Christophe Jeandon

Diporphyrinylamines: Synthesis and Electrochemistry

The synthesis of three possible diporphyrinylamines is described. All compounds were obtained by using the Buchwald-Hartwig aromatic amination reaction. The electronic spectra of the three porphyrin dimers showed characteristic features found in highly delocalized systems. The first oxidation of these compounds took place on the connecting amine function.

Synthesis of extended porphyrins by connection of meso-aryl groups with β-pyrrolic positions

This review focuses on synthetic strategies leading to extended porphyrins, but is limited to examples in which at least one β-pyrrolic carbon is linked to a meso-aryl substituent. Friedel–Crafts reactions are covered first because historically they were the first reactions employed to link β-pyrrolic carbons with meso-aryl groups, thus creating new six-membered fused rings. Other reactions inserting heteroatoms follow. Direct cyclizations between an ortho-carbon and a β-pyrrolic position are presented next. Finally, new highly extended chromophores are described. These compounds are generally obtained in two consecutive reactions. First a Suzuki coupling is used to introduce an aryl group in one or two meso positions. Then the new fused rings are generated by oxidative cyclizations.

Reactivity of oxonaphtoporphyrins. Efficient β-functionalization of the porphyrin ring on reaction with nitrogen or carbon nucleophiles

Abstract Oxonaphtoporphyrins show a 1,4 reactivity involving the conjugated pyrrole double bond, the addition being followed by oxidation or elimination leading to rearomatization. Addition of nitrogen or carbon nucleophiles gives amino and substituted aminoporphyrins, or alkyl and cyanoporphyrins, respectively.

Porphyrin ring contraction: a one-pot reaction leading to divalent corrolesElectronic supplementary information (ESI) available: experimental procedures for syntheses of corrole 4 and ketone 3 (R = OEt), and for preparing 4 from 11 (R = H). See http://www.rsc.org/suppdata/cc/b4/b400812j/

Reaction of nickel meso-tetraarylporphyrins with benzoic anhydride and tin tetrachloride, followed by air oxidation under basic conditions, results in ring contraction, yielding divalent corroles.

Ground and excited state properties of new porphyrin based dyads: a combined theoretical and experimental study.

The properties of the ground and excited states of several porphyrins appended with external chelates coordinated to ruthenium-bisbipyridine units are reported. The important modification of the absorption spectrum upon coordination with the ruthenium complex showed that a significant electronic communication between the two subunits was present in the ground state. Experimental results were compared with quantum chemistry calculations performed at density functional theory and time-dependent density functional theory level. The influence of the exchange-correlation functional on the quality of the computed absorption spectrum is shown, and the better behavior of hybrid functionals over long-range corrected ones was rationalized. The excited states topology analysis, performed using natural transition orbitals, gave a more evident confirmation of the communication between the subunits and showed that these new compounds can be promising as dyes in dye-sensitized solar cells.

Preparation, mass spectrometry and electrochemical studies of metal connected porphyrin oligomers

Oligomers built from metal ions and porphyrins bearing enaminoketones at the ring periphery were prepared. These dimers or trimers, where all porphyrinic rings are coplanar, show large interactions in the ground state between the individual porphyrin cores, as shown by their optical properties and electrochemical studies. In particular, a spectacular decrease of the HOMO-LUMO gap (with values as low as 1.32 eV) was observed for monomeric porphyrins metalated on the external sites. Along with standard analytical methods, APPI (Atmospheric Pressure PhotoIonization) mass spectrometry was found to be a very powerful tool to characterize these metal connected porphyrin oligomers.

A new approach to N-phenylquinolino[2,3,4-at]porphyrins: Electrochemical and photochemical studies

A new route to N-phenylquinolino[2,3,4-at]porphyrins is described and the electrochemical and photochemical properties of the synthesized derivatives were investigated. The electrochemical studies (cyclic voltammetry and rotating disk voltammetry) of the free-base and the corresponding Ni, Cu and Pd complexes have shown that the presence of the phenyl group is responsible for the formation of stable radical cations. The capacity of the N-phenylquinolino[2,3,4-at]porphyrins to generate singlet oxygen was evaluated and some of them have promising features as photosensitizers.

Porphyrins acting as external and internal ligands: preparation of conjugated trimetallic dimeric porphyrins

A porphyrin bearing a peripheral enaminoketone function allows the preparation of conjugated dimeric porphyrins linked through metal ions.

A new porphyrin dimer as an unexpected side-product

The synthesis of new diporphyrinylamines is described. In particular, the possibility to use the Buchwald or Ullmann amination reactions to obtain these compounds is detailed. Attempts to obtain symmetrical diporphyrinylamines linked by a tertiary amine are exposed and the obtention as side-product of an unexpected unsymmetrical porphyrin dimer with a meso–β linkage is described.

Reduction of N-arylporphyrins to N-arylphlorins: opposite stereochemical courses as a function of the reducing agent

Electrochemical or Na2S2O4 reduction of N-arylporphyrins gives stable phlorins epimeric to those obtained by tosylhydrazine or NaBH4 reduction.