Structure and conformation of meso-2,4-di(N-carbazolyl)pentane

• The stereochemistry of the title compound is established as meso.
• The carbazole groups have no parallel planar close contacts (π-type interactions).
• The nitrogens puckering due to packing forces as found in related structures.
• Bond distances and angles agree with density functional calculations.
• The molecular asymmetry for placement of the two carbazoles is intrinsic.

The stereochemistry of the title compound is established as meso. The carbazole groups have no parallel planar close contacts (π-type interactions), which differs from the packing found previously for terminal 1,n-di(N-carbazolyl)alkanes. Bond distances, bond angles, and torsion angles are compared with those calculated for the isolated molecule using M06-2X density functional theory, which is designed to model intramolecular dispersion effects. The results indicate that dispersion effects have a significant influence on the molecular conformation, although packing effects likely determine the magnitude of the puckering about one of the nitrogens (N1) and give a crystal conformation closer to a theoretical local minimum than to the global minimum potential energy, which are calculated to differ by only 6.7 kJ/mol at 298 K.

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