Electrochemical investigations of polymer films and monolayers on electrode surfaces: Determination of the reaction entropy for osium bipyridyl(3)(3+/2+) in nafion, and the influence of supporting electrolyte activity on the formal potential of a monolayer containing a ruthenium redox center, and, Synthesis and characterization of monometallic and bimetallic complexes of ruthenium(II) and iron(II) with 4,4'bipyrimidine (4,4'BPM) and pyridyl viologen PV(2+)

Abstract

This thesis is comprised of two major projects: an analytical project and an inorganic synthesis project. The first project dealt with the investigation of the electrochemistry of thin polymer films and monolayers on electrode surfaces. The second project dealt with the synthesis of novel monometallic and bimetallic complexes of ruthenium and iron in which the metals were bridged by either 4,4$\sp\prime$bipyrimidine or pyridyl viologen.

The first project involved the investigation of the reaction entropy for a redox couple which had been exchanged into an ion-exchange polymer on an electrode surface. The measured values for the reaction entropy were shown to be dominated by the entropy change for partitioning the redox couple into the film and by supporting electrolyte cation transfer between the film and the polymer.

Electrochemical studies were also carried out on an alkanethiol monolayer which contained a ruthenium redox center at the monolayer/solution interface. The electrochemistry supported the fact that the monolayer was displaying permselective behavior with the exclusion of supporting electrolyte cations from the monolayer. Equations were presented that described the electrochemical nature of the monolayer and the dependence of the formal potential for the monolayer on the supporting electrolyte cation transfer at the monolayer/solution interface.

The second section of the thesis dealt with the synthesis and characterization of a number of novel ruthenium and iron complexes utilizing 4,4$\sp\prime$bipyrimidine and pyridyl viologen. The complexes show shifts in the energy of the MLCT bands and reduction potentials which can be correlated to either the reduction potential of the ligand involved in the complex or the relationship between iron and ruthenium in the group VIII family. Comparisons are made between the complexes studied and a number of ruthenium and iron complexes of nitrogen heterocycles from the literature. The properties of the complexes studied are also discussed in relation to their role in the study of electron transfer mechanisms within mixed valence complexes.