Extrazeolite Electron Transfer at Zeolite-Encapsulated Polypyridyl Metal Complex Coated Electrodes

Polypyridyl metal complexes ([Ru(bpy) 3 ] 2+ and [Fe(bpy) 3 ] 2+ ) were synthesized inside the supercages of zeolite-Y and adsorbed on the surface of zeolite-Y (represented as Ru(II)-Y (c/s) and Fe(II)-Y (c/s), where “c” refers the supercage of zeolite-Y and “s” refers the surface of zeolite-Y). These zeolite-encapsulated metal complexes were coated on a platinum electrode, and their electrochemical properties were studied in 0.1 M Na 2 SO 4 and in 0.05 M H 2 SO 4 . The Ru(II)-Y (c) and Fe(II)-Y (c) were electroinactive in 0.1 M Na 2 SO 4 . The same metal complexes in zeolite show electrochemical activity in the presence of H + ions. The electroinactivity of Ru(II)-Y (c) and Fe(II)-Y (c) complexes in 0.1 M Na 2 SO 4 shows that the intrazeolite electron transfer is not occurring. The disintegration of zeolite-Y in the presence of H + ions leads to the random distribution of the polypyridyl metal complexes and shows that extrazeolite electron-transfer mechanism is operating as in the case of zeolite surface adsorbed metal complexes.