Layered inorganic materials as redox agents:: Ferrocenium-intercalated zirconium phosphate

The direct intercalation reaction of ferrocene (bis(eta(5)-cyclopentadienyl)iron(II), Fc) with a highly hydrated layered zirconium phosphate (ZrP) resulted in the formation of the ferrocenium ion (Fc(+)) within the ZrP material. The Fc+-intercalated ZrP material has an interlayer distance of 10.7 angstrom. The intercalated material was used as an electron acceptor for the oxidation of both ferro-cytochrome c and the excited state of tris(2,2'-bipyridine) ruthenium(II) ([Ru- (bpy)(3)](2+)). Upon contact of the material with a 1.5 x 10(-5) M solution of ferro-cytochrome c, the UV-vis absorption spectrum shows the successful formation of ferri-cytochrome c. Luminescence spectroscopy shows that the Fc(+)-intercalated ZrP material quenches the luminescence of [Ru(bpy)(3)](2+). The excited-state quenching mechanism of [Ru(bpy)(3)](2+*) by Fc(+)-intercalated ZrP follows a dynamic plus sphere of action model. The second-order dynamic quenching rate constant k(q) is 2.2 x 10(8) M-1 s(-1).