Chitosan nanocomposites with CdSe/ZnS quantum dots and porphyrin

Water-soluble nanocomposites based on CdSe/ZnS quantum dots (QDs) and hydrophobic tetraphenylporphyrin (TPP) molecules passivated by chitosan (CS) have been formed. Magnetic circular dichroism (MCD) spectra evidence TPP presence in both monomeric and agglomerated forms in the nanocomposites. The nanocomposites demonstrate more pronounced singlet oxygen generation compared to free TPP in CS at the same concentration due to the intracomplex Förster resonance energy transfer (FRET) with a 45% average efficiency.

Enhanced photocatalytic performance of rhodamine B and enrofloxacin by Pt loaded Bi4V2O11: boosted separation of charge carriers, additional superoxide radical production, and the photocatalytic mechanism

Photocatalytic performance is influenced by two contradictory factors, which are light absorption range and separation of charge carriers. Loading noble metals with nanosized interfacial contact is expected to improve the separation and transfer of photo-excited charge carriers while enlarging the light absorption range of the semiconductor photocatalyst. Therefore, it should be possible to improve the photocatalytic performance of pristine nontypical stoichiometric semiconductor photocatalysts by loading a specific noble metal. Herein, a series of novel Pt-Bi4V2O11 photocatalysts have been successfully prepared via a surface reduction technique. The crystal structure, morphology, and photocatalytic performance, as well as photo-electron properties of the as-synthesized samples were fully characterized. Moreover, the series of Pt-Bi4V2O11 samples were evaluated to remove typical organic pollutants, rhodamine B and enrofloxacin, from aqueous solutions. The photoluminescence, quenching experiments and the electron spin resonance technique were utilized to identify the effective radicals during the photocatalytic process and understand the photocatalytic mechanism. The photocatalytic performance of Pt-Bi4V2O11 was tremendously enhanced compared with pristine Bi4V2O11, and there was additional ˙O2- produced during the photocatalytic process. This study deeply investigated the relation between the separation of charge carriers and the light harvesting, and revealed a promising strategy for fabricating efficient photocatalysts for both dyes and antibiotics.

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

While the BF₃ complexes of meso-tetra(aryl)porphyrins are readily decomposed into their components under aqueous conditions, immobilization of meso-tetrakis(N-methylpyridinium-4-yl)porphyrin (H₂TMPyP) on a nanosized polymer (sodium salt of Amberlyst 15, nanoAmbSO₃Na) formed a water-stable BF₃ complex applicable for efficient aerobic photooxidation of 1,5-dihydroxylnaphthalene and sulfides under green conditions. NanoAmbSO₃@H₂TMPyP(BF₃)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. NanoAmbSO₃@H₂TMPyP(BF₃)₂ was also completely stable toward dissociation to its components under different light conditions in acetonitrile. The singlet oxygen quantum yields φ_Δ of H₂TMPyP, nanoAmbSO₃@H₂TMPyP, and their molecular complexes with BF₃, determined chemically by using 1,3-diphenylisobenzofuran, revealed substantially higher values in the case of the heterogenized porphyrin and molecular complex.

Lewis acid induced spectral changes of sterically hindered and unhindered meso-tetra(aryl)porphyrins: fluorescence emission spectra

Fluorescence spectra of a series of electron-rich and electron-deficient meso-tetra(aryl)porphyrins and their molecular complexes with DDQ, TCNE and BF₃ were investigated and compared. In spite of the great resemblance between the absorption spectra of the molecular complexes, large differences were observed between their emission spectra.

Photocatalytic asymmetric epoxidation of trans-stilbene with manganese–porphyrin/graphene-oxide nanocomposite and molecular oxygen: axial ligand effect

An efficient, visible light-driven manganese–porphyrin photocatalyst was developed for the asymmetric epoxidation of trans-stilbene by molecular oxygen under mild conditions.

Kinetic and mechanistic aspects of solid state, nanostructured porphyrin diacid photosensitizers in photooxidation of sulfides

The kinetics and mechanism of aerobic photooxidation of sulfides in the presence of a series of electron-rich and electron-deficient porphyrins immobilized on Amberlyst 15 nanoparticles in the form of porphyrin diacids are reported.

Simple low cost porphyrinic photosensitizers for large scale chemoselective oxidation of sulfides to sulfoxides under green conditions: targeted protonation of porphyrins

Large scale chemoselective photooxidation of sulfides to sulfoxides in the presence of the diacids ofmeso-tetra(phenyl)porphyrin with different acids is reported.

Novel metal free porphyrinic photosensitizers supported on solvent-induced Amberlyst-15 nanoparticles with a porous structure

Immobilization of porphyrins on solvent-induced Amberlyst-15 nanoparticles led to the formation of novel porous porphyrinic photosensitizers with high photocatalytic activity towards the aerobic oxidation of olefins in acetonitrile.

New insights into the influence of weak and strong acids on the oxidative stability and photocatalytic activity of porphyrins

The effects of weak and strong acids on the photocatalytic performance of porphyrins in the aerobic photooxidation of olefins are reported.