Abstract:

The supramolecular assemblies consisting of metal-free tetra(N-trimethylaminobenoxy) phthalocyanate (H2TAPc) and its zinc complex (ZnTAPc) as well as metal-free tetra (4-sulfonatophyenyl) porphyrin (H2TSPP) and its zinc complex (ZnTSPP) in solution were studied by absorption spectroscopy. The stoichiometries of the hetero-aggregates were ascertained by Job’s photometric titration plots, indicating that the aggregates were either face to face heterodimers or sandwich structure heterotrimers. The composition of the hetero-aggregates are controlled by the affinity of the central metal ion of each chromophore for axially bound coordinating solvent molecules. The fluorescence of porphyrin and phthalocyanine in the supramolecular system are quenched by each other. The transient absorption spetra of cationic porphyrin radical (around 600-650nm region) and anionic phthalocyanine radical(around 550-600nm) were observed by nanosecond laser photolysis. The results indicated that intermolecular photoinduced electron transfer process from excited triplet state between the porphyrin and the phthalocyanine occured in the supramolecular system.

Key words: Supramolecular system, Molecular self-assembly, Phthalocyanine, Porphyrin, Photoinduced electron transfer