1-Butyl­benzimidazolium nitrate

The title salt, C₁₁H₁₅N₂⁺·NO₃⁻, was prepared from benzimid­azole by alkyl­ation with n-butane iodide followed by reaction with nitric acid. In the crystal structure, N—H...O hydrogen bonds between the 1-butyl­benzimidazolium cations and nitrate anions are observed.

Key indicators

• Single-crystal X-ray study
• T = 293 K
• Mean [sigma](C-C) = 0.002 Å
• R factor = 0.039
• wR factor = 0.115
• Data-to-parameter ratio = 14.0

checkCIF/PLATON results

No syntax errors found



Alert level C
ABSTM02_ALERT_3_C  The ratio of expected to reported Tmax/Tmin(RR') is < 0.90
            Tmin and Tmax reported:      0.784     1.000
            Tmin(prime) and Tmax expected:      0.977     0.981
            RR(prime) =      0.787
            Please check that your absorption correction is appropriate.
PLAT061_ALERT_3_C Tmax/Tmin Range Test RR' too Large .............       0.79
PLAT062_ALERT_4_C Rescale T(min) & T(max) by .....................       0.98
PLAT125_ALERT_4_C No _symmetry_space_group_name_Hall Given .......          ?
PLAT152_ALERT_1_C Supplied and Calc Volume s.u. Inconsistent .....          ?
PLAT242_ALERT_2_C Check Low       Ueq as Compared to Neighbors for         N3

Alert level G
PLAT199_ALERT_1_G Check the Reported _cell_measurement_temperature        293 K
PLAT200_ALERT_1_G Check the Reported _diffrn_ambient_temperature .        293 K

   0 ALERT level A = In general: serious problem
   0 ALERT level B = Potentially serious problem
   6 ALERT level C = Check and explain
   2 ALERT level G = General alerts; check

   3 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
   2 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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S1. Comment

In crystal engineering the most important driving forces are coordination, (Losier & Zaworotko, 1996 and Ockwig et al., 2005.) however, some weak interactions, such as hydrogen bonding (Juan & Lee, 1999.) often affect the structures of complexes, and they can further link discrete subunits or low-dimentional entities into high-dimensional supramolecular networks. Imidazole groups play important roles in biological systems and constitute most of the metal binding sites of metalloenzymes (Sundberg & Martin, 1974). We are interested in the benzimidazole compounds with hydrogen bonds. Herein, we report the synthesis and crystal structure of 1-butylbenzimidazolium nitrate (2). Benzimidazole was reacted with n-butane iodide to form 1-butylbenzimidazole (1), and 1-butylbenzimidazole was further reacted with nitric acid to afford 1-butylbenzimidazolium nitrate (2). The crystals of (2) suitable for X-ray diffraction were obtained by evaporating slowly a CH₃OH solution at room temperature. In the molecular structure of 2 (Figure 1), the N(1)—C(1), N(1)—C(7), N(2)—C(6) and N(2)—C(7) bond distances are 1.3846 (19), 1.315 (2), 1.3897 (19) and 1.323 (2) Å, respectively, which are similar to those observed in 1-allylimidazole (Kurdziel et al., 2000.), and there exists N1—H1···O3 hydrogen bonds between 1-butylbenzimidazolium ion and nitrate (Table 1).

Related literature

For related literature, see: Juan & Lee (1999); Kurdziel & Glowiak (2000); Losier & Zaworotko (1996); Ockwig et al. (2005); Sundberg & Martin (1974).

S2. Experimental

A 1,4-dioxane solution (50 ml) of benzimidazole (3.662 g, 31.000 mmol) was added to a suspension of oil-free sodium hydride (1.364 g, 34.000 mmol) in 1, 4-dioxane (50 ml) and stirred for 1 h at 90°C. Then a 1, 4-dioxane (50 ml) solution of n-butane iodide (5.152 g, 28.000 mmol) was added dropwise to above the solution. The mixture was stirred for 22 h at 90°C, and a brown solution was obtained. The solvent was removed with a rotary evaporator and H₂O (100 ml) was added to the residue. Then the solution was extracted with CH₂Cl₂ (100 ml), and the extracting solution was dried with anhydrous MgSO₄. After removing CH₂Cl₂, a yellow liquid of 1-butylbenzimidazole was obtained. Yield: 4.591 g (85%). 1-butylbenzimidazole (2.000 g, 9.603 mmol) was reacted with nitric acid to afford 1-butylbenzimidazolium nitrate (2) as a pale yellow solid. Yield: 2.614 g (96%); mp: 258–260°C. Anal. Calcd for C₁₁H₁₅N₃O₃: C 55.69, H 6.37, N 17.71%; found: C 55.48, H 6.22, N 17.65%.

S3. Refinement

All H atoms were initially located in a difference Fourier map. All H atoms were placed in geometrically idealized positions and constrained to ride on their parent atoms with C—H distances in the range 0.93–0.98 Å and U_iso(H) = 1.2U_eq(C).

Computing details

Data collection: SMART (Bruker, 1998); cell refinement: SAINT (Bruker, 1998); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997a); molecular graphics: SHELXTL (Sheldrick, 1997b); software used to prepare material for publication: SHELXTL.

Figures

	Fig. 1. Perspective view of 2 and anisotropic displacement parameters depicting 30% probability.
	Fig. 2. The formation of the title salt.

1-Butylbenzimidazolium nitrate

Crystal data

C11H15N2^+·NO3^−	F(000) = 504
Mr = 237.26	Dx = 1.289 Mg m^−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
a = 5.4051 (19) Å	Cell parameters from 2013 reflections
b = 16.885 (6) Å	θ = 2.4–26.8°
c = 13.626 (5) Å	µ = 0.10 mm^−1
β = 100.439 (4)°	T = 293 K
V = 1223.0 (7) Å^3	Block, colourless
Z = 4	0.24 × 0.22 × 0.20 mm

Data collection

Bruker APEXII CCD area-detector diffractometer	2168 independent reflections
Radiation source: fine-focus sealed tube	1667 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.015
φ and ω scans	θmax = 25.0°, θmin = 1.9°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	h = −6→6
Tmin = 0.784, Tmax = 1.000	k = −20→15
6471 measured reflections	l = −16→16

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)] = 0.039	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.115	H-atom parameters constrained
S = 1.03	w = 1/[σ^2(Fo^2) + (0.0597P)^2 + 0.1736P] where P = (Fo^2 + 2Fc^2)/3
2168 reflections	(Δ/σ)max < 0.001
155 parameters	Δρmax = 0.19 e Å^−3
0 restraints	Δρmin = −0.17 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
O1	0.1856 (3)	0.36499 (9)	0.29577 (11)	0.1054 (6)
O2	−0.0556 (3)	0.30020 (9)	0.37516 (12)	0.1024 (5)
O3	0.1610 (2)	0.39744 (7)	0.44602 (8)	0.0701 (4)
N1	0.3501 (2)	0.53711 (8)	0.39341 (9)	0.0571 (3)
H1	0.3124	0.4905	0.4113	0.068*
N2	0.3537 (2)	0.66503 (7)	0.38025 (9)	0.0538 (3)
N3	0.0971 (3)	0.35307 (8)	0.37095 (11)	0.0645 (4)
C1	0.5190 (3)	0.55428 (9)	0.33119 (10)	0.0517 (4)
C2	0.6668 (3)	0.50653 (11)	0.28269 (12)	0.0650 (5)
H2	0.6646	0.4516	0.2878	0.078*
C3	0.8173 (3)	0.54485 (13)	0.22651 (12)	0.0732 (5)
H3A	0.9206	0.5150	0.1932	0.088*
C4	0.8196 (3)	0.62714 (13)	0.21798 (12)	0.0706 (5)
H4	0.9242	0.6504	0.1791	0.085*
C5	0.6726 (3)	0.67470 (11)	0.26513 (11)	0.0612 (4)
H5	0.6735	0.7295	0.2589	0.073*
C6	0.5219 (3)	0.63639 (9)	0.32282 (10)	0.0509 (4)
C7	0.2568 (3)	0.60384 (10)	0.42069 (12)	0.0584 (4)
H7	0.1392	0.6075	0.4626	0.070*
C8	0.2926 (3)	0.74849 (9)	0.39348 (13)	0.0637 (4)
H8A	0.1384	0.7517	0.4203	0.076*
H8B	0.2636	0.7746	0.3290	0.076*
C9	0.4994 (3)	0.79099 (10)	0.46253 (13)	0.0652 (4)
H9A	0.6576	0.7822	0.4402	0.078*
H9B	0.5142	0.7690	0.5291	0.078*
C10	0.4517 (3)	0.87944 (10)	0.46674 (13)	0.0683 (5)
H10A	0.5992	0.9045	0.5056	0.082*
H10B	0.4293	0.9007	0.3996	0.082*
C11	0.2286 (4)	0.90059 (13)	0.5109 (2)	0.1015 (7)
H11A	0.0784	0.8840	0.4668	0.152*
H11B	0.2242	0.9569	0.5203	0.152*
H11C	0.2390	0.8745	0.5741	0.152*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O1	0.1618 (15)	0.0780 (10)	0.0898 (10)	−0.0088 (10)	0.0584 (10)	−0.0149 (8)
O2	0.1119 (11)	0.0737 (10)	0.1213 (12)	−0.0362 (9)	0.0200 (9)	−0.0161 (8)
O3	0.0881 (8)	0.0599 (7)	0.0618 (7)	−0.0150 (6)	0.0126 (6)	−0.0055 (6)
N1	0.0680 (8)	0.0483 (7)	0.0534 (7)	−0.0099 (6)	0.0071 (6)	0.0019 (6)
N2	0.0558 (7)	0.0485 (7)	0.0546 (7)	−0.0020 (6)	0.0032 (6)	−0.0037 (6)
N3	0.0762 (9)	0.0448 (8)	0.0725 (9)	0.0043 (7)	0.0137 (7)	−0.0009 (7)
C1	0.0577 (8)	0.0498 (9)	0.0440 (8)	−0.0039 (7)	−0.0004 (6)	−0.0023 (6)
C2	0.0713 (10)	0.0591 (10)	0.0595 (9)	0.0054 (8)	−0.0016 (8)	−0.0123 (8)
C3	0.0664 (11)	0.0934 (15)	0.0593 (10)	0.0034 (10)	0.0101 (8)	−0.0177 (9)
C4	0.0690 (11)	0.0902 (14)	0.0527 (9)	−0.0150 (10)	0.0114 (8)	−0.0031 (9)
C5	0.0687 (10)	0.0612 (10)	0.0509 (8)	−0.0116 (8)	0.0030 (8)	0.0030 (7)
C6	0.0540 (8)	0.0516 (9)	0.0441 (8)	−0.0031 (7)	0.0003 (6)	−0.0013 (6)
C7	0.0594 (9)	0.0603 (10)	0.0549 (9)	−0.0078 (8)	0.0086 (7)	−0.0034 (7)
C8	0.0625 (9)	0.0507 (9)	0.0733 (10)	0.0062 (7)	−0.0002 (8)	−0.0058 (8)
C9	0.0614 (9)	0.0581 (10)	0.0718 (10)	0.0037 (8)	0.0003 (8)	−0.0085 (8)
C10	0.0772 (11)	0.0544 (10)	0.0723 (11)	−0.0053 (8)	0.0110 (9)	−0.0009 (8)
C11	0.0955 (15)	0.0696 (14)	0.147 (2)	0.0099 (11)	0.0421 (15)	−0.0130 (13)

Geometric parameters (Å, º)

O1—N3	1.2233 (19)	C4—H4	0.9300
O2—N3	1.2241 (18)	C5—C6	1.390 (2)
O3—N3	1.2645 (18)	C5—H5	0.9300
N1—C7	1.315 (2)	C7—H7	0.9300
N1—C1	1.3846 (19)	C8—C9	1.506 (2)
N1—H1	0.8600	C8—H8A	0.9700
N2—C7	1.323 (2)	C8—H8B	0.9700
N2—C6	1.3897 (19)	C9—C10	1.518 (2)
N2—C8	1.466 (2)	C9—H9A	0.9700
C1—C2	1.384 (2)	C9—H9B	0.9700
C1—C6	1.391 (2)	C10—C11	1.486 (3)
C2—C3	1.375 (2)	C10—H10A	0.9700
C2—H2	0.9300	C10—H10B	0.9700
C3—C4	1.394 (3)	C11—H11A	0.9600
C3—H3A	0.9300	C11—H11B	0.9600
C4—C5	1.369 (2)	C11—H11C	0.9600
C7—N1—C1	108.83 (13)	N1—C7—N2	110.52 (14)
C7—N1—H1	125.6	N1—C7—H7	124.7
C1—N1—H1	125.6	N2—C7—H7	124.7
C7—N2—C6	108.15 (13)	N2—C8—C9	112.12 (13)
C7—N2—C8	125.78 (14)	N2—C8—H8A	109.2
C6—N2—C8	126.07 (13)	C9—C8—H8A	109.2
O1—N3—O2	121.91 (16)	N2—C8—H8B	109.2
O1—N3—O3	119.27 (15)	C9—C8—H8B	109.2
O2—N3—O3	118.81 (15)	H8A—C8—H8B	107.9
C2—C1—N1	132.22 (15)	C8—C9—C10	112.37 (14)
C2—C1—C6	121.68 (15)	C8—C9—H9A	109.1
N1—C1—C6	106.10 (13)	C10—C9—H9A	109.1
C3—C2—C1	116.24 (17)	C8—C9—H9B	109.1
C3—C2—H2	121.9	C10—C9—H9B	109.1
C1—C2—H2	121.9	H9A—C9—H9B	107.9
C2—C3—C4	122.03 (17)	C11—C10—C9	114.04 (16)
C2—C3—H3A	119.0	C11—C10—H10A	108.7
C4—C3—H3A	119.0	C9—C10—H10A	108.7
C5—C4—C3	122.05 (16)	C11—C10—H10B	108.7
C5—C4—H4	119.0	C9—C10—H10B	108.7
C3—C4—H4	119.0	H10A—C10—H10B	107.6
C4—C5—C6	116.22 (16)	C10—C11—H11A	109.5
C4—C5—H5	121.9	C10—C11—H11B	109.5
C6—C5—H5	121.9	H11A—C11—H11B	109.5
C5—C6—N2	131.83 (15)	C10—C11—H11C	109.5
C5—C6—C1	121.78 (14)	H11A—C11—H11C	109.5
N2—C6—C1	106.39 (13)	H11B—C11—H11C	109.5
C7—N1—C1—C2	179.94 (16)	C8—N2—C6—C1	−179.51 (13)
C7—N1—C1—C6	0.11 (16)	C2—C1—C6—C5	0.2 (2)
N1—C1—C2—C3	−179.41 (15)	N1—C1—C6—C5	−179.93 (12)
C6—C1—C2—C3	0.4 (2)	C2—C1—C6—N2	179.97 (13)
C1—C2—C3—C4	−0.6 (2)	N1—C1—C6—N2	−0.18 (15)
C2—C3—C4—C5	0.1 (3)	C1—N1—C7—N2	0.00 (17)
C3—C4—C5—C6	0.5 (2)	C6—N2—C7—N1	−0.12 (17)
C4—C5—C6—N2	179.65 (15)	C8—N2—C7—N1	179.58 (13)
C4—C5—C6—C1	−0.7 (2)	C7—N2—C8—C9	105.17 (18)
C7—N2—C6—C5	179.90 (15)	C6—N2—C8—C9	−75.18 (19)
C8—N2—C6—C5	0.2 (2)	N2—C8—C9—C10	173.05 (14)
C7—N2—C6—C1	0.19 (15)	C8—C9—C10—C11	65.3 (2)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1···O3	0.86	1.87	2.7177 (19)	168