Synthesis, Caharacterization, and Electronic Properties of Metalloporphyrins Annulated to Exocyclic Imidazole and Imidazolium Rings

Full paperInternational audiencemeso-Tetraarylporphyrin complexes (M = Ni, Cu, Zn, H2) fused to an imidazole ring across two neighboring β-pyrrolic positions were synthesized through a cyclization reaction between β,β'-diaminoporphyrins and formic acid or trimethyl orthoformate under acidic conditions. Two synthetic procedures were used to obtain the corresponding porphyrin N,N'-dimethylimidazolium salts derivatives: alkylation of the imidazole nitrogen atoms with iodomethane and the cyclization reaction between the porphyrin bearing two neighboring β-N-methyl groups and trimethyl orthoformate in the presence of ammonium hexafluorophosphate. The electrochemical properties of these porphyrins annulated to an imidazole/imidazolium ring have been investigated by cyclic and rotating disk voltammetry

Propriétés rédox de nouveaux macrocycles polypyrroliques

STRASBOURG-Sc. et Techniques (674822102) / SudocSudocFranceF

Peripherally Metallated Porphyrin Derivatives : Approaches and Properties

During the last 15 years, the synthetic modifications of porphyrins and porphyrazines have evolved rapidly. Despite this progress, the chemistry of porphyrinoids bearing coordination complexes or organometallic fragments at their periphery is still much less developed than the coordination chemistry using the apical positions of the central metal ions or remote coordination sites. The two latter types of coordination chemistry are much easier to perform from a synthetic point of view. However, transition metal-based synthetic chemistry is improving rapidly, allowing the introduction of functionalities, mainly heteroatoms or boron derivatives, at the periphery of aromatic rings. The coordination chemistry or organometallic chemistry that links together two large porphyrinoids while simultaneously allowing large electronic or magnetic interactions between these macrocycles is still limited to a few examples. The synthesis of di- or polyfunctionalized porphyrins must be developed. The inorganic chemistry around the metal ion linkages also needs to be improved and varied to give new compounds with potentially new properties. Finally, once the molecular chemistry is well understood, the chemistry of new molecular materials will need to be developed toward polymeric species

Synthesis, structural characterization, and electrochemical studies of nickel porphyrins bearing two peripheral conjugated chelating groups

International audienc

Porphyrins Fused to N-Heterocyclic Carbenes (NHCs): Modulation of the Electronic and Catalytic Properties of NHCs by the Central Metal of the Porphyrin

International audienceWe report herein a detailed study of the use of porphyrins fused to imidazolium salts as precursors of N-heterocyclic carbene ligands 1M. Rhodium(I) complexes 6M-9M were prepared by using 1M ligands with different metal cations in the inner core of the porphyrin (M= NiII, ZnII, MnIII, AlIII, 2H). The electronic properties of the corresponding N-heterocyclic carbene ligands were investigated by monitoring the spectroscopic changes occurring in the cod and CO ancillary ligands of [(1M)Rh(cod)Cl] and [(1M)Rh(CO)2Cl] complexes (cod= 1,5-cyclooctadiene). Porphyrin-NHC ligands 1M with a trivalent metal cation such as MnIII and AlIII are overall poorer electron donors than porphyrin-NHC ligands with no metal cation or incorporating a divalent metal cation such as NiII and ZnII. Imidazolium salts 3M (M=Ni, Zn, Mn, 2H) have also been used as NHC precursors to catalyze the ring-opening polymerization of l-lactide. The results clearly show that the inner metal of the porphyrin has an important effect on the reactivity of the outer carbene

Metal-acetylide addition to tetracyanoethylene

ISSN:0040-403