[Study on UV-Vis absorption spectra and fluorescence emission spectra of sixteen tetra-substituted metallophthalocyanine complexes].

ABSTRACT

The UV-Visible absorption spectra and the fluorescence emission spectra of sixteen tetra-substituted metallo-phthalocyanine complexes {R4 PcM, where R = 2-[4-(2-sulfonic ethyl) piperazin-1-] ethoxyl (SPEO--), 2-(piperidin-1-yl) ethoxyl (PEO--); substitution position at alpha-position and beta-position of phthalocyanine ring; M = Zn(II), Ni(II), Co(II) and Cu(II)} were measured. The influence of different central ion, substituted group and its position, as well as different solvent on the Q-band of phthalocyanine complex in its UV-Vis absorption spectra was investigated. The influence of different central ion, substituted group and its position on the fluorescence emission spectra was discussed. Some properties of the UV-Vis absorption spectra such as the maximum absorption wavelength (lamdamax ) of Q-band and its molar extinction coefficient (epsilon), and those of the fluorescence emission spectra such as fluorescence quantum yield (phiF), fluorescence lifetime (r) and excited state energy (Es) were studied. The results showed that the lamdamax of Qband of all complexes were located at 681-718 nm, which had a distinct red shift in contrast with unsubstituted metallophthalocyanines (669-671 nm). All complexes of R4 PcM possessed a very high molar extinction coefficient up to 10(5) L x mol(-1) x cm(-1). And the UV-Vis absorption spectra and the fluorescence emission spectra of all complexes exhibited mirror shape concurrently. Two beta-substituted zinc phthalocyanine complexes with formula beta-(SPEO)4PcZn and beta-(PEO)4PcZn possessed very high molar extinction coefficient, fluorescence quantum yield and fluorescence lifetime specially. Therefore, it is hoped that these two would be developing to be new photosensitizers for photodynamic therapy (PDT)and photodynamic diagnosis (PDD).