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Autori: Rodica-Mariana Ion, Daniel Boda
Editorial: Rev.Chim., Bucharest, 59(2), p.205-207, 2008.
Porphyrins can form a variety of structures from linear head-to-tail or J-aggregates to fractal aggregates with different and specific photophysical properties.
In this paper, the controlled aggregation of meso-5 ,10, 15, 20-sulfonato-phenyl porphyrin (H2TPPS44-) was studied at room temperature. Structure of the aggregates was characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and UV-visible spectroscopy. TEM and SEM results indicated the formation of organized nanostructures from the porphyrin derivative. UV-visible-NIR spectroscopic data showed broad red-shifted Soret band, indicating J-aggregation among the monomer units. Conjugate effect of lateral π-π interaction among the tetrapyrrole cores and hydrophobic interaction among the peripheral phenyl rings is believed to lead to the organized nanostructures. Such aggregates have the size of 5-6 nm in solution. The columnar structure formed by porphyrins has a length of 5 to 27 porphyrin unities.
Cuvinte cheie: porphyrin, aggregation, TEM, aggregates