2012 Theses Doctoral

Spin Chemistry of Guest@Host Systems: H₂@C₆₀ and Nitroxide@Octa Acid

Chen, Judy Yih-Ching

This thesis describes the nuclear and electronic spin chemistry of incarcerated guest molecules to form a guest@host complex in conjunction with the utility of nuclear magnetic resonance (NMR) and electron paramagnetic resonance (EPR) spectroscopy.

The first chapter describes the background and motivation of our scientific pursuit.

Chapters 2-4 describe the nuclear spin chemistry of the two allotropes of elemental hydrogen, para-H₂ and ortho-H₂, incarcerated in C₆₀, open-C₆₀ and C₇₀ fullerenes to form endofullerene guest@host complex, symbolized as pH₂@fullerene and oH₂@fullerene, respectively. Chapter 2 presents experimental results of the temperature dependence of the equilibrium of the interconversion of oH₂@fullerene and pH₂@fullerene and the use of different paramagnetic spin catalysts for this interconversion.

Chapters 3 and 4 presents the spin-lattice relaxation (T1) and the paramagnet- enhanced relaxation, relaxivity (Rx) of o¹𝄒²H₂@fullerene (¹𝄒²H₂ = 1H-NMR-active H₂ and HD) as well as the introduction of a new system for magnetic exploration: H₂O@fullerene.

Chapter 5 describes the electron spin chemistry of a paramagnetic nitroxide molecule incarcerated inside a capsule (nitroxide@octa acid) and presents supramolecular effects on paramagnetic interaction between the nitroxide incarcerated inside the capsuleplex with the nitroxide in bulk aqueous media studied by electron paramagnetic resonance (EPR) spectroscopy.