Macrocyclic ligand-complexed transition metal-oxo intermediates are the active oxidizing species in a variety of important biological and catalytic oxidation reactions. Many transition metal catalysts have been designed to mimic the predominant oxidation catalysts in nature, namely the cytochrome P450 enzymes. Iron porphyrin complexes have been the center of research as catalysts. In this study 5,10,15,20- tetramesitylporphyrin (H2TMP) and its corresponding iron complexes FeIII(X)TMP (X= Cl, ClO4, ClO3, NO3, NO2, and BrO3) have been successfully synthesized and fully characterized by UV-vis and NMR spectroscopies. For the catalytic selective oxidation of organic sulfides, the potential of iron(III) porphyrin complexes with iodobenzene diacetate [PhI(OAc)2] have been investigated. Iodobenzene diacetate was found to be an efficient oxygen source in the iron(III) porphyrin-catalyzed oxidation of sulfides to sulfoxides. Iron(III) porphyrin catalysts show an excellent conversion and selectivity for the sulfoxidation reactions. Reaction conditions and environments that effect the catalytic sulfoxidation including solvent, catalytic amount, axial ligand, water, and thioanisole substrates, have been investigated to identify the optimal conditions and the substrate scope. Under optimized conditions, excellent substrate conversions (up to 100%) as well as product selectivies (sulfoxide:sulfone > 95:5) have been achieved. To probe the nature of the oxidizing species in above catalytic sulfoxidations, iron(IV)-oxo porphyrin radical cations model of Compound I were chemically produced from the corresponding iron(III) tetramesitylporphyrin precursors with excess amounts of PhI(OAc)2 (20-50 equivalents) in CH3CN solvent. All O=FeIV(X)TMP·+ (X= Cl, ClO4, ClO3, and NO3) show weaker Soret band and broader Q band that are characteristic of Compound I analogues. A new photochemical method that led to generation of the iron(IV)-oxo porphyrin radical cations was also successfully developed. Iron(IV)-oxo porphyrin radical cations were generated by irradiation of iron(III) porphyrin chlorate or bromate complexes that result in heterolytic cleavage of the O-X bond in the axial ligand.

Ce travail s’inscrit dans le domaine des cages moléculaires, édifices dont la géométrie définit unecavité tridimensionnelle capable de contenir d’autres entités.L’objectif de cette thèse est la synthèse de cages moléculaires covalentes possédant despropriétés d’encapsulation et une taille modulables. Les cages synthétisées avec succèsincorporent des porphyrines de zinc ou bases libres, ainsi que huit ligands triazoles périphériques.Des molécules ont pu être encapsulées par coordination aux porphyrines ou par interactions π, cequi démontre la capacité de la cage à s’adapter à l’invité grâce à sa flexibilité. La coordinationd’ions argent(I) permet de passer d’une conformation aplatie à une conformation ouverte. Lecaractère commutable de la cage a été démontré par décoordination de ces ions. Enfin, lacoordination d’ions argent(I) aux ligands de la cage augmente la stabilité de deux ligandsditopiques, le DABCO et la pipérazine, au sein de la cavité. Elle permet aussi l’accès de la cavité àdes molécules non encapsulées en l’absence d’argent(I). Ces résultats démontrent le contrôleallostérique de l’encapsulation de molécules par un stimulus chimique. / This work belongs to the field of molecular cages, hollow structures enclosing a three-dimensionalcavity able to encapsulate other molecules.The goal of this thesis include the synthesis of molecular covalent cages with a controllablecavity size able to perform switchable guest encapsulation. A DABCO-templated click reactionafforded three flexible covalent cages, endowed with two zinc(II) or free-base porphyrins and eightperipheral triazole ligands. Various guest molecules could be encapsulated by coordination toporphyrins or π-π interactions, in an induced-fit mechanism, probing the ability of the cage to adaptto the guest thanks to its flexibility. Coordination of silver(I) ions to the peripheral triazoles allow toswitch from a flattened to an open and locked conformation. Removal of the ions proved thecommutability of the cage. Finally, coordination of silver(I) ions to triazole ligands increase thestability of two ditopic ligands, DABCO and piperazine, inside the cavity. It also allowed the accessto the cavity of molecules that were not otherwise encapsulated. These results shows the allostericcontrol of guest encapsulation by a chemical stimulus.