N-(4-Bromo-phen-yl)pyrazine-2-carbox-amide

Area of Science:

• Crystallography
• Supramolecular Chemistry
• Organic Chemistry

Background:

• Understanding molecular conformation and crystal packing is crucial for predicting material properties.
• Halogen bonding and pi-pi interactions are key non-covalent forces driving supramolecular assembly.

Purpose of the Study:

• To elucidate the crystal structure and intermolecular interactions of the title compound (C11H8BrN3O).
• To analyze the factors contributing to the molecule's near-planar conformation and its assembly into a layered crystal lattice.

Main Methods:

• Single-crystal X-ray diffraction was employed to determine the three-dimensional molecular and crystal structure.
• Analysis of bond lengths, angles, and non-covalent interactions (hydrogen bonds, halogen bonds, pi-pi stacking) was performed.

Main Results:

• The molecule adopts a nearly planar conformation, stabilized by an intramolecular N-H⋯N hydrogen bond forming an S(5) ring.
• Supramolecular chains are formed via C-H⋯O contacts and linked into double layers by N⋯Br halogen bonds and C-Br⋯π interactions.
• These layers stack along the b-axis through weak π-π interactions between pyrazine and benzene ring centroids.

Conclusions:

• The crystal structure is dictated by a combination of intramolecular hydrogen bonding and various intermolecular forces.
• The specific arrangement of intermolecular interactions (halogen bonds, C-Br⋯π, π-π stacking) leads to a unique double-layer stacking motif.
• This detailed structural analysis provides insights into the solid-state behavior of this class of organic compounds.