organic compounds
1,3-Bis(2,6-diisopropylphenyl)imidazolium perchlorate
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
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 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.
to the diruthenium(II,III) core, as had successfully been accomplished on the analogous dirhodium(II,II) core (AndréThe 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( − x, − 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).
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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 .
details are summarized in Table 2Structural data
CCDC reference: 1833992
https://doi.org/10.1107/S2414314618005163/hb4223sup1.cif
contains datablock I. DOI: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
Data collection: APEX2 (Bruker, 2010); cell
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).C27H37N2+·ClO4− | Dx = 1.184 Mg m−3 |
Mr = 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 |
Bruker APEXII CCD diffractometer | 2695 independent reflections |
Radiation source: fine-focus sealed tube | 1759 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.042 |
φ and ω scans | θmax = 26.0°, θmin = 2.5° |
Absorption correction: multi-scan (SADABS; Bruker, 2010) | h = −10→13 |
Tmin = 0.975, Tmax = 0.986 | k = −15→10 |
7718 measured reflections | l = −18→24 |
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(Fo2) + (0.0691P)2 + 0.6803P] where P = (Fo2 + 2Fc2)/3 |
2695 reflections | (Δ/σ)max < 0.001 |
159 parameters | Δρmax = 0.31 e Å−3 |
0 restraints | Δρmin = −0.42 e Å−3 |
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 Uiso(H) = 1.5 UeqC(methyl), or 1.2 Ueq(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. |
x | y | z | Uiso*/Ueq | ||
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* |
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) |
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. |
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).
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