Effect of fluoro substitution on the packing motifs of benzylidene- and dibenzylidene-cyclopentanones

Abstract

The structure and solid-state reactivity of one fluorinated benzyl(benzylidene)cyclopentanone and two fluorinated dibenzylidenecyclopentanones are reported and the influence of fluoro substitution upon the packing of benzylidenecyclopentanones is discussed. It was shown that intermolecular atom–atom interactions involving the fluoro groups hold sway over the effect of the volume of the substituents upon crystal packing. As a result, the two dibenzylidene compounds have packing motifs very different from that of the unsubstituted parent compound, and thus a different solid-state reactivity pattern. Both the fluorinated dibenzylidene compounds undergo topochemical solid-state dimerisation, whereas the fluorobenzylidene compound was found to be photostable.