2-Ethyl-4-methyl-1H-imidazol-3-ium bromide

In the title mol­ecular salt, C₆H₁₁N₂⁺·Br⁻, the components are linked by N—H...Br...H—N hydrogen bonds into C(8)chains of alternating cations and anions propagating in the b-axis direction; these chains are cross-linked in the c-axis direction by weak C—H...Br hydrogen bonds.

Key indicators

Structure: I

• Single-crystal X-ray study
• T = 100 K
• Mean [sigma](C-C) = 0.001 Å
• R factor = 0.019
• wR factor = 0.042
• Data-to-parameter ratio = 42.8

checkCIF/PLATON results

No syntax errors found



Alert level G
PLAT480_ALERT_4_G Long H...A H-Bond Reported H6C      ..BR       .       3.08 Ang.
PLAT912_ALERT_4_G Missing # of FCF Reflections Above STh/L=  0.600         15 Note
PLAT978_ALERT_2_G Number C-C Bonds with Positive Residual Density.          4 Info

   0 ALERT level A = Most likely a serious problem - resolve or explain
   0 ALERT level B = A potentially serious problem, consider carefully
   0 ALERT level C = Check. Ensure it is not caused by an omission or oversight
   3 ALERT level G = General information/check it is not something unexpected

   0 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   1 ALERT type 2 Indicator that the structure model may be wrong or deficient
   0 ALERT type 3 Indicator that the structure quality may be low
   2 ALERT type 4 Improvement, methodology, query or suggestion
   0 ALERT type 5 Informative message, check

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Computing details

Data collection: APEX2 (Bruker, 2014); cell refinement: SAINT (Bruker, 2014); data reduction: SAINT (Bruker, 2014); program(s) used to solve structure: SHELXT (Sheldrick 2015a); program(s) used to refine structure: SHELXL2018/3 (Sheldrick, 2015b); molecular graphics: SHELXTL (Sheldrick 2008); software used to prepare material for publication: SHELXTL (Sheldrick 2008).

2-Ethyl-4-methyl-1H-imidazol-3-ium bromide

Crystal data

C6H11N2^+·Br^−	F(000) = 384
Mr = 191.08	Dx = 1.574 Mg m^−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
a = 6.8432 (6) Å	Cell parameters from 9911 reflections
b = 15.5962 (13) Å	θ = 3.0–36.4°
c = 7.5748 (7) Å	µ = 5.02 mm^−1
β = 94.360 (4)°	T = 100 K
V = 806.10 (12) Å^3	Prism, colorless
Z = 4	0.25 × 0.15 × 0.15 mm

Data collection

Bruker APEXII CCD diffractometer	3324 reflections with I > 2σ(I)
φ and ω scans	Rint = 0.027
Absorption correction: multi-scan (SADABS; Krause et al., 2015)	θmax = 36.5°, θmin = 2.6°
Tmin = 0.571, Tmax = 0.747	h = −11→11
24466 measured reflections	k = −26→26
3936 independent reflections	l = −12→12

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.019	Hydrogen site location: mixed
wR(F^2) = 0.042	H atoms treated by a mixture of independent and constrained refinement
S = 1.03	w = 1/[σ^2(Fo^2) + (0.0166P)^2 + 0.2838P] where P = (Fo^2 + 2Fc^2)/3
3936 reflections	(Δ/σ)max < 0.001
92 parameters	Δρmax = 0.53 e Å^−3
0 restraints	Δρmin = −0.36 e Å^−3

Special details

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes.

Refinement. All hydrogen atoms were located in difference Fourier maps and those attached to N were refined isotropically. Those attached to carbon atoms were refined in idealized geometry using a riding model with with atomic displacement parameters of U_iso(H) = 1.2U_eq(C) [for CH₃, 1.5U_eq(C)] with C—H distances of 0.95 to 0.99 Å.

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

	x	y	z	Uiso*/Ueq
Br	0.28697 (2)	0.12428 (2)	0.15497 (2)	0.01551 (3)
N1	0.63750 (12)	0.41897 (5)	0.31428 (11)	0.01531 (14)
H1N	0.631 (3)	0.4721 (11)	0.314 (2)	0.037 (5)*
C2	0.49850 (13)	0.36487 (6)	0.25237 (11)	0.01449 (16)
N3	0.56746 (12)	0.28564 (5)	0.28135 (11)	0.01568 (13)
H3N	0.503 (2)	0.2457 (9)	0.254 (2)	0.026 (4)*
C4	0.75365 (14)	0.28880 (6)	0.36671 (13)	0.01609 (15)
C5	0.79682 (13)	0.37312 (6)	0.38762 (13)	0.01694 (15)
H5A	0.914514	0.396452	0.442412	0.020*
C6	0.86990 (17)	0.21085 (7)	0.41511 (15)	0.02302 (19)
H6A	0.793013	0.172611	0.485620	0.035*
H6B	0.990828	0.227271	0.484469	0.035*
H6C	0.902634	0.181162	0.307207	0.035*
C7	0.30245 (14)	0.38674 (7)	0.16718 (13)	0.01933 (17)
H7A	0.201752	0.353879	0.225655	0.023*
H7B	0.296411	0.368801	0.041511	0.023*
C8	0.25416 (18)	0.48149 (8)	0.17584 (17)	0.0284 (2)
H8A	0.120458	0.491216	0.123853	0.043*
H8B	0.346648	0.514173	0.109621	0.043*
H8C	0.264154	0.500287	0.299648	0.043*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Br	0.01508 (4)	0.01385 (4)	0.01734 (4)	0.00039 (3)	−0.00055 (3)	−0.00153 (3)
N1	0.0149 (3)	0.0141 (3)	0.0167 (3)	−0.0012 (3)	−0.0004 (3)	−0.0013 (3)
C2	0.0152 (4)	0.0147 (4)	0.0135 (3)	−0.0015 (3)	0.0006 (3)	−0.0010 (3)
N3	0.0159 (3)	0.0150 (3)	0.0162 (3)	−0.0026 (3)	0.0014 (3)	−0.0022 (3)
C4	0.0150 (4)	0.0173 (4)	0.0160 (4)	0.0012 (3)	0.0015 (3)	−0.0011 (3)
C5	0.0131 (3)	0.0187 (4)	0.0188 (4)	−0.0006 (3)	−0.0001 (3)	−0.0023 (3)
C6	0.0240 (5)	0.0210 (4)	0.0244 (5)	0.0076 (4)	0.0038 (4)	0.0006 (4)
C7	0.0166 (4)	0.0238 (4)	0.0168 (4)	−0.0007 (3)	−0.0036 (3)	−0.0005 (3)
C8	0.0238 (5)	0.0265 (5)	0.0331 (6)	0.0058 (4)	−0.0089 (4)	0.0014 (4)

Geometric parameters (Å, º)

N1—C2	1.3299 (12)	C6—H6A	0.9800
N1—C5	1.3844 (13)	C6—H6B	0.9800
N1—H1N	0.829 (17)	C6—H6C	0.9800
C2—N3	1.3351 (12)	C7—C8	1.5167 (16)
C2—C7	1.4836 (13)	C7—H7A	0.9900
N3—C4	1.3851 (12)	C7—H7B	0.9900
N3—H3N	0.780 (16)	C8—H8A	0.9800
C4—C5	1.3545 (14)	C8—H8B	0.9800
C4—C6	1.4836 (14)	C8—H8C	0.9800
C5—H5A	0.9500
C2—N1—C5	109.52 (8)	H6A—C6—H6B	109.5
C2—N1—H1N	126.7 (12)	C4—C6—H6C	109.5
C5—N1—H1N	123.7 (12)	H6A—C6—H6C	109.5
N1—C2—N3	107.15 (8)	H6B—C6—H6C	109.5
N1—C2—C7	127.33 (8)	C2—C7—C8	113.45 (8)
N3—C2—C7	125.52 (8)	C2—C7—H7A	108.9
C2—N3—C4	110.17 (8)	C8—C7—H7A	108.9
C2—N3—H3N	120.7 (12)	C2—C7—H7B	108.9
C4—N3—H3N	129.1 (12)	C8—C7—H7B	108.9
C5—C4—N3	105.90 (8)	H7A—C7—H7B	107.7
C5—C4—C6	131.20 (10)	C7—C8—H8A	109.5
N3—C4—C6	122.89 (9)	C7—C8—H8B	109.5
C4—C5—N1	107.24 (8)	H8A—C8—H8B	109.5
C4—C5—H5A	126.4	C7—C8—H8C	109.5
N1—C5—H5A	126.4	H8A—C8—H8C	109.5
C4—C6—H6A	109.5	H8B—C8—H8C	109.5
C4—C6—H6B	109.5
C5—N1—C2—N3	−1.28 (10)	N3—C4—C5—N1	−0.29 (11)
C5—N1—C2—C7	178.55 (9)	C6—C4—C5—N1	178.35 (10)
N1—C2—N3—C4	1.11 (10)	C2—N1—C5—C4	0.98 (11)
C7—C2—N3—C4	−178.73 (9)	N1—C2—C7—C8	−8.03 (15)
C2—N3—C4—C5	−0.50 (11)	N3—C2—C7—C8	171.77 (10)
C2—N3—C4—C6	−179.27 (9)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1N···Br^i	0.829 (17)	2.446 (17)	3.2490 (9)	163.3 (16)
N3—H3N···Br	0.780 (16)	2.485 (16)	3.2642 (8)	176.6 (16)
C5—H5A···Br^ii	0.95	2.93	3.7842 (10)	151
C6—H6C···Br^iii	0.98	3.08	3.8349 (11)	135
C7—H7B···Br^iv	0.99	2.93	3.8771 (11)	161

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