Details

Autor(en) / Beteiligte

• Pia Donzello, Maria
• Viola, Elisa
• Giustini, Mauro
• Ercolani, Claudio
• Monacelli, Fabrizio

Titel

Tetrakis(thiadiazole)porphyrazines. 8. Singlet oxygen production, fluorescence response and liposomal incorporation of tetrakis(thiadiazole)porphyrazine macrocycles [TTDPzM] (M = Mg super(II)(H sub(2)O), Zn super(II), Al super(III)Cl, Ga super(III)Cl, Cd super(II), Cu super(II), 2H super(I))

Ist Teil von

• Dalton transactions : an international journal of inorganic chemistry, 2012-05, Vol.41 (20), p.6112-6121

Erscheinungsjahr

2012

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• The photoactivity for the generation of singlet oxygen, super(1)O sub(2), the key cytotoxic agent in the anticancer treatment known as photodynamic therapy (PDT), and the fluorescence response of the highly electron-deficient tetrakis(thiadiazole)porphyrazines of formula [TTDPzM] (M = Mg super(II)(H sub(2)O), Zn super(II), Al super(III)Cl, Ga super(III)Cl, Cd super(II), Cu super(II), 2H super(I)) were examined (c approximately equal to 10 super(-5) M) in dimethylformamide (DMF) and/or in DMF preacidified with HCl (DMF/HCl; [HCl] = 1-4 10 super(-4) M). The singlet oxygen quantum yield ( Phi sub( Delta )) of all the compounds was determined by using a widely employed procedure based on the selective oxidation of the 1,3-diphenylisobenzofuran (DPBF), modified in part as reported. The list of the Phi sub( Delta ) values indicates excellent photosensitizing properties for the series of compounds carrying "closed shell" metal ions, with values measured in DMF/HCl respectful of the "heavy atom effect" for the first four lighter centers, increasing in the order Mg super(II) < Al super(III) < Zn super(II) < Ga super(III). Data of Phi sub( Delta ) concerning the unmetalated species [TTDPzH sub(2)], present in solution in the form of the corresponding anion [TTDPz] super(2-), and the Cd super(II) and Cu super(II) complexes are also presented and discussed. Extensive discussion is also developed on the fluorescence quantum yield values Phi sub(F), with data on the Mg super(II) and Al super(III) compounds in DMF/HCl (0.44 and 0.53, respectively) indicative of promising perspectives for applications in fluorescence imaging techniques. The Phi sub(F) data of the studied porphyrazine series, Phi sub(F) super(Pz), correlate linearly with those of the homologous phthalocyaninato complexes, Phi sub(F) super(Pc), suggesting a closely similar behaviour between the two classes of compounds. The incorporation of [TTDPzZn] into liposomes was successfully achieved following the detergent depletion method (DDM) from a mixed micellar solution by means of gel-filtration. Retention of [TTDPzZn] ( similar to 40%) in its photoactive monomeric form into liposomes is proved by absorption and fluorescence spectra, this proposing the Zn super(II) complex as a promising candidate for use in PDT.