Second Sphere Effects on Oxygen Reduction and Peroxide Activation by Mononuclear Iron Porphyrins and Related Systems

Activation and reduction of O-2 and H2O2 by synthetic and biosynthetic iron porphyrin models have proved to be a versatile platform for evaluating second-sphere effects deemed important in naturally occurring heme active sites. Advances in synthetic techniques have made it possible to install different functional groups around the porphyrin ligand, recreating artificial analogues of the proximal and distal sites encountered in the heme proteins. Using judicious choices of these substituents, several of the elegant second-sphere effects that are proposed to be important in the reactivity of key heme proteins have been evaluated under controlled environments, adding fundamental insight into the roles played by these weak interactions in nature. This review presents a detailed description of these efforts and how these have not only demystified these second-sphere effects but also how the knowledge obtained resulted in functional mimics of these heme enzymes.

Automated summary

Activation and reduction of O-2 and H2O2 by synthetic and biosynthetic iron porphyrin models have been proven to be a versatile platform for evaluating second-sphere effects important in natural heme active sites. By installing different functional groups around the porphyrin ligand, several second-sphere effects have been evaluated under controlled environments, providing fundamental insights into the roles played by these weak interactions in nature.