Involvement of organic fluorine substitution in the crystalline packing structures of tricyclic Diels-Alder adducts derived from diarylfulvenes and N-arylimides

Fluorinated tricyclic Diels-Alder adducts derived from corresponding diarylfulvenes and N-arylmaleimides, each of different degree and positions of the fluorine substituents, and including the nonfluorinated parent compound, have been synthesized. Their X-ray crystal structures were determined in order to study the effect of fluorine substitution on the solid state organization in competition with other weak intermolecular interactions. A balanced interplay of C-H center dot center dot center dot O, C-H center dot center dot center dot F and especially C-H center dot center dot center dot pi contacts is typical of the crystal packings while other potential interactions such as C-F center dot center dot center dot F, C-F center dot center dot center dot pi(F), pi(H)center dot center dot center dot pi(F) and Br center dot center dot center dot Br are secondary or not to be found. Isostructurality calculations and comparison of molecular conformations have been performed in order to structurally classify the compounds depending on the number and mode of fluorination. (C) 2009 Elsevier B.V. All rights reserved.