Fluoro substitution effects in the crystal packing of fluorobenzenes

Abstract

In this paper the effect of fluoro substitution on the packing of the 2-benzyl-5-benzylidene- and 2,5-dibenzylidenecyclopentanone frameworks will be discussed. We chose the fluoro substituent because it has a much smaller van der Waals radius than other substituents used hitherto, while it is very similar to that of hydrogen. This allows a method to distinguish between substituent effects due to size and those due to non-bonded interactions on the crystal packing. It can be shown that intermolecular atom-atom interactions involving the fluoro groups hold sway over the effect of the volume of the subtituents upon crystal packing. A comparison is made between the F…F contacts in these structures and others published in the literature. © 1992, Taylor & Francis Group, LLC. All rights reserved.