Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270102016220/fg1661sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S0108270102016220/fg1661Isup2.hkl |
CCDC reference: 197342
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?).
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.
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.
C22H18N2 | Z = 2 |
Mr = 310.38 | F(000) = 328 |
Triclinic, P1 | Dx = 1.198 Mg m−3 |
Hall symbol: -P 1 | Melting point: 533 K |
a = 8.5768 (5) Å | Mo Kα radiation, λ = 0.71073 Å |
b = 9.8285 (9) Å | Cell parameters from 78 reflections |
c = 10.7315 (7) Å | θ = 4.5–15.0° |
α = 96.288 (6)° | µ = 0.07 mm−1 |
β = 92.042 (4)° | T = 299 K |
γ = 106.338 (5)° | Regular prism, colourless |
V = 860.79 (11) Å3 | 0.65 × 0.65 × 0.36 mm |
Bruker P4 diffractometer | Rint = 0.016 |
Radiation source: fine-focus sealed tube | θmax = 30.0°, θmin = 1.9° |
Graphite monochromator | h = −1→11 |
ω scans | k = −13→13 |
5916 measured reflections | l = −15→15 |
4985 independent reflections | 3 standard reflections every 97 reflections |
3642 reflections with I > 2σ(I) | intensity decay: 2% |
Refinement on F2 | Secondary atom site location: difference Fourier map |
Least-squares matrix: full | Hydrogen site location: inferred from neighbouring sites |
R[F2 > 2σ(F2)] = 0.050 | H-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 reflections | Δρmax = 0.27 e Å−3 |
219 parameters | Δρmin = −0.20 e Å−3 |
0 restraints | Extinction correction: SHELXL97 (Sheldrick, 1997), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
Primary atom site location: structure-invariant direct methods | Extinction coefficient: 0.034 (4) |
C22H18N2 | γ = 106.338 (5)° |
Mr = 310.38 | V = 860.79 (11) Å3 |
Triclinic, P1 | Z = 2 |
a = 8.5768 (5) Å | Mo Kα radiation |
b = 9.8285 (9) Å | µ = 0.07 mm−1 |
c = 10.7315 (7) Å | T = 299 K |
α = 96.288 (6)° | 0.65 × 0.65 × 0.36 mm |
β = 92.042 (4)° |
Bruker P4 diffractometer | Rint = 0.016 |
5916 measured reflections | 3 standard reflections every 97 reflections |
4985 independent reflections | intensity decay: 2% |
3642 reflections with I > 2σ(I) |
R[F2 > 2σ(F2)] = 0.050 | 0 restraints |
wR(F2) = 0.145 | H-atom parameters constrained |
S = 1.04 | Δρmax = 0.27 e Å−3 |
4985 reflections | Δρmin = −0.20 e Å−3 |
219 parameters |
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. |
x | y | z | Uiso*/Ueq | Occ. (<1) | |
N1 | 0.47519 (12) | 0.26420 (11) | 0.39603 (9) | 0.0503 (2) | |
C2 | 0.39422 (15) | 0.31749 (13) | 0.48871 (11) | 0.0520 (3) | |
N3 | 0.46889 (13) | 0.32914 (11) | 0.59994 (9) | 0.0532 (3) | |
C4 | 0.60569 (15) | 0.28237 (13) | 0.58033 (11) | 0.0496 (3) | |
C5 | 0.61126 (15) | 0.24018 (13) | 0.45447 (11) | 0.0482 (3) | |
C6 | 0.42645 (14) | 0.23693 (13) | 0.26405 (11) | 0.0510 (3) | |
C7 | 0.42207 (17) | 0.34995 (15) | 0.19951 (13) | 0.0607 (3) | |
H7 | 0.4539 | 0.4429 | 0.2404 | 0.073* | |
C8 | 0.36975 (19) | 0.32349 (19) | 0.07298 (14) | 0.0726 (4) | |
H8 | 0.3637 | 0.3987 | 0.0293 | 0.087* | |
C9 | 0.32680 (19) | 0.1863 (2) | 0.01208 (14) | 0.0761 (4) | |
H9 | 0.2921 | 0.1691 | −0.0728 | 0.091* | |
C10 | 0.3350 (2) | 0.07479 (19) | 0.07588 (14) | 0.0763 (4) | |
H10 | 0.3076 | −0.0175 | 0.0337 | 0.092* | |
C11 | 0.38393 (18) | 0.09873 (15) | 0.20340 (13) | 0.0639 (3) | |
H11 | 0.3880 | 0.0230 | 0.2471 | 0.077* | |
C12 | 0.23945 (16) | 0.35349 (16) | 0.46493 (14) | 0.0639 (4) | |
H12A | 0.2049 | 0.3889 | 0.5430 | 0.096* | 0.63 (2) |
H12B | 0.1572 | 0.2694 | 0.4274 | 0.096* | 0.63 (2) |
H12C | 0.2564 | 0.4254 | 0.4091 | 0.096* | 0.63 (2) |
H12D | 0.2230 | 0.3593 | 0.3769 | 0.096* | 0.37 (2) |
H12E | 0.2452 | 0.4438 | 0.5121 | 0.096* | 0.37 (2) |
H12F | 0.1503 | 0.2807 | 0.4904 | 0.096* | 0.37 (2) |
C13 | 0.72423 (16) | 0.29509 (13) | 0.68670 (11) | 0.0518 (3) | |
C14 | 0.88829 (18) | 0.31270 (17) | 0.67127 (13) | 0.0660 (4) | |
H14 | 0.9251 | 0.3125 | 0.5908 | 0.079* | |
C15 | 0.9983 (2) | 0.33053 (19) | 0.77360 (15) | 0.0749 (4) | |
H15 | 1.1076 | 0.3409 | 0.7613 | 0.090* | |
C16 | 0.9462 (2) | 0.33292 (19) | 0.89336 (15) | 0.0789 (5) | |
H16 | 1.0200 | 0.3455 | 0.9622 | 0.095* | |
C17 | 0.7844 (2) | 0.3166 (2) | 0.91031 (14) | 0.0813 (5) | |
H17 | 0.7489 | 0.3183 | 0.9912 | 0.098* | |
C18 | 0.6738 (2) | 0.29779 (17) | 0.80862 (13) | 0.0668 (4) | |
H18 | 0.5645 | 0.2868 | 0.8217 | 0.080* | |
C19 | 0.72545 (15) | 0.17892 (13) | 0.38347 (10) | 0.0503 (3) | |
C20 | 0.80897 (18) | 0.24451 (19) | 0.28823 (13) | 0.0689 (4) | |
H20 | 0.7947 | 0.3299 | 0.2676 | 0.083* | |
C21 | 0.91500 (19) | 0.1822 (2) | 0.22297 (14) | 0.0847 (5) | |
H21 | 0.9705 | 0.2261 | 0.1585 | 0.102* | |
C22 | 0.9376 (2) | 0.0571 (2) | 0.25327 (16) | 0.0823 (5) | |
H22 | 1.0084 | 0.0163 | 0.2096 | 0.099* | |
C23 | 0.8569 (2) | −0.0069 (2) | 0.34668 (18) | 0.0854 (5) | |
H23 | 0.8732 | −0.0915 | 0.3676 | 0.103* | |
C24 | 0.7505 (2) | 0.05196 (16) | 0.41149 (15) | 0.0690 (4) | |
H24 | 0.6948 | 0.0058 | 0.4748 | 0.083* |
U11 | U22 | U33 | U12 | U13 | U23 | |
N1 | 0.0495 (5) | 0.0548 (5) | 0.0449 (5) | 0.0157 (4) | 0.0026 (4) | −0.0032 (4) |
C2 | 0.0490 (6) | 0.0528 (6) | 0.0509 (6) | 0.0131 (5) | 0.0065 (5) | −0.0037 (5) |
N3 | 0.0533 (6) | 0.0559 (6) | 0.0485 (5) | 0.0153 (4) | 0.0082 (4) | −0.0020 (4) |
C4 | 0.0522 (6) | 0.0509 (6) | 0.0447 (6) | 0.0142 (5) | 0.0077 (5) | 0.0013 (4) |
C5 | 0.0490 (6) | 0.0506 (6) | 0.0441 (6) | 0.0144 (5) | 0.0043 (4) | 0.0017 (4) |
C6 | 0.0452 (6) | 0.0589 (7) | 0.0453 (6) | 0.0136 (5) | 0.0008 (4) | −0.0046 (5) |
C7 | 0.0618 (8) | 0.0618 (7) | 0.0550 (7) | 0.0164 (6) | −0.0035 (6) | −0.0016 (6) |
C8 | 0.0718 (9) | 0.0880 (11) | 0.0556 (8) | 0.0206 (8) | −0.0046 (7) | 0.0079 (7) |
C9 | 0.0666 (9) | 0.1012 (12) | 0.0489 (7) | 0.0127 (8) | −0.0032 (6) | −0.0084 (7) |
C10 | 0.0756 (10) | 0.0776 (10) | 0.0607 (8) | 0.0095 (8) | 0.0002 (7) | −0.0219 (7) |
C11 | 0.0671 (8) | 0.0585 (7) | 0.0599 (7) | 0.0133 (6) | 0.0035 (6) | −0.0071 (6) |
C12 | 0.0517 (7) | 0.0728 (8) | 0.0667 (8) | 0.0215 (6) | 0.0050 (6) | −0.0036 (6) |
C13 | 0.0614 (7) | 0.0510 (6) | 0.0440 (6) | 0.0189 (5) | 0.0049 (5) | 0.0026 (5) |
C14 | 0.0628 (8) | 0.0854 (10) | 0.0491 (7) | 0.0233 (7) | 0.0032 (6) | 0.0007 (6) |
C15 | 0.0681 (9) | 0.0919 (11) | 0.0657 (9) | 0.0287 (8) | −0.0055 (7) | 0.0014 (8) |
C16 | 0.0945 (12) | 0.0896 (11) | 0.0565 (8) | 0.0373 (9) | −0.0156 (8) | 0.0041 (7) |
C17 | 0.1053 (13) | 0.1051 (13) | 0.0439 (7) | 0.0458 (11) | 0.0064 (7) | 0.0120 (7) |
C18 | 0.0756 (9) | 0.0829 (10) | 0.0481 (7) | 0.0311 (8) | 0.0106 (6) | 0.0104 (6) |
C19 | 0.0480 (6) | 0.0606 (7) | 0.0405 (5) | 0.0161 (5) | 0.0026 (4) | −0.0027 (5) |
C20 | 0.0594 (8) | 0.0996 (11) | 0.0536 (7) | 0.0278 (8) | 0.0089 (6) | 0.0204 (7) |
C21 | 0.0608 (9) | 0.1465 (17) | 0.0460 (7) | 0.0279 (10) | 0.0130 (6) | 0.0113 (9) |
C22 | 0.0615 (9) | 0.1152 (14) | 0.0683 (9) | 0.0362 (9) | 0.0008 (7) | −0.0245 (9) |
C23 | 0.0846 (11) | 0.0763 (10) | 0.0999 (13) | 0.0374 (9) | 0.0152 (10) | −0.0107 (9) |
C24 | 0.0741 (9) | 0.0610 (8) | 0.0753 (9) | 0.0248 (7) | 0.0189 (7) | 0.0034 (7) |
N1—C2 | 1.3732 (15) | C12—H12E | 0.9600 |
N1—C5 | 1.3950 (16) | C12—H12F | 0.9600 |
N1—C6 | 1.4368 (15) | C13—C14 | 1.3868 (19) |
C2—N3 | 1.3123 (16) | C13—C18 | 1.3925 (18) |
C2—C12 | 1.4874 (18) | C14—C15 | 1.385 (2) |
N3—C4 | 1.3900 (15) | C14—H14 | 0.9300 |
C4—C5 | 1.3754 (15) | C15—C16 | 1.375 (2) |
C4—C13 | 1.4721 (17) | C15—H15 | 0.9300 |
C5—C19 | 1.4787 (16) | C16—C17 | 1.373 (3) |
C6—C7 | 1.3803 (19) | C16—H16 | 0.9300 |
C6—C11 | 1.3829 (18) | C17—C18 | 1.382 (2) |
C7—C8 | 1.3880 (19) | C17—H17 | 0.9300 |
C7—H7 | 0.9300 | C18—H18 | 0.9300 |
C8—C9 | 1.375 (2) | C19—C20 | 1.3821 (18) |
C8—H8 | 0.9300 | C19—C24 | 1.3863 (19) |
C9—C10 | 1.371 (2) | C20—C21 | 1.399 (2) |
C9—H9 | 0.9300 | C20—H20 | 0.9300 |
C10—C11 | 1.392 (2) | C21—C22 | 1.368 (3) |
C10—H10 | 0.9300 | C21—H21 | 0.9300 |
C11—H11 | 0.9300 | C22—C23 | 1.350 (3) |
C12—H12A | 0.9600 | C22—H22 | 0.9300 |
C12—H12B | 0.9600 | C23—C24 | 1.381 (2) |
C12—H12C | 0.9600 | C23—H23 | 0.9300 |
C12—H12D | 0.9601 | C24—H24 | 0.9300 |
C2—N1—C5 | 107.14 (10) | H12D—C12—H12E | 109.5 |
C2—N1—C6 | 125.99 (10) | C2—C12—H12F | 109.5 |
C5—N1—C6 | 126.87 (10) | H12A—C12—H12F | 70.8 |
N3—C2—N1 | 111.36 (11) | H12C—C12—H12F | 138.1 |
N3—C2—C12 | 124.87 (11) | H12D—C12—H12F | 109.5 |
N1—C2—C12 | 123.75 (11) | H12E—C12—H12F | 109.5 |
C2—N3—C4 | 106.25 (10) | C14—C13—C18 | 117.88 (13) |
C5—C4—N3 | 109.98 (11) | C14—C13—C4 | 122.39 (11) |
C5—C4—C13 | 130.35 (11) | C18—C13—C4 | 119.63 (12) |
N3—C4—C13 | 119.44 (10) | C15—C14—C13 | 121.16 (14) |
C4—C5—N1 | 105.28 (10) | C15—C14—H14 | 119.4 |
C4—C5—C19 | 132.45 (11) | C13—C14—H14 | 119.4 |
N1—C5—C19 | 122.27 (10) | C16—C15—C14 | 120.15 (16) |
C7—C6—C11 | 120.84 (12) | C16—C15—H15 | 119.9 |
C7—C6—N1 | 119.17 (11) | C14—C15—H15 | 119.9 |
C11—C6—N1 | 119.99 (12) | C17—C16—C15 | 119.42 (15) |
C6—C7—C8 | 119.33 (13) | C17—C16—H16 | 120.3 |
C6—C7—H7 | 120.3 | C15—C16—H16 | 120.3 |
C8—C7—H7 | 120.3 | C16—C17—C18 | 120.76 (14) |
C9—C8—C7 | 120.15 (15) | C16—C17—H17 | 119.6 |
C9—C8—H8 | 119.9 | C18—C17—H17 | 119.6 |
C7—C8—H8 | 119.9 | C17—C18—C13 | 120.63 (15) |
C10—C9—C8 | 120.29 (14) | C17—C18—H18 | 119.7 |
C10—C9—H9 | 119.9 | C13—C18—H18 | 119.7 |
C8—C9—H9 | 119.9 | C20—C19—C24 | 118.23 (13) |
C9—C10—C11 | 120.43 (14) | C20—C19—C5 | 121.82 (12) |
C9—C10—H10 | 119.8 | C24—C19—C5 | 119.95 (12) |
C11—C10—H10 | 119.8 | C19—C20—C21 | 119.85 (16) |
C6—C11—C10 | 118.92 (15) | C19—C20—H20 | 120.1 |
C6—C11—H11 | 120.5 | C21—C20—H20 | 120.1 |
C10—C11—H11 | 120.5 | C22—C21—C20 | 120.52 (15) |
C2—C12—H12A | 109.5 | C22—C21—H21 | 119.7 |
C2—C12—H12B | 109.5 | C20—C21—H21 | 119.7 |
H12A—C12—H12B | 109.5 | C23—C22—C21 | 119.81 (15) |
C2—C12—H12C | 109.5 | C23—C22—H22 | 120.1 |
H12A—C12—H12C | 109.5 | C21—C22—H22 | 120.1 |
H12B—C12—H12C | 109.5 | C22—C23—C24 | 120.66 (17) |
C2—C12—H12D | 109.5 | C22—C23—H23 | 119.7 |
H12A—C12—H12D | 138.1 | C24—C23—H23 | 119.7 |
H12B—C12—H12D | 70.8 | C23—C24—C19 | 120.93 (15) |
C2—C12—H12E | 109.5 | C23—C24—H24 | 119.5 |
H12B—C12—H12E | 138.1 | C19—C24—H24 | 119.5 |
H12C—C12—H12E | 70.8 | ||
C5—N1—C2—N3 | 0.23 (14) | N1—C6—C11—C10 | 179.12 (12) |
C6—N1—C2—N3 | 179.47 (11) | C9—C10—C11—C6 | −1.0 (2) |
C5—N1—C2—C12 | −178.35 (12) | C5—C4—C13—C14 | 23.2 (2) |
C6—N1—C2—C12 | 0.89 (19) | N3—C4—C13—C14 | −150.74 (13) |
N1—C2—N3—C4 | 0.33 (14) | C5—C4—C13—C18 | −160.56 (14) |
C12—C2—N3—C4 | 178.89 (12) | N3—C4—C13—C18 | 25.55 (18) |
C2—N3—C4—C5 | −0.78 (14) | C18—C13—C14—C15 | 0.8 (2) |
C2—N3—C4—C13 | 174.26 (11) | C4—C13—C14—C15 | 177.19 (14) |
N3—C4—C5—N1 | 0.91 (13) | C13—C14—C15—C16 | −0.9 (3) |
C13—C4—C5—N1 | −173.43 (12) | C14—C15—C16—C17 | 0.4 (3) |
N3—C4—C5—C19 | −178.01 (12) | C15—C16—C17—C18 | 0.1 (3) |
C13—C4—C5—C19 | 7.7 (2) | C16—C17—C18—C13 | −0.1 (3) |
C2—N1—C5—C4 | −0.69 (13) | C14—C13—C18—C17 | −0.4 (2) |
C6—N1—C5—C4 | −179.92 (11) | C4—C13—C18—C17 | −176.84 (14) |
C2—N1—C5—C19 | 178.37 (11) | C4—C5—C19—C20 | −121.98 (16) |
C6—N1—C5—C19 | −0.86 (19) | N1—C5—C19—C20 | 59.26 (17) |
C2—N1—C6—C7 | 63.99 (17) | C4—C5—C19—C24 | 58.3 (2) |
C5—N1—C6—C7 | −116.92 (14) | N1—C5—C19—C24 | −120.45 (14) |
C2—N1—C6—C11 | −115.71 (15) | C24—C19—C20—C21 | 0.2 (2) |
C5—N1—C6—C11 | 63.38 (17) | C5—C19—C20—C21 | −179.56 (13) |
C11—C6—C7—C8 | 1.9 (2) | C19—C20—C21—C22 | −0.5 (2) |
N1—C6—C7—C8 | −177.82 (12) | C20—C21—C22—C23 | 0.1 (3) |
C6—C7—C8—C9 | −1.7 (2) | C21—C22—C23—C24 | 0.5 (3) |
C7—C8—C9—C10 | 0.2 (3) | C22—C23—C24—C19 | −0.9 (3) |
C8—C9—C10—C11 | 1.2 (3) | C20—C19—C24—C23 | 0.5 (2) |
C7—C6—C11—C10 | −0.6 (2) | C5—C19—C24—C23 | −179.78 (14) |
Experimental details
Crystal data | |
Chemical formula | C22H18N2 |
Mr | 310.38 |
Crystal system, space group | Triclinic, 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) |
V (Å3) | 860.79 (11) |
Z | 2 |
Radiation type | Mo Kα |
µ (mm−1) | 0.07 |
Crystal size (mm) | 0.65 × 0.65 × 0.36 |
Data collection | |
Diffractometer | Bruker P4 diffractometer |
Absorption correction | – |
No. of measured, independent and observed [I > 2σ(I)] reflections | 5916, 4985, 3642 |
Rint | 0.016 |
(sin θ/λ)max (Å−1) | 0.703 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.050, 0.145, 1.04 |
No. of reflections | 4985 |
No. of parameters | 219 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.27, −0.20 |
Computer programs: XSCANS (Siemens, 1996), XSCANS, SHELXTL-Plus (Sheldrick, 1998), SHELXL97 (Sheldrick, 1997), SHELXTL-Plus, SHELXL97.
N1—C2 | 1.3732 (15) | N3—C4 | 1.3900 (15) |
N1—C5 | 1.3950 (16) | C4—C5 | 1.3754 (15) |
N1—C6 | 1.4368 (15) | C4—C13 | 1.4721 (17) |
C2—N3 | 1.3123 (16) | C5—C19 | 1.4787 (16) |
C2—C12 | 1.4874 (18) | ||
C2—N1—C5 | 107.14 (10) | C5—C4—N3 | 109.98 (11) |
C2—N1—C6 | 125.99 (10) | C5—C4—C13 | 130.35 (11) |
C5—N1—C6 | 126.87 (10) | N3—C4—C13 | 119.44 (10) |
N3—C2—N1 | 111.36 (11) | C4—C5—N1 | 105.28 (10) |
N3—C2—C12 | 124.87 (11) | C4—C5—C19 | 132.45 (11) |
N1—C2—C12 | 123.75 (11) | N1—C5—C19 | 122.27 (10) |
C2—N3—C4 | 106.25 (10) |
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 C≐N and C≐C 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.