O2 and N2O activation by Bi-, Tri-, and tetranuclear Cu clusters in biology.

Copper-cluster sites in biology exhibit unique spectroscopic features reflecting exchange coupling between oxidized Cu's and e (-) delocalization in mixed valent sites. These novel electronic structures play critical roles in O 2 binding and activation for electrophilic aromatic attack and H-atom abstraction, the 4e (-)/4H (+) reduction of O 2 to H 2O, and in the 2e (-)/2H (+) reduction of N 2O. These electronic structure/reactivity correlations are summarized below.