Intercalation Behavior of Pyridine and Related Compounds Into Layered Zirconium Phosphate

Intercalation of pyridine and its related compounds into layered zirconium phosphate, Zr(HPO4)2·H2O (α-ZrP), was examined for the purpose of discussing the effect of a functional group on the uptake behavior. The acid dissociation constants of pyridines strongly affect the intercalation behavior; nicotinic acid (pKa=2.05) was not intercalated, but nicotinamide (pKa=3.47) was readily intercalated. The uptake behavior was influenced by the amino group position on aminopyridines. The 2-, 3-, and 4-aminopyridine intercalation compounds gave the different X-ray diffraction patterns. The possible arrangement of pyridines between the sheets of α-ZrP will be discussed.