Publication Date

April 2015

Advisor(s)

Brian Northrop

Major

Chemistry

Language

English (United States)

Abstract

Covalent organic frameworks (COFs) have shown promise in a wide range of applications, from gas storage materials to optoelectronic devices. However, their nonexistent solubility has limited the understanding of how they assemble, which restricts the ability to optimize their synthesis. In order to better understand how COFs assemble, boronate ester condensations, a common reaction used to assemble COFs, were studied using computational and spectroscopic methods. Boronate ester condensations were investigated using a range of boronic acids with different para-substituents and using two donors, catechol (CAT) and ortho-phenylenediamine (OPDA). These molecules were modeled using three different levels of theory (B3LYP, M06, and CBS-QB3) and the results were compared with spectroscopic results to determine the most accurate level of theory. Spectroscopically, equilibrium reactions were run where the starting materials were allowed to react for a week to ensure that equilibrium was reached. The ratio of products to reactants was then compared to determine the thermodynamic stability of different boronate esters and diazaboroles. It was found that the boronate esters were about 4 kcal/mol more stable than diazaboroles and that CBS-QB3 was most accurate in predicting these results. Exchange reactions, which consisted of reacting a boronate ester and a boronic acid with a different functional group, were run to determine the extent of exchange that occurred with different functional groups. All three theories did a reasonable job predicting the exchanges.

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