Iron(IV) Complexes with Tetraazaadamantane-based Ligands: Synthesis, Structure, Application in Dioxygen Activation and Labeling of Biomolecules

4,6,10-Trihydroxy-1,4,6,10-tetraazaadamantane (TAAD) has been shown to form a stable Fe(IV) complex having a diamantane cage structure, in which the metal center is coordinated by three oxygen atoms of the deprotonated ligand. The complex was characterized by X-ray, HRMS, NMR, FT-IR, Mössbauer spectroscopy and DFT calculations, which supported d4 configuration of iron. The Fe(IV)-TAAD complex showed excellent performance in dioxygen activation under mild conditions serving as a mimetic of the thiol oxidase enzyme. The nucleophilicity of the bridge-head nitrogen atom in TAAD provides a straightforward way for conjugation of Fe(IV)-TAAD complexes to various functional molecules. Using this approach, steroidal and peptide molecules having an iron(IV) label have been prepared for the first time. Also, the Fe(IV)-TAAD complex was covalently bounded to a polystyrene matrix and the resulting material was shown to serve as a heterogeneous catalyst for aerobic oxidation of thiols to disulfides.

Ferrous Complexes with Bis (Meo) in Α-Substituted Tris (Pyridin-2-Ylmethyl) Amine Ligands: Effect of the Bis (Meo) in Α- Substituents in Dioxygen Activation and Biomimetic Reactivity

This report describes how the coordination of FeCl2 with tris(pyridin-2-ylmethyl)amine (TPA) ligands offers the possibilty to activate the molecular dioxygen in biomimetic processes. . It includes all procedures taken to the case for major oxidation reactions carried out in Nature under particular conditions. The aim of the this paper is to present the outcome of a thorough study for complex coordinations with ligands substituted by groups known as electron donors. It demonstrates how ligands with methoxy substituents are likely to be demethylated, and therefore providing entities potentially useful in synthesis. Targeting in modulating the electronic properties at the metal center, a new type of ligand (MeO)2TPA has been prepared and the complex of (MeO)2TPAFeCl2 has been studied by uv-visble ; 1H RMN paramagnatic and conductometry. The effect of (MeO) group in α-substituted on the structure as well as the effect of substitution on the oxygenation of the complex has been verified. Afterwards, the reactivity of the complex towards molecular dioxygen in absence of substrat is checked by uv-visble, 1H RMN paramagnatic and radiocristallography. As well, the reactivity in presence of substrat is tested.

Ferrous Complexes with Bis Meo in Α Substituted Tris Pyridin 2 Ylmethyl Amine Ligands Effect of the Bis Meo in Α Substituents in Dioxygen Activation and Biomimetic Reactivity

This report describes how the coordination of FeCl2 with tris(pyridin-2-ylmethyl)amine (TPA) ligands offers the possibilty to activate the molecular dioxygen in biomimetic processes. . It includes all procedures taken to the case for major oxidation reactions carried out in Nature under particular conditions. The aim of the this paper is to present the outcome of a thorough study for complex coordinations with ligands substituted by groups known as electron donors. It demonstrates how ligands with methoxy substituents are likely to be demethylated, and therefore providing entities potentially useful in synthesis. Targeting in modulating the electronic properties at the metal center, a new type of ligand (MeO)2TPA has been prepared and the complex of (MeO)2TPAFeCl2 has been studied by uv-visble ; 1H RMN paramagnatic and conductometry. The effect of (MeO) group in α-substituted on the structure as well as the effect of substitution on the oxygenation of the complex has been verified. Afterwards, the reactivity of the complex towards molecular dioxygen in absence of substrat is checked by uvvisble, 1H RMN paramagnatic and radiocristallography. As well, the reactivity in presence of substrat is tested.

Aerobic Oxidations in Asymmetric Synthesis: Catalytic Strategies and Recent Developments

Despite the remarkable advances in the area of asymmetric catalytic oxidations over the past decades, the development of sustainable and environmentally benign enantioselective oxidation techniques, especially with the efficiency level similar to natural enzymes, still represents a challenge. The growing demand for enantiopure compounds and high interest to industry-relevant green technological advances continue to encourage the research pursuits in this field. Among various oxidants, molecular oxygen is ubiquitous, being available at low cost, environmentally benign and easy-to-handle material. This review highlights recent achievements in catalytic enantioselective oxidations utilizing molecular oxygen as the sole oxidant, with focus on the mechanisms of dioxygen activation and chirogenesis in these transformations.

Mechanistic insights into dioxygen activation by a manganese corrole complex: a broken-symmetry DFT study

DFT calculations revealed a novel mechanism for the formation of Mn(v)–oxo in the dioxygen activation by a Mn(iii) corrole complex involving a Mn(iii)–alkylperoxo intermediate.

Formation of cobalt-oxygen intermediates by dioxygen activation at a mononuclear nonheme cobalt(II) center

A mononuclear nonheme cobalt(II) complex, [(TMG3tren)CoII(OTf)](OTf) (1), activates dioxygen in the presence of hydrogen atom donor substrates, such as tetrahydrofuran and cyclohexene, resulting in the generation of a cobalt(II)-alkylperoxide intermediate...