Syntheses and photochemical properties of octasubstituted phthalocyaninato zinc complexes

✍ Scribed by Suzanne E. Maree; Tebello Nyokong

• Publisher: John Wiley and Sons
• Year: 2001
• Tongue: English
• Weight: 148 KB
• Volume: 05
• Category: Article
• ISSN: 1088-4246
• DOI: 10.1002/jpp.388

✦ Synopsis

In this work a selection of octasubstituted phthalocyaninato zinc complexes were synthesized and their photochemistry studied. The substituents included cholesterol (3a), estrone (3b), naphthol (3c) and phenoxy groups substituted with CH~3~ (3d), C ( CH ~3~)~3~ (at two positions, 3e), C ( CH ~3~)~3~ (3f), NO~2~ (3g), NH ~2~ (3h), COH (3i), COOH (3j), and H (3k). In general, complexes containing electron-donating groups attached to the phenoxy ring (e.g. 3e and 3f) were found to be photochemically unstable with photobleaching quantum yields of the order of 10^-3^. In the presence of electron-withdrawing groups (3g, 3i, and 3j) the photobleaching quantum yields were of the order of 10^-6^ to 10^-5^. Singlet oxygen quantum yields (Φ~Δ~) ranged from 0.01 to 0.73. The lowest Φ~Δ~ was observed for the highly aggregated complex 3c. All the complexes showed aggregation at high concentrations. Electrochemical reduction using a thin-layer spectroelectrochemistry cell showed that the complexes become more monomeric following reduction.