Dihydrogen complexes of metalloporphyrins: characterization and hydrogen-transfer reactivity

Extensive reports of η² coordination of dihydrogen to transition metals have recently led to speculation that the η²-dihydrogen complexes and their corresponding transition-metal hydrides may be important in the biological activation of molecular hydrogen. We now report that protonation of transition-metal porphyrin hydrides has yielded the first known dihydrogen complex of a metalloporphyrin and a system that performs some functions of hydrogenase enzymes.