Molecular iron complexes as catalysts for selective C–H bond oxygenation reactions

Abstract

The selective oxygenation of C-H bonds is a promising and interesting task for both academia and chemical industry. Inspired by the efficiency and selectivity of naturally occurring enzymes, iron heme and nonheme complexes have proven to be valuable candidates for the development of environmentally friendly catalysts as alternative to traditional systems. This feature article summarises developments of the last decade regarding oxygenation reactions of aliphatic and aromatic substrates with various oxidants catalysed by molecular iron complexes. With a special focus on the catalytic performance of the systems, both the potential and the limitations as well as mechanistic aspects are discussed in some detail.

New Trends in Oxidative Functionalization of Carbon–Hydrogen Bonds: A Review

“…Heme and nonheme oxidation catalysts have been intensively used in oxidations of alkanes aromatics, as well as in epoxidations [171][172][173][174]. Metalloporphyrins [175][176][177][178] play a very important role in such studies; they are models of enzyme reaction centers.…”

Carbon‐Nanotube‐Appended PAMAM Dendrimers Bearing Iron(II) α‐Keto Acid Complexes: Catalytic Non‐Heme Oxygenase Models

“…Interestingly, the complex under stoichiometric conditions can activate weak C−H bonds of hydrocarbons and carry out hydrogen‐atom transfer (HAT) reactions. For example, fluorene was converted to fluorenone (23 %), dihydroanthracene was converted to anthracene, and 1‐adamatanol (16 %) formed from adamantane as the substrate (Figures S15–S17, Supporting Information) . Thus, the synthesized oxygenase model can oxidize a wide array of substrates and is capable of performing both OAT and HAT reactions.…”

“…Hammett analyses with various para ‐substituted thioanisoles revealed a negative ρ value (−0.93), characteristic of electrophilic oxidants (Figure S20, Supporting Information). These results suggest the formation of an iron(IV)‐oxo intermediate ( 4‐Fe Im ) as the oxidant for substrates oxidation (Scheme ) …”

Homogenous Meets Heterogenous and Electro‐Catalysis: Iron‐Nitrogen Molecular Complexes within Carbon Materials for Catalytic Applications

“…As significant example of heme‐containing enzymes are cytochrome P450, with their active site containing a Fe 3+ ‐porphyrin cofactor . From a chemical perspective, they constitute exceptional catalysts for C−H oxidation using O 2 . Since then, organic chemists have successfully mimicked and exploited the Fe−N cooperation via the elegant design of N‐based pincer ligands for a myriad of oxidative and hydrogenative processes .…”