| This dissertation details the results of experimental and theoretical investigations of the synthesis and decomposition of substituted secondary amine diazeniumdiolate (NONOates), the mechanisms of reactions of N-hydroxysulfenamides from thiols and nitroxyl, the calculation of theoretical reduction potentials for biologically relevant nitrogen oxides and sulfur oxoanions, and the conformational analysis of nitroxide spin labeled side chains in proteins.;In Chapter 1, the effect of the substituent on the decomposition of secondary amine NONOates is discussed. Amino NONOates with strong electron-withdrawing substituents are predicted to primarily generate HNO upon decomposition in aqueous solution. 1-(Bis-(2,2,2-trifluoroethyl)amino)diazen-1-ium-1,2-diolate was synthesized and was shown to be a dual HNO and NO donor.;Chapter 2 describes the reaction of mono- and disubstituted N-methylanilines with nitric oxide. Quantum mechanical calculations support a stepwise addition mechanism of NO in the synthesis of diazeniumdiolate from N-methyl-4-nitroaniline, but not from anilines without powerful electron-withdrawing substituents.;In Chapter 3, the mechanism of sulfenic acid formation from hindered aromatic thiols and nitroxyl is discussed. The thermodynamics of N-hydroxysulfenamide reactions with various reagents are assessed.;Chapter 4 reports improved theoretical reduction potentials for a series of nitrogen oxide related species and sulfur oxoanions, determined with the high accuracy complete basis set method, CBS-QB3, and SM6 continuum solvation model for aqueous solvation energies.;In Chapter 5, the preferred conformations of nitroxide spin labels are studied through density functional theory and ab initio calculations. The contribution of CalphaH...S, NH...S, and CH...O interactions to the stabilization of some rotamers is also evaluated. |
