Probing zeolites with organic molecules: Supercages of X and Y zeolites are superpolar

Supercages of Li+- and Na+-exchanged X and Y zeolites are much more polar t han even water. The extent of polarity depends on the nature and the number of cations present within a supercage. The polarity of Li+- and Nat-exchan ged X and Y zeolites decreases in the presence of water. In presence of wat er the contribution of cations toward polarity is much smaller than water i tself. In this study polarity has been monitored with organic probe molecul es, Nile red, pyrene 1-carboxaldehyde and coumarin-500. A connection betwee n "polarity" and "electric field" within a cage has also been established. Since the supercages are much more polar than all organic solvents, they ca n be characterized as "superpolar". Because of this one may be able to achi eve excited-state switching of carbonyl compounds within a zeolite while su ch may not be possible in organic solvents. The n pi*-pi pi* state switchin g of acetophenones is easily achieved within a zeolite while such does not occur in polar solvent methanol-ethanol mixture.