Exploring the Synthesis and Properties of Fluorinated Cationic Triangulenes and Their Precursors

Abstract

Fluorination of tris(2,6-dimethoxyphenyl)-methylium ((DMP)3C+) was achieved through the partial defluorination of the methyl 2,3,5,6-tetrafluorobenzoate via nucleophilic aromatic substitution. Using the fluorinated 2F((DMP)3C+) as a precursor, fluorinated tetramethoxy- and dimethoxyquin- acridinium salts (2F4 and 2F5 respectively) and trioxo-, azadioxo-, and diazaoxo- triangulenium salts (2F6, 2F7 and 2F8 respectively) were synthesized successfully in good to moderate yields. Fluorination induced significant red shifts in absorption (16 to 29 nm) and emission (13 to 41 nm) maxima, and increased electrophilicity as evidenced by lower reduction potentials. X-ray structural analysis showed distinct packing patterns compared to the non-fluorinated analogues, indicating the presence of molecular dipoles.