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

The crystal structures of the title compounds, viz. $C_{24}H_{14}F_2N_2O_2$, (I), and $C_{25}H_{17}FN_2O_2$, (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 ¯uorine 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 $N-H...O$ and $C-H...O$ hydrogen bonds. The dihedral angle between the planes of the 4-¯uorophenyl ring and the pyridine ring is $26.8 (1)^0$ in (I), while that between the planes of the 4-methylphenyl and pyridine rings is $29.5 (1)^0$ in (II)