0000000000329223
AUTHOR
Benoit Habermeyer
Dioxygen reduction by cobalt(II) octaethylporphyrin at liquid|liquid interfaces.
Oxygen reduction catalyzed by cobalt(II) (2,3,7,8,12,13,17,18-octaethylporphyrin) [Co(OEP)] at soft interfaces is studied by voltammetry and biphasic reactions. When Co(OEP) is present in a solution of 1,2-dichloroethane in contact with an aqueous acidic solution, oxygen is reduced if the interface is positively polarized (water phase versus organic phase). This reduction reaction is facilitated when an additional electron donor, here ferrocene, is present in excess in the organic phase.
Control over the oxidative reactivity of metalloporphyrins. Efficient electrosynthesis of meso,meso-linked zinc porphyrin dimer.
The electrochemical oxidation of zinc(II) 5,15-p-ditolyl-10-phenylporphyrin at its first oxidation potential leads to the formation of the corresponding meso-meso porphyrin dimer as the main product. The number of electrons abstracted, the addition of the hindered base 2,6-lutidine as well as operating in DMF, instead of a CH(2)Cl(2)/CH(3)CN mixture are the key parameters to obtain high yields of the desired coupling product. Indeed, when the electrolyses are carried out in the CH(2)Cl(2)/CH(3)CN mixture, the unexpected zinc(II) 5-chloro-10,20-p-ditolyl-15-phenyl porphyrin is produced as a by-product, the chlorine atom originating from the CH(2)Cl(2) solvent. The monomer and the dimer are c…
Dynamics of closure of zinc bis-porphyrin molecular tweezers with copper(II) ions and electron transfer.
Zinc bis-porphyrin molecular tweezers composed of a N(4) spacer bound through pyridyl units to the meso position of porphyrins were synthesized, and the tweezers are closed by the coordination of a copper(II) ion inside the spacer ligand. The effect of the π-π interaction between the porphyrin rings in the closed conformation on the absorption spectra of multi-electron oxidized species and the reduction potentials were clarified by chemical and electrochemical oxidation of the closed form of the zinc bis-porphyrin molecular tweezers in comparison with the open form without copper(II) ion and the corresponding porphyrin monomer. The shifts in redox potentials and absorption spectrum of the p…
Facile formation of a meso–meso linked porphyrin dimer catalyzed by a manganese(iv)–oxo porphyrin
A manganese(IV)-oxo porphyrin catalyzes C-C bond formation between zinc porphyrins at the meso-position with a two-electron oxidant to afford the meso-meso linked porphyrin dimer efficiently. The meso-meso linked dimer is formed via formation of the porphyrin radical cation, and the rate-determining step in the catalytic cycle is the formation of a manganese(IV)-oxo porphyrin with a two-electron oxidant.
Electrochemistry, spectroelectrochemistry and catalytic activity of biscobalt bisporphyrin dyads towards dioxygen reduction
Three face-to-face biscobalt bisporphyrin dyads, including one incorporating a copper(II) ion inside the linker, were synthesized and characterized both spectroscopically and electrochemically in three non-aqueous solvents, dichloromethane, benzonitrile and pyridine. The electrocatalytic reduction of dioxygen with these derivatives on an electrode surface in 1.0 M HClO4 was also investigated and the results are compared to that obtained with "regular" Pacman biscobalt bisporphyrins under the same experimental conditions. Surprisingly, the tris-metal species ( Cu-bisCo ) catalyzes the reduction of O2 mainly via a 2e- transfer process, leading to H2O2 , while the bis-metal (bisCo) catalyst p…
Towards the synthesis of substituted porphyrins by a pyridyl group bearing a reactive functionality
Pyridyl-substituted porphyrins bearing a reactive functionality were prepared via Suzuki cross-coupling reactions and resulted in very good yields. These compounds are precursors of new porphyrin architectures able to coordinate two metals: one in the porphyrin core and the second around the pyridyl moiety. During the coupling reactions, a higher reactivity of a chloro picolyl group was evidenced compared to a bromo function on the same reacting molecule.
Bactericidal efficiency of porphyrin systems
Photodynamic Inactivation is an innovative technique used to combat bacterial and viral infections which involves the use of photosensitizing agents along with light to generate cytotoxic reactive oxygen species able to kill bacteria and viruses. In the first section of this minireview, porphyrin-based fluorophores are shown to be remarkable dye candidates for PDI (photodynamic inactivation) applications. The second section is dedicated to the description of porphyrin-based antimicrobial materials and their potentialities for industrial applications such as in food packaging or antimicrobial medical devices and hygiene. Finally, the failings and perspectives of PDI are analyzed to demonstr…
Three-Metal Coordination by Novel Bisporphyrin Architectures
The synthesis and characterization of a new type of bisporphyrin system is reported where the two macrocycles are linked in a cofacial arrangement by a substituted carbazole bridge. The three nitrogen atoms of the carbazole bridge in the compounds may complex a metal ion and thus provide a new parameter for varying the physical properties and flexibility of the dyad after formation of a three-metal system. In the present study, four bis-metalloporphyrin complexes were synthesized and examined by electrochemistry and thin-layer spectroelectrochemistry in CH(2)Cl(2) and PhCN. Two of the examined compounds contain Cu(II) or Zn(II) porphyrins and a carbazole linker with a bound Cu(II) ion, givi…
X-ray induced PDT and scintillating particles
International audience
CCDC 1502145: Experimental Crystal Structure Determination
Related Article: Jean-Michel Barbe, Benoit Habermeyer, Tony Khoury, Claude P. Gros, Philippe Richard, Ping Chen, and Karl M. Kadish|2010|Inorg.Chem.|49|8929|doi:10.1021/ic101170k