Comparative study on the interfacial electron transfer of zinc porphyrins with meso-π-extension at a 2 n pattern

Meso-Tetrapyrenylporphyrins: Synthesis, structural, spectral, electrochemical properties and Förster energy transfer (FRET) studies

Meso-tetrapyrenylporphyrin and its metal (Co[Formula: see text], Cu[Formula: see text], Ni[Formula: see text] and Zn[Formula: see text]) complexes were synthesized, characterized and studied for their spectral, electrochemical and energy transfer properties. DFT optimization was carried out to gain an insight into the interactions between the porphyrin [Formula: see text]-system and the pyrenyl substituents. The pyrenyl substituents and the porphyrin core remain essentially orthogonal to each other in both the free base and the metallated porphyrins. Redox potentials of the pyrenylporphyrins are marginally shifted as compared to their corresponding phenyl derivatives. Förster resonance energy transfer (FRET) studies were carried out in toluene for free-base pyrenylporphyrin and its Zn(II) complex. Since pyrene is a good donor, an efficient energy transfer from pyrene (D) to the porphyrin core (A) on the order of 80–85% was observed for these two compounds. It was observed that energy transfer occurs mainly via ”through-bond” (TB) interaction rather than ”through-space” (TS) interaction.

Synthesis of a porphyrin-hexaarylbenzene-hexabenzocoronene triad

The synthesis of a triad consisting of porphyrin and hexabenzocoronene (HBC) units, which are connected via a central hexaarylbenzene (HAB) core, is presented. The ortho substitution pattern at the core results in a close proximity of the two chromophores, which influences their properties such as the intensity ratio of UV-vis absorption bands.

Behaviors of the Interfacial Consecutive Multistep Electron Transfer Controlled by Varied Transition Metal Ions in Porphyrin Cores

Almost all life activities involve the process of multistep electron transfer (ET) which occurs on biomembrane. Metalloporphyrins (MTPPs) are a class of molecules which are closely related to life course. Here, the n-step (n = 1, 2) ET behaviors controlled by different metal ions in porphyrin cores were investigated by thin-layer cyclic voltammetry (TLCV). The bimolecular ET was reacted between the MTPP (M = Fe, Zn, Co, Cu, Ni) and Fe(CN)₆^4- in nitrobenzene and aqueous phase, respectively, and the interface between nitrobenzene and aqueous phase was considered as a bionic membrane. The thin-layer theory, which has been revised, was used to calculate the kinetic constants for each step electron transfer reactions. It was shown that the kinetic data were affected dramatically by the different coordinated ions in porphyrin complexes.

Synthesis, singlet oxygen generation, photocytotoxicity and subcellular localization of azobisporphyrins as potentially photodynamic therapeutic agents in vitro cell study

Three azobisporphyrins (Por1, Por2 and Por3) were synthesized by coupling two molecules of (4-nitrophenyl/pyridyl) porphyrins in the presence of KOH/butanol. The structures of porphyrins were confirmed by UV, IR, NMR and mass spectra and elemental analysis. With tetraphenylporphyrin (H2TPP) as a control, the singlet oxygen (1O[Formula: see text] generation of porphyrins was evaluated through 1,3-diphenylisobenzofuran (DPBF) method. The order of ability to generate 1O2 for three azobisporphyrins was Por 1 [Formula: see text]Por 2 > Por 3[Formula: see text] H2TPP. The photocytotoxicity and sub-cellular localization of azobisporphyrins over Hela cells were studied through MTT analysis and confocal laser scanning microscope, respectively. The results indicated Por 1 and Por 2 displayed the low dark-cytotoxicity, while Por 3 induced a concentration-dependent cytotoxicity to Hela cells with the concentration of porphyrins ranging from 1 to 100 [Formula: see text] M. With the light dose at 4 J/cm2, Por 3 killed more than 60% Hela cells at 2 [Formula: see text] M, indicating a high photocytoxicity. As seen from the laser scanning confocal microscopy images, Por 3 was mainly localized in cell membrane, while Por 1 and Por 2 do not displayed significant fluorescent emission in Hela cells. These results suggest the synthesized cationic azobisporphyrin could be used as a potential therapeutic agent for photodynamic therapy of cancers.