POLYMER-MODIFIED ELECTRODES WITH PENDANT [RH-III(C(5)ME(5))(L)CL](-COMPLEXES FORMED BY GAMMA-IRRADIATION CROSS-LINKING())

The immobilization of copolymers of hydrophilic N-vinyl-pyrrolidone an d polymerizable derivatives of the transition metal complex (pentameth ylcyclopentadienyl-2,2'-bipyridine chloro) rhodium(III) ([Rh-III(C(5)M e(5))(bpy)Cl](+)) by gamma-irradiation on an electrode surface to obta in swellable and highly permeable redox active polymer films which swe ll easily is described. These polymer films swell easily in water and thus provide a three-dimensional reaction layer, which should be advan tageous for electrocatalytic processes mediated by the surface-confine d rhodium complex. Rotating disk voltammetry is used to investigate th e influence of radiation dose and the amount of immobilized polymer on the permeability of the polymer films. Furthermore, cyclic voltammogr ams show that the rhodium complex retains its electrochemical activity and also its ability to mediate the electrochemical reduction of the cofactor nicotinamide adenine dinucleotide (NAD(+)).