INTERACTION OF 2 EQUIVALENT ELECTRON-TRANSFER ATOM-TRANSFER CENTERS VIA 2,2'-BIPYRIMIDINE AS BRIDGING LIGAND

The redox pair [(p-cym) OsCl](+)/ [ (p-cym)Os], p-cym = eta(6)-p-cymen e ( 1,4-(C6H4MePr)-Pr-i), involving a two electron process coupled wit h chloride dissociation, has been studied in the mono- and dinuclear c omplex with the 2,2'-bipyrimidine (bpym) ligand. Whereas the mononucle ar system exhibits the well-known ECE pattern on reduction, the struct urally characterized trans-{(mu-bpym) [(p-cym) OsCl](2)}(PF6)(2) shows several special features, including the decoupling of the first ECE p rocess into an E and EC step (electron reservoir function of bpym) and a splitting of 420 mV for the reduction steps associated with the chl oride transfer (electronic communication between EC reaction centers). (C) 1998 Elsevier Science S.A. All rights reserved.