Date of Award

12-2011

Access Control

Campus-Only Access

Degree Name

Forensic Science, M.S.

Department

Chemistry Department

Advisor

Kimberly A. Bagley, Ph.D., Professor of Chemistry

Department Home page

http://chemistry.buffalostate.edu/

First Reader

Kimberly A. Bagley, Ph.D., Professor of Chemistry

Second Reader

Maria D. Pacheco, Ph.D., Associate Professor of Chemistry

Third Reader

William S. Durfee, Ph.D., Associate Professor of Chemistry

Abstract

The ground state form of sodium nitroprusside, Na2[Fe(CN)5NO], contains a nitrogen bound NO ligand, which gives rise to an infrared band assignable to the NO stretch, n(NO), near 1950 cm-1. Irradiation of sodium nitroprusside at cryogenic temperatures gives rise to two linkage isomers, which differ in how the NO is coordinated to the Fe. These two isomers also differ in the temperature range over which they are stable and are therefore referred to as metastable states. Metastable State I (SI) has been shown to contain an oxygen bound NO (isonitrosyl) and is stable at temperatures below 190K. Metastable State II has been shown to contain a side bound NO and is stable below 130K. It has long been known that infrared spectroscopy can be used to distinguish between SI and SII, since n(NO) is significantly different in the ground state compared to SI and SII. In this study, high-resolution infrared difference spectroscopy has been used to show that multiple forms of both SI and SII, differing slightly in their n(NO), are realizable under various irradiation conditions. Specifically, at least four different SII-like conformers are realizable. Two of these conformers are formed under all irradiation conditions and can be assigned to staggered and eclipsed forms of a side bound NO. This finding is in agreement with theoretical predictions. Surprisingly, two SI-like conformers are also realizable, with the relative amounts of each conformer dependent on how SI is formed. Time-resolved infrared spectroscopy has been used to study the thermally induced decay pathways for these SI and SII conformers. These studies shed light on the nature of the surprising number of SI and SII conformers detected via high-resolution infrared difference spectroscopy.

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