Influence of the macrocycle structure on the ability of Co(II)-porphyrins to oxidize in the presence of organic bases

Мамардашвили, Г. М.; Kaigorodova, Elena Yu.; Симонова, О. Р.; Мамардашвили, Н. Ж.

doi:10.1080/00958972.2018.1535112

Cited by 5 publications

(1 citation statement)

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“…It is known that cobalt cation in the porphyrin coordination center can have two oxidation states (2 + and 3 + ), and both states can quite easily transform into each other. So, when Co(II)-tetraarylporphyrins are dissolved in electron-donating or non-polar solvents in the presence of organic bases, the Co(II) cation almost instantaneously oxidizes into Co(III), coordinating on itself two additional electron-donating ligands or one ligand and one solvent molecule [ 49 , 50 , 51 , 52 ]. The catalyst for this process is molecular oxygen contained in the air.…”

Section: Results and Its Discussionmentioning

confidence: 99%

Molecular Recognition of Imidazole Derivatives by Co(III)-Porphyrins in Phosphate Buffer (pH = 7.4) and Cetylpyridinium Chloride Containing Solutions

et al. 2021

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Bymeans of spectrophotometric titration and NMR spectroscopy, the selective binding ability ofthe Co(III)-5,15-bis-(3-hydroxyphenyl)-10,20-bis-(4-sulfophenyl)porphyrin (Со(III)Р1) andCo(III)-5,15-bis-(2-hydroxyphenyl)-10,20-bis-(4-sulfophenyl)porphyrin (Со(III)Р2) towards imidazole derivatives of various nature (imidazole (L1), metronidazole (L2), and histamine (L3)) in phosphate buffer (pH 7.4) has been studied. It was found that in the case of L2, L3 the binding of the “first” ligand molecule by porphyrinatesCo(III)P1 and Co(III)P2 occurs with the formation of complexes with two binding sites (donor–acceptor bond at the center and hydrogen bond at the periphery of the macrocycle), while the “second” ligand molecule is added to the metalloporphyrin only due to the formation of the donor–acceptor bond at the macrocycle coordination center. The formation of stable complexes with two binding sites has been confirmed by density functional theory method (DFT) quantum chemical calculations and two-dimensional NMR experiments. It was shown that among the studied porphyrinates, Co(III)P2 is more selective towards to L1-L3 ligands, and localization of cobalt porphyrinates in cetylpyridinium chloride (CPC) micelles does not prevent the studied imidazole derivatives reversible binding. The obtained materials can be used to develop effective receptors for recognition, delivery, and prolonged release of drug compounds to the sites of their functioning. Considering that cetylpyridinium chloride is a widely used cationic biocide as a disinfectant, the designed materials may also prove to be effective antimicrobial agents.

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