Strengths, Weaknesses, Opportunities and Threats: Computational Studies of Mn- and Fe-Catalyzed Epoxidations

Abstract

Abstract:The importance of epoxides as synthetic intermediates in a number of highly added-value chemicals, as well as the search for novel and more sustainable chemical processes have brought considerable attention to the catalytic activity of manganese and iron complexes towards the epoxidation of alkenes using non-toxic terminal oxidants. Particular attention has been given to Mn(salen) and Fe(porphyrin) catalysts. While the former attain remarkable enantioselectivity towards the epoxidation of cis-alkenes, the latter also serve as an important model for the behavior of cytochrome P450, thus allowing the exploration of complex biological processes. In this review, a systematic survey of the bibliographical data for the theoretical studies on Mn-and Fe-catalyzed epoxidations is presented. The most interesting patterns and trends are reported and finally analyzed using an evaluation framework similar to the SWOT (Strengths, Weaknesses, Opportunities and Threats) analysis performed in enterprise media, with the ultimate aim to provide an overview of current trends and areas for future exploration.

Oxidation of Organic Functionalities by PhI(OAc)2 Catalysed by Magnetically Separable Fe3O4@dopa‐Supported Mn(III) Complexes: Combined Experimental and Theoretical Approach

“…Starting with a Mn(III) salen catalyst and a iodosylarene terminal oxidant, as in our case, several mechanistic pathways have been proposed in the literature for the oxidation of different substrates. The most commonly accepted one is the O‐rebound mechanism that consists of the initial oxidation of the catalyst to Mn(V)=O species followed by the O‐transfer to the substrate from this active form of the catalyst ,…”

Experimental and theoretical investigation of the catalytic performance of reduced Schiff base and Schiff base iron complexes: Transformation to magnetically retrievable catalyst

“…The FTIR spectral studies of FeRL displayed bands at 1570 cm −1 due to the C─N stretching and a distinct peak at 3195 cm −1 due to N─H stretching vibration. [ 30–36 ] The synthetic route for the synthesis of FeRL is given in Scheme 1.…”

“…The O‐rebound mechanism is accepted for many oxidation processes catalyzed by non‐heme iron catalysts. [ 34 ] It assumes that in the course of the oxidation of organic molecules, iron (III) complexes become initially oxidized to an Fe(V) = O intermediate. Then, this species evolves through an O‐transfer to the substrate.…”

“…However, their relative stability seems to be relevant in the comparative efficiency of the catalysts. [ 34 ] The characterization of high valent metal‐oxo species as well as their antecedents such as metal‐hydroperoxo, ‐peroxo and ‐superoxo species has been a topic of immense interest for researchers worldwide. In the present work, density functional theory calculations are used to characterize the structure of the corresponding Fe V = O species and quantify their relative stability (Figure 1).…”

Χημικά Τροποποιημένα Υλικά Άνθρακα Για Καταλυτικές Τεχνολογίες

“…Ο μηχανισμός μεταφοράς οξυγόνου από το οξο-σύμπλοκο στο διπλό δεσμό του αλκενίου είναι αμφιλεγόμενος [347,355,356]. Η μεταφορά οξυγόνου από το οξο-ενδιάμεσο στο αλκένιο έχει προταθεί πως συμβαίνει μέσω διάφορων μεταβατικών καταστάσεων (Εικόνα 4.18): α) συγχρονισμένος μηχανισμός, β) δημιουργία ρίζας άνθρακα, γ) καρβοκατιόντος, δ) σχηματισμού π-κατιοντικής ρίζας και ε) δημιουργία πενταμελούς δακτυλίου που περιέχει ένα Ν ή ένα άτομο Ο του υποκαταστάτη [309].…”