DIFFUSE-REFLECTANCE LASER PHOTOLYSIS STUDY ON TRIPLET COMPLEX BETWEEN AROMATICS AND TL+ INCLUDED IN TL+-EXCHANGED X-TYPE ZEOLITE

Triplet-triplet absorption spectra of anthracene, phenanthrene, and naphthalene in thallium ion (Tl+)-exchanged X-type zeolites (TlX) were found to be significantly different from those of the aromatics in sodium ion (Na+)-or cesium ion (Cs+)-exchanged zeolites (NaX or CsX); broad and stuctureless spectra with a small red-shift are ascribed to a triplet complex of the aromatics with Tl+. The complex formation is considered to be responsible for the enhanced intersystem crossing observed for the aromatics in TlX, and this is in contrast with the observation in CsX where a simple heavy atom-assisted intersystem crossing is operative.