Selective hydroxylation of alkanes catalyzed by iron(IV)corrole

Corroles at work: a small macrocycle for great applications

Corrole chemistry has witnessed an impressive boost in studies in the last 20 years, thanks to the possibility of preparing corrole derivatives by simple synthetic procedures. The investigation of a large number of corroles has highlighted some peculiar characteristics of these macrocycles, having features different from those of the parent porphyrins. With this progress in the elucidation of corrole properties, attention has been focused on the potential for the exploitation of corrole derivatives in different important application fields. In some areas, the potential of corroles has been studied in certain detail, for example, the use of corrole metal complexes as electrocatalysts for energy conversion. In some other areas, the field is still in its infancy, such as in the exploitation of corroles in solar cells. Herein, we report an overview of the different applications of corroles, focusing on the studies reported in the last five years.

Non-heme μ-Oxo- and bis(μ-carboxylato)-bridged diiron(iii) complexes of a 3N ligand as catalysts for alkane hydroxylation: stereoelectronic factors of carboxylate bridges determine the catalytic efficiency

The stereoelectronic factors of carboxylate bridges in diiron(iii) complexes determine the efficiency of catalytic alkane hydroxylation with m-CPBA.

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

This feature article summarises recent developments in homogeneous C–H bond oxygenation catalysed by molecular iron complexes.

Synthesis and catalytic properties of trans-A2B2-type metalloporphyrins in cyclohexane oxidation

A new efficient and mild protocol for synthesizing a series of trans-A2B2-porphyrins through a TFA-catalyzed condensation reaction between various aldehydes and dipyrromethanes has been developed. Several trans-A2B2-metalloporphyrins (cobalt, nickel) were synthesized and used to catalyze cyclohexane oxidation C–H bonds with dioxygen in the absence of additives and solvents. The results show that the catalytic activities were relative to the nature of the substituted groups and the central metal ions of trans-A2B2-metalloporphyrin. Cobalt metalloporphyrin presents better catalytic performance in the conversion of cyclohexane than the nickel metalloporphyrin under the same reaction conditions.

Significant effect of spin flip on the oxygen atom transfer reaction from (oxo)manganese(V) corroles to thioanisole: insights from density functional calculations

The electronic and structural features of (oxo)manganese(V) corroles and their catalyzed oxygen atom transfers to thioanisole in different spin states have been investigated by the B3LYP functional calculations. Calculations show that these corrole-based oxidants and their complexes with thioanisole generally have the singlet ground state, and their triplet forms are also accessible in consideration of the spin-orbit coupling interaction. Due to strong d-π conjugation interactions between Mn and the corrole ring arising from the π electron donation of the corrole moiety, the five-coordinated Mn approximately has the stable 18-electron configuration. The predicted free energy barriers for the singlet oxygen atom transfer reactions are generally larger than 22 kcal mol(-1), while the spin flip in reaction may remarkably increase the reactivity. In particular, the bromination on β-pyrrole carbon atoms of the meso-substituted (oxo)manganese(V) corrole strikingly enhances the spin-orbit coupling interaction and results in the dramatic increase of reactivity. The multiple spin changes are predicted to be involved in the low-energy reaction pathway. The present results show good agreement with the experimental observation and provide a detailed picture for the oxygen atom transfer reaction induced by the (oxo)manganese(V) corroles.