Porphyrins fused to <i>N</i>-heterocyclic carbene palladium complexes as tunable precatalysts in Mizoroki–Heck reactions: How the porphyrin can modulate the apparent catalytic activity?

International audienc

Expanding the light absorption of poly(3-hexylthiophene) by end-functionalization with π-extended porphyrins.

Poly(3-hexylthiophene)s end-functionalized with π-extended porphyrins have been synthesized in a one-pot procedure. The polymers show a broad absorption profile extending to 700 nm and a fibrillar microstructure, which can be tuned through judicious selection of the porphyrin molar ratio

In vitro toxicity and photodynamic properties of porphyrinoids bearing imidazolium salts and N-heterocyclic carbene gold(I) complexes

Porphyrins bearing imidazolium salts were synthesized and used as N-heterocylic carbene (NHC) precursors for the preparation of gold(I) complexes. The dark toxicity and phototoxicity of the obtained compounds were investigated in vitro on MCF-7 breast cancer cells. The obtained data showed that porphyrins equipped with imidazolium salts are non-toxic in the dark and present interesting photodynamic properties. On the contrary, corresponding NHC-gold(I) complexes are not suitable photosensitizers for photodynamic therapy (PDT) applications. Their dark toxicity strongly depends on the nature of the linker between the porphyrin core and the NHC. This work was extended to the synthesis of a pyropheophorbide a derivative with a pendant imidazolium group for PDT applications using excitation wavelengths of 450 nm, 545 nm, and importantly of 650 nm

Organometallic and coordination chemistry, GECOM-CONCOORD 2013

International audienc

Synthèse et étude de porphyrines possèdant des sites chelatants externes (Construction d'oligomères de porphyrines assemblées par des cations métalliques)

Ce travail de thèse est consacré à la synthèse d'oligomères de porphyrines. En terme d'interaction entre les porphyrines, la méthode utilisée consiste à combiner l'efficacité de l'approche covalente (les porphyrines et les sites de liaisons sont coplanaires pour de meilleurs recouvrements orbitalaires) et la modularité de la liaison de coordination (un cation métallique sert à relier les porphyrines entre elles). Les études de la réactivité de dérivés d'une oxonaphtoporphyrine ont abouti à la synthèse de porphyrines comportant un site chélatant externe de type énaminocétone O,N, coplanaire et conjugué avec le macrocycle porphyrinique. Ces composés ont été utilisés pour la synthèse de dimères de porphyrines reliées par des cations métalliques. L'étude de leurs propriétés par diverses méthodes analytiques (spectroscopie électronique, électrochimie) a démontré de fortes interactions électroniques entre les porphyrines à l'état fondamental.Afin de former des oligomères utilisant le même type de connexions entre les macrocycles, des porphyrines comportant deux sites de coordination externe de type énaminocétone ont été synthétisées. L'étape-clé pour la formation de ces composés est une double cyclisation intramoléculaire de type Friedel-Crafts pour obtenir des dicétones. Leur amination a permis d'obtenir des bis-énaminocétones. Des réactions de thionation des fonctions carbonyles permettent également la formation de composés comportant un ou deux des sites chélatants externes de type énaminothiocétone S,N.A partir de ces composés, plusieurs méthodologies de synthèse permettent d'obtenir des oligomères de porphyrines assemblées par des cations métalliques et possédant des bandes d'absorption dans le proche infrarouge. Suivant la structure de la porphyrine (O,N/O,N, O,N/S,N ou S,N/S,N) et du centre métallique utilisé, quatre méthodologies différentes ont été développées. Diverses méthodes analytiques ont également été utilisées pour caractériser ces oligomères.This thesis is devoted to the synthesis of porphyrin oligomers. To optimize the interactions between the porphyrins, we used an approach combining the efficiency of the covalent approach (the porphyrins and the links between them are coplanar for better orbital overlap) and the modularity of the coordination bond (a cationic metal center is used to link the porphyrins).The studies on the reactivity of oxonaphtoporphyrin derivatives resulted in the synthesis of porphyrins bearing an enaminoketone O,N external coordination site, coplanar and conjugated with the core of the porphyrin. These compounds were used to synthetize porphyrin dimers linked by metal ions. The study of their properties with different analytical tools (electronic spectroscopy, electrochemistry) demonstrated strong electronic interactions between the porphyrins in the ground state.In order to build oligomers with the same type of connection between the aromatic rings, porphyrins bearing two external chelating sites have been synthetized. The key step is a double intramolecular Friedel-Crafts cyclization in order to obtain diketones. Their amination gave bis-enaminoketones O,N/O,N. Thionation reactions gave compounds with one or two enaminothioketone S/N external chelating sites.Having these molecular building blocks in hand, several methodologies have been developed to obtain porphyrin oligomers connected by cationic metal centers with absorption bands in near infrared. Depending on the structure of the porphyrins (O,N/O,N, O,N/S,N ou S,N/S,N) and the metal ion used, four different routes were followed. Different analytical tools have been used to characterize these oligomers.STRASBOURG-Sc. et Techniques (674822102) / SudocSudocFranceF

Cofacial porphyrin dimers assembled from N-heterocyclic carbene–metal bonds

International audienc

Synthèse et caractérisation de polyphosphintes de métaux modifiés

National audienc

Molecular Systems Combining Porphyrinoids and N‐Heterocyclic Carbenes

International audiencePorphyrins and N-heterocyclic carbenes (NHCs) are both relevant ligands in the fields of coordination and organometallic chemistry. Despite evident structural differences, porphyrins and NHCs have a lot in common such as their ability to form strong metalligand bonds and their use in catalysis, materials science and biomedicine. During the last decade, several molecular systems combining porphyrins and NHC ligands were reported in the literature. The present review gathers relevant examples where NHC ligands are either axially bonded to metalloporphyrins or covalently attached to the porphyrin cores. Structural diversity, electronic interplay between porphyrins and NHCs and some relevant applications in catalysis and biomedicine are notably described. Finally, molecular systems combining NHCs with other original porphyrinoids such as Nconfused porphyrins, subporphyrins and norcorroles are also presented