title: 4-(4-fluoro-3-phenoxyphenyl)-6-(4-fluorophenyl)-2-oxo-1,2-dihydropyridine-3-carbonitrile and the 6-(4-methylphenyl)- analogue.
abstract: 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-H...O and C-H...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).
authors.affiliation: Solid State and Structural Chemistry Unit, Indian Institute of Science, Bangalore 560 012, Karnataka, India. deepak@sscu.iisc.ernet.in
authors.forename: Deepak
authors.initials: D
authors.lastname: Chopra
authors.forename: T P
authors.initials: TP
authors.lastname: Mohan
authors.forename: B
authors.initials: B
authors.lastname: Vishalakshi
authors.forename: T N
authors.initials: TN
authors.lastname: Guru Row