SYNTHESIS AND SPECTROSCOPIC PROPERTIES OF A NOVEL ZINC PHTHALOCYANINEWITH 4 17-MEMBERED CROWN-ETHER VOIDS

A novel zinc phthalocyanine containing four 17-crown-5 ether voids(17C 5ZnPc) has been synthesized and characterized. UV-visible absorption a nd fluorescence emission spectra and associated photophysical paramete rs have been determined. In contrast to most of the crown ether substi tuted phthalocyanines, no cofacial dimer formation is observed in the presence of alkali metal salts. In addition to the fluorescence at 710 nm from S-1, a strong upper excited state (Soret S-2) emission around 424 nm has been detected for the first time in the phthalocyanine ser ies. Fluorescence decay of S-1 and S-2 emission can be analyzed by mon o-and biexponential fits respectively. X-ray structure analysis showed that the crown ether unit is conformationally deformed and oblate tha t may account for the unusual spectroscopic properties.