Degree Type

Dissertation

Date of Award

1990

Degree Name

Doctor of Philosophy

Department

Chemistry

First Advisor

James Espenson

Abstract

The quenching of the [superscript]2E state of CrL[subscript]3[superscript]3+ (where L = 2,2[superscript]'-bipyridine, 1,10-phenanthroline and their substituted analogues) by oxalate ions and by the organochromium complexes L[superscript]'CrR[superscript]2+ (where L[superscript]' = (15) aneN[subscript]4 and R = primary alkyl, secondary alkyl, arylalkyl) was studied. Also investigated was the reactions of the organochromiums with Ru(bpy)[subscript]3[superscript]3+. Both formation of CrL[subscript]3[superscript]2+ and the loss of [superscript]\*CrL[subscript]3[superscript]3+ can be monitored conveniently enabling the determination of the kinetics as well as the products of the reaction;The reaction of oxalate ions at neutral pH with the excited chromium polypyridyl complexes is an electron transfer process as shown by the trend in rate constants with the one electron reduction potentials of the various [superscript]\*CrL[subscript]3[superscript]3+ species. The quenching reaction apparently proceeds via an ion-pairing pathway. A reactive species is produced in the quench which either produces another equivalent of electron transfer products or a secondary transient depending on the identity of the chromium polypyridyl complex;Reaction of the [superscript]\*CrL[subscript]3[superscript]3+ with the organochromiums appears to be an electron transfer process based on the reactivity pattern in varying the chromium polypyridyl (and consequently the potential) as well as the trend in varying the organic moiety of the L[superscript]'CrR[superscript]2+. This last reactivity pattern is that observed in the reactions of the organochromiums and the good outer sphere electron transfer agent, Ru(bpy)[subscript]3[superscript]3+. One electron oxidation of L[superscript]'CrR[superscript]2+ produces an unstable species which may undergo a one electron reduction (back electron transfer) or homolyze producing organic radicals.

DOI

https://doi.org/10.31274/rtd-180813-11195

Publisher

Digital Repository @ Iowa State University, http://lib.dr.iastate.edu/

Copyright Owner

Carl R. Steffan

Language

en

Proquest ID

AAI9110568

File Format

application/pdf

File Size

197 pages

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