1,3-Bis(2,6-diiso­propyl­phen­yl)imidazolium perchlorate

Minaker, S.A.; Wang, R.; Aquino, M.A.S.

doi:10.1107/S2414314618005163

organic compounds

IUCrDATA

ISSN: 2414-3146

Volume 3| Part 4| April 2018| x180516

https://doi.org/10.1107/S2414314618005163

Open

access

1,3-Bis(2,6-diisopropylphenyl)imidazolium perchlorate

Samuel A. Minaker,^a Ruiyao Wang ^b and Manuel A. S. Aquino ^a ^*

^aDepartment of Chemistry, St. Francis Xavier University, PO Box 5000, Antigonish, Nova Scotia, B2G 2W5, Canada, and ^bDepartment of Chemistry, Xi'an Jiaotong-Liverpool University, 111 Renai Road, Suzhou, Jiangsu 215123, People's Republic of China
^*Correspondence e-mail: maquino@stfx.ca

Edited by W. T. A. Harrison, University of Aberdeen, Scotland (Received 30 March 2018; accepted 31 March 2018; online 17 April 2018)

The title salt, C₂₇H₃₇N₂⁺·ClO₄⁻, arose as an unexpected oxidation product of the carbene 1,3-bis(2,6-diisopropylphenyl)-1,3-dihydro-2H-imidazol-2-ylidene in methanol. The five-membered cationic imidazolium ring is planar by symmetry and the complete cation is generated by a crystallographic twofold axis passing through the central N-bonded C atom and the mid-point of the C=C bond; the Cl atom of the perchlorate anion also lies on the rotation axis. The phenyl rings of the 2,6-diisopropylphenyl groups are each perpendicular to the imidazolium ring [dihedral angle = 90.0 (3)°]. In the crystal, weak C—H⋯O and bifurcated C—H⋯(O,O) interactions between the imidazolium ring H atoms and the perchlorate O atoms lead to [001] chains.

Keywords: crystal structure; imidazolium; carbene.

CCDC reference: 1833992

Structure description

Our ongoing research into the chemistry of diruthenium(II,III) tetracarboxylates led us to attempt axial coordination of N-heterocyclic carbenes to the diruthenium(II,III) core, as had successfully been accomplished on the analogous dirhodium(II,II) core (André et al., 2008 ). Our attempts have been unsuccessful but we were able to isolate crystals of an oxidized imidizolium species as its title perchlorate salt in the course of one of our reactions.

The molecule consists of an imidazolium core with isopropylphenyl substituents attached to each heterocyclic nitrogen atom (Fig. 1). The bond lengths in the heterocycle: C2—C2( $[3\over2]$ − x, $[1\over2]$ − y, z) = 1.340 (4), N1—C1 = 1.326 (2) and N1—C2 = 1.378 (3) Å, are consistent with a double bond between the C2 carbon atoms and bond delocalization over the N—C—N part of the ring, similar to other isopropylphenyl derivatives (e.g. Arduengo et al., 1999 ; Berger et al., 2012 ; Blue et al., 2006 ). In the crystal, extensive C—H⋯O hydrogen bonding is seen (Table 1) involving the C1—H1 grouping and the perchlorate anion (symmetrically bifurcating two of the perchlorate oxygen atoms) as well as the C2—H2A grouping and the other perchlorate oxygen atom, leading to [001] chains (Fig. 2).

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C1—H1A⋯O1	0.95	2.37	3.232 (3)	151
C1—H1A⋯O1ⁱ	0.95	2.37	3.232 (3)	151
C2—H2A⋯O2ⁱⁱ	0.95	2.32	3.096 (3)	138
Symmetry codes: (i) $[-x+{\script{3\over 2}}, -y+{\script{1\over 2}}, z]$ ; (ii) $[-x+{\script{3\over 2}}, y, z+{\script{1\over 2}}]$ .

Figure 1
The molecular structure of the title compound with displacement ellipsoids at the 50% probability level. H atoms are omitted for clarity and unlabelled atoms are generated by the symmetry operator (−x + $[{3\over 2}]$ , −y + $[{1\over 2}]$ , z).

Figure 2
Packing diagram viewed along the [010] axis showing the hydrogen-bonding interactions.

Crystal structures of perchlorate salts of imidazolium derivatives are rare (Crees et al., 2010 ; Pesch et al., 2004 ; Fürstner et al., 2006 ) and there are none for the isopropylphenyl derivative.

Synthesis and crystallization

Crystals of the title compound were isolated as a byproduct of the reaction of [Ru₂(μ-O₂CCH₃)₄(MeOH)₂](ClO₄) (0.100 g, 0.166 mmol) in 10 ml of methanol with a twofold excess of the carbene 1,3-bis(2,6-diisopropylphenyl)-1,3-dihydro-2H-imidazol-2-ylidene (0.131 g, 0.333 mmol) in 5 ml of methanol. This solution was stirred for 2 h and after slow evaporation yielded a brown powder (ruthenium complex) and crystals of the de-protonated, oxidized, imidazolium, 1,3-bis(2,6-diisopropylphenyl)imidazolium, as a perchlorate salt.

Refinement

Crystal data, data collection and structure refinement details are summarized in Table 2.

Table 2
Experimental details

Crystal data
Chemical formula	C₂₇H₃₇N₂⁺·ClO₄⁻
M_r	489.04
Crystal system, space group	Orthorhombic, Pccn
Temperature (K)	180
a, b, c (Å)	11.0729 (12), 12.6284 (13), 19.6141 (19)
V (Å³)	2742.7 (5)
Z	4
Radiation type	Mo Kα
μ (mm⁻¹)	0.17
Crystal size (mm)	0.15 × 0.10 × 0.08

Data collection
Diffractometer	Bruker APEXII CCD
Absorption correction	Multi-scan (SADABS; Bruker, 2010 )
T_min, T_max	0.975, 0.986
No. of measured, independent and observed [I > 2σ(I)] reflections	7718, 2695, 1759
R_int	0.042
(sin θ/λ)_max (Å⁻¹)	0.617

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.051, 0.150, 1.04
No. of reflections	2695
No. of parameters	159
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.31, −0.42
Computer programs: APEX2 and SAINT (Bruker, 2010), SHELXT2018/1 (Sheldrick, 2015a ), SHELXL2018/1 (Sheldrick, 2015b ) and SHELXTL (Sheldrick, 2008 ).

Structural data

CCDC reference: 1833992

Crystal structure: contains datablock I. DOI: https://doi.org/10.1107/S2414314618005163/hb4223sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S2414314618005163/hb4223Isup2.hkl

Supporting information file. DOI: https://doi.org/10.1107/S2414314618005163/hb4223Isup3.cml

checkCIF report

Computing details top

Data collection: APEX2 (Bruker, 2010); cell refinement: SAINT (Bruker, 2010); data reduction: SAINT (Bruker, 2010); program(s) used to solve structure: SHELXT2018/1 (Sheldrick, 2015a); program(s) used to refine structure: SHELXL2018/1 (Sheldrick, 2015b); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

1,3-Bis(2,6-diisopropylphenyl)imidazolium perchlorate top

Crystal data top

C₂₇H₃₇N₂⁺·ClO₄⁻	D_x = 1.184 Mg m⁻³
M_r = 489.04	Mo Kα radiation, λ = 0.71073 Å
Orthorhombic, Pccn	Cell parameters from 1213 reflections
a = 11.0729 (12) Å	θ = 2.5–21.3°
b = 12.6284 (13) Å	µ = 0.17 mm⁻¹
c = 19.6141 (19) Å	T = 180 K
V = 2742.7 (5) Å³	Block, colourless
Z = 4	0.15 × 0.10 × 0.08 mm
F(000) = 1048

Data collection top

Bruker APEXII CCD diffractometer	2695 independent reflections
Radiation source: fine-focus sealed tube	1759 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.042
φ and ω scans	θ_max = 26.0°, θ_min = 2.5°
Absorption correction: multi-scan (SADABS; Bruker, 2010)	h = −10→13
T_min = 0.975, T_max = 0.986	k = −15→10
7718 measured reflections	l = −18→24

Refinement top

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)] = 0.051	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.150	H-atom parameters constrained
S = 1.04	w = 1/[σ²(F_o²) + (0.0691P)² + 0.6803P] where P = (F_o² + 2F_c²)/3
2695 reflections	(Δ/σ)_max < 0.001
159 parameters	Δρ_max = 0.31 e Å⁻³
0 restraints	Δρ_min = −0.42 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.

Refinement. All of the H atoms were placed in geometrically calculated positions, with C—H = 0.95 (aromatic), 1.00 (CH, aliphatic) and 0.98 Å (CH₃), and refined as riding atoms, with U_iso(H) = 1.5 UeqC(methyl), or 1.2 U_eq(other C). In addition, the methyl groups were refined with AFIX 137, which allowed the rotation of the methyl groups whilst keeping the C—H distances and X—C—H angles fixed.

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

	x	y	z	U_iso*/U_eq
N1	0.78014 (16)	0.33094 (13)	0.41998 (9)	0.0274 (4)
Cl1	0.7500	0.2500	0.18392 (4)	0.0497 (3)
O1	0.85386 (16)	0.24115 (18)	0.22649 (9)	0.0646 (6)
O2	0.75960 (19)	0.34257 (19)	0.14182 (10)	0.0745 (7)
C1	0.7500	0.2500	0.38038 (16)	0.0275 (7)
H1A	0.7500	0.2500	0.3319	0.033*
C2	0.7687 (2)	0.30046 (17)	0.48715 (11)	0.0336 (5)
H2A	0.7845	0.3430	0.5261	0.040*
C3	0.8224 (2)	0.43217 (16)	0.39426 (11)	0.0303 (5)
C4	0.7371 (2)	0.51047 (17)	0.38081 (12)	0.0347 (5)
C5	0.7810 (2)	0.60378 (19)	0.35238 (14)	0.0470 (7)
H5A	0.7261	0.6589	0.3411	0.056*
C6	0.9023 (2)	0.61800 (19)	0.34024 (15)	0.0506 (7)
H6A	0.9300	0.6825	0.3209	0.061*
C7	0.9836 (2)	0.53943 (19)	0.35594 (14)	0.0467 (7)
H7A	1.0671	0.5509	0.3477	0.056*
C8	0.9462 (2)	0.44387 (17)	0.38346 (12)	0.0361 (6)
C9	0.6034 (2)	0.49721 (19)	0.39413 (13)	0.0399 (6)
H9A	0.5925	0.4311	0.4215	0.048*
C10	0.5331 (3)	0.4840 (3)	0.32793 (16)	0.0674 (9)
H10A	0.5674	0.4253	0.3016	0.101*
H10B	0.5382	0.5494	0.3012	0.101*
H10C	0.4483	0.4687	0.3384	0.101*
C11	0.5522 (3)	0.5888 (2)	0.43552 (15)	0.0548 (7)
H11A	0.5988	0.5969	0.4777	0.082*
H11B	0.4676	0.5743	0.4467	0.082*
H11C	0.5573	0.6542	0.4088	0.082*
C12	1.0364 (2)	0.35671 (19)	0.39863 (14)	0.0440 (6)
H12A	0.9918	0.2978	0.4216	0.053*
C13	1.0910 (3)	0.3128 (3)	0.33389 (16)	0.0695 (10)
H13A	1.0264	0.2959	0.3015	0.104*
H13B	1.1367	0.2484	0.3445	0.104*
H13C	1.1451	0.3656	0.3137	0.104*
C14	1.1353 (3)	0.3938 (3)	0.44702 (17)	0.0696 (9)
H14A	1.1877	0.3339	0.4586	0.104*
H14B	1.0986	0.4221	0.4887	0.104*
H14C	1.1832	0.4493	0.4249	0.104*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
N1	0.0325 (9)	0.0239 (9)	0.0257 (9)	−0.0005 (7)	0.0004 (8)	−0.0008 (8)
Cl1	0.0373 (5)	0.0842 (7)	0.0277 (5)	0.0176 (5)	0.000	0.000
O1	0.0438 (11)	0.1088 (17)	0.0412 (11)	0.0205 (11)	−0.0120 (9)	0.0006 (11)
O2	0.0759 (15)	0.1031 (17)	0.0445 (11)	0.0105 (13)	0.0023 (11)	0.0287 (12)
C1	0.0312 (15)	0.0269 (16)	0.0244 (15)	−0.0015 (13)	0.000	0.000
C2	0.0446 (13)	0.0339 (11)	0.0224 (11)	0.0038 (10)	−0.0015 (10)	−0.0053 (10)
C3	0.0377 (12)	0.0236 (11)	0.0295 (12)	−0.0040 (9)	0.0038 (10)	−0.0027 (10)
C4	0.0406 (13)	0.0277 (11)	0.0358 (13)	0.0009 (10)	0.0062 (11)	0.0003 (10)
C5	0.0529 (15)	0.0279 (12)	0.0602 (18)	0.0054 (11)	0.0120 (13)	0.0086 (13)
C6	0.0573 (17)	0.0284 (13)	0.0660 (19)	−0.0074 (12)	0.0207 (14)	0.0056 (13)
C7	0.0431 (14)	0.0384 (14)	0.0585 (18)	−0.0084 (11)	0.0150 (13)	−0.0054 (13)
C8	0.0367 (13)	0.0317 (12)	0.0400 (14)	−0.0008 (10)	0.0050 (10)	−0.0076 (11)
C9	0.0369 (13)	0.0338 (13)	0.0488 (16)	0.0047 (10)	0.0041 (11)	0.0082 (12)
C10	0.0490 (16)	0.081 (2)	0.072 (2)	0.0045 (16)	−0.0060 (15)	−0.0132 (19)
C11	0.0513 (16)	0.0511 (17)	0.0620 (18)	0.0074 (13)	0.0158 (14)	0.0025 (15)
C12	0.0354 (13)	0.0371 (13)	0.0596 (17)	0.0017 (10)	0.0020 (12)	−0.0050 (13)
C13	0.0500 (17)	0.082 (2)	0.076 (2)	0.0255 (16)	−0.0133 (15)	−0.0375 (19)
C14	0.068 (2)	0.069 (2)	0.071 (2)	0.0156 (17)	−0.0245 (18)	−0.0213 (18)

Geometric parameters (Å, º) top

N1—C1	1.326 (2)	C7—H7A	0.9500
N1—C2	1.378 (3)	C8—C12	1.516 (3)
N1—C3	1.452 (3)	C9—C11	1.523 (3)
Cl1—O1	1.4255 (17)	C9—C10	1.523 (4)
Cl1—O1ⁱ	1.4255 (17)	C9—H9A	1.0000
Cl1—O2	1.435 (2)	C10—H10A	0.9800
Cl1—O2ⁱ	1.435 (2)	C10—H10B	0.9800
C1—N1ⁱ	1.327 (2)	C10—H10C	0.9800
C1—H1A	0.9500	C11—H11A	0.9800
C2—C2ⁱ	1.340 (4)	C11—H11B	0.9800
C2—H2A	0.9500	C11—H11C	0.9800
C3—C4	1.393 (3)	C12—C13	1.512 (4)
C3—C8	1.395 (3)	C12—C14	1.523 (4)
C4—C5	1.391 (3)	C12—H12A	1.0000
C4—C9	1.512 (3)	C13—H13A	0.9800
C5—C6	1.375 (3)	C13—H13B	0.9800
C5—H5A	0.9500	C13—H13C	0.9800
C6—C7	1.375 (4)	C14—H14A	0.9800
C6—H6A	0.9500	C14—H14B	0.9800
C7—C8	1.385 (3)	C14—H14C	0.9800

C1—N1—C2	108.75 (18)	C11—C9—C10	110.3 (2)
C1—N1—C3	123.79 (18)	C4—C9—H9A	107.7
C2—N1—C3	127.41 (17)	C11—C9—H9A	107.7
O1—Cl1—O1ⁱ	108.30 (16)	C10—C9—H9A	107.7
O1—Cl1—O2	109.94 (12)	C9—C10—H10A	109.5
O1ⁱ—Cl1—O2	109.44 (12)	C9—C10—H10B	109.5
O1—Cl1—O2ⁱ	109.44 (12)	H10A—C10—H10B	109.5
O1ⁱ—Cl1—O2ⁱ	109.94 (12)	C9—C10—H10C	109.5
O2—Cl1—O2ⁱ	109.75 (19)	H10A—C10—H10C	109.5
N1—C1—N1ⁱ	108.3 (3)	H10B—C10—H10C	109.5
N1—C1—H1A	125.8	C9—C11—H11A	109.5
N1ⁱ—C1—H1A	125.8	C9—C11—H11B	109.5
C2ⁱ—C2—N1	107.09 (11)	H11A—C11—H11B	109.5
C2ⁱ—C2—H2A	126.5	C9—C11—H11C	109.5
N1—C2—H2A	126.5	H11A—C11—H11C	109.5
C4—C3—C8	124.2 (2)	H11B—C11—H11C	109.5
C4—C3—N1	118.17 (19)	C13—C12—C8	111.4 (2)
C8—C3—N1	117.58 (19)	C13—C12—C14	110.4 (2)
C5—C4—C3	116.1 (2)	C8—C12—C14	111.9 (2)
C5—C4—C9	120.4 (2)	C13—C12—H12A	107.6
C3—C4—C9	123.5 (2)	C8—C12—H12A	107.6
C6—C5—C4	121.4 (2)	C14—C12—H12A	107.6
C6—C5—H5A	119.3	C12—C13—H13A	109.5
C4—C5—H5A	119.3	C12—C13—H13B	109.5
C7—C6—C5	120.4 (2)	H13A—C13—H13B	109.5
C7—C6—H6A	119.8	C12—C13—H13C	109.5
C5—C6—H6A	119.8	H13A—C13—H13C	109.5
C6—C7—C8	121.4 (2)	H13B—C13—H13C	109.5
C6—C7—H7A	119.3	C12—C14—H14A	109.5
C8—C7—H7A	119.3	C12—C14—H14B	109.5
C7—C8—C3	116.4 (2)	H14A—C14—H14B	109.5
C7—C8—C12	120.8 (2)	C12—C14—H14C	109.5
C3—C8—C12	122.7 (2)	H14A—C14—H14C	109.5
C4—C9—C11	111.9 (2)	H14B—C14—H14C	109.5
C4—C9—C10	111.4 (2)

C2—N1—C1—N1ⁱ	−0.03 (11)	C5—C6—C7—C8	0.8 (4)
C3—N1—C1—N1ⁱ	177.7 (2)	C6—C7—C8—C3	−0.1 (4)
C1—N1—C2—C2ⁱ	0.1 (3)	C6—C7—C8—C12	178.2 (3)
C3—N1—C2—C2ⁱ	−177.6 (2)	C4—C3—C8—C7	−1.7 (4)
C1—N1—C3—C4	90.2 (2)	N1—C3—C8—C7	177.1 (2)
C2—N1—C3—C4	−92.5 (3)	C4—C3—C8—C12	−179.9 (2)
C1—N1—C3—C8	−88.6 (2)	N1—C3—C8—C12	−1.1 (3)
C2—N1—C3—C8	88.7 (3)	C5—C4—C9—C11	−52.5 (3)
C8—C3—C4—C5	2.5 (3)	C3—C4—C9—C11	128.8 (2)
N1—C3—C4—C5	−176.2 (2)	C5—C4—C9—C10	71.5 (3)
C8—C3—C4—C9	−178.8 (2)	C3—C4—C9—C10	−107.1 (3)
N1—C3—C4—C9	2.5 (3)	C7—C8—C12—C13	−66.9 (3)
C3—C4—C5—C6	−1.7 (4)	C3—C8—C12—C13	111.3 (3)
C9—C4—C5—C6	179.5 (3)	C7—C8—C12—C14	57.3 (3)
C4—C5—C6—C7	0.1 (4)	C3—C8—C12—C14	−124.6 (3)

Symmetry code: (i) −x+3/2, −y+1/2, z.

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C1—H1A···O1	0.95	2.37	3.232 (3)	151
C1—H1A···O1ⁱ	0.95	2.37	3.232 (3)	151
C2—H2A···O2ⁱⁱ	0.95	2.32	3.096 (3)	138

Symmetry codes: (i) −x+3/2, −y+1/2, z; (ii) −x+3/2, y, z+1/2.

Funding information

Funding for this research was provided by: Natural Sciences and Engineering Research Council of Canada (grant to Manuel Aquino).

References

André, V., Duarte, M. T., Trindade, A. F., Góis, P. M. P. & Afonso, C. A. M. (2008). Acta Cryst. C64, m345–m348. CSD CrossRef IUCr Journals Google Scholar
Arduengo, A. J., Krafczyk, R. & Schmutzler, R. (1999). Tetrahedron, 55, 14523–14534. CSD CrossRef CAS Google Scholar
Berger, M., Auner, N. & Bolte, M. (2012). Acta Cryst. E68, o1844. CSD CrossRef IUCr Journals Google Scholar
Blue, E. D., Gunnoe, T. B., Peterson, J. L. & Boyle, P. D. (2006). J. Organomet. Chem. 691, 5988–5993. CSD CrossRef CAS Google Scholar
Bruker (2010). APEX2, SAINT, and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA. Google Scholar
Crees, R. S., Cole, M. L., Hanton, L. R. & Sumby, C. J. (2010). Inorg. Chem. 49, 1712–1719. CSD CrossRef CAS Google Scholar
Fürstner, A., Alcarazo, M., César, V. & Lehmann, C. W. (2006). Chem. Commun. 2176–2178. Google Scholar
Pesch, J., Harms, K. & Bach, T. (2004). Eur. J. Org. Chem. pp. 2025–2035. CSD CrossRef Google Scholar
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar
Sheldrick, G. M. (2015a). Acta Cryst. A71, 3–8. Web of Science CrossRef IUCr Journals Google Scholar
Sheldrick, G. M. (2015b). Acta Cryst. C71, 3–8. Web of Science CrossRef IUCr Journals Google Scholar

This is an open-access article distributed under the terms of the Creative Commons Attribution (CC-BY) Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are cited.