Photophysical Properties Of Phthalocyanines Research Articles

Synthesis and Photophysical Properties of Phthalocyanines with 4-(1-Methyl-1-phenylethyl)phenoxy Groups

Synthesis and Photophysical Properties of Phthalocyanines with 4-(1-Methyl-1-phenylethyl)phenoxy Groups

Apomyoglobin is an efficient carrier for zinc phthalocyanine in photodynamic therapy of tumors

The spectral and the photophysical properties of phthalocyanines have made these dyes attractive for applications in photodynamic therapy of cancer. One important known issue of these compounds is their tendency to aggregate in aqueous media, which decreases their fluorescence, triplet, and singlet oxygen quantum yields. We report on the use of apomyoglobin as a carrier for zinc phthalocyanine (ZnPc) to overcome solubility limitations of the dye. We show that the protein is able to bind ZnPc in monomeric form, preserving its photophysics. Confocal fluorescence imaging of PC3 and HeLa cells, treated with the complex between ZnPc and apomyoglobin, demonstrates that the photosensitizer is uptaken quickly by cells. Illumination of treated cells strongly decreases viability, as demonstrated by live/dead fluorescence assay.

Photophysical properties of pyridyloxy phthalocyanine encapsulated in nanoparticles

Two aluminum chloride phthalocyanines with pyridyloxy substitution at α/β positions were synthesized. Their structures were characterized by infrared spectroscopy, proton nuclear magnetic resonance as well as elemental analysis. Tetra-α(β)-(2-pyridyloxy) aluminum chloride phthalocyanines were encapsulated into a diblock copolymer methoxy-poly(ethylene glycol)-block-poly(L-lysine) through a cosolvent method. The morphologies and photophysical properties of phthalocyanines encapsulated in nanoparticles were studied by transmission electron microscope, ultraviolet-visible, and fluorescence spectroscopic methods. The photophysical properties of phthalocyanines encapsulated into nanoparticles exhibited substitution positions dependence. The phthalocyanines with substitution at α positions were found to be an excellent candidate for use as photosensitizers for treatment of cancer by photodynamic therapy.

Morpholinyl dendrimer phthalocyanine: synthesis, photophysical properties and photoinduced intramolecular electron transfer.

In this work, a novel series of morpholinyl dendrimer phthalocyanines were synthesized. Their structures were characterized by 1H NMR, IR, elemental analysis, ESI-MS as well as MALDI-TOF MS. The photophysical properties of these phthalocyanines were studied by UV/Vis and fluorescence spectroscopic methods. The photophysical properties of these dendrimer phthalocyanines exhibited dependence on the number of morpholinyl groups and the central ion. The photoinduced intramolecular electron transfer from the morpholinyl groups to the phthalocyanine ring was evidenced by the remarkably quenched fluorescence intensity and shortened lifetime of the silicon phthalocyanine. This difference in photoinduced intramolecular electron transfer effect for axially and peripherally substituted morpholinyl dendrimer phthalocyanines was also studied. Besides, introduction of morpholinyl groups on the dendrimer structure could enhance water solubility as well as increase the singlet oxygen quantum yield.

Solvent Effect, Photochemical and Photophysical Properties of Phthalocyanines with Different Metallic Nuclei

Photophysical and photochemical properties of lithium phthalocyanine ( 1 ), gallium(III) phthalocyanine chloride ( 2 ), titanium(IV) phthalocyanine dichloride ( 3 ) and iron(II) phthalocyanine ( 4 ) were investigated in dimethyl sulfoxide (DMSO), tetrahydrofuran (THF) and DMSO-THF mixtures. The influence of the central metal on these properties was analyzed according to solvent type, axial ligands and their paramagnetic and diamagnetic effect. Fluorescence lifetimes were recorded using a time correlated single photon counting setup (TCSPC) technique. In order to demonstrate the generation of reactive oxygen species under light irradiation, the indirect method (applying 1,3-diphenylisobenzofuran (DPBF) as chemical suppressor) and the direct method (analyzing the phosphorescence decay curves of singlete oxygen at 1270 nm) were employed. Compounds 1 , 2 and 3 showed a monomeric behavior in all media while compound 4 presented low aggregation in DMSO, but a very pronounced aggregation behavior in THF. Steady-state fluorescence anisotropy was compared with emission spectra and complex 4 presented values beyond the expected limits. DOI: http://dx.doi.org/10.17807/orbital.v9i5.1047

Synthesis and photophysical properties of phthalocyanines having calixpyrrole units

Calixpyrrole-armed metal phthalocyanine undergoes complexation by anions at the apical metal position upon light excitation.

Aggregation and photophysical properties of phthalocyanines in supramolecular complexes

The concentration dependence of the degree of association of zinc and aluminum phthalocyanines in supramolecular systems is determined. Complexes containing rare photoactive associates with an absorption maximum significantly shifted to longer wavelengths are obtained. The radiative lifetimes, extinction coefficients, and energy of HOMO-LUMO electronic transitions of isolated and associated metal phthalocyanine complexes are determined. It is demonstrated that the existence of the metal phthalocyanine largely in an aggregated state is characteristic of zinc phthalocyanine systems, while aluminum phthalocyanine, having an additional extraligand, chloride ion, is stabilized in the isolated state.

Photophysical study of Zn phthalocyanine in binary solvent mixtures

Photophysical properties of phthalocyanines are important in photodynamic therapy, where these compounds are proposed as photosensitizing agents. We report here some significant solvent effects on the photophysical properties of Zn phthalocyanine (ZnPc) observed in binary solvent mixture dimethyl sulfoxide/water at several ratios of cosolvents. The absorbance of ZnPc at the maximum of Q band has a sharp drop in intensity for a water mass percent in the solvent mixture larger than 40%. The same characteristic shows also the quantum yield of fluorescence. A particular result is the increase of singlet oxygen lifetime for water percentage raise up to 20% in the solvent mixture. The effects are discussed in connection with the particular solvent microenvironment, involving DMSO/water clusters formation and the strong interaction between the solute and the solvent.