The theoretical chemistry and biochemistry of nitroxyl and nitric oxide and their NONOate donors

This dissertation describes the theoretical investigations toward understanding the decomposition of the diazeniumdiolates (NONOates) as well as the chemical biology, based upon predicted reduction potentials, of NO, HNO and the NONOates.; Chapter 1 reviews the current state of the art computational methods available to theoretical chemists as well as provides a background to the past theoretical work done to understand the chemistry of various nitrogen oxides. Chapter 1 also provides a summary of the subsequent chapters of this thesis.; Chapter 2 describes the theoretically predicted mechanism for the decomposition of dialkylamino NONOates (R2N[NONO]-). Density functional theory and the complete basis set method (CBS-QB3) were used to model the pH dependent decomposition process and found that protonation of the amino nitrogen yields an intermediate that will rapidly decompose to the free amine and the NO dimer.; Chapter 3 describes the theoretically predicted mechanism for the pH dependent generation of HNO and NO from Angeli's salt (-O[NONO] -). This work found that HNO is generated via the protonation of the terminal nitrogen while NO is produced via diprotonation yielding water and the NO dimer.; Chapter 4 describes the theoretically predicted mechanism for the pH dependent production of HNO and NO from monoalkylamino NONOates (RNH[NONO] -). This work demonstrates that HNO is generated in a pH independent tautomerization process, while NO is produced from the protonation of the amino nitrogen.; Chapter 5 discusses the use of the CBS-QB3 method combined with the PCM and CPCM solvation methods for water to predict the reduction potentials for a variety or nitrogen oxides. An excellent correlation was constructed from 36 experimentally known reduction potentials and their corresponding theoretically predicted reduction potentials. This correlation was then used to predict the reduction potential for nitrogen oxides that are either not unknown with certainty or have not yet been determined experimentally.