Abstract
Objective: The aim of the present work is to describe the synthesis and photochemical studies of a silicon tribenzonaphthoporphyrazate (Si-tri-PcNc) derivative to be used in photomedicine. Background Data: Properties of the photosensitizer localization in tumor tissue and photochemical generation of reactive oxygen species are combined with precise delivery of laser-generated light to induce a procedure offering effective local tumoricidal activity. This technique is called photodynamic therapy (PDT). Methods: This new phthalocyanine(Pc) compound obtained from 2,3-dicyanonaphthalene and phthalonitrile is analyzed and chemically characterized by 1H-NMR, elemental analyses, infrared (IR), ultraviolet and visibile absorption spectroscopy(UV-Vis) and fluorescence spectra. Results: The spectroscopic analysis of this compound in EtOH showed an electronic spectrum with characteristic bands in the Soret and Q region. Steady-state and time-resolved spectral analyses revealed a fluorescence quantum yield of Øf = 0.24, in agreement with other Pc compounds. This compound also shows a triplet excited lifetime of 0.40 µsec in air-saturated solution and a transient with the maximum absorption located at 610 nm, 120 nm shifted to the red if compared to the excited triplet state observed with other Pc compounds. Conclusion: Based on our results, we can assume that Si-tri-PcNc induces a higher singlet oxygen production under photoactivation, which is in agreement with the expected photobiological behavior. This result could lead to the testing and eventual use of this new generation of dyes in PDT.
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