Electrochemistry of zeolite NaY-encapsulated rhodium(III) phthalocyanine

Electrochemistry has proven to be a very valuable ancillary technique to characterize chemically-modified zeolites and especially intrazeolitic ship-in-a-bottle complexes. In this study, the cyclic voltammograms for zeolite RhNaY- and NaY-encapsulated rhodium phthalocyanine (RhPc) are reported. Site isolation of the metal complexes in the NaY supercages precludes the dimerization observed in solution and allows clear observation of the Rh(III)Pc/Rh(II)Pc couple at room temperature. The observed redox activity is interpreted as arising from electron transfer to complexes trapped in the outermost supercages or subsurface zones. The very low electroactivity of such confined complexes (less than 1% of the total loading) and the nature of the electroactive sites are discussed.