Honors Theses

Date of Award

2017

Document Type

Undergraduate Thesis

Department

Chemistry and Biochemistry

First Advisor

Nathan Hammer

Relational Format

Dissertation/Thesis

Abstract

The free radical chlorine dioxide (ClO2) is a strong oxidizing agent that is used to purify drinking water and medical equipment. The existing literature shows discrepancies in the explanation of the solvent dependent properties of ClO2. The following thesis investigates these properties by integrating integrates inorganic synthesis, spectroscopic analyses, and computational methods. ClO2/water hydrogen-bonded networks were computed with the DFT method B3LYP with 6-31G(d,p) and 6-311++G(2df, 2pd) basis sets. Raman frequency computations were performed on local minima geometries. Experimental Raman spectra of chlorine dioxide solvated in water and methanol were obtained, and the fundamental symmetric stretch (nu1) of each spectrum were compared to the computed frequencies. An overall red shift of 12 cm-1 for nu1 was observed in the computational spectra as ClO2 became more solvated, indicating hydrogen-bond formation between ClO2 and water. However, no shift was observed in the experimental spectra. This is due to the difference in mole fraction(ClO2) values for the computations and experiment. However, the experimental value for nu1 was different in water (945 cm-1) and methanol (940 cm-1) solutions. Also included is an advanced undergraduate laboratory exercise that takes advantage of the unique spectroscopic properties of chlorine dioxide to allow for a direct comparison of its symmetric stretch in both the ground and excited states. Students synthesize aqueous chlorine dioxide, analyze a vibronic progression of the symmetric stretch in the excited state using UV-Vis spectroscopy, and also record the energy of the symmetric stretch in the ground state using Raman spectroscopy. In addition to offering advanced undergraduate students the opportunity to study the chemistry of a radical first-hand, this exercise also reinforces the use of synthetic techniques for the purpose of studying how a molecule's physical properties vary with the electronic state.

Included in

Chemistry Commons

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