2-Methyl-imidazolium picrate.

In both ionic components of the title salt, C(4)H(7)N(2) (+)·C(6)H(2)N(3)O(7) (-), the rings are approximately planar; the maximum deviation from the mean plane is an order of magnitude larger in the picrate ring [0.0289 (10) Å] than in the imidazolium ring [0.0028 (10) Å. The nitro groups are twisted with respect to the six-atom ring plane; the NO(2) groups next to the oxide O atom, at the 2- and 6-positions, are twisted more [by 53.59 (9) and 18.46 (12)°] than the NO(2) group at the 4-postition, for which the twist angle is 7.28 (16)°. In the crystal, N-H⋯O hydrogen bonds, in which the hydroxyl O atom acts as a double acceptor and one of the O atoms from a nitro group acts as an additional acceptor, connect mol-ecules into chains along the c-axis direction. Relatively short C-H⋯O contacts and π-π inter-actions between symmetry-related six-membered rings [centroid-centroid distances = 3.5938 (10) and 3.6223 (10) Å] also occur.

Related literature

For the crystal structure of imidazolium picrate, see: Soriano-García et al. (1990 ▶). For the structures of picrates of some other imidazole derivatives, see, for example: Nardelli et al. (1987 ▶); Du & Zhao (2003 ▶); MacDonald et al. (2005 ▶); Pi et al. (2009 ▶).

Experimental

Crystal data

C4H7N2 +·C6H2N3O7 −

M = 311.22

Monoclinic,

a = 7.0983 (9) Å

b = 21.644 (2) Å

c = 8.1583 (9) Å

β = 100.327 (12)°

V = 1233.1 (2) Å3

Z = 4

Mo Kα radiation

μ = 0.15 mm−1

T = 295 K

0.3 × 0.2 × 0.2 mm

Data collection

Oxford Diffraction Xcalibur Eos diffractometer

Absorption correction: multi-scan (CrysAlis PRO; Oxford Diffraction, 2009 ▶) T min = 0.964, T max = 1.000

4778 measured reflections

2483 independent reflections

1792 reflections with I > 2σ(I)

R int = 0.014

Refinement

R[F 2 > 2σ(F 2)] = 0.039

wR(F 2) = 0.101

S = 1.03

2483 reflections

235 parameters

All H-atom parameters refined

Δρmax = 0.30 e Å−3

Δρmin = −0.27 e Å−3

Data collection: CrysAlis PRO (Oxford Diffraction, 2009 ▶); cell refinement: CrysAlis PRO; data reduction: CrysAlis PRO; program(s) used to solve structure: SIR92 (Altomare et al., 1993 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: Stereochemical Workstation Operation Manual. (Siemens, 1989 ▶); software used to prepare material for publication: SHELXL97.

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536810053390/dn2638sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S1600536810053390/dn2638Isup2.hkl

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

C4H7N2+·C6H2N3O7−	F(000) = 640
Mr = 311.22	Dx = 1.676 Mg m−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 2592 reflections
a = 7.0983 (9) Å	θ = 2.9–28.2°
b = 21.644 (2) Å	µ = 0.15 mm−1
c = 8.1583 (9) Å	T = 295 K
β = 100.327 (12)°	Block, yellow
V = 1233.1 (2) Å3	0.3 × 0.2 × 0.2 mm
Z = 4

Oxford Diffraction Xcalibur Eos diffractometer	2483 independent reflections
Radiation source: Enhance (Mo) X-ray Source	1792 reflections with I > 2σ(I)
graphite	Rint = 0.014
Detector resolution: 16.1544 pixels mm-1	θmax = 28.2°, θmin = 2.9°
ω scans	h = −8→9
Absorption correction: multi-scan (CrysAlis PRO; Oxford Diffraction, 2009)	k = −15→28
Tmin = 0.964, Tmax = 1.000	l = −10→10
4778 measured reflections

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)] = 0.039	Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.101	All H-atom parameters refined
S = 1.03	w = 1/[σ2(Fo2) + (0.060P)2] where P = (Fo2 + 2Fc2)/3
2483 reflections	(Δ/σ)max = 0.001
235 parameters	Δρmax = 0.30 e Å−3
0 restraints	Δρmin = −0.27 e Å−3

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.

	x	y	z	Uiso*/Ueq
C1	0.3265 (2)	0.93118 (8)	0.60988 (19)	0.0241 (4)
O1	0.38378 (17)	0.88003 (5)	0.67241 (14)	0.0347 (3)
C2	0.2787 (2)	0.98440 (7)	0.70037 (19)	0.0253 (4)
N2	0.2874 (2)	0.98159 (7)	0.88019 (17)	0.0358 (4)
O21	0.2016 (3)	1.02077 (8)	0.94412 (17)	0.0716 (5)
O22	0.3770 (3)	0.94120 (7)	0.96128 (17)	0.0656 (5)
C3	0.2171 (2)	1.03981 (8)	0.6272 (2)	0.0266 (4)
H3	0.189 (2)	1.0723 (8)	0.691 (2)	0.028 (5)*
C4	0.1956 (2)	1.04630 (8)	0.4569 (2)	0.0267 (4)
N4	0.1304 (2)	1.10493 (7)	0.38329 (19)	0.0348 (4)
O41	0.1247 (2)	1.11171 (7)	0.23347 (17)	0.0615 (5)
O42	0.08086 (19)	1.14506 (6)	0.47167 (17)	0.0479 (4)
C5	0.2260 (2)	0.99677 (8)	0.3565 (2)	0.0272 (4)
H5	0.205 (3)	0.9999 (9)	0.243 (2)	0.041 (5)*
C6	0.2876 (2)	0.94228 (7)	0.43176 (19)	0.0248 (4)
N6	0.3054 (2)	0.89003 (7)	0.32303 (17)	0.0310 (3)
O61	0.45451 (19)	0.86075 (6)	0.34477 (16)	0.0436 (4)
O62	0.1676 (2)	0.87781 (7)	0.21488 (17)	0.0537 (4)
N11	0.5304 (2)	0.76346 (7)	0.59823 (18)	0.0353 (4)
H11	0.491 (3)	0.8016 (10)	0.617 (3)	0.054 (6)*
C12	0.4264 (2)	0.72364 (8)	0.49579 (19)	0.0310 (4)
C12A	0.2238 (3)	0.73045 (13)	0.4178 (3)	0.0484 (5)
H12A	0.163 (5)	0.6936 (15)	0.401 (4)	0.129 (13)*
H12B	0.155 (4)	0.7574 (13)	0.480 (3)	0.094 (9)*
H12C	0.213 (4)	0.7461 (14)	0.318 (4)	0.111 (11)*
N13	0.5382 (2)	0.67629 (7)	0.47868 (18)	0.0341 (4)
H13	0.506 (3)	0.6450 (11)	0.416 (3)	0.056 (7)*
C14	0.7165 (3)	0.68530 (9)	0.5723 (2)	0.0377 (4)
H14	0.811 (3)	0.6565 (10)	0.574 (2)	0.046 (6)*
C15	0.7118 (3)	0.74005 (9)	0.6470 (2)	0.0391 (5)
H15	0.808 (3)	0.7634 (10)	0.719 (3)	0.057 (6)*

	U11	U22	U33	U12	U13	U23
C1	0.0225 (7)	0.0236 (9)	0.0259 (8)	0.0002 (7)	0.0035 (6)	0.0003 (7)
O1	0.0505 (7)	0.0247 (7)	0.0282 (6)	0.0088 (6)	0.0053 (5)	0.0019 (5)
C2	0.0274 (8)	0.0263 (9)	0.0219 (8)	−0.0003 (7)	0.0038 (6)	0.0000 (7)
N2	0.0501 (9)	0.0318 (9)	0.0252 (7)	0.0080 (7)	0.0062 (7)	−0.0004 (7)
O21	0.1138 (13)	0.0717 (12)	0.0334 (7)	0.0473 (10)	0.0244 (8)	0.0002 (8)
O22	0.1215 (14)	0.0427 (9)	0.0296 (7)	0.0315 (9)	0.0057 (8)	0.0062 (7)
C3	0.0266 (8)	0.0239 (9)	0.0299 (9)	0.0008 (7)	0.0070 (7)	−0.0040 (8)
C4	0.0280 (8)	0.0209 (9)	0.0321 (9)	0.0018 (7)	0.0077 (7)	0.0050 (7)
N4	0.0378 (8)	0.0286 (9)	0.0385 (8)	0.0024 (7)	0.0084 (7)	0.0083 (7)
O41	0.1011 (12)	0.0457 (9)	0.0393 (8)	0.0197 (8)	0.0173 (8)	0.0183 (7)
O42	0.0632 (9)	0.0264 (7)	0.0563 (9)	0.0118 (6)	0.0165 (7)	0.0024 (7)
C5	0.0292 (8)	0.0304 (10)	0.0223 (8)	−0.0002 (7)	0.0052 (7)	0.0037 (8)
C6	0.0261 (8)	0.0239 (9)	0.0250 (8)	−0.0007 (7)	0.0067 (6)	−0.0028 (7)
N6	0.0395 (8)	0.0282 (8)	0.0265 (7)	−0.0004 (7)	0.0093 (6)	−0.0008 (6)
O61	0.0498 (8)	0.0378 (8)	0.0451 (8)	0.0136 (7)	0.0134 (6)	−0.0063 (6)
O62	0.0563 (8)	0.0575 (10)	0.0419 (8)	−0.0018 (7)	−0.0060 (7)	−0.0211 (7)
N11	0.0479 (9)	0.0240 (8)	0.0329 (8)	−0.0010 (8)	0.0044 (7)	−0.0042 (7)
C12	0.0424 (10)	0.0252 (9)	0.0256 (8)	−0.0034 (8)	0.0067 (7)	−0.0002 (7)
C12A	0.0426 (12)	0.0519 (15)	0.0477 (12)	−0.0025 (11)	0.0000 (10)	0.0012 (12)
N13	0.0501 (9)	0.0230 (8)	0.0293 (8)	−0.0043 (7)	0.0077 (7)	−0.0044 (7)
C14	0.0426 (11)	0.0329 (11)	0.0381 (10)	0.0036 (9)	0.0084 (9)	0.0046 (9)
C15	0.0416 (10)	0.0374 (12)	0.0356 (10)	−0.0071 (9)	−0.0005 (8)	0.0006 (9)

C1—O1	1.2557 (19)	N6—O61	1.2193 (18)
C1—C2	1.441 (2)	N6—O62	1.2226 (19)
C1—C6	1.450 (2)	N11—C12	1.329 (2)
C2—C3	1.376 (2)	N11—C15	1.375 (2)
C2—N2	1.459 (2)	N11—H11	0.89 (2)
N2—O22	1.2067 (19)	C12—N13	1.319 (2)
N2—O21	1.2145 (19)	C12—C12A	1.472 (3)
C3—C4	1.377 (2)	C12A—H12A	0.91 (3)
C3—H3	0.918 (18)	C12A—H12B	0.96 (3)
C4—C5	1.389 (2)	C12A—H12C	0.87 (3)
C4—N4	1.444 (2)	N13—C14	1.370 (2)
N4—O42	1.2200 (19)	N13—H13	0.86 (2)
N4—O41	1.2245 (19)	C14—C15	1.336 (3)
C5—C6	1.365 (2)	C14—H14	0.92 (2)
C5—H5	0.911 (19)	C15—H15	0.96 (2)
C6—N6	1.457 (2)
O1—C1—C2	125.83 (14)	O61—N6—O62	123.62 (15)
O1—C1—C6	122.88 (14)	O61—N6—C6	118.85 (14)
C2—C1—C6	111.17 (14)	O62—N6—C6	117.53 (14)
C3—C2—C1	124.06 (14)	C12—N11—C15	109.23 (16)
C3—C2—N2	115.19 (14)	C12—N11—H11	123.3 (13)
C1—C2—N2	120.72 (14)	C15—N11—H11	126.7 (13)
O22—N2—O21	121.74 (15)	N13—C12—N11	107.04 (16)
O22—N2—C2	120.29 (14)	N13—C12—C12A	126.31 (18)
O21—N2—C2	117.97 (15)	N11—C12—C12A	126.64 (18)
C2—C3—C4	119.73 (16)	C12—C12A—H12A	112 (2)
C2—C3—H3	120.5 (11)	C12—C12A—H12B	112.4 (16)
C4—C3—H3	119.7 (11)	H12A—C12A—H12B	110 (2)
C3—C4—C5	121.00 (15)	C12—C12A—H12C	111 (2)
C3—C4—N4	118.57 (15)	H12A—C12A—H12C	104 (3)
C5—C4—N4	120.34 (15)	H12B—C12A—H12C	107 (3)
O42—N4—O41	122.90 (16)	C12—N13—C14	110.12 (16)
O42—N4—C4	118.99 (15)	C12—N13—H13	125.4 (15)
O41—N4—C4	118.10 (15)	C14—N13—H13	124.5 (15)
C6—C5—C4	118.21 (15)	C15—C14—N13	106.55 (17)
C6—C5—H5	120.2 (12)	C15—C14—H14	132.4 (13)
C4—C5—H5	121.6 (12)	N13—C14—H14	121.0 (13)
C5—C6—C1	125.60 (15)	C14—C15—N11	107.06 (17)
C5—C6—N6	116.91 (14)	C14—C15—H15	132.4 (13)
C1—C6—N6	117.40 (14)	N11—C15—H15	120.5 (13)
O1—C1—C2—C3	179.72 (16)	C4—C5—C6—C1	−0.5 (2)
C6—C1—C2—C3	−4.2 (2)	C4—C5—C6—N6	175.84 (13)
O1—C1—C2—N2	−2.4 (2)	O1—C1—C6—C5	−179.73 (16)
C6—C1—C2—N2	173.62 (14)	C2—C1—C6—C5	4.1 (2)
C3—C2—N2—O22	−163.80 (17)	O1—C1—C6—N6	3.9 (2)
C1—C2—N2—O22	18.2 (2)	C2—C1—C6—N6	−172.26 (13)
C3—C2—N2—O21	16.4 (2)	C5—C6—N6—O61	129.43 (16)
C1—C2—N2—O21	−161.61 (17)	C1—C6—N6—O61	−53.90 (19)
C1—C2—C3—C4	0.9 (2)	C5—C6—N6—O62	−51.0 (2)
N2—C2—C3—C4	−177.07 (14)	C1—C6—N6—O62	125.64 (17)
C2—C3—C4—C5	3.3 (2)	C15—N11—C12—N13	−0.36 (19)
C2—C3—C4—N4	179.90 (14)	C15—N11—C12—C12A	178.83 (19)
C3—C4—N4—O42	−6.2 (2)	N11—C12—N13—C14	0.53 (19)
C5—C4—N4—O42	170.49 (15)	C12A—C12—N13—C14	−178.67 (18)
C3—C4—N4—O41	174.92 (16)	C12—N13—C14—C15	−0.49 (19)
C5—C4—N4—O41	−8.4 (2)	N13—C14—C15—N11	0.25 (19)
C3—C4—C5—C6	−3.4 (2)	C12—N11—C15—C14	0.1 (2)
N4—C4—C5—C6	−179.99 (15)

D—H···A	D—H	H···A	D···A	D—H···A
C5—H5···O21i	0.911 (19)	2.478 (19)	3.378 (2)	169.4 (16)
N11—H11···O1	0.89 (2)	1.95 (2)	2.8357 (19)	172.9 (19)
N13—H13···O1ii	0.86 (2)	2.09 (2)	2.819 (2)	143 (2)
N13—H13···O22ii	0.86 (2)	2.14 (2)	2.782 (2)	131.3 (19)

Table 1

Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C5—H5⋯O21i	0.911 (19)	2.478 (19)	3.378 (2)	169.4 (16)
N11—H11⋯O1	0.89 (2)	1.95 (2)	2.8357 (19)	172.9 (19)
N13—H13⋯O1ii	0.86 (2)	2.09 (2)	2.819 (2)	143 (2)
N13—H13⋯O22ii	0.86 (2)	2.14 (2)	2.782 (2)	131.3 (19)

Symmetry codes: (i) ; (ii) .