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Hematoporphyrin IX, H₂HMP, 8,13-bis(1-hydroxyethyl)-3,7,12,17-tetramethyl-21H,23H-porphine-2,18-dipropionic acid and protoporphyrin IX, H₂PP, 8,13-divinyl-3,7,12,17-tetramethyl-21H,23H-porphine-2,18-dipropionic acid were efficiently immobilized on niobium oxide grafted on a silica gel surface, SiO₂/Nb₂O₅, by the -COO–Nb bond formed between the porphyrin carboxyl groups and the grafted Nb₂O₅. These immobilized porphyrins, SiO₂/Nb₂O₅/H₂HMP and SiO₂/Nb₂O₅/H₂PP, were further reacted with Co(II) in dimethylformamide, resulting in SiO₂/Nb₂O₅/CoHMP and SiO₂/Nb₂O₅/CoPP metallated complexes. The UV-vis spectra of the solid materials showed changes of the Q-bands (a_2u → e_g transition) upon metallation, indicating that by incorporation of Co(II) in the porphyrin ring the local symmetry changed from D_2h to D_4h. These materials, when incorporated in carbon paste electrodes, presented the property of electrocatalyzing O₂ reduction. Rotating disk experiments were performed in order to estimate the number of electrons involved in the process. It was observed that, for both modified electrodes, O₂ was reduced to water in a four-electron process. Amperometric studies showed the potentiality of both modified electrodes as sensors for the determination of dissolved dioxygen. The response time was less than 3 s. A linear response for both systems was obtained between 2 and 12 ppm.

Cationic 2,9,16,23-tetra(3-N,N,N-trimethylaminoethyloxy)phthalocyaninatozinc(II) (complex 1) and 2²,2³-di(4-N,N,N-trimethylaminophenyl)benzo[b]-7,8,12,13,17,18-hexa(4-t-butylphenyl) porphyrazinatozinc(II) (complex 2) were loaded on the surface of silica gel by use of an electrostatic interaction with deprotonated silanol groups of silica gel. While complex 1 formed its dimer with increase in the amount of the complex in the composite, complex 2 hardly formed the dimer in the composite due to the steric hindrance of its peripheral substituents. 1,3-diphenylisobenzofuran was photo-oxidized using the composites as the sensitizer in aerated methanol. The reaction proceeded with singlet dioxygen generated by the visible-light irradiation upon the sensitizer. While the initial reaction rate with the composite of complex 2 steadily increased in accordance with increase in the amount of the complex, that with the composite of complex 1 at first increased, but subsequently decreased due to the formation of the photo-inactive dimer. Bilirubinditaurate was also photo-oxidized using the composites as the sensitizer in an aerated aqueous solution. The reaction proceeded with superoxide instead of singlet dioxygen. The relationship between the initial reaction rate and the amount of the complex was similar to that in methanol.

New heterogeneous photodynamic sensitizers, in which the active phase, (polycholinyl)tetra-3-phenylthiophthalocyanine of aluminum, grafted to aminopropylated silica gels with pore sizes of 10, 25 and 75 nm, were tested in MS2 coli phage and poliovirus photoinactivation. In aqueous suspensions of the photosensitizers, the photoantiviral activity of the active phase was observed. It was found that both phthalocyanine and viruses cannot penetrate into 10 and 25 nm pores. In the sample with 75 nm pores, both the active phase and virus localize predominantly inside pores, providing conditions for most efficient photovirucidal activity.

Experimental studies were carried out to validate the effects of dielectric cores in microwave assisted freeze drying. Silica gel was prepared as a porous material using the hydrolysis process, and quartz glass and sintered silicon carbide (SiC) were selected as the dielectric materials, respectively. The microwave input power varied from 91.4 to 96.5 Watts at a frequency of 2,450 MHz. Results show that using the dielectric material with a large loss factor can significantly enhance ordinary microwave freeze drying. At the input power of 91.4 Watts, the drying time with the sintered silicon carbide core was 160.8 min, 43.6% shorter than 285.1 min obtained with the quartz glass core. When the input power was 96.5 Watts, the drying time was reduced from 266.2 to 115.6 min with the enhancement being 56.6%. Analysis of energy utilization shows that the dielectric material with a larger loss factor can result in the higher energy efficiency.