Electrochemistry of zeolite-encapsulated complexes. Part 4.—Characterization of transition-metal polypyridinediyl and phenanthroline complexes entrapped in Y faujasite-type zeolite

CoII–, NiII– and FeII–polypyridinediyl and –phenanthroline complexes have been entrapped in the supercages of zeolite Y. The redox properties of these zeolite-encapsulated complexes are investigated by cyclic voltammetry in acetonitrile solution. The results show a similarity between the redox behaviour of the entrapped complexes and that of the dissolved monomers in solution. They also indicate that, by electrochemical measurements, it is possible to point out the existence of different structures of the entrapped Ni–bipyridine complex. The electroactivity of the encapsulated bis(bipyridine)–nickel complex towards the reduction of organic halides is discussed.