4-(4-Fluoro-3-phenoxyphenyl)-6-(4-fluorophenyl)-2-oxo-1,2 dihydropyridine-3-carbonitrile and the 6-(4-methylphenyl) -analogue

The crystal structures of the title compounds, viz. C24H14F2N2O2, (I), and C25H17FN2O2, (II), respectively, have been determined in order to unravel the role of an ordered F atom in generating stable supramolecular assemblies. On changing the substitution from fluorine to a methyl group, C H F-... interactions are replaced by C-H-...pi interactions, revealing the importance of such weak interactions when present alongside N-(HO)-O-... and C-(HO)-O-... hydrogen bonds. The dihedral angle between the planes of the 4-fluorophenyl ring and the pyridine ring is 26.8 (1)degrees in (I), while that between the planes of the 4-methylphenyl and pyridine rings is 29.5 (1)degrees in (II)