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Abstract: A new type of hybrid photosensitizers was obtained by efficient adsorption of a photoactive polymer by an organically modified nanoclay. The polymer bore naphthyl and rose bengal chromophores, which absorbed light both in the ultraviolet and visible spectral region. Adsorption of the polymer on nanoclay prevented aggregation of chromophores. The obtained hybrid photosensitizer efficiently adsorbs hydrophobic compounds. It was also found to be an efficient photosensitizer in singlet oxygen generation. The hybrid photosensitizers combine the advantages of both component systems, i.e. possibility to attach a wide range of chromophores to the polymeric chain and resulting ability to photosensitize reactions, on one hand, and the ability to adsorb hydrophobic pollutants and easy separation from water characteristic of nanoclays, on the other. [ABSTRACT FROM AUTHOR]

Abstract: Photooxidation of phenol sensitized by Aldrich humic acid (AHA) has been studied in an aqueous solution at neutral and basic pH. Solutions containing phenol and AHA of various concentrations were irradiated with monochromatic light at 253.7nm or with polychromatic light within the wavelength range of 310–420nm. The quantum yields of phenol photodegradation under these conditions were determined. At the wavelength of 253.7nm direct degradation of phenol was much more effective than that sensitized by AHA. With polychromatic light the photooxidation was found to be strongly dependent on pH of aqueous solution and independent on AHA concentration. [Copyright &y& Elsevier]

Phthalocyanines are promising photosensitizers for photodynamic therapy (PDT). A novel zinc 1,8(11),15(18),22(25)-tetraiodo-3,10(9),17(16),24(23)-tetra- tert -butylphthalocyanine has been synthesized and characterized. The synthesis of iodinated phthalocyanine was achieved through templated cyclotetramerization of 6- tert -butyl-4-iodo-1,3-diiminoisoindoline around zinc ions (Zn 2+ ). A six step route leading to 6- tert -butyl-4-iodo-1,3-diiminoisoindoline was proposed. The synthesis started with a regiospecific iodination of 4- tert -butyl- o -xylene to 5- tert -butyl-2,3-dimethyl-iodobenzene, followed by oxidation of the methyl groups to phthalic acid, conversion of phthalic acid to phthalimide, hydrolysis of phthalimide to phthalamide, conversion of phthalamide to phthalonitrile, followed by conversion of phthalonitrile to a more reactive 6- tert -butyl-4-iodo-1,3-diiminoisoindoline. Highly desirable photophysical and photochemical properties were induced in zinc phthalocyanine by iodination of the aromatic rings, while the presence of tert -butyl groups rendered the compound non-aggregating in solution. The photosensitizer studied exhibits absorption band within the so-called “therapeutic window”, with λ max at 689 nm and very high molar absorption coefficient of 295 000 [M −1  cm −1 ] in DMF. Transient absorption experiment revealed T 1  → T n absorption spanning from ca. 400 nm to ca. 600 nm and allowed determination of the excited triplet state lifetime ( τ T ). The estimated τ T in THF equaled 3.3 μs. The phosphorescence maximum was found to be located at λ P 1103 nm and the excited triplet state energy ( E T ) equaled 1.12 eV in 2-methyltetrahydrofuran at 77 K. The photosensitizer studied is characterized by a high value of singlet oxygen quantum yield (Φ Δ ) of ca. 0.76 and the photooxygenation process proceeds via Type II mechanism under the experimental conditions applied. The photodegradation studies revealed that the iodinated phthalocyanine was moderately stable in the presence of oxygen with quantum yield of photodegradation (Φ d ) equaled 4.01 × 10 −4 . Moderate photostability of photosensitizer is advantageous from a PDT point of view where rapid breakdown and fast clearance from the patient’s system is necessary to avoid prolonged skin photosensitivity following treatment. [ABSTRACT FROM AUTHOR]

Highlights: [•] The hybrid photosensitizer was obtained using pegylated porphyrin and a nanoclay. [•] The pegylated porphyrin intercalated into the nanoclay. [•] The photosensitizer generated singlet oxygen which could oxidize phenol. [•] The efficiency of phenol photooxidation depended on pH. [•] The photosensitizer could be reused. [Copyright &y& Elsevier]

Highlights: [•] Mg tetraiodophthalocyanine is described with the purpose of applying it as a photosensitizer to eradicate cancerous cells. [•] Magnesium phthalocyanine produces singlet oxygen and other reactive oxygen species with an excellent quantum yield of 0.95. [•] It possesses the ability to penetrate lipid membranes of liposomes with binding constant equal K b =40.5±6.4 (mg/mL)−1. [•] Limited photostability of the dye is advantageous for the PDT to promote rapid breakdown and clearance after treatment. [ABSTRACT FROM AUTHOR]