HEAVY-ATOM-INDUCED PHOSPHORESCENCE OF AROMATICS AND OLEFINS INCLUDED WITHIN ZEOLITES

Photophysical properties of naphthalene and other aromatic guest molecules included in X-type faujasite zeolites (M+ X, M = Li, Na, K, Rb, Cs, Tl) have been investigated. As expected for an external heavy atom perturbed excited state, both singlet and triplet excited state lifetimes and emission efficiencies depend upon the identity and accessibility of the cation present within the zeolite supercage. The large magnitude of the external-heavy-atom perturbation is not unique to the X-type faujasites; similar effects for organic guests included in Y-type faujasites, in pentasils (ZSM-5 and ZSM-11), and in other zeolites (mordenite, beta, L, and OMEGA) have been demonstrated. The power of the heavy-atom-cation effect in zeolites has been demonstrated by recording phosphorescence data from several olefins whose phosphorescence data has not been recorded previously. The heavy atom cation induced phosphorescence technique has been utilized to understand basic features of interaction between the zeolite and guest aromatic molecules.