Quantum chemistry and catalysis

Why do platinum, palladium, nickel and iron, as well as other Group‐VIII transition metals, continually turn up as the active sites in catalysts? Why do certain enzymes and proteins—substances such as hemoglobin and ferredoxin that catalyze metabolic processes in living organisms—also appear to rely on transition metals for their action? How do catalysts work anyway, and could we design better ones? We are much nearer answering these questions and other related ones now that new methods, both theoretical and experimental, are available to investigate the electronic structure of complex molecules and materials of the type important to catalysis.