The crystal structure of triphenylene

Abstract

Crystals of triphenylene are orthorhombic with four molecules in a unit cell of dimensions a = 13.17, b ---16-73, e = 5.26/~, space group P212121. The gross features of the structure, previously determined from two projections, have been confirmed using new three-dimensional data, the positional and isotropic thermal parameters of the carbon atoms have been refined by differential syntheses, and the hydrogen atoms have been located. There are small, but significant, deviations from a completely planar arrangement. These displacements are best described in terms of the plane of the central ring: atoms of two of the outer rings are displaced in one direction, and those of the third ring in the opposite direction from this plane. This slight molecular distortion is probably the result of intramolecular steric effects. The mean bond distances agree closely with the values predicted by valence-bond and molecular-orbital calculations. All the intermolecular separations correspond to normal van der Waals interactions.

Electron Crystallography of Small Organic Molecules: Criteria for Data Collection and Strategies for Structure Solution

“…After least-squares refinement, minimizing w(lF, I-ICI) 2, where w = 1/a2(F,,) and a,. (Fo) is an e.s.d, based on counting statistics, the final model from X-ray intensities was very close to the one detcrmincd by Ahmed & Trotter (1963). On average, atomic positions wcre within 0.03 A of thc loci found earlier (Table 2), with equivalent Bi~o values ranging from 3.9 to 6.2 ~2.…”

“…The mean difference in atomic positions, after transposition of the phase model to the same origin as that of the original X-ray determination, is only 0.10 ,~. Although hydrogen positions were included for the molecular search during energy minimization, inclusion of theoretical positions [or those given by Ahmed & Trotter (1963)] did not improvc the fit to the experimental data. A packing diagram is shown in Fig.…”

“…For the atomic coordinates in Table 2, obtained from the energy-minimization procedure, the corresponding mean phase difference to the Ahmed & Trotter (1963) X-ray structure is only 5" for all 86 reflections, corresponding to R --0.29 (Table 3). Qualitatively, diffraction simulations for three zones can be (Ahmed & Trotter, 1963) Electron diffraction (energy minimization) (Fig. 3) to the experimental patterns in Fig.…”

“…In the most recent X-ray determination of triphenylene, by Ahmed & Trotter (1963), 971 hkl intensities were measured visually from Weissenberg films using the hkO, hkl ..... hk4 zones. Structure amplitudes were derived in the usual fashion with no need for an absorption correction.…”

An Efficient Route to Stable Room‐Temperature Liquid‐Crystalline Triphenylenes

“…[8] It is therefore likely that substitution with deactivating groups may proceed beyond one-fold reaction, giving a mixture of mono-, di-and trisubstituted products. The Friedel-Crafts acetylation of triphenylene for example is known to yield either 2-acetylor 2,6-(or 2,7-)diacetyltriphenylene, depending on the temperature (refluxing carbon disulfide/refluxing 1,2-dichloroethane).…”