2,4,6-Tris(2,4-dimethylphenyl)-1,3,5-triazine

Two virtually superimposable molecules comprise the asymmetric unit of the title compound, C27H27N3. The range of dihedral angles between the central 1,3,5-triazine ring and the attached benzene rings is 20.88 (14)–31.36 (14)°, and the shape of each molecule is of a flattened bowl. The crystal packing features weak C—H⋯π bonds and π–π interactions between triazine and benzene rings [centroid–centroid separations = 3.7696 (17) and 3.7800 (18) Å] that result in the formation of supramolecular layers in the ac plane. The crystal studied was a non-merohedral twin with a minor twin component of 20.7 (3)%.

Two virtually superimposable molecules comprise the asymmetric unit of the title compound, C 27 H 27 N 3 . The range of dihedral angles between the central 1,3,5-triazine ring and the attached benzene rings is 20.88 (14)-31. 36 (14) , and the shape of each molecule is of a flattened bowl. The crystal packing features weak C-HÁ Á Á bonds andinteractions between triazine and benzene rings [centroid-centroid separations = 3.7696 (17) and 3.7800 (18) Å ] that result in the formation of supramolecular layers in the ac plane. The crystal studied was a non-merohedral twin with a minor twin component of 20.7 (3)%.
Two independent molecules comprise the crystallographic asymmetric unit of (I), Fig. 1 (14) and 20.88 (14)°, respectively. Within each molecule, one of the 2,4-dimethylphenyl residues is orientated in the opposite direction to the other two so that the molecules do not have molecular 3-fold symmetry. Overall, the shape of each molecule is of a flattened bowl.
The crystal packing is dominated by C-H···π, Table 1, and π-π interactions. The former occur between the independent molecules with each forming two donor and two acceptor interactions. The π-π interactions occur between like molecules with the shortest contacts occurring between triazine and benzene rings

Experimental
The compound was synthesized by the Friedel-Crafts arylation of cyanuric chloride with excess m-xylene in the presence of aluminium trichloride (Orban et al., 1988).
Aluminium chloride (8.7 g, 0.066 mol) was added to cyanuric chloride (4.0 g, 0.022 mol) in chlorobenzene (20 ml). The suspension was stirred by spinning a stirrer at about 250 rpm. It was then heated at 358 K for 20 min. m-Xylene (3.0 ml, 0.0242 mol) was added over 30 min; the reaction was exothermic. A second 3 ml portion was added over the next 30 min.
The small amount of hydrogen chloride gas that was released was neutralized by 5% sodium hydroxide. A further 3 ml was added over 30 min while keeping the mixture heated at 373 K. The dark-brown reaction mixture was additionally stirred at 378 K for another 20 min.
The warm reaction mixture was added to water (30 ml). The mixture was stirred at 333 K for 10 min. The organic phase was separated and treated with 5% hydrochloric acid. This procedure was repeated.
The solvent was removed and the dark-brown residue was dried at 373 K. It was then transferred it into a 100 ml distillation flask. Toluene (50 ml) was added and the mixture heated at 348 K. To this was added ethanol (15 ml). The solution was set aside for the crystallization of the compound to give 5.4 g of a light-yellow product. The pure compound was obtained as colourless plates after recrystallization from a toluene and ethanol (5:1) mixture in a yield of 3.5 g.

Refinement
Carbon-bound H-atoms were placed in calculated positions [C-H = 0.95 to 0.98 Å, U iso (H) 1.2 to 1.5U eq (C)] and were included in the refinement in the riding model approximation. The crystal is a non-merohedral twin with a twin component of 20.7 (3)%; the twin components were identified by the TwinRotMat routine in PLATON (Spek, 2009).

Figure 1
The molecular structures of the two independent molecules comprising the asymmetric unit of (I) showing displacement ellipsoids at the 70% probability level.

Figure 2
An overlay diagram of two independent molecules in (I). The N1-containing molecule is illustrated in red and the N4molecule in blue. Molecules have been aligned so that the N1,N2,N3 and N5,N6,N4 planes are overlapped.

Figure 3
A view in projection down the c axis of the unit-cell contents for (I). The C-H···π and π-π interactions are shown as purple and orange dashed lines, respectively.