Mononuclear Iron(III) Complexes as Functional Models of Catechol Oxidases and Catalases

Abstract

Mononuclear amino triphenolate iron(III) complexes have been synthesized and characterized (UV/Vis spectroscopy, cyclic voltammetry, ESI-MS, 1H NMR spectroscopy, X-ray diffraction). These complexes act as biomimetic catalysts promoting the aerobic auto-oxidation of 3,5-di-tert-butylcatechol to the corresponding o-benzoquinone at room temperature and displaying catalase activity for the hydrogen peroxide dismutation with remarkable activity (TON up to 4000)

Vanadium(V) Catalysts with High Activity for the Coupling of Epoxides and CO2: Characterization of a Putative Catalytic Intermediate

“…Successful catalysts for cyclic organic carbonate (COC) formation include the use of abundant main-group metals such as aluminum, iron, and zinc and transition metals (Co, Cr), most often in combination with N x , O y -coordinating ligands such as salens ( x = y = 2) and aminotriphenolates ( x = 1, y = 3) . We have been interested in the use of O 3 N -chelating aminotriphenolate ligands and their complexes for catalytic applications and have reported on the use of Ti­(IV) derivatives for the oxidation of sulfides and secondary amines into nitrones, Mo­(VI) and W­(VI) complexes for the oxidation of sulfides, olefins and chloro- and bromoperoxidation, and more recently the Fe­(III)-mediated formation of cyclic carbonates and the preparation of catechol oxidase and catalase mimics . The use of aminophenolate type ligands is beneficial toward the stabilization of different (higher) oxidation states such as V­(III) and V­(V), and the V­(V) complexes have previously been successfully used in the context of haloperoxidase models in sulfoxidation chemistry .…”

Structural and bio-catalytic aspects of nano crystallite iron(iii) complexes containing triazole-based ligands

“…The representative spectral profiles obtained by the stoppedfollow technique (Fig. [12][13][14][15] show that the first step is fast and the second step is slow. These spectral features in Fig.…”

“…6 Oxidation mimicking studies using iron(III) complexes showed selective catalytic oxidation of catechol because it oxidized catechol to ortho quinone instead of ring-breaking. [7][8][9][10][11][12][13][14][15] Several studies have reported the catalytic activity of iron complexes for the selective oxidation of o-aminophenols to produce the pharmaceutically important amino-3-H-phenoxazin-3-one (APX) instead of ring-opening. [16][17][18][19][20][21][22][23][24] The current study aims to gain a deeper understanding of the natural process of metal ions as catalysts and gain experience in designing more efficient catalysts.…”

Organic Polyradicals as Redox Mediators: Effect of Intramolecular Radical Interactions on Their Efficiency

“…In recent years, we reported about the use of tetradentate metal complexes in catalysis, − molecular recognition, − and as molecular scaffolds for multiple functionalization. Among the different structures, μ-oxo dinuclear titanium complex 1 represents the ideal architecture to become a scaffold for multiple functionalization (Scheme ).…”