Porphyrin-Oligopyridine Triads: Synthesis and Optical Properties

The synthesis of two triads with two porphyrinyl units linked by oligopyridine derivatives and a new β-functionalized porphyrin-dihydroazepine is described. One of the porphyrin-oligopyridine triads has a quinquepyridine unit connecting the porphyrins β-pyrrolic positions, while the other one has an asymmetric quaterpyridine with one of the pyridines fused to the porphyrin. All compounds have fluorescence emission quantum yields in the range of <i>meso</i>-tetraphenylporphyrin (16–22%)

Synthesis, Spectroscopy Studies, and Theoretical Calculations of New Fluorescent Probes Based on Pyrazole Containing Porphyrins for Zn(II), Cd(II), and Hg(II) Optical Detection

New pyrazole–porphyrin conjugates were successfully prepared from a reaction of β-porphyrin–chalcone derivatives with phenylhydrazine in acetic acid followed by an oxidative step. This fast and efficient synthetic approach provided the expected compounds in yields up to 82%. The sensing ability of the new porphyrin–pyrazole derivatives to detect the metal ions Ag⁺, Na⁺, K⁺, Mg²⁺, Ca²⁺, Ni²⁺, Cu²⁺, Zn²⁺, Cd²⁺, Hg²⁺, Pb²⁺, and Cr³⁺ was studied by spectrophotometric and spectrofluorimetric titrations. In the presence of Zn²⁺, the conjugates exhibit changes in the emission spectra that are desired for a ratiometric-type fluoroionophoric detection probe. The studies were extended to gas phase, where the pyrazole–porphyrin conjugates show ability to sense metal ions with high selectivity toward Cu²⁺ and Ag⁺, and in poly­(methyl methacrylate) doped films with promising results for Zn²⁺ detection

<i>meso</i>‑Tetraphenylbenzoporphyrin‑2²,2³‑dicarboxylic Anhydride: A Platform to Benzoporphyrin Derivatives

A method to synthesize <i>meso</i>-tetraphenylbenzoporphyrin-2²,2³-dicarboxylic anhydride is reported. This compound reacts with alkylamines and arylamines to afford the corresponding “phthalimides” in moderate to excellent yields. The reaction of the title compound with benzene-1,4-diamine or with benzene-1,3-diamine yields the corresponding <i>N</i>,<i>N</i>′-(phenylene)­bisphthalimides, whereas with benzene-1,2-diamine or naphthalene-1,8-diamine it affords heterocyclic-fused porphyrins. Molecular mechanics simulations elucidates the multiplicity of signals observed in the NMR spectra of the <i>N</i>,<i>N</i>′-(1,4-phenylene)­bisphthalimide <b>11</b>. This molecule exhibits two preferential conformations corresponding to a coplanar and an almost perpendicular arrangement of the benzoporphyrin units relative to the central benzenic ring

Inexpensive and Efficient Ullmann Methodology To Prepare Donor-Substituted Porphyrins

The preparation of porphyrins functionalized with one or two carbazoles (or phenoxazines) is described. The electron donors were introduced into one or two porphyrin <i>meso</i> positions by using the inexpensive Ullmann coupling procedure. Very good yields were obtained, and for two new compounds, the X-ray structures were solved. Preliminary electrochemical data coupled with electronic spectroscopy are also reported

Mitochondria-Targeted Photodynamic Therapy with a Galactodendritic Chlorin to Enhance Cell Death in Resistant Bladder Cancer Cells

Here, we report the rational design of a new third-generation photosensitizer (PS), a chlorin conjugated with galactodendritic units, ChlGal₈, to improve the effectiveness of bladder cancer treatment. ChlGal₈ shows better photochemical and photophysical properties than a recently reported homologous porphyrin, PorGal₈. In addition to inheriting excellent photostability, the ability to generate singlet oxygen, and the ability to interact with the proteins galectin-1 and human serum albumin (HSA), ChlGal₈ exhibits high absorption in the red region of the electromagnetic spectrum. In vitro studies of anticancer activity of ChlGal₈ revealed that once this PS is taken up by UM-UC-3 bladder cancer cells, it induces high cytotoxicity after a single dose of light irradiation. In HT-1376 bladder cancer cells resistant to therapy, a second light irradiation treatment enhanced in vitro and in vivo photodynamic efficacy. The enhanced phototoxicity in HT-1376 cancer cells seems to be due to the ability of ChlGal₈ to accumulate in the mitochondria, via facilitative glucose transporter 1 (GLUT1), in the period between single and repeated irradiation. A photodynamic therapy (PDT) regimen using an extra dose of light irradiation and ChlGal₈ as PS represents a promising strategy in treating resistant cancers in a clinical setting

Fluorescent Bioactive Corrole Grafted-Chitosan Films

Transparent corrole grafted-chitosan films were prepared by chemical modification of chitosan with a corrole macrocycle, namely, 5,10,15-tris­(pentafluorophenyl)­corrole (TPFC), followed by solvent casting. The obtained films were characterized in terms of absorption spectra (UV–vis), FLIM (fluorescence lifetime imaging microscopy), structure (FTIR, XPS), thermal stability (TGA), thermomechanical properties (DMA), and antibacterial activity. The results showed that the chemical grafting of chitosan with corrole units did not affect its film-forming ability and that the grafting yield increased with the reaction time. The obtained transparent films presented fluorescence which increases with the amount of grafted corrole units. Additionally, all films showed bacteriostatic effect against S. aureus, as well as good thermomechanical properties and thermal stability. Considering these features, promising applications may be envisaged for these corrole-chitosan films, such as biosensors, bioimaging agents, and bioactive optical devices