The IR studies of the interaction of organic molecules with Ag+ ions in zeolites

We studied the properties of Ag+ ions in zeolites AgZSM-5, AgY and AgX with CO as a probe molecule. We studied also how Ag+ interacts with molecules of propene, acetylene, benzene and acetone. IR studies of CO sorption showed that Ag+ in zeolites were less electron donor than Cu+. In the case of zeolite AgX two kinds of Ag+ sites with various electron donor properties for example at various location (SII and SIII) were found. The interaction of organic molecules with Ag+ ions in zeolites results in the weakening of CC bond in propene, CC bond in acetylene, CC bond in aromatic ring in benzene as well as CO bond in acetone. This was realized by π back donation of d electrons of Ag+ to antibonding π* orbitals of multiple bonds. However, the effect of multiple bonds weakening by Ag+ ions is weaker than by Cu+ ions due to weaker electron donor properties of Ag+. The coadsorption of CO and organic molecules on the same Ag+ ion was also studied.