A quantitative Kohn–Sham approach to elementary redox reactions in artificial, bio-inspired and biological catalysis

Although seemingly distant, there is a strong synergy between redox reactions and catalyzed processes and, not infrequently, one is often accompanied by the other. Density functional theory has been extensively used to study selected cases ranging from small-scale inorganic catalysis to enzymatic processes as well as bioinspired molecular systems. In the first part, [2+2+2] cycloaddition reactions have been used as a study case to draw the essential elements for a rational design of group 9 metal half-sandwich catalysts. Secondly, the problem of the oxidative stress has been introduced as well as few small organic molecules acting as antioxidants: a deep study on the radical scavenging activity of these bioinspired mimics has been performed and the presence of different chalcogens (S, Se, Te) has been carefully analyzed in order to detect any potential glutathione peroxidase‐like activity. Lastly, the role of the aforementioned chalcogen nuclei has been investigated in four selected enzymes which share a common peroxidatic (seleno)cysteine in the active site and play a crucial role in balancing the harmful condition of oxidative stress. In all the reported examples, it emerges that elementary redox reactions play a role of paramount importance.