Journal of Porphyrins and Phthalocyanines

Synthetic strategies for electron-deficient meso-perfluoroalkylporphyrins bearing diverse functional groups are described. Scalable and efficient syntheses for 5-triisopropylsilylethynyl-10,15,20-tris(heptafluoropropyl)porphyrin and 5-triisopropylsilylethynyl-10,20-bis(heptafluoropropyl)porphyrin that equip meso-ethynyl functional groups via the bilane route have been established, along with a refined route to [5,15-bis(heptafluoropropyl)porphinato]zinc(II). meso-Position halogenation of [5,15-bis(heptafluoropropyl)porphinato]zinc(II) was achieved by selective meso-nitration and subsequent reduction, diazonium salt formation, and iodination reactions. Computational data describe the low energy excited states of these chromophores and the electronic structural factors that control reactivity of these meso-perfluoroalkyl substituted porphyrin complexes. meso-Functionalized [5-triisopropylsilylethynyl-10,20-bis(heptafluoropropyl)porphinato]zinc(II) and [5-iodo-10,20-bis(heptafluoropropyl)porphinato]zinc(II) building blocks lay the foundation for the construction of highly conjugated multiporphyrin arrays that feature electronic structural properties important for the development of n-type materials and high potential photooxidants.

Organic triplet-triplet annihilation photon upconversion (TTA-UC) systems have attracted considerable attention owing to their promising applicability in solar energy harvesting, optoelectronic devices, photocatalysts, and bio-imaging. In this study, a series of BODIPYs prepared by incorporating substituted/ unsubstituted arylselenium groups, 1 (R = H), 2 (R = OMe), and 3 (R = F), were evaluated as triplet photosensitizers for TTA-UC. Direct Se-C bond formation on the BODIPY core provided a facile intersystem crossing (ISC) channel from the excited singlet state to the metastable triplet state, being the most effective in 2, as inferred from the singlet oxygen generation experiments, possibly because of the n-electron arising from the OMe group. The UC behavior of systems comprising the sensitizers and perylene as the acceptor in deaerated toluene was investigated using a 524 nm-wavelength laser to detect upconverted emission at 449 nm; thus, the UC yield decreased in the order of 21% for 3 > 16% for 2 > 12% for 1. This trend is consistent with the Stern-Volmer constants calculated from the quenched triplet state lifetimes of the sensitizers as a function of the concentration of the perylene quencher. This suggests that the UC efficiency was mainly governed by the intermolecular triplet-triplet energy transfer (TTET) process between arylselanyl-BODIPY photosensitizers and the perylene acceptor. This result was rationalized by the efficient population of the long-lived triplet excited state of the sensitizer, which is advantageous for diffusion-controlled TTA-UC behavior.

The desired asymmetric metal-free porphyrin derivatives were prepared by condensing freshly prepared the phenyl dipyrraomethane and triphenyl tetrapyrrane building blocks with the different molar ratios of acetaldehyde (${\mathrm{\text{CH}}}_3$CHO), and glutaraldehyde (OHC(${\mathrm{\text{CH}}}_2{)}_3$CHO, Glu). The obtained asymmetric [3+1] (${\mathrm{\text{MePh}}}_3$Por, ${\mathrm{\text{Ph}}}_3$Por-$\mu$-(${\mathrm{\text{CH}}}_2{)}_3{\mathrm{\text{Ph}}}_3$Por) and [2+2] (${\mathrm{\text{Me}}}_2{\mathrm{\text{Ph}}}_2$Por, ${\left({\mathrm{\text{Ph}}}_2\mathrm{\text{Por}}\right)}_{\times }-\mu$-(${\mathrm{\text{CH}}}_2{)}_3$ oligomer) porphyrin derivatives were characterized by UV-Vis, FT-IR, and ¹H NMR. Their photoelectric properties were investigated by examining their current density-voltage (J-V) curves in dark, and under artificial sunlight, illumination using standard bulk heterojunction cell arrangements. The ${\mathrm{\text{J}}}_{\mathrm{\text{photo}}}$-V plots show that they display photosensitive semiconducting properties in the range of ($\sigma$ = 1.7–14.5 $\mu$S/cm) with negligible photovoltaic effects. All data were compared to those of symmetric metal-free ${\mathrm{\text{Ph}}}_4$Por($\sigma$ = 33.8 $\mu$S/cm). Density functional theory (DFT) is employed to validate the ground-state molecular geometry.

The role of Cl and H atoms inside AlPc organic molecule by experimental, DFT, and TD-DFT methods is investigated. A detailed study of Pc, AlPc-Cl, and AlH-Pc absorption wavelengths, energies, and oscillator strengths are achieved. To strengthen such investigation, HOMO-LUMO and DOS spectrum analysis are described showing the optical band of 2.01, 2.11, and 2.18 eV for Al-Pc, AlH-Pc, and AlCl-Pc compounds respectively, and nonlinear optical properties are presented. Furthermore, the values of calculated dipole moment, polarizability, and second-order static hyperpolarizability of AlCl-Pc, AlH-Pc, Al-Pc, and Pc compounds are studied. The heterojunctions based on AlPc-Cl and AlPc-H are fabricated by low-cost routes. I-V characteristics are demonstrated under dark and room temperatures. A high rectifying ratio of our heterostructures based on AlPc is exhibited. Non-ideal behavior, $n>$ 1, of the fabricated heterostructures due to the presence of interface states is revealed.

We studied the interaction of water-soluble cationic metalloporphyrins, $p$Py and TMPyP, with the DNA double helix in ionic liquid solutions using CD and absorption spectra. The dispersibility of their porphyrin complexes was improved by electrostatic interactions of the anions of the ionic liquid. In the case of Cu(II) and Zn(II) complexes, the $p$Py complexes with pyridinium cations attached to the meso-phenyl groups via methylene groups intercalated into the DNA double helix, while the compact TMPyP complexes with pyridinium cations at the meso-position could not interact with DNA. Thus, it was suggested that the solvation behavior by ionic liquids depends on the structure of the porphyrin and also affects its interaction with DNA. Neither Mn(III) complexes with axial ligands could interact with DNA, regardless of the presence of the ionic liquids, due to their steric hindrance.

Photodynamic therapy (PDT) is an interesting and promising approach to tackle a broad spectrum of cancer. With the combination of a photosensitizer, light and oxygen, PDT achieves a unique selectivity by the production of localized reactive oxygen species (ROS) inside cells, which leads to their destruction. In addition, the luminescence properties of photosensitizers can be exploited to develop imaging tools. Unfortunately, the cancer selectivity and homogeneity of most photosensitizers are frequently limiting the performances of PDT and cancer detection/characterization by luminescence imaging. Consequently, our study aims to use cellulose nanocrystals to transport and deliver radiolabeled photo-responsive metalla-assemblies to create a new generation of theranostic agents for PDT and imaging applications. The synthesis, structural characterization, cytotoxicity evaluation, and in vivo biodistribution imaging of the compounds are presented. The best candidates show excellent biological activity and selectivity towards ovarian carcinoma cell line (A2780), cisplatin-resistant ovarian carcinoma cell line (A2780cis) versus normal human embryonic kidney cells (HEK293T), as well as efficient imaging properties, suggesting a potential use as multimodal theranostic agents.

Medicinal effects of hydrophobic derivatives of vitamin ${\mathrm{\text{B}}}_{12}$ have been insignificantly investigated primarily due to their low solubility in aqueous solutions. One of the ways to increase their water solubility is the complexation with proteins. Here, we report the results of the studies of the reactions between aquacyano cobyrinic acid or monocyano cobesters (i.e., heptamethyl, heptaethyl, heptapropyl, and heptabutyl cobyrinates) and bovine serum albumin (BSA). The weakest binding is observed between aquacyano cobyrinic acid and BSA. In the case of monocyano heptaethyl cobyrinate, one BSA molecule is capable of binding up to six corrinoid molecules preventing its precipitation. Moreover, the pronounced effect of BSA on the solubility in water was observed in the case of monocyano heptapropyl cobyrinate. The absence of the precipitation of monocyano heptabutyl cobyrinate was observed only in the presence of high excess of BSA. BSA modification by diethyl pyrocarbonate, a chemical predominantly reactive toward imidazole motifs, indicated that a major fraction of BSA is bound with monocyano heptaethyl, heptapropyl, and heptabutyl cobyrinates via histidine residues. We showed that nitrosyl complexes of heptaethyl and heptapropyl cobyrinates can be stabilized from precipitation in aqueous solutions using BSA.