Significantly Increased Stability of Donor–Acceptor Molecular Complexes under Heterogeneous Conditions: Synthesis, Characterization, and Photosensitizing Activity of a Nanostructured Porphyrin–Lewis Acid Adduct

Abstract

While the BF 3 complexes of meso-tetra(aryl)porphyrins are readily decomposed into their components under aqueous conditions, immobilization of meso-tetrakis(N-methylpyridinium-4-yl)porphyrin (H 2 TMPyP) on a nanosized polymer (sodium salt of Amberlyst 15, nanoAmbSO 3 Na) formed a waterstable BF 3 complex applicable for efficient aerobic photooxidation of 1,5-dihydroxylnaphthalene and sulfides under green conditions. NanoAmbSO 3 @H 2 TMPyP(BF 3 ) 2 was characterized by diffuse reflectance UV−vis spectroscopy, dynamic light scattering, thermal gravimetric analysis, Brunauer−Emmett−Teller analysis, Fourier transform infrared spectroscopy, field emission scanning electron microscopy, and energy-dispersive X-ray spectroscopy techniques. The catalyst was successfully used for 10 consecutive reactions with no detectable degradation of the complex and decrease in the catalyst activity. NanoAmbSO 3 @H 2 TMPyP(BF 3 ) 2 was also completely stable toward dissociation to its components under different light conditions in acetonitrile. The singlet oxygen quantum yields φ Δ of H 2 TMPyP, nanoAmbSO 3 @H 2 TMPyP, and their molecular complexes with BF 3 , determined chemically by using 1,3diphenylisobenzofuran, revealed substantially higher values in the case of the heterogenized porphyrin and molecular complex.

Periodate-Mediated Aerobic Oxidation of Sulfides over a Bifunctional Porphyrin-polyoxometalate Catalyst: Photosensitized Singlet Oxygen Oxidation of Iodate to Periodate

“…It is noticeable that under long-term photooxidation reactions, the amberlyst-supported porphyrin was much more stable than the nonimmobilized porphyrin. 66,67 As mentioned above, in the metal-catalyzed oxidation of organic substrates with periodate, iodate is formed as the reduced form of the terminal oxidant. 19−28 In view of the ability of photosensitized singlet oxygen to react with iodate, leading to the formation of periodate, the oxidation of methyl phenyl sulfide was conducted in the presence of molecular oxygen as the terminal oxidant.…”

Visible Light-Induced Aerobic Oxidative Dehydrogenation of C–N/C–O to C=N/C=O Bonds Using Metal-Free Photocatalysts: Recent Developments

“…Recycling of the methylene blue-dyed polyester fabrics and 99 was not carried out, while 98 was recovered and reused three times, with a slight decrease in its activity at the third catalytic cycle. In addition, two C60-BODIPY photosensitizers (C60-B1/C60-B2, 100a,b) [227], a C70-BODIPY-triphenylamine triad (C70-B-T, 101) [228] and a meso-tetrakis(N-methylpyridinium-4-yl)porphyrin supported on the sodium salt of Amberlyst 15 nanoparticles and complexed with formic acid (nanoAmbSO3@H2TYMPyP(HCO2H)2, 102a) [229] and BF3 (nanoAmbSO3@H2TYMPyP(BF3)2, 102b) [230] were employed in the mentioned transformation, obtaining Juglone (85, R 1 = R 2 = R 5 = H, R 4 = OH) in high yield (only quantum yield was given in the case of using 100 and 101) (Figure 31). The recyclability of 100 and 101 was not tested, while 102a and 102b were recycled but in a different photo-oxidation reaction.…”

Manganese porphyrins/mesoporous amberlyst 15 nanocomposites: Robust biomimetic catalysts for aqueous oxidation of olefins

“…Meso-tetra(2-, 3-, or 4-pyridyl)porphyrins, the Nmethylated porphyrins, and manganese porphyrins were prepared according to the Adler method. [22,23] (See previous works [15,16,24,25] for more details including the synthesis procedure and spectral data. )…”

“…The sodium salt of nanoAmbSO 3 was prepared by the addition of an excess amount of 1-M sodium hydroxide solution to amberlyst 15 (1.5 g) in 30-ml distilled water [24,25] and magnetic stirring of the mixture for 24 h. After this time, the solid was separated by centrifuge. The thoroughly washed precipitate (by distilled water in a centrifuge tube until neutral) was dried in a vacuum desiccator (24 h).…”

“…The formation of nearly spherical nanoparticles with an average diameter of less than 40 nm was revealed from FESEM images (Figure 4). As was described elsewhere, [21,24] the polymer nanoparticles (sodium salt) and the polymer supported manganese porphyrins are prepared by magnetically stirring the beads of amberlyst 15 in an alkaline (NaOH, 1 M) aqueous solution, overnight at room temperature. The immobilization of different cationic porphyrins on these nanoparticles led to no meaningful difference between the size of the nanostructured polymers.…”