Electronic, molecular, and solid-state structural effects of strong electron withdrawing and donating groups in functionalized fluorophthalonitriles

Perfluoro phthalonitrile substituted separately with perfluoroalkyl (EWG) and NH 2 , NHMe, and NMe 2 (EDG) groups generate a series of aromatic C-H bonds-free nitriles that can now lose electrons, whose HOMO–LUMO gap is narrowed by EDG beyond the level induced by EWG, and whose dipole moments double. Molecular parameters vary linearly with Hammett’s free-energy constants, their electronic underpinning being uncovered by DFT calculations. The phthalonitriles’ assembling in solid-state structures is determined by forces that transition from van der Waals, in the case of EWG, to H-bonding and/or [Formula: see text]-stacking interactions in the case of EDG, as revealed by their single-crystal X-ray structures.