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

Abstract

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.

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

“…In continuation of previous studies performed concerning the photocatalytic activity of the molecular complexes and diacids of porphyrins, − ,− , in the present study, the molecular complex of a cationic porphyrin (H 2 TMPyP) supported on the neutralized nanoparticles of Amberlyst 15 (nanoAmbSO 3 Na) with BF 3 was synthesized and characterized (Figure ). In contrast to the corresponding nonimmobilized analogue, − , the heterogenized molecular complex was found to be very stable toward dissociation into its components in solvents as polar as water.…”

“…Nanoparticles of Amberlyst 15 (nanoAmbSO 3 H) and its sodium salt (nanoAmbSO 3 Na) were prepared and characterized according to the previous report. 17,18 2.5. Immobilization of H 2 TMPyP(BF 3 ) 2 on NanoAmbSO 3 Na.…”

“…46 The procedure was described elsewhere. [10][11][12][13][17][18][19]41 3. RESULTS AND DISCUSSION 3.1.…”

“…The same pattern was observed upon diprotonation of porphyrins. 12,13,17,18,41,49 The molecular complexation of H 2 TMPyP with BF 3 led to the appearance of the absorption bands of the corresponding molecular complex at 443 and 652 nm (Figure 3). The addition of different equivalents of BF 3 (0.5−2) gradually increases the intensity of the Soret and Q bands.…”

“…Singlet molecular oxygen ( 1 O 2 , 1 Δ g ) is a reactive oxygen species (ROS) with extensive applications in organic syntheses, wastewater treatment, and biological therapies. − This species can be prepared by chemical and photochemical methods. , The presence of a photosensitizer with intense absorption bands in the visible wavelength region is among the main requirements for light-induced generation of 1 O 2 . Porphyrins and related aromatic macrocyclic compounds are among the main photosensitizers commonly used for photosensitization of molecular oxygen because of the intense absorption of visible light, , high photooxidative stability, − various positions for functionalization of the aromatic macrocycle, their ability for S 1 to T 1 intersystem crossing, and straightforward immobilization on different supports. − Although most of these properties stem from the aromaticity of the porphyrin core, computational studies show that the aromatic macrocycle can easily accept nonplanar conformations with little or no decrease in the porphyrin ring current. − The wavelength and molar absorptivity of the absorption bands of these aromatic macroheterocycles are determined by the substituents introduced at the porphyrin periphery as well as the central nitrogen atoms. In spite of the observation of similar bands in the case of meso -tetra­(aryl)- and meso -tetra­(alkyl)­porphyrins, bearing a planar or nearly planar conformation, the longer wavelength band of the latter, known as the Q (0,0) band, appears at relatively longer wavelengths compared to that of the former .…”