On the Existence of Different Zeolite-Associated Topological Redox Isomers. Electrochemistry of the Y Zeolite-Associated Mn(Salen)N3 Complex

The electrochemical properties of Y zeolite-associated Mn III (salen)N 3 (salen = trans -( R, R )-1,2-bis(salicyldeneamino)cyclohexane) has been investigated using polymer film electrodes immersed into neutral aqueous solutions. Zeolite Y-associated Mn(III)−salen complexes are reduced in one-electron reversible process at −0.25 V versus SCE. The electrochemical response is discussed in terms of the existence of two topological redox isomers: a weakly boundary-associated Mn(salen) complex, whose electrochemical response corresponds to a reversible one-electron transfer controlled by diffusion of the positive ions of the supporting electrolyte through the zeolite surface windows and channels, and a strongly boundary-associated Mn(salen) complex for which the electrochemical response parallels that of reagents attached to the electrode surface. Kinetic and thermochemical data for such processes are obtained from the temperature dependence of electrochemical parameters.