Theoretical analysis of oxygen-bridged Cu pairs in Cu-exchanged zeolites

O- and O-2-bridged Cu pairs in zeolitic environments are examined using den sity functional theory with cluster models. Both types of oxocation ([CuOCu ](2+) and [CuO2Cu](2+)) are found to be highly stable for conditions likely to exist in Cu-ZSM-5. A variety of geometric isomers with different electr onic states and preferred Cu-Cu distances are described. Possible implicati ons for "autoreduction", NO decomposition, and other reactions involving Cu pairs in ZSM-5 are explored.