Bernard Boitrel

Characterization and application of a new diprotected cyclam: a novel two-step synthesis of linked tetraazamacrocycles

Abstract The synthesis and separation of the 1,8-di-(tertbutyloxycarbonyl) cyclam (1,8-diboc cyclam) among other isomers allow the facile obtention of singly or doubly linked, and bridged tetraazamacrocycles within a two-step synthesis in a very convenient way. This strategy can be applied to a large scale preparation of several types of dioxygen carriers or activators.

SYNTHESIS OF BIOMIMETIC HEME PRECURSORS

Abstract Three kinds of biomimetic heme precursors have been prepared. The first type is based on tetra-aminoporphyrins: either 5,10,15,20-tetrakis ( o -aminophenyl)porphyrin (various atropoisomers), or 5,15-bis(2′,6′-diaminophenyl)porphyrin. The second type is based on octa-aminoporphyrins: 5,10,15,20-tetrakis (2′,6′-diamino-4′- tert -butylphenyl)porphyrin. One example of “basket handle” porphyrin demonstrates selective discrimination between O 2 and CO with an M value [ M = p 1/2 (O 2 )/ p 1/2 (CO)] of 105. This is similar to values reported for various natural hemoproteins. The third type is based on aminoporphyrin templates [5, 5,10- or 5,15- and 5,10,15-(2′,6′-dinitro,4′- tert -butylphenyl)porphyrins] which have been tested in asymmetric epoxidation.

Synthesis and X-ray characterization of a new bis-crown ether porphyrin

Abstract The easy one-step synthesis of a new bis-diaza crown ether porphyrin starting from the widely used αβαβ-tetrakis (o-aminophenyl)porphyrin (TAPP αβαβ) allows access to a new family of potential multisite complexing agents.

Assignments of the chemical shifts of meso-phenyl protons and carbons of tetrakis-5,10,15,20 (α,β,α,β-ortho-amidophenyl) porphyrins

Abstract 1 H and 13 C NMR studies of “bis-strapped” porphyrins, namely meso -5,10,15,20-tetrakis-(α,β,α,β- ortho -amidophenyl)porphyrin derivatives, permitted to conclusively assign the chemical shifts relative to the meso -phenyl protons and carbons.

First synthesis of single-strapped cyclam-porphyrins

The first synthesis of strapped cyclam porphyrins is described ; these will be studied as dioxygen carriers as well as cytochrome C oxidase models. The original derivatives are characterized by mass spectrometry and 1H NMR spectroscopy. The cofacial conformation of the two different macrocycles is confirmed by 1H NMR data.

The overhanging carboxylic acid strategy: an alternative route to the porphyrin core expansion/modification for the coordination of large metal ions

This account summarizes how the binding properties of a regular porphyrin macrocycle for large cations can be significantly modified and even tuned when the surrounding skeleton delivers at least one carboxylic acid group close to the N-core. While kinetics of metal insertion are drastically improved, unique dinuclear species can be obtained with a possible control of the nuclearity. The first incorporation of an α-core emitter radioisotope of particular interest for cancer therapy was recently demonstrated. All in all, this overhanging carboxylic acid strategy can be regarded as an alternative to either expanded porphyrins for the coordination of large cations from groups 14–15 (PbII, BiIII) or contracted and isomeric porphyrins for the coordination of smaller cations from group 12 (HgII)

Synthesis and Spectral and Structural Characterization of a New Series of Bis‐Strapped Chiral Porphyrins Derived from L‐Proline

New chiral porphyrins were obtained in reasonable yields in three steps, starting from the aâaâ atropisomer of mesotetrakis(o-aminophenyl)porphyrin (TAPP). These potential catalysts for the enantioselective epoxidation of alkenes were obtained by the reaction of different linkers on the same Lprolinoyl-picket porphyrin. Their 1H NMR spectral characteristics, as well as the crystal structure of one of them, clearly indicate that the orientation of the proline cycle depends on the linker used to tether the two pickets on each side of the porphyrin. The same linker is employed for both sides of the porphyrin; hence the resulting D2-symmetric superstructure.

Bismuth porphyrin complexes: syntheses and structural studies

The synthesis of several new bismuth porphyrin complexes Bi(por)(X) containing the tpp or tpClpp (tpClpp = 5,10,15,20-tetra-p-chlorophenylporphyrin) porphyrin ligand and anions X = NO3, Cl, Br, I are described. Molecular structures reported for Bi(tpClpp)(X) for X = Cl, Br show that the complexes crystallise as centrosymmetric dimers doubly bridged through Cl or Br. Bi(tpClpp)(NO3) crystallises as a less symmetric dimer in which one NO3 ligand bridges the two bismuth centres and the second NO3 ligand interacts with only one bismuth atom. In all three structures the bismuth atoms are significantly displaced from the porphyrin N4 planes and the Bi–halide or Bi–O distances are very long.

Unexpected tetracoordinated iron(II) bis-strapped chiral porphyrin bearing a nitrogen base on one handle

Abstract Insertion of iron into a bis-strapped porphyrin bearing a pyridine handle yields an unexpected tetracoordinated iron(Il)-porphyrin due to the conformational rigidity of the straps.