2-(2,4,6-Trimethyl-phen-yl)-1,10-phenanthroline

Area of Science:

• Crystal Engineering
• Supramolecular Chemistry
• Organic Solid-State Chemistry

Background:

• Understanding the spatial arrangement and intermolecular interactions of organic molecules is fundamental in crystal engineering.
• Phenanthroline derivatives are widely studied for their electronic and photophysical properties, making their solid-state behavior of interest.
• Mesityl groups are often incorporated to influence molecular packing and solubility.

Purpose of the Study:

• To elucidate the crystal structure of the title molecule, C(21)H(18)N(2).
• To quantify the dihedral angle between the mesityl group's benzene ring and the phenanthroline ring system.
• To identify and characterize the intermolecular interactions stabilizing the crystal lattice, specifically π-π stacking.

Main Methods:

• Single-crystal X-ray diffraction was employed to determine the three-dimensional molecular structure and packing.
• Analysis of the crystal structure involved calculating dihedral angles between specific ring systems.
• Intermolecular interactions, such as π-π stacking, were identified and quantified by measuring centroid-centroid distances.

Main Results:

• The crystal structure of C(21)H(18)N(2) was successfully determined.
• A significant dihedral angle of 82.69(4)° was observed between the mean plane of the mesityl benzene ring and the phenanthroline ring system.
• The crystal structure is stabilized by π-π stacking interactions between the phenanthroline system and the mesityl benzene ring of adjacent molecules, with centroid-centroid distances of 3.7776(14) Å and 3.7155(13) Å.

Conclusions:

• The determined crystal structure provides precise geometric information about the molecule's conformation in the solid state.
• The significant dihedral angle suggests a non-planar arrangement, influencing molecular packing.
• π-π stacking interactions play a critical role in the self-assembly and stabilization of the crystal lattice, offering insights for designing related materials.