Synthesis, Characterization, and Electrochemistry of Open-Chain Pentapyrroles and Sapphyrins with Highly Electron-Withdrawing meso -Tetraaryl Substituents - Université de Bourgogne Accéder directement au contenu
Article Dans Une Revue Chemistry - A European Journal Année : 2017

Synthesis, Characterization, and Electrochemistry of Open-Chain Pentapyrroles and Sapphyrins with Highly Electron-Withdrawing meso -Tetraaryl Substituents

Résumé

A series of open-chain pentapyrroles and sapphyrins with highly electron-withdrawing substituents (i.e., CN, CF3 , or CO2 Me) on the meso-phenyl rings was synthesized and characterized as to the spectral properties, protonation reactions, and electrochemistry in non-aqueous media. The investigated compounds are represented as (Ar)4 PPyH3 and (Ar)4 SapH3 where PPy and Sap correspond to the tri-anion of the open-chain pentapyrrole and sapphyrin, respectively, and Ar=p-CNPh, p-CF3 Ph, or p-CO2 MePh. UV/Vis and 1 H NMR spectroscopy as well as mass spectrometry data are given for the confirmation of the structures for the newly synthesized compounds. An X-ray structure for one of the pentapyrroles, that is, (p-CF3 Ph)4 PPyH3 (2), is also presented. The protonation processes were examined by UV/Vis absorption spectroscopy during the titration of the compounds with trifluoroacetic acid (TFA) in CH2 Cl2 . Equilibrium constants for the protonation reactions were calculated by using both the Hill equation and the mole ratio method. The protonation-initiated conversion of pentapyrroles to sapphyrins upon oxidation was also investigated. Cyclic voltammetry was used to measure the redox potentials in CH2 Cl2 , PhCN, and/or pyridine (Py). Electrochemical properties, protonation constants, and chemical reactions of the six compounds in the two series were then analyzed as a function of the solvent properties and the type of the electron-withdrawing groups on the meso-phenyl rings.
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Dates et versions

hal-01589768 , version 1 (19-09-2017)

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Wenqian Shan, Nicolas Desbois, Virginie Blondeau-Patissier, Mario L. Naitana, Valentin Quesneau, et al.. Synthesis, Characterization, and Electrochemistry of Open-Chain Pentapyrroles and Sapphyrins with Highly Electron-Withdrawing meso -Tetraaryl Substituents. Chemistry - A European Journal, 2017, 23 (52), pp.12833 - 12844. ⟨10.1002/chem.201701968⟩. ⟨hal-01589768⟩
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