organic compounds\(\def\hfill{\hskip 5em}\def\hfil{\hskip 3em}\def\eqno#1{\hfil {#1}}\)

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ISSN: 2056-9890

1,3-Bis(2,6-diiso­propyl­phen­yl)-4,5-di­hydro-1H-imidazol-3-ium triiodide

aSchool of Chemistry, University of KwaZulu-Natal, Westville Campus, Private Bag X54001, Durban 4000, South Africa
*Correspondence e-mail: bala@ukzn.ac.za

(Received 29 October 2010; accepted 4 November 2010; online 10 November 2010)

In the crystal structure of the title compound, C27H39N2+·I3, the imidazolidinium ring is perpendicular to a mirror plane which bis­ects the cation. The dihedral angle between the imidazolidinium ring and the benzene ring is 89.0 (2)°. The triiodide anion also lies on a mirror plane and is almost linear with an I—I—I bond angle of 178.309 (18)°.

Related literature

For a related structure with a 1,3-(2,6-diisopropyl­phen­yl)imidazolidinium unit, see: Giffin et al. (2010[Giffin, N. A., Hendsbee, A. D. & Masuda, J. D. (2010). Acta Cryst. E66, o2090-o2091.]). For its synthesis, see: Llewellyn et al. (2006[Llewellyn, S., Green, M., Green, J. & Cowley, R. (2006). Dalton Trans. pp. 2535-2541.]).

[Scheme 1]

Experimental

Crystal data
  • C27H39N2+·I3

  • Mr = 772.30

  • Monoclinic, C 2/m

  • a = 18.0288 (5) Å

  • b = 15.4554 (5) Å

  • c = 13.8457 (6) Å

  • β = 129.456 (1)°

  • V = 2978.81 (18) Å3

  • Z = 4

  • Mo Kα radiation

  • μ = 3.16 mm−1

  • T = 173 K

  • 0.39 × 0.22 × 0.14 mm

Data collection
  • Bruker APEXII CCD diffractometer

  • Absorption correction: integration (XPREP; Bruker, 2005[Bruker (2005). APEX2, SAINT and XPREP. Bruker AXS Inc., Madison, Wisconsin, USA.]) Tmin = 0.438, Tmax = 0.642

  • 12244 measured reflections

  • 3772 independent reflections

  • 2536 reflections with I > 2σ(I)

  • Rint = 0.048

Refinement
  • R[F2 > 2σ(F2)] = 0.039

  • wR(F2) = 0.122

  • S = 0.97

  • 3772 reflections

  • 155 parameters

  • H-atom parameters constrained

  • Δρmax = 1.92 e Å−3

  • Δρmin = −1.30 e Å−3

Data collection: APEX2 (Bruker, 2005[Bruker (2005). APEX2, SAINT and XPREP. Bruker AXS Inc., Madison, Wisconsin, USA.]); cell refinement: SAINT (Bruker, 2005[Bruker (2005). APEX2, SAINT and XPREP. Bruker AXS Inc., Madison, Wisconsin, USA.]); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); molecular graphics: SHELXTL (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); software used to prepare material for publication: SHELXTL.

Supporting information


Comment top

We were using a general synthetic method that involved the deprotonation of N-heterocyclic carbene (NHC) salts with strong bases to generate free carbenes, followed by in situ metalation with an iron(II) precursor to generate iron(II) based NHC complexes. In order to obtain piano stool type compounds, η5-CpFe(CO)2I was used as the iron(II) precursor. Piano-stool type complexes are of interest due to their outstanding spectroscopic and structural features which has made them the subject of many elegant studies in the past. But in this instance, the title compound C27H39N2I3, (I), was obtained as a triiodide adduct of the protonated NHC ligand. A molecule of the cationic NHC is characterized by a bisecting mirror plane, while the triiodide counterion is symmetrical around the central iodine atom I2. The imidazolidinium ring is nearly orthogonal to the phenyl rings of the N-substituents with torsion angles N13–N1–C1–C6 close to 90°. The triiodide counterion is linear.

Related literature top

For a related structure with a 1,3-(2,6-diisopropylphenyl)imidazolidinium unit, see: Giffin et al. (2010). For the related synthesis, see: Llewellyn et al. (2006).

Experimental top

To a suspension of 1,3-bis(2,6-diisopropylphenyl)imidazolidinium chloride (0.1 g) in dry THF (15 ml) was added potassium tert-butoxide (0.031 g). After 1 h, this solution was added to a solution of [η5-CpFe(CO)2I] (0.07 g) in dry toluene (40 ml). After stirring for 20 hrs, the resulting precipitate was centrifuged and washed once with dry toluene (30 ml). The toluene extracts were combined and left standing in air to form shiny black crystals of (I).

Refinement top

Hydrogen atoms were first located in a difference map and then positioned geometrically (C—H = 0.95–1.00 Å) and allowed to ride on their respective parent atoms. The highest peak and the deepest hole in the difference Fourier map are located 0.87 and 0.65 Å, respectively, from atom I3.

Structure description top

We were using a general synthetic method that involved the deprotonation of N-heterocyclic carbene (NHC) salts with strong bases to generate free carbenes, followed by in situ metalation with an iron(II) precursor to generate iron(II) based NHC complexes. In order to obtain piano stool type compounds, η5-CpFe(CO)2I was used as the iron(II) precursor. Piano-stool type complexes are of interest due to their outstanding spectroscopic and structural features which has made them the subject of many elegant studies in the past. But in this instance, the title compound C27H39N2I3, (I), was obtained as a triiodide adduct of the protonated NHC ligand. A molecule of the cationic NHC is characterized by a bisecting mirror plane, while the triiodide counterion is symmetrical around the central iodine atom I2. The imidazolidinium ring is nearly orthogonal to the phenyl rings of the N-substituents with torsion angles N13–N1–C1–C6 close to 90°. The triiodide counterion is linear.

For a related structure with a 1,3-(2,6-diisopropylphenyl)imidazolidinium unit, see: Giffin et al. (2010). For the related synthesis, see: Llewellyn et al. (2006).

Computing details top

Data collection: APEX2 (Bruker, 2005); cell refinement: SAINT (Bruker, 2005); data reduction: SAINT (Bruker, 2005); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

Figures top
[Figure 1] Fig. 1. Molecular structure of the title compound with the atom labelling scheme for non-hydrogen atoms. Ellipsoids are drawn at the 50% probability level. All H atoms have been omitted.
1,3-Bis(2,6-diisopropylphenyl)-4,5-dihydro-1H-imidazol-3-ium triiodide top
Crystal data top
C27H39N2+·I3F(000) = 1496
Mr = 772.30Dx = 1.722 Mg m3
Monoclinic, C2/mMo Kα radiation, λ = 0.71073 Å
Hall symbol: -C 2yCell parameters from 3850 reflections
a = 18.0288 (5) Åθ = 2.9–28.1°
b = 15.4554 (5) ŵ = 3.16 mm1
c = 13.8457 (6) ÅT = 173 K
β = 129.456 (1)°Block, brown
V = 2978.81 (18) Å30.39 × 0.22 × 0.14 mm
Z = 4
Data collection top
Bruker APEXII CCD
diffractometer
3772 independent reflections
Radiation source: fine-focus sealed tube2536 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.048
φ and ω scansθmax = 28.3°, θmin = 1.9°
Absorption correction: integration
(XPREP; Bruker, 2005)
h = 1724
Tmin = 0.438, Tmax = 0.642k = 2018
12244 measured reflectionsl = 1811
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.039Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.122H-atom parameters constrained
S = 0.97 w = 1/[σ2(Fo2) + (0.065P)2 + 5.5612P]
where P = (Fo2 + 2Fc2)/3
3772 reflections(Δ/σ)max = 0.026
155 parametersΔρmax = 1.92 e Å3
0 restraintsΔρmin = 1.30 e Å3
Crystal data top
C27H39N2+·I3V = 2978.81 (18) Å3
Mr = 772.30Z = 4
Monoclinic, C2/mMo Kα radiation
a = 18.0288 (5) ŵ = 3.16 mm1
b = 15.4554 (5) ÅT = 173 K
c = 13.8457 (6) Å0.39 × 0.22 × 0.14 mm
β = 129.456 (1)°
Data collection top
Bruker APEXII CCD
diffractometer
3772 independent reflections
Absorption correction: integration
(XPREP; Bruker, 2005)
2536 reflections with I > 2σ(I)
Tmin = 0.438, Tmax = 0.642Rint = 0.048
12244 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0390 restraints
wR(F2) = 0.122H-atom parameters constrained
S = 0.97Δρmax = 1.92 e Å3
3772 reflectionsΔρmin = 1.30 e Å3
155 parameters
Special details top

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 (Å2) top
xyzUiso*/Ueq
C10.3529 (2)0.3426 (2)0.2270 (3)0.0250 (7)
C20.3463 (2)0.3008 (2)0.3116 (3)0.0277 (7)
C30.3832 (3)0.2177 (2)0.3478 (3)0.0328 (8)
H30.38080.18760.40550.039*
C40.4236 (3)0.1775 (2)0.3015 (4)0.0388 (9)
H40.44800.12030.32740.047*
C50.4285 (3)0.2201 (2)0.2178 (3)0.0354 (8)
H50.45690.19190.18730.043*
C60.3926 (2)0.3033 (2)0.1777 (3)0.0296 (7)
C70.4002 (3)0.3505 (2)0.0879 (3)0.0332 (8)
H70.35830.40310.05670.040*
C80.3653 (4)0.2949 (3)0.0245 (4)0.0578 (13)
H8A0.36380.32970.08490.087*
H8B0.30060.27340.06400.087*
H8C0.40900.24590.00290.087*
C90.5022 (3)0.3801 (4)0.1556 (4)0.0573 (13)
H9A0.52400.41450.22890.086*
H9B0.50500.41560.09920.086*
H9C0.54400.32960.18250.086*
C100.3020 (3)0.3437 (2)0.3629 (3)0.0310 (8)
H100.27000.39810.31410.037*
C110.3788 (4)0.3692 (5)0.4980 (4)0.080 (2)
H11A0.40770.31700.54970.120*
H11B0.35000.40400.52590.120*
H11C0.42840.40310.50620.120*
C120.2256 (5)0.2874 (4)0.3461 (6)0.0741 (17)
H12A0.17840.27010.25820.111*
H12B0.19320.32000.37060.111*
H12C0.25570.23560.39860.111*
C130.3643 (3)0.50000.2404 (4)0.0239 (9)
H130.43040.50000.31220.029*
C140.2147 (2)0.4503 (2)0.0778 (3)0.0298 (7)
H14A0.16900.42720.08820.036*
H14B0.19800.42720.00050.036*
N10.31536 (19)0.42912 (17)0.1873 (2)0.0250 (6)
I10.24578 (3)0.00000.27734 (5)0.06328 (17)
I20.34949 (3)0.00000.54335 (4)0.05203 (15)
I30.45122 (3)0.00000.81697 (5)0.06143 (17)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
C10.0219 (16)0.0203 (15)0.0278 (14)0.0005 (12)0.0134 (12)0.0018 (12)
C20.0229 (16)0.0261 (17)0.0252 (14)0.0019 (13)0.0111 (13)0.0014 (12)
C30.0311 (19)0.0298 (19)0.0313 (16)0.0006 (15)0.0170 (14)0.0027 (14)
C40.035 (2)0.0253 (19)0.045 (2)0.0043 (16)0.0201 (17)0.0037 (15)
C50.034 (2)0.0302 (19)0.0416 (18)0.0031 (16)0.0240 (16)0.0041 (15)
C60.0221 (17)0.0294 (18)0.0328 (15)0.0029 (14)0.0153 (14)0.0042 (14)
C70.0312 (19)0.0338 (19)0.0393 (17)0.0014 (15)0.0246 (16)0.0014 (15)
C80.068 (3)0.060 (3)0.038 (2)0.019 (3)0.030 (2)0.011 (2)
C90.048 (3)0.081 (4)0.051 (2)0.027 (3)0.035 (2)0.012 (2)
C100.0318 (18)0.0329 (19)0.0272 (15)0.0007 (15)0.0182 (14)0.0011 (14)
C110.050 (3)0.115 (5)0.043 (2)0.019 (3)0.015 (2)0.035 (3)
C120.103 (5)0.059 (3)0.118 (5)0.025 (3)0.097 (4)0.029 (3)
C130.021 (2)0.026 (2)0.0233 (19)0.0000.0131 (17)0.000
C140.0198 (16)0.0267 (18)0.0303 (15)0.0005 (13)0.0101 (13)0.0013 (13)
N10.0201 (13)0.0214 (14)0.0267 (12)0.0006 (11)0.0118 (11)0.0002 (10)
I10.0473 (3)0.0391 (3)0.0848 (3)0.0000.0333 (2)0.000
I20.0325 (2)0.0354 (2)0.0847 (3)0.0000.0356 (2)0.000
I30.0361 (2)0.0614 (3)0.0792 (3)0.0000.0331 (2)0.000
Geometric parameters (Å, º) top
C1—C61.403 (5)C9—H9C0.9800
C1—C21.407 (5)C10—C111.509 (5)
C1—N11.441 (4)C10—C121.518 (6)
C2—C31.386 (5)C10—H101.0000
C2—C101.518 (5)C11—H11A0.9800
C3—C41.384 (5)C11—H11B0.9800
C3—H30.9500C11—H11C0.9800
C4—C51.385 (5)C12—H12A0.9800
C4—H40.9500C12—H12B0.9800
C5—C61.388 (5)C12—H12C0.9800
C5—H50.9500C13—N11.302 (3)
C6—C71.520 (5)C13—N1i1.302 (3)
C7—C91.511 (5)C13—H130.9500
C7—C81.521 (5)C14—N11.484 (4)
C7—H71.0000C14—C14i1.535 (7)
C8—H8A0.9800C14—H14A0.9900
C8—H8B0.9800C14—H14B0.9900
C8—H8C0.9800I1—I22.8824 (7)
C9—H9A0.9800I2—I32.9808 (7)
C9—H9B0.9800
C6—C1—C2123.1 (3)H9A—C9—H9C109.5
C6—C1—N1118.5 (3)H9B—C9—H9C109.5
C2—C1—N1118.4 (3)C11—C10—C12111.6 (4)
C3—C2—C1116.8 (3)C11—C10—C2110.7 (3)
C3—C2—C10120.7 (3)C12—C10—C2112.0 (3)
C1—C2—C10122.5 (3)C11—C10—H10107.5
C4—C3—C2121.5 (3)C12—C10—H10107.5
C4—C3—H3119.3C2—C10—H10107.5
C2—C3—H3119.3C10—C11—H11A109.5
C5—C4—C3120.4 (3)C10—C11—H11B109.5
C5—C4—H4119.8H11A—C11—H11B109.5
C3—C4—H4119.8C10—C11—H11C109.5
C4—C5—C6120.9 (4)H11A—C11—H11C109.5
C4—C5—H5119.5H11B—C11—H11C109.5
C6—C5—H5119.5C10—C12—H12A109.5
C5—C6—C1117.3 (3)C10—C12—H12B109.5
C5—C6—C7120.7 (3)H12A—C12—H12B109.5
C1—C6—C7121.9 (3)C10—C12—H12C109.5
C9—C7—C8110.7 (3)H12A—C12—H12C109.5
C9—C7—C6110.2 (3)H12B—C12—H12C109.5
C8—C7—C6111.8 (3)N1—C13—N1i114.6 (4)
C9—C7—H7108.0N1—C13—H13122.7
C8—C7—H7108.0N1i—C13—H13122.7
C6—C7—H7108.0N1—C14—C14i102.77 (16)
C7—C8—H8A109.5N1—C14—H14A111.2
C7—C8—H8B109.5C14i—C14—H14A111.2
H8A—C8—H8B109.5N1—C14—H14B111.2
C7—C8—H8C109.5C14i—C14—H14B111.2
H8A—C8—H8C109.5H14A—C14—H14B109.1
H8B—C8—H8C109.5C13—N1—C1125.5 (3)
C7—C9—H9A109.5C13—N1—C14109.9 (3)
C7—C9—H9B109.5C1—N1—C14124.6 (3)
H9A—C9—H9B109.5I1—I2—I3178.309 (18)
C7—C9—H9C109.5
C6—C1—C2—C31.3 (5)C1—C6—C7—C9103.2 (4)
N1—C1—C2—C3180.0 (3)C5—C6—C7—C849.3 (5)
C6—C1—C2—C10179.2 (3)C1—C6—C7—C8133.2 (4)
N1—C1—C2—C100.5 (4)C3—C2—C10—C1172.8 (5)
C1—C2—C3—C40.7 (5)C1—C2—C10—C11106.7 (4)
C10—C2—C3—C4179.8 (3)C3—C2—C10—C1252.4 (5)
C2—C3—C4—C50.4 (6)C1—C2—C10—C12128.1 (4)
C3—C4—C5—C60.5 (6)N1i—C13—N1—C1179.3 (2)
C4—C5—C6—C11.0 (5)N1i—C13—N1—C140.1 (5)
C4—C5—C6—C7178.7 (3)C6—C1—N1—C1389.2 (4)
C2—C1—C6—C51.4 (5)C2—C1—N1—C1392.0 (4)
N1—C1—C6—C5179.8 (3)C6—C1—N1—C1489.9 (4)
C2—C1—C6—C7179.1 (3)C2—C1—N1—C1488.9 (4)
N1—C1—C6—C72.2 (5)C14i—C14—N1—C130.1 (3)
C5—C6—C7—C974.3 (4)C14i—C14—N1—C1179.3 (3)
Symmetry code: (i) x, y+1, z.

Experimental details

Crystal data
Chemical formulaC27H39N2+·I3
Mr772.30
Crystal system, space groupMonoclinic, C2/m
Temperature (K)173
a, b, c (Å)18.0288 (5), 15.4554 (5), 13.8457 (6)
β (°) 129.456 (1)
V3)2978.81 (18)
Z4
Radiation typeMo Kα
µ (mm1)3.16
Crystal size (mm)0.39 × 0.22 × 0.14
Data collection
DiffractometerBruker APEXII CCD
Absorption correctionIntegration
(XPREP; Bruker, 2005)
Tmin, Tmax0.438, 0.642
No. of measured, independent and
observed [I > 2σ(I)] reflections
12244, 3772, 2536
Rint0.048
(sin θ/λ)max1)0.668
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.039, 0.122, 0.97
No. of reflections3772
No. of parameters155
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)1.92, 1.30

Computer programs: APEX2 (Bruker, 2005), SAINT (Bruker, 2005), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), SHELXTL (Sheldrick, 2008).

 

Acknowledgements

We wish to thank Dr Manuel Fernandes for the data collection and the University KwaZulu-Natal and the NRF for financial support.

References

First citationBruker (2005). APEX2, SAINT and XPREP. Bruker AXS Inc., Madison, Wisconsin, USA.  Google Scholar
First citationGiffin, N. A., Hendsbee, A. D. & Masuda, J. D. (2010). Acta Cryst. E66, o2090–o2091.  Web of Science CSD CrossRef IUCr Journals Google Scholar
First citationLlewellyn, S., Green, M., Green, J. & Cowley, R. (2006). Dalton Trans. pp. 2535–2541.  Web of Science CSD CrossRef Google Scholar
First citationSheldrick, G. M. (2008). Acta Cryst. A64, 112–122.  Web of Science CrossRef CAS IUCr Journals Google Scholar

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