(1-Hy­droxy­ethyl­idene)(meth­yl)aza­nium bromide–N-methyl­acetamide (1/1)

Abstract

The asymmetric unit of the organic hybrid salt, C₃H₈NO⁺·Br⁻·C₃H₇NO, comprises an N-methyl­acetamide cation, a N-methyl­acetamide mol­ecule and a bromide anion. The amide species are linked head-to-head through a short O⋯H⋯O hydrogen bond, giving a monocation, which is extended by N—H⋯Br hydrogen bonds into chains along the b-axis direction.

Related literature  

For general background to frameworks and structural phase transitions, see: Ye et al. (2009 ▶); Zhang et al. (2009 ▶). For the structure of the hemihydro­chloride of N-methyl­acetamide, see: Jaber et al. (1983 ▶).

Experimental  

Crystal data  

• C₃H₈NO⁺·Br⁻·C₃H₇NO

• M _r = 227.11

• Orthorhombic,

• a = 6.8830 (14) Å

• b = 23.029 (5) Å

• c = 13.291 (3) Å

• V = 2106.7 (8) ų

• Z = 8

• Mo Kα radiation

• μ = 3.87 mm⁻¹

• T = 298 K

• 0.20 × 0.20 × 0.20 mm

Data collection  

• Rigaku SCXmini diffractometer

• Absorption correction: multi-scan (CrystalClear; Rigaku, 2005 ▶) T _min = 0.461, T _max = 0.480

• 10344 measured reflections

• 1311 independent reflections

• 858 reflections with I > 2σ(I)

• R _int = 0.073

Refinement  

• R[F ² > 2σ(F ²)] = 0.044

• wR(F ²) = 0.101

• S = 1.06

• 1311 reflections

• 80 parameters

• H atoms treated by a mixture of independent and constrained refinement

• Δρ_max = 0.40 e Å⁻³

• Δρ_min = −0.25 e Å⁻³

Data collection: CrystalClear (Rigaku, 2005 ▶); cell refinement: CrystalClear; data reduction: CrystalClear; program(s) used to solve structure: SHELXTL (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL.

Supplementary Material

Supplementary material file. DOI: 10.1107/S1600536812016984/zs2188Isup3.cml

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Table 1. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N2—H2⋯Br1i	0.89 (5)	2.51 (5)	3.402 (5)	178 (5)
O1—H3⋯O2	1.16 (7)	1.27 (7)	2.437 (4)	179 (6)
N1—H1⋯Br1	0.83 (4)	2.48 (5)	3.304 (4)	174 (5)

Symmetry code: (i) .

supplementary crystallographic information

Comment

Recent studies have revealed that small molecular compounds which have one or more amidogens may possess dielectric-ferroelectric properties (Ye et al., 2009; Zhang et al., 2009). Our research has been aimed at the synthesis of aromatic amidogen-containing compounds which may possess these properties. As part of our ongoing studies, we report here the crystal structure of the title compound, C₆H₁₅N₂⁺ Br^-, the hydrobromide of N-methylacetamide The structure of the analogous hydrochloride of N-methylacetamide has previously been reported (Jaber et al., 1983).

The structure of the title compound, determined at ambient temperature (298 K), reveals that the asymmetric unit contains an N-methylacetamide cation, a N-methylacetamide molecule and a bromide anion (Fig. 1). The transferred proton is found within a short O1···H···O2 hydrogen bond (Table 1) linking the two molecules head-to-head in the monocation. These cations and the bromide anions form N—H···Br hydrogen-bonding associations giving one-dimensional chains which extend along the b-cell direction (Fig. 2). Unfortunately, the dielectric constant of the title compound as a function of temperature indicates that the permittivity is basically temperature-independent below the melting point (368-369 K) and that it has no dielectric disuniform from 80 K to 405 K.

Experimental

The N-methylacetamide(1.46 g, 20 mmol) and hydrobromic acid (1.62 g, 20 mmol) was combined in 30 ml of aqueous solution. The mixture was stirred for 30 min to allow complete reaction and good quality blocky single crystals were obtained by slow evaporation after ca. two weeks (yield, 42%)

Refinement

The H atoms on the amide groups and the H within the short intramolecular O···H···O hydrogen bond were located in difference-Fourier analysis and their positional and isotropic displacement parameters were refined. The methyl H atoms were placed in geometrically idealized positions and constrained to ride on their parent atoms with C—H = 0.96 Å and with U_iso(H) = 1.5U_eq(C).

Figures

Fig. 1.

The molecular structure of the title compound, with the inter-species hydrogen bonds shown as dashed lines. Displacement ellipsoids are drawn at the 30% probability level.

Fig. 2.

A view of the packing of the title compound, showing the hydrogen-bonded chain extension along the b axis. Dashed lines indicate hydrogen bonds.

Crystal data

C3H8NO+·Br−·C3H7NO	F(000) = 928
Mr = 227.11	Dx = 1.432 Mg m−3
Orthorhombic, Cmca	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -C 2bc 2	Cell parameters from 3638 reflections
a = 6.8830 (14) Å	θ = 3.0–27.5°
b = 23.029 (5) Å	µ = 3.87 mm−1
c = 13.291 (3) Å	T = 298 K
V = 2106.7 (8) Å3	Block, colorless
Z = 8	0.20 × 0.20 × 0.20 mm

Data collection

Rigaku SCXmini diffractometer	858 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.073
Graphite monochromator	θmax = 27.5°, θmin = 3.1°
ω scans	h = −8→8
Absorption correction: multi-scan (CrystalClear; Rigaku, 2005)	k = −29→29
Tmin = 0.461, Tmax = 0.480	l = −17→17
10344 measured reflections	2 standard reflections every 150 reflections
1311 independent reflections	intensity decay: none

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)] = 0.044	Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.101	H atoms treated by a mixture of independent and constrained refinement
S = 1.06	w = 1/[σ2(Fo2) + (0.0445P)2 + 0.3335P] where P = (Fo2 + 2Fc2)/3
1311 reflections	(Δ/σ)max < 0.001
80 parameters	Δρmax = 0.40 e Å−3
0 restraints	Δρmin = −0.25 e Å−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.

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 (Ų)

	x	y	z	Uiso*/Ueq	Occ. (<1)
Br1	0.5000	0.147343 (18)	0.08336 (4)	0.0651 (3)
H1	0.5000	0.233 (2)	0.196 (4)	0.069 (16)*
N1	0.5000	0.25929 (16)	0.2388 (3)	0.0553 (10)
O1	0.5000	0.35425 (13)	0.2661 (3)	0.0714 (10)
C2	0.5000	0.4921 (2)	0.2594 (4)	0.0578 (12)
H2	0.5000	0.573 (2)	0.277 (4)	0.092 (19)*
N2	0.5000	0.54618 (17)	0.2301 (3)	0.0635 (11)
O2	0.5000	0.45173 (14)	0.1949 (3)	0.0717 (10)
C5	0.5000	0.31197 (19)	0.2038 (3)	0.0506 (11)
C6	0.5000	0.24321 (19)	0.3449 (3)	0.0658 (14)
H7A	0.5414	0.2758	0.3846	0.099*	0.50
H7B	0.5874	0.2113	0.3552	0.099*	0.50
H7C	0.3712	0.2320	0.3647	0.099*	0.50
C4	0.5000	0.3231 (2)	0.0925 (3)	0.0695 (15)
H8A	0.5940	0.3526	0.0769	0.104*	0.50
H8B	0.3734	0.3359	0.0719	0.104*	0.50
H8C	0.5326	0.2880	0.0575	0.104*	0.50
C3	0.5000	0.4790 (2)	0.3693 (4)	0.0724 (15)
H9A	0.4649	0.5133	0.4061	0.109*	0.50
H9B	0.6273	0.4666	0.3894	0.109*	0.50
H9C	0.4078	0.4488	0.3831	0.109*	0.50
C1	0.5000	0.5647 (2)	0.1246 (4)	0.0804 (16)
H10A	0.6291	0.5759	0.1053	0.121*	0.50
H10B	0.4138	0.5972	0.1165	0.121*	0.50
H10C	0.4571	0.5332	0.0828	0.121*	0.50
H3	0.5000	0.401 (3)	0.231 (5)	0.15 (3)*

Atomic displacement parameters (Ų)

	U11	U22	U33	U12	U13	U23
Br1	0.0934 (5)	0.0415 (3)	0.0606 (4)	0.000	0.000	−0.0013 (2)
N1	0.074 (3)	0.039 (2)	0.052 (2)	0.000	0.000	−0.001 (2)
O1	0.124 (3)	0.0397 (18)	0.051 (2)	0.000	0.000	−0.0049 (15)
C2	0.060 (3)	0.046 (3)	0.068 (3)	0.000	0.000	−0.005 (3)
N2	0.077 (3)	0.042 (2)	0.071 (3)	0.000	0.000	−0.007 (2)
O2	0.115 (3)	0.0394 (17)	0.061 (2)	0.000	0.000	−0.0052 (16)
C5	0.054 (3)	0.045 (3)	0.052 (3)	0.000	0.000	−0.002 (2)
C6	0.084 (4)	0.054 (3)	0.059 (3)	0.000	0.000	0.008 (2)
C4	0.099 (4)	0.057 (3)	0.052 (3)	0.000	0.000	0.003 (2)
C3	0.104 (4)	0.055 (3)	0.058 (3)	0.000	0.000	−0.003 (3)
C1	0.100 (4)	0.062 (3)	0.080 (4)	0.000	0.000	0.022 (3)

Geometric parameters (Å, º)

N1—C5	1.299 (5)	C6—H7B	0.9600
N1—C6	1.458 (6)	C6—H7C	0.9600
N1—H1	0.83 (4)	C4—H8A	0.9600
O1—C5	1.278 (5)	C4—H8B	0.9600
O1—H3	1.16 (7)	C4—H8C	0.9600
C2—O2	1.266 (5)	C3—H9A	0.9600
C2—N2	1.304 (5)	C3—H9B	0.9600
C2—C3	1.491 (6)	C3—H9C	0.9600
N2—C1	1.466 (6)	C1—H10A	0.9600
N2—H2	0.89 (5)	C1—H10B	0.9600
C5—C4	1.502 (6)	C1—H10C	0.9600
C6—H7A	0.9600
C5—N1—C6	125.7 (4)	H7B—C6—H7C	109.5
C5—N1—H1	116 (4)	C5—C4—H8A	109.5
C6—N1—H1	118 (4)	C5—C4—H8B	109.5
C5—O1—H3	116 (3)	H8A—C4—H8B	109.5
O2—C2—N2	119.9 (5)	C5—C4—H8C	109.5
O2—C2—C3	121.0 (4)	H8A—C4—H8C	109.5
N2—C2—C3	119.0 (4)	H8B—C4—H8C	109.5
C2—N2—C1	124.3 (5)	C2—C3—H9A	109.5
C2—N2—H2	118 (4)	C2—C3—H9B	109.5
C1—N2—H2	118 (4)	H9A—C3—H9B	109.5
C2—O2—H3	115 (3)	C2—C3—H9C	109.5
O1—C5—N1	118.6 (4)	H9A—C3—H9C	109.5
O1—C5—C4	120.6 (4)	H9B—C3—H9C	109.5
N1—C5—C4	120.8 (4)	N2—C1—H10A	109.5
N1—C6—H7A	109.5	N2—C1—H10B	109.5
N1—C6—H7B	109.5	H10A—C1—H10B	109.5
H7A—C6—H7B	109.5	N2—C1—H10C	109.5
N1—C6—H7C	109.5	H10A—C1—H10C	109.5
H7A—C6—H7C	109.5	H10B—C1—H10C	109.5
C6—N1—C5—O1	0.00	C1—N2—C2—O2	0.00
C6—N1—C5—C4	180.00	C1—N2—C2—C3	180.00

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N2—H2···Br1i	0.89 (5)	2.51 (5)	3.402 (5)	178 (5)
O1—H3···O2	1.16 (7)	1.27 (7)	2.437 (4)	179 (6)
N1—H1···Br1	0.83 (4)	2.48 (5)	3.304 (4)	174 (5)

Symmetry code: (i) x, y+1/2, −z+1/2.