Electrolyte Effects on the Kinetics of Comproportionation Electron-Transfer Reactions and on Intervalence Charge-Transfer Band Energies of Binuclear Ruthenium Ammine Complexes

Author

Zhiji HanFollow

Date of Graduation

Fall 5-22-2015

Document Type

Thesis

Degree Name

Master of Science in Chemistry

College/School

College of Arts and Sciences

Department/Program

Chemistry

First Advisor

Jeff C. Curtis

Abstract

Chapter 1 describes an overview of electron-transfer reactions. The kinetic equations for ET reactions have also been described in detail.

Chapter 2 describes a series of novel kinetic accelerations which deviate strongly from the predictions of the classical Debye-Huckle theory with a range of different added “inert” electrolytes. The greater catalytic effects seen with the heavier halides and other catalytic electrolytes (especially certain dicarboxylates) indicate an important role for hole-transfer superexchange in the ET transition state. The hypothesis of a catalytic ternary association complex, [RuII--X--RuIII] has also been explored by kinetic modeling of the reaction. An increasing ratio of anion-catalyzed k_etx to uncatalyzed k_et is obtained when proceeding down the halide series. Activation parameters show a strong enthalpy-entropy compensation effect according to the identity of the added halide. Interestingly, the enthalpy activation decreases successively upon going to the heavier halides and in fact ∆H^‡ becomes negative in the most extreme case of added I^-.

Chapter 3 describes a detailed study of electrolyte effects on the position and band shape of the intervalence charge transfer (IVCT) band of dimeric systems in aqueous solution such as (NH₃)₅Ru^II-(bis-bipyridylethylene)-Ru^III(NH₃)₅(5+). Unexpectedly, the energetics of optical electron transfer blue shift upon adding F^- but red shift upon adding other halides. This interesting observation correlates with the known water structure “making” or “breaking” effects of the added halide anions

Recommended Citation

Han, Zhiji, "Electrolyte Effects on the Kinetics of Comproportionation Electron-Transfer Reactions and on Intervalence Charge-Transfer Band Energies of Binuclear Ruthenium Ammine Complexes" (2015). Master's Theses. 122.
https://repository.usfca.edu/thes/122