

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536808012154/cs2071sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536808012154/cs2071Isup2.hkl

checkCIF report

Comment top

Ionic liquids, specially functional ionic liquids, have received growing attention recently due to their tuneable features for various chemical tasks. (S. Luo, et al., 2006). The title compound, readily synthesized from commercially available L-valine and 2-aminopyridine, might have potential utilities in some specific chemical tasks, when it is converted into a kind of functional ionic liquid by neutralization with sodium hydroxide. The structure of (S)-1-(2-ammonio-3-methylbutyl)pyridin-2(1H)-iminium dibromide is shown in Fig. 1.

The crystal is built of doubly protonated cations and bromide anions. The protonation of the amines is appropriate like in the scheme, for the C1—N2 bond distance reveals its double bond property. The dihedral angle between the plane of three alkyl carbons C6/C7/C8 and the pyridine ring is 84.80 (2) °, which means the two planes are approximately perpendicular to one another. The atom N3 of the ammonium group bonded to the alkyl chain is displaced from the plane of three carbons C6/C7/C8 by 1.150 (8) Å. The iminium N2 lies on the opposite side of this plane. The crystal structure is stablized by hydrogen-bonds between the atoms N and Br as well as by intermolecular C—H—Br interactions. The molecular packing of the title compound showing H-bridge interactions between cationic-anionic groups is shown in Fig. 2.

Related literature top

For the synthesis of (S)-1-bromo-3-methylbutan-2-amine hydrobromide, see: Xu et al. (2006). For related literature, see: Luo et al. (2006).

Experimental top

The title compound was synthesized by treating 2-aminopyridine (0.94 g,10 mmol) with (S)-1-bromo-3-methylbutan-2-amine hydrobromide (2.47 g,10 mmol) in MeCN (30 ml) under stirring at 353 K for 24 h (yield 81%). The compound (S)-1-bromo-3-methylbutan-2-amine hydrobromide was obtained from commercially available L-valine by reduction with NaBH₄ and subsequent bromination with PBr₃ (Xu et al., 2006). Suitable crystals of the title compound were obtained by slow evaporation of an ethanol solution at room temperature.

Computing details top

Data collection: SMART (Bruker, 2001); cell refinement: SMART (Bruker, 2001); data reduction: SAINT-Plus (Bruker, 2000); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

Figures top

	Fig. 1. The asymmetric unit of the title compound with the atomic labeling scheme. Displacement ellipsoids are drawn at the 50% probability level.
	Fig. 2. The molecular packing of the title compound showing H-bridge interactions between cationic-anionic groups.

(S)-1-(2-Ammonio-3-methylbutyl)-1,2-dihydropyridin-2-iminium dibromide top

Crystal data top

C₁₀H₁₉N₃²⁺·2Br⁻	F(000) = 340
M_r = 341.10	D_x = 1.607 Mg m⁻³
Monoclinic, P2₁	Mo Kα radiation, λ = 0.71073 Å
a = 5.9311 (11) Å	Cell parameters from 1818 reflections
b = 12.456 (2) Å	θ = 5.4–53.4°
c = 9.6807 (18) Å	µ = 5.73 mm⁻¹
β = 99.733 (3)°	T = 293 K
V = 704.9 (2) Å³	Prismatic, colorless
Z = 2	0.45 × 0.34 × 0.20 mm

Data collection top

Bruker SMART APEX CCD diffractometer	2307 independent reflections
Radiation source: fine-focus sealed tube	2054 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.038
ϕ and ω scans	θ_max = 27.0°, θ_min = 2.1°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	h = −7→7
T_min = 0.381, T_max = 1.000	k = −12→15
4117 measured reflections	l = −12→12

Refinement top

Refinement on F²	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F² > 2σ(F²)] = 0.041	H atoms treated by a mixture of independent and constrained refinement
wR(F²) = 0.092	w = 1/[σ²(F_o²) + (0.0533P)²] where P = (F_o² + 2F_c²)/3
S = 0.99	(Δ/σ)_max < 0.001
2307 reflections	Δρ_max = 0.91 e Å⁻³
147 parameters	Δρ_min = −0.71 e Å⁻³
3 restraints	Absolute structure: Flack (1983), 696 Friedel pairs
Primary atom site location: structure-invariant direct methods	Absolute structure parameter: 0.06 (2)

Crystal data top

C₁₀H₁₉N₃²⁺·2Br⁻	V = 704.9 (2) Å³
M_r = 341.10	Z = 2
Monoclinic, P2₁	Mo Kα radiation
a = 5.9311 (11) Å	µ = 5.73 mm⁻¹
b = 12.456 (2) Å	T = 293 K
c = 9.6807 (18) Å	0.45 × 0.34 × 0.20 mm
β = 99.733 (3)°

Data collection top

Bruker SMART APEX CCD diffractometer	2307 independent reflections
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	2054 reflections with I > 2σ(I)
T_min = 0.381, T_max = 1.000	R_int = 0.038
4117 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.041	H atoms treated by a mixture of independent and constrained refinement
wR(F²) = 0.092	Δρ_max = 0.91 e Å⁻³
S = 0.99	Δρ_min = −0.71 e Å⁻³
2307 reflections	Absolute structure: Flack (1983), 696 Friedel pairs
147 parameters	Absolute structure parameter: 0.06 (2)
3 restraints

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

	x	y	z	U_iso*/U_eq
Br1	1.02019 (11)	0.21057 (4)	0.84434 (6)	0.03666 (18)
Br2	0.61945 (10)	0.78903 (5)	0.54550 (7)	0.03742 (19)
N1	0.7631 (8)	0.4733 (4)	0.2958 (5)	0.0269 (11)
N2	0.4665 (11)	0.5923 (5)	0.3096 (7)	0.0398 (14)
N3	0.9054 (9)	0.3672 (4)	0.5746 (5)	0.0291 (11)
H3A	0.7799	0.3302	0.5406	0.044*
H3B	0.9481	0.3518	0.6651	0.044*
H3C	1.0172	0.3496	0.5280	0.044*
C1	0.5506 (11)	0.5110 (5)	0.2454 (6)	0.0295 (14)
C2	0.4223 (13)	0.4609 (6)	0.1291 (7)	0.0404 (17)
H2	0.2766	0.4863	0.0937	0.048*
C3	0.5050 (15)	0.3772 (7)	0.0677 (7)	0.052 (2)
H3	0.4149	0.3427	−0.0072	0.062*
C4	0.7331 (15)	0.3408 (7)	0.1176 (8)	0.052 (2)
H4	0.7975	0.2856	0.0725	0.062*
C5	0.8497 (13)	0.3880 (6)	0.2301 (7)	0.0378 (16)
H5	0.9953	0.3628	0.2661	0.045*
C6	0.9101 (11)	0.5224 (6)	0.4176 (7)	0.0314 (14)
H6A	0.8922	0.5998	0.4119	0.038*
H6B	1.0686	0.5060	0.4131	0.038*
C7	0.8569 (10)	0.4843 (5)	0.5581 (6)	0.0274 (13)
H7	0.6928	0.4945	0.5567	0.033*
C8	0.9855 (11)	0.5495 (6)	0.6818 (7)	0.0369 (16)
H8	0.9549	0.6256	0.6605	0.044*
C9	0.8975 (15)	0.5251 (8)	0.8154 (7)	0.057 (2)
H9A	0.9414	0.4535	0.8456	0.086*
H9B	0.7338	0.5309	0.7994	0.086*
H9C	0.9614	0.5753	0.8867	0.086*
C10	1.2447 (12)	0.5333 (8)	0.6994 (8)	0.057 (2)
H10A	1.3194	0.5787	0.7734	0.086*
H10B	1.2962	0.5514	0.6135	0.086*
H10C	1.2809	0.4596	0.7224	0.086*
H2A	0.355 (12)	0.623 (8)	0.260 (9)	0.09 (4)*
H2B	0.525 (13)	0.636 (6)	0.371 (7)	0.06 (3)*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Br1	0.0508 (4)	0.0348 (4)	0.0231 (3)	−0.0033 (3)	0.0026 (3)	−0.0009 (3)
Br2	0.0309 (3)	0.0355 (4)	0.0448 (4)	0.0023 (3)	0.0033 (3)	−0.0065 (3)
N1	0.033 (3)	0.025 (3)	0.024 (3)	0.001 (2)	0.007 (2)	0.004 (2)
N2	0.040 (4)	0.035 (4)	0.041 (4)	0.006 (3)	−0.002 (3)	−0.003 (3)
N3	0.032 (3)	0.029 (3)	0.026 (3)	−0.004 (2)	0.004 (2)	0.003 (2)
C1	0.041 (4)	0.028 (4)	0.018 (3)	−0.001 (3)	0.002 (3)	0.006 (3)
C2	0.042 (4)	0.051 (5)	0.025 (3)	−0.004 (3)	−0.005 (3)	0.006 (3)
C3	0.074 (5)	0.054 (5)	0.025 (4)	−0.011 (4)	−0.002 (4)	−0.012 (4)
C4	0.077 (6)	0.049 (5)	0.032 (4)	0.006 (4)	0.014 (4)	−0.010 (3)
C5	0.051 (4)	0.038 (4)	0.026 (4)	0.009 (3)	0.012 (3)	0.003 (3)
C6	0.031 (3)	0.032 (4)	0.028 (3)	−0.003 (3)	−0.004 (3)	0.001 (3)
C7	0.021 (3)	0.030 (3)	0.029 (3)	0.001 (2)	−0.001 (2)	0.003 (3)
C8	0.046 (4)	0.030 (4)	0.031 (4)	0.002 (3)	−0.004 (3)	−0.006 (3)
C9	0.066 (5)	0.077 (6)	0.025 (4)	0.014 (5)	−0.003 (4)	−0.015 (4)
C10	0.035 (4)	0.088 (7)	0.043 (5)	−0.016 (4)	−0.008 (3)	−0.014 (5)

Geometric parameters (Å, º) top

Br1—H3B	2.4578	C4—C5	1.325 (10)
Br2—H2B	2.55 (7)	C4—H4	0.9300
N1—C1	1.356 (8)	C5—H5	0.9300
N1—C5	1.380 (8)	C6—C7	1.523 (9)
N1—C6	1.476 (8)	C6—H6A	0.9700
N2—C1	1.329 (9)	C6—H6B	0.9700
N2—H2A	0.84 (8)	C7—C8	1.538 (9)
N2—H2B	0.84 (7)	C7—H7	0.9800
N3—C7	1.490 (8)	C8—C9	1.506 (11)
N3—H3A	0.8900	C8—C10	1.531 (10)
N3—H3B	0.8900	C8—H8	0.9800
N3—H3C	0.8900	C9—H9A	0.9600
C1—C2	1.396 (9)	C9—H9B	0.9600
C2—C3	1.334 (11)	C9—H9C	0.9600
C2—H2	0.9300	C10—H10A	0.9600
C3—C4	1.431 (11)	C10—H10B	0.9600
C3—H3	0.9300	C10—H10C	0.9600

C1—N1—C5	119.8 (6)	C7—C6—H6A	108.8
C1—N1—C6	122.1 (5)	N1—C6—H6B	108.8
C5—N1—C6	118.2 (5)	C7—C6—H6B	108.8
C1—N2—H2A	114 (7)	H6A—C6—H6B	107.7
C1—N2—H2B	133 (6)	N3—C7—C6	109.6 (5)
H2A—N2—H2B	107 (9)	N3—C7—C8	111.9 (5)
C7—N3—H3A	109.5	C6—C7—C8	112.3 (6)
C7—N3—H3B	109.5	N3—C7—H7	107.6
H3A—N3—H3B	109.5	C6—C7—H7	107.6
C7—N3—H3C	109.5	C8—C7—H7	107.6
H3A—N3—H3C	109.5	C9—C8—C10	111.4 (6)
H3B—N3—H3C	109.5	C9—C8—C7	111.3 (6)
N2—C1—N1	119.7 (6)	C10—C8—C7	111.9 (6)
N2—C1—C2	121.4 (7)	C9—C8—H8	107.3
N1—C1—C2	118.8 (7)	C10—C8—H8	107.3
C3—C2—C1	121.2 (7)	C7—C8—H8	107.3
C3—C2—H2	119.4	C8—C9—H9A	109.5
C1—C2—H2	119.4	C8—C9—H9B	109.5
C2—C3—C4	119.7 (7)	H9A—C9—H9B	109.5
C2—C3—H3	120.2	C8—C9—H9C	109.5
C4—C3—H3	120.2	H9A—C9—H9C	109.5
C5—C4—C3	117.9 (7)	H9B—C9—H9C	109.5
C5—C4—H4	121.0	C8—C10—H10A	109.5
C3—C4—H4	121.0	C8—C10—H10B	109.5
C4—C5—N1	122.5 (7)	H10A—C10—H10B	109.5
C4—C5—H5	118.7	C8—C10—H10C	109.5
N1—C5—H5	118.7	H10A—C10—H10C	109.5
N1—C6—C7	113.7 (5)	H10B—C10—H10C	109.5
N1—C6—H6A	108.8

C5—N1—C1—N2	179.3 (6)	C6—N1—C5—C4	−178.0 (7)
C6—N1—C1—N2	−2.4 (9)	C1—N1—C6—C7	82.3 (7)
C5—N1—C1—C2	1.2 (8)	C5—N1—C6—C7	−99.4 (7)
C6—N1—C1—C2	179.5 (6)	N1—C6—C7—N3	64.0 (7)
N2—C1—C2—C3	−177.9 (7)	N1—C6—C7—C8	−170.9 (5)
N1—C1—C2—C3	0.2 (10)	N3—C7—C8—C9	−67.1 (7)
C1—C2—C3—C4	−2.8 (11)	C6—C7—C8—C9	169.2 (6)
C2—C3—C4—C5	4.2 (11)	N3—C7—C8—C10	58.3 (8)
C3—C4—C5—N1	−3.0 (11)	C6—C7—C8—C10	−65.5 (8)
C1—N1—C5—C4	0.3 (10)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N2—H2B···Br2	0.84 (7)	2.55 (7)	3.368 (7)	167 (8)
N2—H2A···Br1ⁱ	0.84 (8)	2.53 (8)	3.357 (6)	168 (10)
N3—H3C···Br2ⁱⁱ	0.89	2.50	3.369 (5)	166
N3—H3B···Br1	0.89	2.46	3.238 (5)	147
N3—H3A···Br2ⁱⁱⁱ	0.89	2.43	3.281 (5)	160
C3—H3···Br1^iv	0.93	3.02	3.892 (8)	157
C4—H4···Br1^v	0.93	2.91	3.748 (8)	150
C6—H6A···Br1^vi	0.97	2.96	3.528 (7)	119
C5—H5···Br2ⁱⁱ	0.93	2.83	3.721 (7)	162
C8—H8···Br2	0.98	2.93	3.793 (7)	147

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

Experimental details

Crystal data
Chemical formula	C₁₀H₁₉N₃²⁺·2Br⁻
M_r	341.10
Crystal system, space group	Monoclinic, P2₁
Temperature (K)	293
a, b, c (Å)	5.9311 (11), 12.456 (2), 9.6807 (18)
β (°)	99.733 (3)
V (Å³)	704.9 (2)
Z	2
Radiation type	Mo Kα
µ (mm⁻¹)	5.73
Crystal size (mm)	0.45 × 0.34 × 0.20

Data collection
Diffractometer	Bruker SMART APEX CCD diffractometer
Absorption correction	Multi-scan (SADABS; Sheldrick, 1996)
T_min, T_max	0.381, 1.000
No. of measured, independent and observed [I > 2σ(I)] reflections	4117, 2307, 2054
R_int	0.038
(sin θ/λ)_max (Å⁻¹)	0.639

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.041, 0.092, 0.99
No. of reflections	2307
No. of parameters	147
No. of restraints	3
H-atom treatment	H atoms treated by a mixture of independent and constrained refinement
Δρ_max, Δρ_min (e Å⁻³)	0.91, −0.71
Absolute structure	Flack (1983), 696 Friedel pairs
Absolute structure parameter	0.06 (2)

Computer programs: SMART (Bruker, 2001), SAINT-Plus (Bruker, 2000), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), SHELXTL (Sheldrick, 2008).

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N2—H2B···Br2	0.84 (7)	2.55 (7)	3.368 (7)	167 (8)
N2—H2A···Br1ⁱ	0.84 (8)	2.53 (8)	3.357 (6)	168 (10)
N3—H3C···Br2ⁱⁱ	0.89	2.50	3.369 (5)	166.2
N3—H3B···Br1	0.89	2.46	3.238 (5)	146.6
N3—H3A···Br2ⁱⁱⁱ	0.89	2.43	3.281 (5)	160.4
C3—H3···Br1^iv	0.93	3.02	3.892 (8)	156.9
C4—H4···Br1^v	0.93	2.91	3.748 (8)	150.2
C6—H6A···Br1^vi	0.97	2.96	3.528 (7)	118.5
C5—H5···Br2ⁱⁱ	0.93	2.83	3.721 (7)	161.9
C8—H8···Br2	0.98	2.93	3.793 (7)	147.2

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

References

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Volume 64| Part 6| June 2008| Page o1025

doi:10.1107/S1600536808012154

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