Redox‐Switchable Catalysis

Abstract

The ability to control catalytic properties, such as selectivity and rate during the reaction, represents an attractive tool which can potentially deliver the synthesis of specialized products from a large pool of building blocks. This can be achieved by the incorporation of an on / off switch into the backbone of (pre‐)catalysts. The electronic or solubility properties of the switch can be then reversibly modified through the action of external triggers, a process which in turn modulates the catalytic activity. Incorporation of switches that can be reversibly reduced or oxidized represents one of the most versatile methods for controlling the catalytic activity in situ. This article describes the current state of research in the field of redox‐switchable catalysis, with a focus on homogenous metal‐mediated processes. The first part presents an overview of the types of redox switches and of the methods employed for delivering the redox stimuli. The second part then focuses on the catalytic transformations which can be controlled in this fashion, which include polymerization catalysis, metathesis, hydroelementation, and other catalytic reactions for the synthesis of fine chemicals.

Diazines and Triazines as Building Blocks in Ligands for Metal-Mediated Catalytic Transformations

“…In situ oxidation and reduction in the presence of ferrocenium salts and cobaltocene respectively allowed multiple switching between the two kinetic regimes. Therefore, the (P Pz DI)­Fe­(CO) 2 -derived NHC acts as a redox switch, which is able to operate at significantly more milder potentials compared to the well-established metallocene-based redox switches …”