Effect of substituent position on assembly of compounds bearing ortho/para over meta directing groups

Abstract

This research investigated the impact of substituent location on intermolecular interactions and crystal packing. A class of N-(dichlorophenyl)-2-pyrazincarboxamide derivatives were synthesized and characterized: 2,5-dichloro (2,5-diCl), 3,4-dichloro (3,4-diCl), and 2,4-dichloro (2,4-diCl). Comparison with their monochloro counterparts (2-chloro (2-Cl), 3-chloro (3-Cl), and 4-chloro (4-Cl)) revealed a distinct structural variation upon introducing a second chlorine substituent at the ortho/para positions of the phenyl ring. Conversely, incorporating a second chlorine atom at the meta position resulted in similar molecular packing. These findings suggest that ortho/para directing groups play a dominant role in dictating the crystal assemblies of the studied compounds.

Keywords

• Pyrazincarboxmaide
• Substituent effect
• Assembly
• Chloro-substituent
• Structural Variation