A second monoclinic polymorph of 2,3-di-phenyl-pyrazine.

Area of Science:

• Crystallography
• Solid-state chemistry
• Organic chemistry

Background:

• 2,3-diphenyl-pyrazine is a known compound with established crystal forms.
• Understanding polymorphism is crucial for material properties and applications.

Purpose of the Study:

• To characterize a novel crystalline form of 2,3-diphenyl-pyrazine (Compound I).
• To compare the crystal structure and intermolecular interactions of this new polymorph with a previously reported form.
• To survey the bonding modes of 2,3-diphenyl-pyrazine as a ligand.

Main Methods:

• Single-crystal X-ray diffraction analysis to determine the crystal structure of Compound I.
• Analysis of dihedral angles, hydrogen bonding (C-H⋯N), and π-π stacking interactions.
• Comparison of Hirshfeld surfaces and energy frameworks between polymorphs.

Main Results:

• Compound I crystallizes in the space group P2₁/c with specific dihedral angles (53.12° and 33.28°) between the pyrazine and phenyl rings.
• Intermolecular interactions include C-H⋯N hydrogen bonds forming dimers, π-π stacking between pyrazine rings, and C-H⋯π interactions.
• Compound I represents a new polymorph of 2,3-diphenyl-pyrazine, distinct from the C2/c form.

Conclusions:

• The novel polymorph of 2,3-diphenyl-pyrazine exhibits unique structural features and intermolecular interactions.
• Detailed analysis of Hirshfeld surfaces and energy frameworks provides insights into crystal packing differences between polymorphs.
• The study contributes to the understanding of structure-property relationships in organic crystalline materials.