CoSalen immobilized to chitosan and its electrochemical behavior

A chitosan (CS) immobilized cobalt complex (CS¯CoSalen) was prepared by immersing a CS film into the saturated aqueous solution of a cobalt(II) complex of N,Nʹ-bis(salicylaldehyde)ethylenediimino (CoSalen). The CS¯CoSalen was characterized, and it was found that CoSalen was immobilized onto CS through the coordination of the amino group of CS. The cobalt(II) ion in the CS¯CoSalen has a fivecoordination structure. Its vacant sixth coordination site was found to bind molecular oxygen reversibly. Electrochemical studies demonstrated that the CS¯CoSalen is active for the catalysis of the electrochemical reduction of oxygen to hydrogen peroxide in an aqueous medium.