Perhalogenated Anions as Structure Directing Agents of Cationic Coordination Polymers

We investigate the synthesis of coordination polymers (CPs) comprising silver cations, 4,4′-bipyridine and the charge-balancing perhalogenated acetate anions trifluoroacetate (CF3COO–), trichloroacetate (CCl3COO–), tribromoacetate (CBr3COO–) or triiodoacetate (CI3COO–). The syntheses involved anion exchange using the starting CP silver 4,4′-bipyridine acetate. Multianalytical characterization was conducted using powder X-ray diffraction, single crystal X-ray diffraction, optical microscopy and thermogravimetric analysis. Our findings revealed that CPs were formed with CF3COO– or CCl3COO– as the charge-balancing anion and exhibited notable stability. In contrast, reactions with CBr3COO– and CI3COO– showed that the starting anion undergoes decomposition to bromide, iodide or triiodide before being incorporated into the resulting material. This study sheds light on the interactions between perhalogenated anions and CPs and the potential for the use of CPs in the removal of perhalogenated “forever chemicals.”