Crystal structure of 2-cyano-1-methyl­pyridinium bromide

Abstract

In the title mol­ecular salt, C₇H₇N₂ ⁺·Br⁻, all the non-H atoms lie on crystallographic mirror planes. The packing consists of (010) cation–anion layers, with the cations forming dimeric units via very weak pairwise C—H⋯N inter­actions. Weak C—H⋯Br inter­actions link the cations to the anions.

Related literature  

For structures of other salts of the 2-cyano-1-methyl­pyridinium cation, see: Koplitz et al. (2012 ▸); Kammer et al. (2013 ▸); Vaccaro et al. (2015 ▸). For structures of salts of the isomeric 2-cyano­anilinium cation, see: Oueslati et al. (2005 ▸); Cui & Wen (2008 ▸); Zhang, L. (2009 ▸); Zhang, Y. (2009 ▸); Cui & Chen (2010 ▸); Vumbaco et al. (2013 ▸).

Experimental  

Crystal data  

• C₇H₇N₂ ⁺·Br⁻

• M _r = 199.06

• Monoclinic,

• a = 13.3039 (12) Å

• b = 6.5892 (6) Å

• c = 9.3753 (8) Å

• β = 92.419 (1)°

• V = 821.13 (13) ų

• Z = 4

• Mo Kα radiation

• μ = 4.93 mm⁻¹

• T = 150 K

• 0.20 × 0.15 × 0.06 mm

Data collection  

• Bruker SMART APEX CCD diffractometer

• Absorption correction: multi-scan (TWINABS; Sheldrick, 2009 ▸) T _min = 0.44, T _max = 0.74

• 22367 measured reflections

• 1179 independent reflections

• 1084 reflections with I > 2σ(I)

• R _int = 0.021

Refinement  

• R[F ² > 2σ(F ²)] = 0.023

• wR(F ²) = 0.048

• S = 1.02

• 1179 reflections

• 62 parameters

• H-atom parameters constrained

• Δρ_max = 0.51 e Å⁻³

• Δρ_min = −0.44 e Å⁻³

Data collection: APEX2 (Bruker, 2014 ▸); cell refinement: SAINT (Bruker, 2014 ▸); data reduction: SAINT and CELL_NOW (Sheldrick, 2008a ▸); program(s) used to solve structure: SHELXT (Sheldrick, 2015a ▸); program(s) used to refine structure: SHELXL2014 (Sheldrick, 2015b ▸); molecular graphics: DIAMOND (Brandenburg & Putz, 2012 ▸); software used to prepare material for publication: SHELXTL (Sheldrick, 2008b ▸).

Supplementary Material

CCDC reference: 1430625

Additional supporting information: crystallographic information; 3D view; checkCIF report

Table 1. Hydrogen-bond geometry (, ).

DHA	DH	HA	D A	DHA
C5H5N2i	0.95	2.66	3.549(3)	155
C1H1ABr1ii	0.98	2.96	3.876(2)	156
C2H2Br1ii	0.95	2.66	3.586(2)	166
C3H3Br1iii	0.95	2.77	3.711(2)	170

Symmetry codes: (i) ; (ii) ; (iii) .

supplementary crystallographic information

S1. Comment

The cation in the title compound has crystallographically imposed mirror symmetry with the methyl H atoms slightly disordered about the mirror. The packing thus consists of cation/anion layers (Fig. 2) with the cations forming dimeric units via weak, pairwise C5—H5···N2 interactions (Fig. 3 and Table 1). Within the layers weak C—H···Br interactions tie the cations and anions together (Fig. 3 and Table 1).

S2. Experimental

2-Cyanopyridine (4.04 g, 38.8 mmol) was first melted in a warm water bath and then dissolved in toluene (15 ml). Gaseous bromomethane was condensed (roughly 5 ml, 170 mmol) and added to this solution slowly. The reaction mixture was thoroughly mixed to yield a light amber homogenous solution and left to evaporate slowly. Light yellow shiny flakes of 2-cyano-1-methylpyridinium bromide (m.p. 196.4–197.4 C) were collected by vacuum filtration.

S3. Refinement

H-atoms attached to carbon were placed in calculated positions (C—H = 0.95 - 0.98 Å). All were included as riding contributions with isotropic displacement parameters 1.2 - 1.5 times those of the attached atoms. Trial refinements with the single-component reflection file extracted from the full dataset with TWINABS and with the full, 2-component reflection file indicated the former refinement to be superior.

Figures

Fig. 1.

The title compound with labeling scheme and 50% probability ellipsoids.

Fig. 2.

Packing viewed down the c axis showing the layer structure.

Fig. 3.

Packing viewed down the b axis showing the weak C—H···N (blue dotted lines) and C—H···Br (orange dotted lines) interactions.

Crystal data

C7H7N2+·Br−	F(000) = 392
Mr = 199.06	Dx = 1.610 Mg m−3
Monoclinic, C2/m	Mo Kα radiation, λ = 0.71073 Å
a = 13.3039 (12) Å	Cell parameters from 9936 reflections
b = 6.5892 (6) Å	θ = 2.2–29.1°
c = 9.3753 (8) Å	µ = 4.93 mm−1
β = 92.419 (1)°	T = 150 K
V = 821.13 (13) Å3	Block, colourless
Z = 4	0.20 × 0.15 × 0.06 mm

Data collection

Bruker SMART APEX CCD diffractometer	1179 independent reflections
Radiation source: fine-focus sealed tube	1084 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.021
Detector resolution: 8.3660 pixels mm-1	θmax = 29.1°, θmin = 2.2°
φ and ω scans	h = −18→18
Absorption correction: multi-scan (TWINABS; Sheldrick, 2009)	k = −8→8
Tmin = 0.44, Tmax = 0.74	l = −12→12
22367 measured reflections

Refinement

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)] = 0.023	Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.048	H-atom parameters constrained
S = 1.02	w = 1/[σ2(Fo2) + (0.0234P)2] where P = (Fo2 + 2Fc2)/3
1179 reflections	(Δ/σ)max = 0.001
62 parameters	Δρmax = 0.51 e Å−3
0 restraints	Δρmin = −0.44 e Å−3

Special details

Experimental. The diffraction data were obtained from 3 sets of 400 frames, each of width 0.5° in ω, colllected at φ = 0.00, 90.00 and 180.00° and 2 sets of 800 frames, each of width 0.45° in φ, collected at ω = -30.00 and 210.00°. The scan time was 20 sec/frame. Analysis of 1897 reflections having I/σ(I) > 13 and chosen from the full data set with CELL_NOW (Sheldrick, 2008a) showed the crystal to belong to the monoclinic system and to be twinned by a 180 ° rotation about a*. The raw data were processed using the multi-component version of SAINT under control of the two-component orientation file generated by CELL_NOW.

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. H-atoms attached to carbon were placed in calculated positions (C—H = 0.95 - 0.98 Å). All were included as riding contributions with isotropic displacement parameters 1.2 - 1.5 times those of the attached atoms. Trial refinements with the single-component reflection file extracted from the full dataset with TWINABS and with the full, 2-component reflection file indicated the former refinement to be superior.

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

	x	y	z	Uiso*/Ueq	Occ. (<1)
N1	0.29873 (14)	0.0000	0.32868 (18)	0.0177 (4)
N2	0.53530 (17)	0.0000	0.1900 (3)	0.0399 (6)
C1	0.36322 (18)	0.0000	0.4616 (2)	0.0239 (5)
H1A	0.3212	0.0177	0.5440	0.036*	0.5
H1B	0.4118	0.1116	0.4584	0.036*	0.5
H1C	0.3993	−0.1293	0.4701	0.036*	0.5
C2	0.19853 (17)	0.0000	0.3369 (2)	0.0218 (5)
H2	0.1698	0.0000	0.4280	0.026*
C3	0.13619 (18)	0.0000	0.2157 (2)	0.0269 (5)
H3	0.0652	0.0000	0.2229	0.032*
C4	0.17863 (19)	0.0000	0.0830 (3)	0.0273 (5)
H4	0.1368	0.0000	−0.0017	0.033*
C5	0.28191 (18)	0.0000	0.0749 (2)	0.0237 (5)
H5	0.3120	0.0000	−0.0152	0.028*
C6	0.34090 (17)	0.0000	0.1994 (2)	0.0198 (4)
C7	0.44985 (19)	0.0000	0.1969 (3)	0.0280 (5)
Br1	0.36532 (2)	0.5000	0.29528 (2)	0.02252 (9)

Atomic displacement parameters (Ų)

	U11	U22	U33	U12	U13	U23
N1	0.0207 (9)	0.0176 (8)	0.0152 (9)	0.000	0.0033 (7)	0.000
N2	0.0292 (12)	0.0484 (15)	0.0431 (14)	0.000	0.0139 (10)	0.000
C1	0.0261 (12)	0.0271 (12)	0.0182 (11)	0.000	−0.0025 (9)	0.000
C2	0.0220 (11)	0.0245 (11)	0.0196 (11)	0.000	0.0076 (8)	0.000
C3	0.0219 (11)	0.0337 (13)	0.0251 (12)	0.000	0.0018 (9)	0.000
C4	0.0300 (13)	0.0314 (13)	0.0203 (11)	0.000	−0.0022 (9)	0.000
C5	0.0315 (13)	0.0232 (11)	0.0170 (10)	0.000	0.0085 (9)	0.000
C6	0.0207 (11)	0.0178 (10)	0.0216 (11)	0.000	0.0080 (8)	0.000
C7	0.0274 (13)	0.0294 (13)	0.0280 (13)	0.000	0.0104 (10)	0.000
Br1	0.02982 (14)	0.02142 (12)	0.01687 (12)	0.000	0.00747 (8)	0.000

Geometric parameters (Å, º)

N1—C2	1.339 (3)	C2—H2	0.9500
N1—C6	1.357 (3)	C3—C4	1.388 (3)
N1—C1	1.482 (3)	C3—H3	0.9500
N2—C7	1.141 (3)	C4—C5	1.379 (3)
C1—H1A	0.9800	C4—H4	0.9500
C1—H1B	0.9800	C5—C6	1.379 (3)
C1—H1C	0.9800	C5—H5	0.9500
C2—C3	1.378 (3)	C6—C7	1.451 (3)
C2—N1—C6	120.12 (19)	C2—C3—H3	120.5
C2—N1—C1	119.61 (18)	C4—C3—H3	120.5
C6—N1—C1	120.28 (18)	C5—C4—C3	119.5 (2)
N1—C1—H1A	109.5	C5—C4—H4	120.2
N1—C1—H1B	109.5	C3—C4—H4	120.2
H1A—C1—H1B	109.5	C6—C5—C4	119.1 (2)
N1—C1—H1C	109.5	C6—C5—H5	120.4
H1A—C1—H1C	109.5	C4—C5—H5	120.4
H1B—C1—H1C	109.5	N1—C6—C5	120.9 (2)
N1—C2—C3	121.25 (19)	N1—C6—C7	117.8 (2)
N1—C2—H2	119.4	C5—C6—C7	121.3 (2)
C3—C2—H2	119.4	N2—C7—C6	177.7 (3)
C2—C3—C4	119.1 (2)
C6—N1—C2—C3	0.000 (1)	C1—N1—C6—C5	180.000 (1)
C1—N1—C2—C3	180.000 (1)	C2—N1—C6—C7	180.000 (1)
N1—C2—C3—C4	0.000 (1)	C1—N1—C6—C7	0.000 (1)
C2—C3—C4—C5	0.000 (1)	C4—C5—C6—N1	0.000 (1)
C3—C4—C5—C6	0.000 (1)	C4—C5—C6—C7	180.0
C2—N1—C6—C5	0.000 (1)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
C5—H5···N2i	0.95	2.66	3.549 (3)	155
C1—H1A···Br1ii	0.98	2.96	3.876 (2)	156
C2—H2···Br1ii	0.95	2.66	3.586 (2)	166
C3—H3···Br1iii	0.95	2.77	3.711 (2)	170

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