Synthesis, characterization and electrochemical properties of meso-thiocarboxylate-substituted porphyrin derivatives

Considering the versatility of 5,10,15,20-tetrakis(pentafluorophenyl)porphyrin (TPPF20) to react with nucleophiles we highlight here the synthesis and characterization of several mono- and tetra-thiocarboxylate derivatives. The selective displacement of the para-fluorine groups in TPPF20 by thiocarboxylic acids demonstrates that TPPF20 is an ideal platform for the rapid formation of thiocarboxylate porphyrins. The optical and electrochemical features of the thiocarboxylate derivatives were also examined thinking on their potential use in photovoltaic devices. From their electrochemical characterization the following parameters were taken into account: (i) electronegative induced effect of the thiocarboxylate dyes owing the presence of the fluorine and sulfur atoms on the molecular structure of the porphyrin; and (ii) the free rotation and flexibility features that such S atom gives to the porphyrin relatively to the semiconductor.

Synthesis of hexaphyrins and N-fused pentaphyrins bearing pyridin-4-ylsulfanyl groups

In recent years much attention has been devoted to expanded macrocyclic chemistry. Nevertheless, while several advancements were achieved in the synthesis of novel expanded porphyrin architectures, not much has been developed in the functionalization of these macrocycles. This report shows the selective replacement of the p-fluorine atoms of meso-pentakis(pentafluorophenyl) N-fused [22]pentaphyrin and meso-hexakis(pentafluorophenyl) [26]hexaphyrin with 4-mercaptopyridine moieties, thus increasing their potential as ligands for coordination chemistry and catalysis or electronic transfer applications striving new synthetic methodologies and a new set of specific applications for this type of compounds.

Synthesis and cell phototoxicity of a triply bridged fused diporphyrin appended with six thioglucose units

A triply bridged fused diporphyrin appended with six thioglucose units is reported. This new, chemically and photochemically stable amphiphilic compound is taken up by breast cancer cells and causes cell death upon light exposure. Photophysical studies reveal absorption bands in the near IR region, and photosensitized formation of singlet oxygen in high quantum yields.

From porphyrin benzylphosphoramidate conjugates to the catalytic hydrogenation of 5,10,15,20-tetrakis(pentafluorophenyl)porphyrin

Three new porphyrin aminoalkyl dibenzylphosphoramidates were synthesized by nucleophilic aromatic substitution of one p-fluorine atom of 5,10,15,20-tetrakis(pentafluorophenyl)porphyrin (TPPF₂₀) by primary aminoalkyl dibenzylphosphoramidates. The nucleophilic aromatic substitution was promoted by microwave irradiation in N-methyl-2-pyrrolidinone. Attempts to remove the benzyl groups of the phosphoramidate moiety by hydrogenolysis with 10% Pd/C led to the cleavage of the P–N bond and the reduction of the macrocycle to hydroporphyrin-type derivatives. The extent of the effect of the catalytic hydrogenation to TPPF₂₀ with 10% Pd/C was then studied with a variety of solvents. The results showed that ethanol/DMF is the solvent of choice to produce chlorin TPCF₂₀ and an ethanol/DMF/NEt₃ mixture is more adequate to produce isobacteriochlorin (TPIF₂₀).

Star-shaped polymer consisting of a porphyrin core and poly(L-lysine) dendron arms: synthesis, drug delivery, and in vitro chemo/photodynamic therapy

A novel star-shaped polymer, porphyrin-poly(L-lysine) dendrons (PP-PLLD), is synthesized by the click reaction between azido-modified porphyrin and propargyl focal point poly(L-lysine) dendrons. Its chemical structure is characterized by (1) H nuclear magnetic resonance, Fourier transform infrared spectroscopy, and gel permeation chromatography (GPC) is analyses etc. Due to its amphiphilic property, the obtained PP-PLLD has a low critical micelle concentration in an aqueous solution, and can load doxorubicin (DOX) with a loading amount of 64 μg mg(-1) . By in vitro toxicity assay, PP-PLLD has no dark cytotoxicity but has significant phototoxicity. Moreover, DOX-loaded PP-PLLD shows a higher cytotoxicity under the light condition than PP-PLLD or DOX alone, suggesting PP-PLLD has a potential application in combined photodynamic therapy and chemotherapy.