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 NH2, NHMe, and NMe2 (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 pi-stacking interactions in the case of EDG, as revealed by their single-crystal X-ray structures.