Download citation
Download citation
link to html
In 2-methyl-1,4,5-tri­phenyl-1H-imidazole, C22H18N2, the three substituent phenyl groups are not delocalized with the imidazole moiety; the dihedral angles these phenyl groups form with the imidazole ring are in the range 25.90 (5)-63.49 (6)°.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270102016220/fg1661sup1.cif
Contains datablocks I, global

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S0108270102016220/fg1661Isup2.hkl
Contains datablock I

CCDC reference: 197342

Comment top

During the synthesis of a large set of chiral α-diimines by condensation of α-diketones with chiral primary amines following a known procedure (Mehrotra & Singh, 1980), we obtained the title compound, (I), as an unexpected by-product (see Experimental). \sch

Compound (I) (Table 1, Fig. 1) is a tetra-substituted imidazole. The imidazole ring presents the common aromatic geometry, with delocalized CN and CC π bond lengths in the range 1.3123 (16)–1.3950 (16) Å. Due to the substitution at N1, no tautomeric forms are possible for the imidazole moiety, in the solid state or in solution.

The phenyl groups bonded to N1, C4 and C5 are not delocalized with the imidazole ring; dihedral angles between the least-squares planes of the imidazole and phenyl rings are 63.49 (6), 25.90 (5) and 58.75 (6)° for the C6—C11, C13—C18 and C19—C24 rings, respectively. This relative conformation for the phenyl rings seems to minimize steric hindrance in the overall molecule. A similar non-conjugated arrangement was previously observed for a symmetrically tetra-substituted imidazole (Buttke et al., 1997). In this case, the substituents on N1, C2, C4 and C5 are 4-methoxyphenyl groups, and the calculated dihedral angles between the phenyl moieties and the imidazole ring are 105.9 (substituent on N1), 15.1 (substituent on C2), 47.9 (substituent on C4) and 101.9° (substituent on C5). Thus, with respect to (I), a significantly different conformation is observed for the groups bonded to the imidazole core. However, it cannot be determined whether these variations are related to the fact that (I) is a non-symmetrical substituted imidazole, or result from stacking effects in the solid state.

The fourth substituent in (I) is a methyl group bonded to C2, which has the methyl H atoms disordered over two orientations. Two of the shorter intramolecular contacts involve atom H12D of the minor disorder component and a neighbouring phenyl ring on N1 (intramolecular contact distances are C6···H12D 2.64 Å and C7···H12D 2.61 Å). Such contacts may not exist in solution, but if they do, they are weak enough to allow free rotation of the methyl group in solution at room temperature, in agreement with the sharp singlet observed in NMR for these H atoms, at δ 2.35 p.p.m. (200 MHz, CDCl3).

The packing of the molecule of (I) in the solid state is determined by the low Laue symmetry and the above-mentioned conformation for the phenyl groups. These two features avoid any significant stacking intermolecular interactions in the cell; the shortest interaction between rings is 4.26 Å, for two symmetry-related imidazole rings [symmetry operator: 1 - x, 1 - y, 1 - z]. On the other hand, the lack of suitable donor groups for hydrogen bonding favours the separation of the molecules in the cell. The shortest observed intermolecular contact is through the non-substituted N-imidazole atom, C7—H7···N3i [symmetry code: (i) 1 - x, 1 - y, 1 - z], with a long H···N contact distance of 2.58 Å and a contact angle of 167°. A consequence of this packing structure is a relatively low packing index (Spek, 1998) of 66.1% for this small molecule.

Experimental top

Benzil (0.5 g., 2.38 mmol) was reacted with (S)-(-)-α-methylbenzylamine (0.7 ml, 5.2 mmol) under an inert atmosphere at 423 K for 30 min. The crude product was extracted with hexane-water (Ratio?), filtered over Na2SO4, reduced by evaporation and purified by chromatography (Al2O3, 150 mesh, hexane-AcOEt 95:5), yielding four compounds, 2,3,5,6-tetraphenylpyrazine, 2,4,5-triphenyl-1H-imidazole, 2-methyl-1,4,5-triphenyl-2,3-dihydro-1H-imidazole and (I) (respective yields: 25, 20, 15 and 30%). This last was crystallized from petroleum ether-EtOH (Ratio?).

Refinement top

The disordered H atoms bonded to atom C12 were found in difference maps and their site occupancy factors (SOF) refined in two parts, with the sum of SOF for the two disordered components constrained to 1. The remaining H atoms, bonded to sp2-hybridized C atoms, were placed at idealized positions, with constrained C—H distances of 0.96 Å for methyl and 0.93 Å for aryl. In the final cycles, all H atoms were constrained to ride on their parent atoms, with Uiso(H) = xUeq(parent) where x = 1.5 for methyl and 1.2 for all others.

Computing details top

Data collection: XSCANS (Siemens, 1996); cell refinement: XSCANS; data reduction: XSCANS; program(s) used to solve structure: SHELXTL-Plus (Sheldrick, 1998); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SHELXTL-Plus; software used to prepare material for publication: SHELXL97.

Figures top
[Figure 1] Fig. 1. The structure of (I), with displacement ellipsoids at the 30% probability level. H atoms are shown as small spheres of arbitrary radii. For the C12 methyl group, the H atoms corresponding to the minor component of the disorder have been omitted.
2-Methyl-1,4,5-triphenyl-1H-imidazole top
Crystal data top
C22H18N2Z = 2
Mr = 310.38F(000) = 328
Triclinic, P1Dx = 1.198 Mg m3
Hall symbol: -P 1Melting point: 533 K
a = 8.5768 (5) ÅMo Kα radiation, λ = 0.71073 Å
b = 9.8285 (9) ÅCell parameters from 78 reflections
c = 10.7315 (7) Åθ = 4.5–15.0°
α = 96.288 (6)°µ = 0.07 mm1
β = 92.042 (4)°T = 299 K
γ = 106.338 (5)°Regular prism, colourless
V = 860.79 (11) Å30.65 × 0.65 × 0.36 mm
Data collection top
Bruker P4
diffractometer
Rint = 0.016
Radiation source: fine-focus sealed tubeθmax = 30.0°, θmin = 1.9°
Graphite monochromatorh = 111
ω scansk = 1313
5916 measured reflectionsl = 1515
4985 independent reflections3 standard reflections every 97 reflections
3642 reflections with I > 2σ(I) intensity decay: 2%
Refinement top
Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.050H-atom parameters constrained
wR(F2) = 0.145 w = 1/[σ2(Fo2) + (0.0582P)2 + 0.1152P]
where P = (Fo2 + 2Fc2)/3
S = 1.04(Δ/σ)max < 0.001
4985 reflectionsΔρmax = 0.27 e Å3
219 parametersΔρmin = 0.20 e Å3
0 restraintsExtinction correction: SHELXL97 (Sheldrick, 1997), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: structure-invariant direct methodsExtinction coefficient: 0.034 (4)
Crystal data top
C22H18N2γ = 106.338 (5)°
Mr = 310.38V = 860.79 (11) Å3
Triclinic, P1Z = 2
a = 8.5768 (5) ÅMo Kα radiation
b = 9.8285 (9) ŵ = 0.07 mm1
c = 10.7315 (7) ÅT = 299 K
α = 96.288 (6)°0.65 × 0.65 × 0.36 mm
β = 92.042 (4)°
Data collection top
Bruker P4
diffractometer
Rint = 0.016
5916 measured reflections3 standard reflections every 97 reflections
4985 independent reflections intensity decay: 2%
3642 reflections with I > 2σ(I)
Refinement top
R[F2 > 2σ(F2)] = 0.0500 restraints
wR(F2) = 0.145H-atom parameters constrained
S = 1.04Δρmax = 0.27 e Å3
4985 reflectionsΔρmin = 0.20 e Å3
219 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*/UeqOcc. (<1)
N10.47519 (12)0.26420 (11)0.39603 (9)0.0503 (2)
C20.39422 (15)0.31749 (13)0.48871 (11)0.0520 (3)
N30.46889 (13)0.32914 (11)0.59994 (9)0.0532 (3)
C40.60569 (15)0.28237 (13)0.58033 (11)0.0496 (3)
C50.61126 (15)0.24018 (13)0.45447 (11)0.0482 (3)
C60.42645 (14)0.23693 (13)0.26405 (11)0.0510 (3)
C70.42207 (17)0.34995 (15)0.19951 (13)0.0607 (3)
H70.45390.44290.24040.073*
C80.36975 (19)0.32349 (19)0.07298 (14)0.0726 (4)
H80.36370.39870.02930.087*
C90.32680 (19)0.1863 (2)0.01208 (14)0.0761 (4)
H90.29210.16910.07280.091*
C100.3350 (2)0.07479 (19)0.07588 (14)0.0763 (4)
H100.30760.01750.03370.092*
C110.38393 (18)0.09873 (15)0.20340 (13)0.0639 (3)
H110.38800.02300.24710.077*
C120.23945 (16)0.35349 (16)0.46493 (14)0.0639 (4)
H12A0.20490.38890.54300.096*0.63 (2)
H12B0.15720.26940.42740.096*0.63 (2)
H12C0.25640.42540.40910.096*0.63 (2)
H12D0.22300.35930.37690.096*0.37 (2)
H12E0.24520.44380.51210.096*0.37 (2)
H12F0.15030.28070.49040.096*0.37 (2)
C130.72423 (16)0.29509 (13)0.68670 (11)0.0518 (3)
C140.88829 (18)0.31270 (17)0.67127 (13)0.0660 (4)
H140.92510.31250.59080.079*
C150.9983 (2)0.33053 (19)0.77360 (15)0.0749 (4)
H151.10760.34090.76130.090*
C160.9462 (2)0.33292 (19)0.89336 (15)0.0789 (5)
H161.02000.34550.96220.095*
C170.7844 (2)0.3166 (2)0.91031 (14)0.0813 (5)
H170.74890.31830.99120.098*
C180.6738 (2)0.29779 (17)0.80862 (13)0.0668 (4)
H180.56450.28680.82170.080*
C190.72545 (15)0.17892 (13)0.38347 (10)0.0503 (3)
C200.80897 (18)0.24451 (19)0.28823 (13)0.0689 (4)
H200.79470.32990.26760.083*
C210.91500 (19)0.1822 (2)0.22297 (14)0.0847 (5)
H210.97050.22610.15850.102*
C220.9376 (2)0.0571 (2)0.25327 (16)0.0823 (5)
H221.00840.01630.20960.099*
C230.8569 (2)0.0069 (2)0.34668 (18)0.0854 (5)
H230.87320.09150.36760.103*
C240.7505 (2)0.05196 (16)0.41149 (15)0.0690 (4)
H240.69480.00580.47480.083*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
N10.0495 (5)0.0548 (5)0.0449 (5)0.0157 (4)0.0026 (4)0.0032 (4)
C20.0490 (6)0.0528 (6)0.0509 (6)0.0131 (5)0.0065 (5)0.0037 (5)
N30.0533 (6)0.0559 (6)0.0485 (5)0.0153 (4)0.0082 (4)0.0020 (4)
C40.0522 (6)0.0509 (6)0.0447 (6)0.0142 (5)0.0077 (5)0.0013 (4)
C50.0490 (6)0.0506 (6)0.0441 (6)0.0144 (5)0.0043 (4)0.0017 (4)
C60.0452 (6)0.0589 (7)0.0453 (6)0.0136 (5)0.0008 (4)0.0046 (5)
C70.0618 (8)0.0618 (7)0.0550 (7)0.0164 (6)0.0035 (6)0.0016 (6)
C80.0718 (9)0.0880 (11)0.0556 (8)0.0206 (8)0.0046 (7)0.0079 (7)
C90.0666 (9)0.1012 (12)0.0489 (7)0.0127 (8)0.0032 (6)0.0084 (7)
C100.0756 (10)0.0776 (10)0.0607 (8)0.0095 (8)0.0002 (7)0.0219 (7)
C110.0671 (8)0.0585 (7)0.0599 (7)0.0133 (6)0.0035 (6)0.0071 (6)
C120.0517 (7)0.0728 (8)0.0667 (8)0.0215 (6)0.0050 (6)0.0036 (6)
C130.0614 (7)0.0510 (6)0.0440 (6)0.0189 (5)0.0049 (5)0.0026 (5)
C140.0628 (8)0.0854 (10)0.0491 (7)0.0233 (7)0.0032 (6)0.0007 (6)
C150.0681 (9)0.0919 (11)0.0657 (9)0.0287 (8)0.0055 (7)0.0014 (8)
C160.0945 (12)0.0896 (11)0.0565 (8)0.0373 (9)0.0156 (8)0.0041 (7)
C170.1053 (13)0.1051 (13)0.0439 (7)0.0458 (11)0.0064 (7)0.0120 (7)
C180.0756 (9)0.0829 (10)0.0481 (7)0.0311 (8)0.0106 (6)0.0104 (6)
C190.0480 (6)0.0606 (7)0.0405 (5)0.0161 (5)0.0026 (4)0.0027 (5)
C200.0594 (8)0.0996 (11)0.0536 (7)0.0278 (8)0.0089 (6)0.0204 (7)
C210.0608 (9)0.1465 (17)0.0460 (7)0.0279 (10)0.0130 (6)0.0113 (9)
C220.0615 (9)0.1152 (14)0.0683 (9)0.0362 (9)0.0008 (7)0.0245 (9)
C230.0846 (11)0.0763 (10)0.0999 (13)0.0374 (9)0.0152 (10)0.0107 (9)
C240.0741 (9)0.0610 (8)0.0753 (9)0.0248 (7)0.0189 (7)0.0034 (7)
Geometric parameters (Å, º) top
N1—C21.3732 (15)C12—H12E0.9600
N1—C51.3950 (16)C12—H12F0.9600
N1—C61.4368 (15)C13—C141.3868 (19)
C2—N31.3123 (16)C13—C181.3925 (18)
C2—C121.4874 (18)C14—C151.385 (2)
N3—C41.3900 (15)C14—H140.9300
C4—C51.3754 (15)C15—C161.375 (2)
C4—C131.4721 (17)C15—H150.9300
C5—C191.4787 (16)C16—C171.373 (3)
C6—C71.3803 (19)C16—H160.9300
C6—C111.3829 (18)C17—C181.382 (2)
C7—C81.3880 (19)C17—H170.9300
C7—H70.9300C18—H180.9300
C8—C91.375 (2)C19—C201.3821 (18)
C8—H80.9300C19—C241.3863 (19)
C9—C101.371 (2)C20—C211.399 (2)
C9—H90.9300C20—H200.9300
C10—C111.392 (2)C21—C221.368 (3)
C10—H100.9300C21—H210.9300
C11—H110.9300C22—C231.350 (3)
C12—H12A0.9600C22—H220.9300
C12—H12B0.9600C23—C241.381 (2)
C12—H12C0.9600C23—H230.9300
C12—H12D0.9601C24—H240.9300
C2—N1—C5107.14 (10)H12D—C12—H12E109.5
C2—N1—C6125.99 (10)C2—C12—H12F109.5
C5—N1—C6126.87 (10)H12A—C12—H12F70.8
N3—C2—N1111.36 (11)H12C—C12—H12F138.1
N3—C2—C12124.87 (11)H12D—C12—H12F109.5
N1—C2—C12123.75 (11)H12E—C12—H12F109.5
C2—N3—C4106.25 (10)C14—C13—C18117.88 (13)
C5—C4—N3109.98 (11)C14—C13—C4122.39 (11)
C5—C4—C13130.35 (11)C18—C13—C4119.63 (12)
N3—C4—C13119.44 (10)C15—C14—C13121.16 (14)
C4—C5—N1105.28 (10)C15—C14—H14119.4
C4—C5—C19132.45 (11)C13—C14—H14119.4
N1—C5—C19122.27 (10)C16—C15—C14120.15 (16)
C7—C6—C11120.84 (12)C16—C15—H15119.9
C7—C6—N1119.17 (11)C14—C15—H15119.9
C11—C6—N1119.99 (12)C17—C16—C15119.42 (15)
C6—C7—C8119.33 (13)C17—C16—H16120.3
C6—C7—H7120.3C15—C16—H16120.3
C8—C7—H7120.3C16—C17—C18120.76 (14)
C9—C8—C7120.15 (15)C16—C17—H17119.6
C9—C8—H8119.9C18—C17—H17119.6
C7—C8—H8119.9C17—C18—C13120.63 (15)
C10—C9—C8120.29 (14)C17—C18—H18119.7
C10—C9—H9119.9C13—C18—H18119.7
C8—C9—H9119.9C20—C19—C24118.23 (13)
C9—C10—C11120.43 (14)C20—C19—C5121.82 (12)
C9—C10—H10119.8C24—C19—C5119.95 (12)
C11—C10—H10119.8C19—C20—C21119.85 (16)
C6—C11—C10118.92 (15)C19—C20—H20120.1
C6—C11—H11120.5C21—C20—H20120.1
C10—C11—H11120.5C22—C21—C20120.52 (15)
C2—C12—H12A109.5C22—C21—H21119.7
C2—C12—H12B109.5C20—C21—H21119.7
H12A—C12—H12B109.5C23—C22—C21119.81 (15)
C2—C12—H12C109.5C23—C22—H22120.1
H12A—C12—H12C109.5C21—C22—H22120.1
H12B—C12—H12C109.5C22—C23—C24120.66 (17)
C2—C12—H12D109.5C22—C23—H23119.7
H12A—C12—H12D138.1C24—C23—H23119.7
H12B—C12—H12D70.8C23—C24—C19120.93 (15)
C2—C12—H12E109.5C23—C24—H24119.5
H12B—C12—H12E138.1C19—C24—H24119.5
H12C—C12—H12E70.8
C5—N1—C2—N30.23 (14)N1—C6—C11—C10179.12 (12)
C6—N1—C2—N3179.47 (11)C9—C10—C11—C61.0 (2)
C5—N1—C2—C12178.35 (12)C5—C4—C13—C1423.2 (2)
C6—N1—C2—C120.89 (19)N3—C4—C13—C14150.74 (13)
N1—C2—N3—C40.33 (14)C5—C4—C13—C18160.56 (14)
C12—C2—N3—C4178.89 (12)N3—C4—C13—C1825.55 (18)
C2—N3—C4—C50.78 (14)C18—C13—C14—C150.8 (2)
C2—N3—C4—C13174.26 (11)C4—C13—C14—C15177.19 (14)
N3—C4—C5—N10.91 (13)C13—C14—C15—C160.9 (3)
C13—C4—C5—N1173.43 (12)C14—C15—C16—C170.4 (3)
N3—C4—C5—C19178.01 (12)C15—C16—C17—C180.1 (3)
C13—C4—C5—C197.7 (2)C16—C17—C18—C130.1 (3)
C2—N1—C5—C40.69 (13)C14—C13—C18—C170.4 (2)
C6—N1—C5—C4179.92 (11)C4—C13—C18—C17176.84 (14)
C2—N1—C5—C19178.37 (11)C4—C5—C19—C20121.98 (16)
C6—N1—C5—C190.86 (19)N1—C5—C19—C2059.26 (17)
C2—N1—C6—C763.99 (17)C4—C5—C19—C2458.3 (2)
C5—N1—C6—C7116.92 (14)N1—C5—C19—C24120.45 (14)
C2—N1—C6—C11115.71 (15)C24—C19—C20—C210.2 (2)
C5—N1—C6—C1163.38 (17)C5—C19—C20—C21179.56 (13)
C11—C6—C7—C81.9 (2)C19—C20—C21—C220.5 (2)
N1—C6—C7—C8177.82 (12)C20—C21—C22—C230.1 (3)
C6—C7—C8—C91.7 (2)C21—C22—C23—C240.5 (3)
C7—C8—C9—C100.2 (3)C22—C23—C24—C190.9 (3)
C8—C9—C10—C111.2 (3)C20—C19—C24—C230.5 (2)
C7—C6—C11—C100.6 (2)C5—C19—C24—C23179.78 (14)

Experimental details

Crystal data
Chemical formulaC22H18N2
Mr310.38
Crystal system, space groupTriclinic, P1
Temperature (K)299
a, b, c (Å)8.5768 (5), 9.8285 (9), 10.7315 (7)
α, β, γ (°)96.288 (6), 92.042 (4), 106.338 (5)
V3)860.79 (11)
Z2
Radiation typeMo Kα
µ (mm1)0.07
Crystal size (mm)0.65 × 0.65 × 0.36
Data collection
DiffractometerBruker P4
diffractometer
Absorption correction
No. of measured, independent and
observed [I > 2σ(I)] reflections
5916, 4985, 3642
Rint0.016
(sin θ/λ)max1)0.703
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.050, 0.145, 1.04
No. of reflections4985
No. of parameters219
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.27, 0.20

Computer programs: XSCANS (Siemens, 1996), XSCANS, SHELXTL-Plus (Sheldrick, 1998), SHELXL97 (Sheldrick, 1997), SHELXTL-Plus, SHELXL97.

Selected geometric parameters (Å, º) top
N1—C21.3732 (15)N3—C41.3900 (15)
N1—C51.3950 (16)C4—C51.3754 (15)
N1—C61.4368 (15)C4—C131.4721 (17)
C2—N31.3123 (16)C5—C191.4787 (16)
C2—C121.4874 (18)
C2—N1—C5107.14 (10)C5—C4—N3109.98 (11)
C2—N1—C6125.99 (10)C5—C4—C13130.35 (11)
C5—N1—C6126.87 (10)N3—C4—C13119.44 (10)
N3—C2—N1111.36 (11)C4—C5—N1105.28 (10)
N3—C2—C12124.87 (11)C4—C5—C19132.45 (11)
N1—C2—C12123.75 (11)N1—C5—C19122.27 (10)
C2—N3—C4106.25 (10)
 

Follow Acta Cryst. C
Sign up for e-alerts
Follow Acta Cryst. on Twitter
Follow us on facebook
Sign up for RSS feeds