PREPARATION AND PHOTOSTABILITY OF PORPHYRINS INCORPORATED INTO ALPO4-5 MOLECULAR-SIEVES BY CRYSTALLIZATION INCLUSION

Catio nic porphyrins such as tetrakis(N-alkylyridyl)porphyrins 2,3, te trakis(N-methylpyridyloxy)-phthalocyanines 5 or tetrakis(N-alkylpyrido )tetraazaporphyrin 6,7 in either metal-free or zinc-containing forms a re incorporated readily into AlPO4-5 molecular sieves by crystallizati on inclusion. The dye molecules, which are much larger than the channe l diameter of the molecular sieve, are encapsulated in mesopores as re vealed from adsorption isotherms. The chromophores are predominantly p resent as monomers as gleaned from u.v./vis spectra. The surprisingly strongly enhanced photostability, in comparison to the photostability in solution, is a direct proof for the encaged state of the porphyrins and a fundamental prerequisite for any potential application under vi sible light conditions.