Degree Type

Dissertation

Date of Award

1986

Degree Name

Doctor of Philosophy

Department

Chemistry

Abstract

The kinetics and mechanisms of the reactions of nitrous acid with pentaaquoorganochromium(III) complexes were studied. Nitrous acid reacts with (H(,2)O)(,5)CrR('2+) complexes via an NO('+) intermediate by either an electrophilic or electron transfer mechanism depending on the nature of the R group. The rate constants for the aliphatic organochromium complexes can be correlated using a linear free energy correlation which implies a common transition state for these reactions. The lack of steric effects for the reactions of the alkyl-chromium complexes, and the detection of Cr('2+) as an intermediate in the reactions of the (alpha)-hydroxy- and (alpha)-alkoxyalkylchromium complexes suggests that these complexes react with HONO by an electron transfer mechanism. A mechanism has been proposed in which NO('+) is formed which then oxidizes CrR('2+) by one electron to give CrR('3+). This species decomposes to Cr('3+) and R(.) when R is an alkyl group, but forms Cr('2+) and ROH when R is an (alpha)-hydroxy- or (alpha)-alkoxyalkyl group. R(.) and Cr('2+) react with the NO formed in the reaction to give RNO and CrNO('2+), respectively;In contrast, aralkylchromium(III) complexes react with nitrous acid by an electrophilic mechanism as indicated by the products and correlations of the rate constants with other electrophilic reactions in the literature;Photochemically generated tris(2,2'-bipyridyl)-ruthenium(III) oxidizes a range of pentaaquoorganochromium(III) complexes by one electron. The trends in the rate constants and the usual behavior of Ru(bpy)(,3)('3+) suggest that electron transfer is occurring by an outer-sphere mechanism. In the case of CrCH(,2)CH(,3)('2+), the intermediate;formed, CrCH(,2)CH(,3)('3+), decays to Cr('3+) and (.)CH(,2)CH(,3) as shown by kinetic studies and a product analysis; ('1)DOE Report IS-T-1193. This work was performed under contract W-7405-Eng-82 with the Department of Energy.

DOI

https://doi.org/10.31274/rtd-180813-11192

Publisher

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

Copyright Owner

Jon David Melton

Language

en

Proquest ID

AAI8615069

File Format

application/pdf

File Size

139 pages

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