1,2,3,5-Tetra­methyl-1H-pyrazol-2-ium triiodide

Oberparleiter, S.; Laus, G.; Wurst, K.; Schottenberger, H.

doi:10.1107/S2414314616013316

organic compounds

IUCrDATA

ISSN: 2414-3146

Volume 1| Part 8| August 2016| x161331

doi:10.1107/S2414314616013316

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1,2,3,5-Tetramethyl-1H-pyrazol-2-ium triiodide

Stefan Oberparleiter,^a Gerhard Laus,^a ^* Klaus Wurst ^a and Herwig Schottenberger ^a

^aUniversity of Innsbruck, Faculty of Chemistry and Pharmacy, Innrain 80, 6020 Innsbruck, Austria
^*Correspondence e-mail: gerhard.laus@uibk.ac.at

Edited by W. T. A. Harrison, University of Aberdeen, Scotland (Received 18 August 2016; accepted 18 August 2016; online 26 August 2016)

The title salt, C₇H₁₃N₂⁺·I₃⁻, was obtained unintentionally by methylation of 3,6-bis(3,5-dimethylpyrazol-1-yl)-1,2,4,5-tetrazine and subsequent fragmentation. The pyrazolium ring is almost planar (r.m.s. deviation = 0.003 Å) and the triiodide anion deviates slightly from linearity [I—I—I = 177.099 (12)°]. No directional interactions occur in the crystal.

Keywords: pyrazole; triiodide; crystal structure.

CCDC reference: 1499905

Structure description

Quaternary pyrazolium salts have been prepared by alkylation of pyrazoles (Elguero et al., 1969 ) and a one-pot synthesis of the related 1,2,3,5-tetramethylpyrazolium chloride has been reported (Hobbs & Wilson, 1972 ). Pyrazolium salts are well known plant-growth regulators (Jäger & Lürssen, 1976 ) and herbicides (Jäger & Eue, 1976 ).

The molecular structure of the ion pair of the title compound is shown in Fig. 1. The pyrazolium ring is almost perfectly planar (r.m.s. deviation = 0.003 Å). The triiodide ion deviates significantly from linearity with an I1—I2—I3 angle of 177.099 (12)°, which is close to the mean value for triiodide ions taken from the Cambridge Structure Database (Version 5.37; Groom et al., 2016 ) of 178°. There are no directional classic hydrogen bonds in this structure, although Hirshfeld surface calculation (Spackman & Jayatilaka, 2009 ) revealed a large percentage of H⋯I interactions (39.5% of the total surface) with distances to the extent of the sum of van der Waals radii. The crystal packing is shown in Fig. 2.

Figure 1
The molecular structure of the ion pair of the title compound, showing the atom labels and 50% probability displacement ellipsoids for non-H atoms.

Figure 2
Crystal packing of the title compound.

A few related structures (Han & Huynh, 2007 ; Han et al., 2007 , 2010 , 2011 ) of pyrazolium salts and derived N-heterocyclic carbene (NHC) complexes have been reported.

Synthesis and crystallization

A solution of 3,6-bis(3,5-dimethylpyrazol-1-yl)-1,2,4,5-tetrazine (0.5 g, 1.85 mmol; Coburn et al., 1991 ) and CH₃I (0.46 ml, 7.4 mmol) in CHCl₃ (4 ml) was heated at 368 K for five days in a sealed tube. Red crystals (0.89 g, 95%) precipitated which were washed with CHCl₃ and dried, m.p. 442 K. The PXRD (Mo Kα radiation) of the bulk material was identical to the one calculated from the single-crystal diffraction data (Fig. 3), indicating phase purity. ¹H NMR (300 MHz, DMSO-d₆): δ 2.40 (s, 6H), 3.89 (s, 6H), 6.53 (s, 1H) p.p.m. ¹³C NMR (75 MHz, DMSO-d₆): δ 11.3, 33.5, 106.9, 145.1 p.p.m. IR (neat): ν 3287, 3084, 2991, 2930, 1680, 1609, 1577, 1480, 1420, 1274, 1161, 1077, 1046, 1023, 968, 941, 842, 816, 756, 719, 659, 646, 621, 588, 554, 516, 470, 420 cm⁻¹.

Figure 3
Pawley fit (R_wp = 6.62%, R_exp = 6.43%, R_p = 5.23%, gof = 1.03) of the PXRD data with a model calculated from the structural data of the single-crystal structure determination. Black dots indicate raw data, while the red line indicates the calculated model. The difference curve is shown in blue.

Refinement

Crystal data, data collection and structure refinement details are summarized in Table 1.

Table 1
Experimental details

Crystal data
Chemical formula	C₇H₁₃N₂⁺·I₃⁻
M_r	505.89
Crystal system, space group	Monoclinic, P2₁/n
Temperature (K)	193
a, b, c (Å)	9.6719 (7), 13.4005 (9), 11.1874 (8)
β (°)	112.994 (2)
V (Å³)	1334.77 (16)
Z	4
Radiation type	Mo Kα
μ (mm⁻¹)	6.99
Crystal size (mm)	0.16 × 0.13 × 0.08

Data collection
Diffractometer	Bruker D8 QUEST PHOTON 100
Absorption correction	Multi-scan (SADABS; Bruker, 2014 )
T_min, T_max	0.397, 0.562
No. of measured, independent and observed [I > 2σ(I)] reflections	22167, 2648, 2400
R_int	0.028
(sin θ/λ)_max (Å⁻¹)	0.619

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.026, 0.062, 1.24
No. of reflections	2648
No. of parameters	113
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.40, −1.21
Computer programs: APEX2 and SAINT (Bruker, 2014), SHELXTL-XT2014/4 and SHELXL2014/7 (Sheldrick, 2015 ), ORTEP-3 for Windows (Farrugia, 2012 ) and Mercury (Macrae et al., 2006 ).

Structural data

CCDC reference: 1499905

Crystal structure: contains datablock I. DOI: 10.1107/S2414314616013316/hb4073sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S2414314616013316/hb4073Isup2.hkl

Supporting information file. DOI: 10.1107/S2414314616013316/hb4073Isup5.mol

Supporting information file. DOI: 10.1107/S2414314616013316/hb4073Isup6.cml

checkCIF report

Computing details top

Data collection: APEX2 (Bruker, 2014); cell refinement: SAINT (Bruker, 2014); data reduction: SAINT (Bruker, 2014); program(s) used to solve structure: SHELXTL-XT2014/4 (Sheldrick, 2015); program(s) used to refine structure: SHELXL2014/7 (Sheldrick, 2015); molecular graphics: ORTEP-3 for Windows (Farrugia, 2012); software used to prepare material for publication: Mercury (Macrae et al., 2006).

1,2,3,5-Tetramethyl-1H-pyrazol-2-ium triiodide top

Crystal data top

C₇H₁₃N₂⁺·I₃⁻	D_x = 2.517 Mg m⁻³
M_r = 505.89	Melting point: 442 K
Monoclinic, P2₁/n	Mo Kα radiation, λ = 0.71073 Å
a = 9.6719 (7) Å	Cell parameters from 9875 reflections
b = 13.4005 (9) Å	θ = 2.4–26.0°
c = 11.1874 (8) Å	µ = 6.99 mm⁻¹
β = 112.994 (2)°	T = 193 K
V = 1334.77 (16) Å³	Prism, red
Z = 4	0.16 × 0.13 × 0.08 mm
F(000) = 912

Data collection top

Bruker D8 QUEST PHOTON 100 diffractometer	2648 independent reflections
Radiation source: Incoatec Microfocus	2400 reflections with I > 2σ(I)
Multi layered optics monochromator	R_int = 0.028
Detector resolution: 10.4 pixels mm^-1	θ_max = 26.1°, θ_min = 2.4°
φ and ω scans	h = −11→11
Absorption correction: multi-scan (SADABS; Bruker, 2014)	k = −16→16
T_min = 0.397, T_max = 0.562	l = −13→13
22167 measured reflections

Refinement top

Refinement on F²	0 restraints
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F² > 2σ(F²)] = 0.026	H-atom parameters constrained
wR(F²) = 0.062	w = 1/[σ²(F_o²) + (0.0207P)² + 3.0909P] where P = (F_o² + 2F_c²)/3
S = 1.24	(Δ/σ)_max = 0.001
2648 reflections	Δρ_max = 0.40 e Å⁻³
113 parameters	Δρ_min = −1.21 e Å⁻³

Special details top

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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq
I1	0.53163 (4)	0.57210 (2)	0.18064 (3)	0.04747 (10)
I2	0.31387 (3)	0.58881 (2)	0.29850 (2)	0.02818 (8)
I3	0.09003 (3)	0.59495 (2)	0.41519 (3)	0.04406 (10)
C1	0.6156 (5)	0.8272 (3)	0.4063 (4)	0.0339 (9)
C2	0.4931 (5)	0.8817 (3)	0.4027 (4)	0.0368 (9)
H2	0.4512	0.9379	0.3490	0.044*
C3	0.4422 (4)	0.8404 (3)	0.4907 (4)	0.0337 (9)
C4	0.7113 (6)	0.8394 (4)	0.3308 (5)	0.0484 (11)
H4A	0.8144	0.8549	0.3901	0.073*
H4B	0.6719	0.8939	0.2683	0.073*
H4C	0.7107	0.7774	0.2842	0.073*
C5	0.3137 (5)	0.8684 (4)	0.5255 (5)	0.0458 (11)
H5A	0.2409	0.8136	0.5030	0.069*
H5B	0.2652	0.9285	0.4774	0.069*
H5C	0.3503	0.8816	0.6190	0.069*
C6	0.7544 (5)	0.6788 (3)	0.5368 (4)	0.0408 (10)
H6A	0.8132	0.6818	0.4827	0.061*
H6B	0.7076	0.6128	0.5282	0.061*
H6C	0.8207	0.6903	0.6278	0.061*
C7	0.5258 (5)	0.6932 (3)	0.6445 (4)	0.0361 (9)
H7A	0.4429	0.7120	0.6696	0.054*
H7B	0.6206	0.6954	0.7210	0.054*
H7C	0.5092	0.6255	0.6086	0.054*
N1	0.6383 (4)	0.7550 (2)	0.4950 (3)	0.0294 (7)
N2	0.5329 (4)	0.7627 (2)	0.5471 (3)	0.0295 (7)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
I1	0.04624 (18)	0.05257 (19)	0.0537 (2)	−0.00103 (13)	0.03051 (15)	−0.00763 (14)
I2	0.03148 (14)	0.02296 (13)	0.02863 (14)	−0.00115 (9)	0.01014 (11)	−0.00118 (9)
I3	0.04725 (18)	0.04483 (18)	0.05066 (19)	0.00210 (12)	0.03060 (15)	0.00475 (13)
C1	0.043 (2)	0.0233 (18)	0.033 (2)	−0.0066 (16)	0.0124 (17)	−0.0009 (15)
C2	0.046 (2)	0.0222 (18)	0.033 (2)	0.0001 (17)	0.0053 (18)	0.0019 (16)
C3	0.033 (2)	0.0242 (18)	0.036 (2)	0.0010 (15)	0.0043 (17)	−0.0058 (16)
C4	0.060 (3)	0.044 (3)	0.046 (3)	−0.010 (2)	0.026 (2)	0.002 (2)
C5	0.038 (2)	0.039 (2)	0.058 (3)	0.0099 (19)	0.017 (2)	−0.006 (2)
C6	0.041 (2)	0.037 (2)	0.043 (2)	0.0130 (18)	0.0160 (19)	0.0050 (19)
C7	0.046 (2)	0.030 (2)	0.032 (2)	0.0008 (17)	0.0161 (18)	0.0053 (16)
N1	0.0321 (16)	0.0241 (16)	0.0311 (16)	0.0013 (13)	0.0114 (13)	0.0003 (12)
N2	0.0341 (17)	0.0245 (15)	0.0294 (16)	0.0015 (13)	0.0117 (14)	0.0010 (13)

Geometric parameters (Å, º) top

I1—I2	2.8972 (4)	C5—H5A	0.9800
I2—I3	2.9336 (4)	C5—H5B	0.9800
C1—N1	1.340 (5)	C5—H5C	0.9800
C1—C2	1.379 (6)	C6—N1	1.454 (5)
C1—C4	1.486 (6)	C6—H6A	0.9800
C2—C3	1.377 (6)	C6—H6B	0.9800
C2—H2	0.9500	C6—H6C	0.9800
C3—N2	1.350 (5)	C7—N2	1.456 (5)
C3—C5	1.488 (6)	C7—H7A	0.9800
C4—H4A	0.9800	C7—H7B	0.9800
C4—H4B	0.9800	C7—H7C	0.9800
C4—H4C	0.9800	N1—N2	1.361 (4)

I1—I2—I3	177.099 (12)	H5A—C5—H5C	109.5
N1—C1—C2	107.1 (4)	H5B—C5—H5C	109.5
N1—C1—C4	122.8 (4)	N1—C6—H6A	109.5
C2—C1—C4	130.1 (4)	N1—C6—H6B	109.5
C3—C2—C1	108.0 (4)	H6A—C6—H6B	109.5
C3—C2—H2	126.0	N1—C6—H6C	109.5
C1—C2—H2	126.0	H6A—C6—H6C	109.5
N2—C3—C2	107.1 (4)	H6B—C6—H6C	109.5
N2—C3—C5	122.0 (4)	N2—C7—H7A	109.5
C2—C3—C5	130.8 (4)	N2—C7—H7B	109.5
C1—C4—H4A	109.5	H7A—C7—H7B	109.5
C1—C4—H4B	109.5	N2—C7—H7C	109.5
H4A—C4—H4B	109.5	H7A—C7—H7C	109.5
C1—C4—H4C	109.5	H7B—C7—H7C	109.5
H4A—C4—H4C	109.5	C1—N1—N2	109.2 (3)
H4B—C4—H4C	109.5	C1—N1—C6	128.9 (4)
C3—C5—H5A	109.5	N2—N1—C6	121.9 (3)
C3—C5—H5B	109.5	C3—N2—N1	108.5 (3)
H5A—C5—H5B	109.5	C3—N2—C7	129.1 (4)
C3—C5—H5C	109.5	N1—N2—C7	122.3 (3)

N1—C1—C2—C3	−0.3 (5)	C2—C3—N2—N1	−0.3 (4)
C4—C1—C2—C3	179.5 (4)	C5—C3—N2—N1	179.4 (4)
C1—C2—C3—N2	0.4 (4)	C2—C3—N2—C7	−178.6 (4)
C1—C2—C3—C5	−179.3 (4)	C5—C3—N2—C7	1.1 (6)
C2—C1—N1—N2	0.2 (4)	C1—N1—N2—C3	0.1 (4)
C4—C1—N1—N2	−179.7 (4)	C6—N1—N2—C3	179.3 (3)
C2—C1—N1—C6	−179.0 (4)	C1—N1—N2—C7	178.6 (3)
C4—C1—N1—C6	1.1 (6)	C6—N1—N2—C7	−2.2 (5)

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